Text

Metallurgical Investigation of Cracking in Reactor Vessel Nozzle Safe-End
	ML19269C765
Person / Time
Site:	Duane Arnold
Issue date:	12/26/1978
From:	Burghard H, Bursle A; IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	;
Shared Package
ML112231884	List: ML112231883; ML19269C765;
References
	SWRI02-5389-001, SWRI2-5389-1, NUDOCS 7902120164
	Download: ML19269C765 (125)
	v • d • e

{{#Wiki_filter:SOUTHWEST RESEARCH INSTITUTE Post Office Drawer 28510, 6220 Culebro Road Son Antonio, Texas 78284 METALLURGICAL INVESTIGATION OF CRACKING IN A REACTOR VESSEL NOZZLE SAFE-END FIN AL IlEPOllT Swill Project 02 5389 001 To Iowa Electric Light and Power Co. IE Tower 200 Fir-t Street 5.E. Cedar Itapid-Iowa 52106 December 26,1978 P re po r e d b". Approved: H. C. B u rg ha rd, Jr. A. J. B u rsle U. S. Lindholm, Director Depa rtment o f Mate rials Sciences qgozi2OF

TABLE OF CONTENTS PAGE

1.0 INTRODUCTION

1 2.0 MACROSCOPIC ASPECTS OF CRACKING 6 2.1 Nondestructive Inspections 6 2.2 Crack Location and Configuration 6 3.0 MATERIALS CHARACTERIZATION 14 3.1 Chemical Composition 14 3.2 Microstructure 14 4.0 CHARACTERIZATION OF CRACKING 25 4.1 Microstructural Features 25 4.2 Fractographic Features 34 5.0 SURFACE DEFOSIT ANALYSES 41 6.0

SUMMARY

AND CONCLUSIONS 47 APPENDIX A - Radiographs A-1 APPENDIX B - Macrographs of Metallographic Sections B-1 APPENDIX C - Microhardness Data C-1 APPENDIX D - Micrographs From Sections Through Crack D-1 APPENDIX E - Selected SEM Fractographs E-1 APPENDIX F - Surface Deposit Analysis Data F-1 APPENDIX G - Stress Corrosion Cracking Susceptibility of Inconel 600 in High-Purity Environments - Literature Review G-1 11

1.0 1NTRODUCTION A safe-end forging removed from a recirculation inlet nozzle of the reactor vessel at the Duane Arnold Energy Center was submitted to Southwest Research Institute by Iowa Electric Light and Power Company. Through-wall cracking of this component had developed in service. A diagram of the re-circulation inlet nozzle with the attached safe-end and thermal sleeve is shown in Figure 1-1. The safe-end sample, shown in Figure 1-2, was identified as recircu-lation inlet nozzle 2A. Penetration of the wall of the safe-end had oc-curred over approximately 85" of the outside surface (from 75* clockwise to 160*). The appearance of the crack on the outside surface is shown in Figure 1-3. The safe-end and thermal sleeve materials were specified as Inconel 600 to meet the requirements of ASME SB 166. The thermal sleeve attachment weld was reported to have been made with Inconel 182 stick electrodes. In the initial fabrication of the safe-end a repair weld was made on the outside of the forging to cocrect a machining error. This repair weld was visually evident on the outside of the sample, see Figures 1-2 and 1-3. A metallurgical examination of the safe-end was initiated to establish the nature and extent of the cracking and to identify the mechanism and cause of failure. This investigation included ultrasonic inspection of the safe-end sample, chemical analysis of the safe-end and thermal sleeve ma-terials, and metallographic examinations of representative sections through the thermal sleeve attachment area. Fractographic examinations of represen-tative crack surface specimens and analyses of surface deposits were also pe r f o rmed. The locations of the metallographic sections and the crack surface specimens examined in this investigation are indicated in Figure 1-4. All saw cutting operations performed in the removal of these specimens were performed without lubricants to prevent contamination of the sample. The sample was radioactively contaminated so that it was necessary to perform all saw cutting and specimen grinding operations in a special radiation con-tainment facility.

SS E C 6 E 1 I 3P re N v O T I T I N S N 2 I A 0 3 p 0 R 1 1T 9 n y 01 / y y 0 \\ 0 D6 N _Y = L E E E N L E NO y Z F Z D A C "4 N 0 A I N L / C 1 T ES 7 LS E \\ N L I L Z \\ N E Z O E O E Y = N I T T S A T L N \\ E U O \\ \\ L C B R R N I A \\ , \\ I CC E N \\ R O I \\ TA LU CR I CE R 1 1 E RU G IF -)- V 0 l 0 4 E 0 j 1 "4 E 6 L / S L l 3 l L E I j N A 0 O M 1 C R N E I H T

3

= :7~;_,

,,; - ~~:-. I 'b " ',[ 3,. ~ 1' .; y U. e- ~ '- Ju;, '', a ':P m. a. 2-34314 FIGURE 1-2. SAFE-END SAMPLE. Arrows mark the ends of the through-wall-

crack,

). ;. ;-{ y..... y:Mu_ _.. _, _ _. ~..... ;(;

x.. m3.

. +, q y~,. _ _..: r q:- , q

g. '

n w_ s. g.{,. * .p ..;G f.5W. f g.g ..J. =, .N-e.. W - .s 7g, 'x*.. (p ).. .y '. s, ' ; / g w%". 4 gas 2 y g 5 er A .4.[ 4 Nw ' %.."4.',4", A ^ ', < a., .w + V jf - (9 '. +r ~ >s ~. ^ l.? ? g ' ? '4 y." 4 4. .x

h. ?'. ; - k.,,Q +' j -

.. ~ & Ylh l. ^ - +

', Q' '. ;.l, ;,,

. a - 9t .3 5 %e ... g,.. ~ x cerw . ;NN .g, ., 5,.

..,..L v..m f

g 4,' wr3 l r tg. -g. g, y r, ' a .4.,... a.>.,. v..~ m _c a .w. c - N fc([. w.',$n[,)', ~

' *.['.

y n,3.

h.

l 2 lla q t~y,.,A ~* v %6 .a.- g.y..., - m, 3. f, ~, j, .. Q.t.( H g p,, .c 3 - ;-, y.g j, .g.

w. g,.,, -

w, s.- %..v; 7 37 dy *, a y, g ,.'.v.... ~...f .C'> %.

T.;

a.. <

,;.% 2, s; ~ ' ' ~/ i, %e V,; '. a,-3 fy ', f.p ;, :..,. + g,

j., ; +..

~. k . c,. i - p W... ~ am s CNN.. ? ? Y: 2.' t '[ 5,dh$g:. M' .I' EN N.. 6.nu a.d.. m,., .4 s a,%. r-W . w% 1.n. si 'N x v i f;4.. = - - - . A. -,. -.. n

.,n.

3+,--e -. - .c.. ../ q.- -f 2-34320 2-34322 (a) At 150' (b) At 90* , ;ww,. .. mm" ' ;a n g('- c _ _ _.. .(- f,. ( Aa v4 y' C e y. .p , y.

*,,. dr
f 7 4

. g 'ih .;- ; ?.f t Q Q .- ~. + ; 9,. > + p..a A. u. v. s, + s.., e c-

s..

%f: .'y s ,.p M +- . ? .ame,.s' &-.. ~, m,.y * ^ %.,., ' s. ,y A '_ a_# 'W

l pr 9

j.,.

~

. g.,

.r.a .s.__f' 3. 3s*

w s A., 2

[- 4, -n- ~ m, s " ( Q' A W '- d ~ - y -.g( ' L.. 7 e " I N' n* . 'y., . - *.f 'o ^ 6 M. q ~f'

g

$ \\ *.. I ,.,.._.,,......Y_..._...._f,....x ... si g g. /.. 2-34321 (c) FIGURE l-3. CRACK ON OUTSIDE SURFACE OF SAFE-END. Arrows indicate end of through-wall crack. 3 Note shift in crack path in (c). Actual size.

5 TCP ( STA. 0 20 1 330 \\ / 300 10f I 8 \\,gcdzz:r g s _,300_ f N 3 600 f \\// 17 9 ,/ fl 9 95 8 \\\\ 16 270 - 8658 y Y lI 5 5 ll ~5 {- g\\ lI '"1 // \\ // 15 \\ 2 / \\ p/ 6 \\ // 6 7 / \\ IHROUGH-WALL 0 \\ \\ 1 / 120 / CRACK w-q' g / x 14 ~ / / l\\ / 7 7 210 / \\ 6 1500 180 8 'N / 12 9 STA. 10 P///M FRACT0 GRAPHIC SPECIMENS h % SURFACE DEPOSIT SPECIMENS FIGURE 1-4. SPECIMEN LOCATIONS

6 2.0 _ MACROSCOPIC ASPECTS OF CR CKING 2.1 Nondestructive Inspections A radiographic inspection of the safe-end was performed on site at t e Duane Arnold Energy Center after removal of the safe-end sample from the reactor vessel. This inspection identified major cracking over approximately 280* of the circumference. No identifiable crack indications were noted in the region extending from 270 to 345. Copies of repre-sentative portions of the radiographs are included in Appendix A. A limited ultrasonic inspection of the safe-end sample was performed after receipt at SwRI. A 1.5 MHz transducer was employed in the inspection and the sound beam was directed from the large end toward the smaller end. The cracking in the safe-end was readily detectable by this technique. Particular attention was paid to the zone in which no definite radiographic crack indications were obtained. Definite ultrasonic crack indications were noted over the entire segment from 270 to 0, establishing that major cracking extended completely around the inside surface of the safe-end. 2.2 Crack Location and Configuration A total of eleven longitudinal sections were examined macro-scopically to establish the general location and confib ration of cracking. As shown in Figure 1-4, the particular sections included locations near each end of the through-wall portion of the crack and sections selected on the basis of the radiographic crack indications to provide for evaluation over the complete circumference. + A diagram of a typical longitudinal section, showing the relative positions of the attachment weld, crevice, and repair weld is shown in Figure 2-1. Macrographs of representative sections are shown in Figures 2-2 through 2-5. Additional macrographs are included in Appendix B. Major cracking was evident in all of the sections examined. At all locations, the crack originated near the tip of the crevice adjacent to the attachment weld and extended outward through the safe-end wall. In that portion of the through-wall crack extending from approximately 125 to 160*,

SAFE-EnD - 0. 70" REPAIR WELD / k THERMAL SLEEVE F ~ j L

0. 44" -~

~ l ATTACHMENT WELD FIGURE 2-1. TYPICAL LONGITUDINAL SECTION TilROUGil TilERMAL SLEEVE ATTACilMENT AREA w

8 _, ~ [: 21 .2 f ;- - -%.,g y v. -1 4. i..' i

?N y

k Q ?h b b' (n 3,ca{iO$O.5,{- wew s l'7:;f; >,. +- ., e J. < '. 7: q.. 3 - 3 9 $fy

'"r m f,

-a p. - 1_ ._ _ _m. . m. .m 2-34348 2X

. M,

' s

.. ~ y p. v'Ty. e. l.~...... p"rs ..e K' % f* %'l'.a '$ ~ l V., .] , m.. z.g_4. -%..,w g. )., c ..;3-JQ p ~ 3s . 5 .a ,,g-' T ' h{',.,. '. 9~ ~. ^ g f.'

"e.C

'd. .5 3 . [ y-. y 7 A, y~[ I

4 u..

. r U. '% y gg., k 7 #.'. ,." V V t > k}f +w yfg:_. :.,_ W A., aq h$. %u;n,s ;s.. y }

k -e rM

? p) a ..e s i$ i* )dA 1 2-34349 SX FIGURE 2-2. LONGITL'DINAL SECTION AT TiiERMAL SLEEVE ATTAChM NT. Section 1-1, Figure 1-4 Lapito's etch.

9 n.'M% Aj r n ay a u 2-34461 2X e rn - ;; y ^ 1.. e, + ~...i-. vy 44 DT

y 9

t fg v. .:s;;A, ~e Jp ', s.; 4 wl ?;. s +, - eq s' #",Qp'55 % g k' a d.s h{:fh? Y r =, p,7. '.. .g s g'* A y ti g%'3'--?.^- Y 4,j TC * > ./ -'. wes,x'* a f4;,2:c.'iy$N~ l T' 'h $ ?,7,,( ,c N b;El h kl 5i4~5052 N ii3 b CL J 2-34462 SX FIGUR.E 2-3. LONGIT'JDINAL SECTION AT TiiEFJL.AL SLEEVE AITACIDENT. Section 4-4, Figure 1-4 Lapito's etch.

10 m* . ;.~) * ' -e n; J. % r.4 ^ .\\ Y.'. ~ W .,m. I. l .v e 2.:, 's gr f#-, -. (c4 1 -- v. .,, ~ ,y f.'. :. ". ' ~ g.- (q y _ 'Wpj 4.e. ,( .y a(7? c...- . - --,= 9 .m,W_, : 'W$l9 ShS*'k $ r k.r' d'. 2-34447 2X Lapito's etch y. m 5~ p ~9c-mgrym e. m :; -' ~_ =f - j. Rg

4 f

,s v gf. -, '. ' e r-3 2-34492 5X Etchant: 3:1 Phosphoric acid FIGURE 2-4. LONGITUDINAL SECTION AT THERMAL SLEEVE ATTACCENT. Section 5-5, Figure 1-4

11 g: j Ub Ai 2-34868 FIGURE 2-5. LONGITUDINAL SECTION AT THERMAL SLEEVE ATTACHMENT. Section 9-9, Figure 1-4. Etchant: 8:1 Phosphoric acid. 7X

12 the later stages of cracking propagated through the repair weld, see Figures 2-2, B-1(b), B-1(c) and B-1(d). In the zone from approximately 75 to 125* crack propagation occurred completely within the safe-end base metal and penetrated the outside surface adjacent to the fusion line of the repair weld, (Figure 2-3). The crack length 4 ' remaining ligament (radial distance from the crack tip to the outside rface) were measured in all eleven sections. The results are plotted in Figure 2-6. Examination of sections 5-5, 8-8, 9-9, 10-10 and 11-11 verified the existence of major cracking in the zone from 270 to 330. The radiographic inspection of this area did not reveal definite crack indications.

Crack Length Unbroken Ligament - 1.0 in. l-Through-wall Crack ~ r s = \\ A l-s 's / 's 'sW~__ d w___m \\ / \\ / l l l l l l l g l I I i 1 i i I i i. i 180* 225* 270* 315*- 0* 45* 90* 135* 180* FIGURE 2-6. CRACK LENGTH AND UNBROKEN LIGAMENT VS ANGULAR POSITION U

14 3.0 MATERIALS CHARACTERIZATION 3.1 Chemical Composition Samples of the safe-end, thermal sleeve, attachment weld metal and repair weld metal were analyzed to determine the bu'.k chemical composition. The results of these analyses are presented in Table 3-1 together with the composition limits specified by ASME SB 166 for wrought Inconel 600 and by AWS-5.11-76 for as deposited Inconel 182 weld metal. These analyses established that both the safe-end forging and the thermal sleeve material conform to the compositional requirements of SB 166. It was reported that Inconel 182 stick electrodes were em-ployed for the weld repair and thermal sleeve attachment weld. The com-position of the attachment weld conforms to the specified composition for deposited ENiCrFe-3 weld deposit metal (Inconel 182) in all respects. The composition determined for the repair weld meets the requirements for ENiCrFe-3 except for a slightly low manganese content. 3.2 Microstructure The typical microstructure of the safe-end forging, as observed at locations remote from the velds, is shown in Figure 3-1. The micrographs shown illustrate the microstructural features revealed by dual etching. The specimens were polished and etched in 10% nital and examined on the optical metallograph. Subsequently, the specimens were repolished, reetched in 8:1 phosphoric acid, and examined at the identical location to provide a direct comparison of microstructural features revealed by the two etching techniques. The 10% nital etch will delineate grain boundaries in Inconel 600 regardless of the heat treating condition. The phosphoric acid etch selectively attacks precipitated carbides in the microstructure. As a re-sult, grain boundaries and other microstructural features are delineated by this etch only if they are decorated with precipitated carbides. Thus, the lack of any grain boundary etching effect with the phosphoric acid etch, at a location where grain boundaries have been identified by a nital etch, is a specific indication of a fully solution treated microstructure.

TABLE 3-1 CllEMICAL COMPOSITION Composition - Wt.% Item Ni Cr Fe Co C Mn Cu Si S Safe-end 74.82 15.18 8.61 0.06 0.07 0.18 0.13 0.29 0.005 Thermal Sleeve 77.42 14.8F 6.98 0.04 0.07 0.28 0.01 0.15 0.005 ASME SB-166 72.0 14.0-6.0-Incl. 0.15 1.00 0.50 0.50 0.015 Min. 17.0 10.0 w/Ni Max. Max. Max. Max. Max. Repair Weld 70.46 14.54 8.21 0.04 0.05 4.80 0.06 0.53 0.008 Attachment Weld 67.90 14.48 8.16 0.03 0.05 7.10 0.16 0.51 0.018 AWS-5.11-76 59.0 13.0 10.0 0.12 0.10 5.0-0.5 1.0 0.015 ENiCrFe-3 Min. 17.0 Max. Max. Max. 9.5 Max. Max. L_ Ut

s g,yeg, gqg7 q,h.q 5iM,,E..(,:16 y q7. f ......-s. 3

w., w, C,.t..u,.4.,.s,,,_,

n, 1 s %.. -s w.., w. o,. .e-._ m,, r. :.f.. d.. \\.*s..,, 4. 7z~c.;p; '.,;@./.;. n. A q_.. .+ 1s ,4 ~..,'t,,. e 3 .,.,v. 3.,f pp .i* c.,g .pf. v a. t g.py ',9:p ~ 3" Wi .' g g,. g h- . ;. ;e f ,.s y. y u,..N ... J.,p.. :.f.a.,..e.M... 7x f s 4 . r. 3....w....s. r ....c..

e..J

e. t.,s.sa w.

w L,;.v s.. - - .*9 2-t r., o., 2,-.,; .3 gc i-(- eg ,,g. .y s

e. e.... c.p.p.

o m- . n a., u :.,i.,,c..-.i,.., s .,,:...m,. .w. .-,,,3.. .s, .,..,,,.t.,=..c. c,. m' -l, ,m.>.y.. t y. _s,,':w9.; ,a .u., ;p. p< ;,...- %y .3 L ~w , ~.. g. s. ,/ .v, .f. y ;,s -.. 2 ,:4 ( N ,e... ,.f : )- s p.. e.s...< :, u,... m;. v m,. n...,. y . ~, ._ - G. p. ',a. *:,. s e y 3 . '. *, ^.7.- ,.,.<s<, ,'s 46, s . ), - ', .J%. r; - -- -....A: 4 3, 4. w, J. ; ' ',;p.- w j g e s p ,o. .\\.. ..,. ~, m c. A,.,*..., - + m. v. r, ..y .s. s ~~~. ,...~. N_~~

~~,/,'. :l.. L y':, ~~~
~~o . ~ ~ ~.. \\ .:s. e.; ;,; ~ >~ s t I .m c )' ' r e ~; 4 sm. .I a. ^ !,p u.~~
~~e i.~~
~~.s, -.t- .t.., -]. 3 1l i .s i 2-34400 1000X 2-34401 1000X (a) 10 '.' Nital electrolytic etch .,w, p... .. w,7;;ylp,,...A.3, fg-..~~
~~k.. 4,.ng. s < g.. c~~
~~.,g .r. a, o ,,,g... p-:.,s,t,;, e 7,,. g. g.%m+m. g.f. w%c. _% e su. m.. n,,.. .y. p y.s. q . Q..p,<.h. w. 4~~
~~g.. ;.,,.j s~~
.,h y.9 A. u.2M;n,y::,y,ypp o,.m - e. 9.m. ja t w L. ,..m,,MQ#.-. ;. ' 9.. i L :;. .p n. .y.t,f,.. s..iQ.::f,.q-s,a.p,.. %v.cp .,.,a + x,- .-2 g p.;4 1 M %). e{/ g,9 <p~ Q.[ \\q .g @.m. c.,y M. n . e.,; y .m, y W my,(l'$DY$da:., w w .s ( A:;Ay. ah.c.er pe g 6. W. W [ Q a n l3 6 u@s.dWMdJ T &A',?. y m mw
~~Qn-6&%.Q'?.C3f.YTW4W6 W%C @.M @Y S @;:~~
W:V : M$g. m.&.-w&.n y".'. il!h$hdh. Au-q.w kN Db. hMN5 a w+. w :p w;m.;m.. x, w' n. n 9 m:ygn. ? m m , u% 3 v-p . e *m. g3 w:.5.. 4<m*'.w..n. DMQ :: t w wm c '4 uGyg;n.,c n; : ..=.t s. %;, \\ 2 %.,.,.r....&..,..d....'.w- ,, &.s..y:v,,^ .e. .- c .s. w... w - = w A,.,wm.i .;.a s.9. %. o,;- .ed,, YM.:q .,,. M k -. a e. m;W-. g ~ n..: ~.
~~g. :A r.. v\\.,,: - m... %g..,ru,,,. w.~~
~~M w: . ric. y 4 v g.: w,:.n. % : NSdN @m,.MNNNN [v,*.g. - 8 -nev'j.[7t$-W';*[M.'[D.,s%;m-#,*4: '8 c 5 . /e &s w w m w- ,,,..;,,,,.:s,g...n.a, . o,,./, - . r.a .ey s. %u ^ ~.s~~mn .w.,,.~~
~~r se f~~
~~tw1.~~
~~Q p d..., # s ,p c -,. y .. m,.. s.,, x%;.S.y%,..-..., s 4 A*a ?c.8. v v.m i y ;4.c h.gc %.s.i,,# W;.t.,p. m m.y a.y. f ~ y,..n..m.g..~,w. c a , 3 y v - a,~,: ,3 e...,, ... f. W~~
p..hy,q5.

;Q&M,.Qpty..Ag.
. s m s : :'w;Ff ;,'u:4 .,<l i w .fg:y:y.V,. t .r (SWj;% ml.4 f W'9.oc Q p $ m,y u,5 p,;.:, Qg 9'p,K Q M, $ %..@e.-1,.:.s,$y;.,,k,$$$.%,.d .;gg SI. _ + .w .a M 3, w .w. f.Nisty p % QM',[c:$ M,c z 'd T 'O;'. " @W.h F: < &.C;. -Y J W&s..'.'.W'&a.fic.W:.s%Y,k Q&6h & % d@N & % -E-J.% % Wb w.T.m. I;::%'?&Q<.@'m.l/}jy:i.f 'N L S% q-y.:, * -7 ?w$,Np l &. y,w$ : n:.9M,w :.,;.',:wjggu.gyl*l': .y..p$.;.y. r$ ':Y }.0 l. k,y&:0~ w'?$1n,;tyh&, A m;.&.. 'p ;N 3 .s e m Wy-y , c.m. ~y
~~s a~~
~~W: Q9.. M QN,'fb ,5 -f )i 4.;. e n,a.. j;~,4,.. A.n.g,zy.s, g s,,.h.. ...,.?',r. t m (. . u~~
~~2..;.x.~~
~~4 y~~
c

w., %.,,.
~~.. u c. . :.,.; ~, E.u. y<.'.r.,f.r v.. .~r~ r< ,,... Vm.,1 ,n. .,a. n.~~
w
.g.A e, . n.s l w. .s .y., r# o w. - o y.. o n.,.,rr r.1/w.. :,-. e x... u. y ,:,' 3. st: Q:,. s j &s6.v. s e.4.w,,.. f. s.y s. s. g ..-n n.....s.- ..f ~,, ;o L M %~ ~ n W_~ o. - -, w,u,. n..a.- n g .~ v~M. s .e 1 e. i'qbMW. l 'a-U. 2-34432 100X 2-34433 1000X ('o ) 8:1 phosphoric acid electrolytic etch FIGURE 3-1. MICROS RUCTURE OF SAFE-END. Location 1, Figure 3-3.
17 The safe-end material exhibits clearly delineated grain bound-aries after the phosphoric etch, (See Figure 3-1). At some grain boundary locations, relatively large, discrete carbide particles are evident. Exten-sive matrix carbides are also resolved after the phosphoric acid etch. This observed condition is consistent with the fact that the safe-ena was subjected to two 1100*-1175* stress relieving operations with a total time at temper-ature of approximately 16 hours. The microstructure of the thermal sleeve is shown in Figure 3-2. It is evident from the features shown in these micrographs that the thermal sleeve is sensitized (carbides precipitated at grain boundaries). Apparently the material was furnished in a sensitized condition since no stress relief treatments were performed after installation of the thermal sleeve [ Figure 3-2(b)]. The more extensive grain boundary carbide precip-itation evident at locations near the weld is attributed to the thermal cycle experienced during the welding operation. The grain size for the two components was determined to be: Safe-end: ASTM 4.0-4.5 Thermal sleeve: ASTM 6.7 ASME SB 166 does not specify any limits for the grain size of wrought Inconel 600 material. However, the CB&I specification for nickel-chromium-iron forgings (MS-16) states that the grain size shall be as small as practical, with the objective of producing material with an ASTM grain size of 5. CBFI specification MS-16 states that the Inconel forgings be furnished in the annealed condition in accordance with ASME SB 166. The ASME specification does not specify the particular heat treating parameters for the annealed condition, thus it is possible for material furnished to these specifications to be in a sensitized condition. Micrographs illustrating the microstructure of the heat-affected zones (RAZ) associated with the repair weld are shown in Figures 3-4 and 3-5. In each case, a zone of more pronounced grain boundary sensitization is apparent immediately adjacent to the fusion line. This feature is normal for the fabrication sequence employed, since sensitization in the RAZ is inherent
18 . ~ :. Lr. .. ~ ^ ' ?. . 4 ' S.[.,[ ( }., e, f[j 'j;,.] ',h.M.]gj]% & :*:*'.; s,., .w -.'y#.6 n:. Q'.'.ht.~ #.W h. L t' -\\f ./ p. r.,- 1 5% ), v. i. %'% . ?: '~ d'h .5'a..s/.[,"'g*h.,*; ^' C..~%e. ' L3 a-.. w. ,t. ' C', j' s. . T'Y.f' ~. 4 a, x - - [~p. ,,g .*l~ 4 . ' qp,f.,<.+g. .u I ^ Q, 6-ytg .s, f ,.t .'y % - n-
s
~~.g. .. to s ..J.,+.* ,A r .p ,e. . ~;s. af .r.-~~
~~x,.~~
p,. 7 y. p ~;s c. .q v.. .,]. c -r s... '.s\\ (, "r . :n.: ?. r.'..,2 ka;.x,,q.w . 4 r 3,a2[<:.t 4-t .j, a::; ~ f. c, j Y' ?g.g [:p;j r v .;r. IlQ&[~ ~.- r'f, & L:e. T-i .c 5 -* {W ?.Nc M Et$$'%*. ' t..A s .y 2-34423 (a) Near attachment weld. 200X ~.., -w ,-e.;w (, n .% :.m.,,,,. % '*** l i b ~g.u.: ':...W. Nls.t34..; r n; - ....s.- f
~~a..h;f M. ; :.mI;.l. gf ^ Y,5, c $ w.A/ g.2.'.\\~~
~~m :.. ~ 1. s ? Q:6 .y n s.. .c. . f w. s. n.4"W.<; C.wW< > L. ;G V 4 .,a~~
~~o.. r... 9.,~~
~~w L,.s. %.. y -w g~~~
~~,,,e. n,..~~
~~4 p. war. a.c..x.9.y}.,,..~~
~~m..~~
ff ;. .c.... .,. /. u 2 . e. :. ~.$>gs.:. %. .g.Vg #p.,,;. 2 ... -. K: 9.~~. d ; p.g y; 4, - m. ..,. s.g . 8 .,:';.:&;,;y.,...j ud.yu., =. ),. \\ g.k.4}U-b . p; r*-:eA.. ..A e.t .: b ~ 9. q 4'. 's' h ?~. hY..f ec*,.. ..*';.r. ~. ,J
~~Q\\,,~~
~~.\\.,3.u. v.. <- e., + y.s. . e A $.., :as.s.n..v .a. o q?,, e ~ +-.:.~~
s
...;,;,..n ~- .s. t :, .,. r_. M-- 4.' ? k.- -:.d 2-34486 (b) Remote from attachment weld. 500X FIGURE 3-2. MICROSTRUCTURE OF THERMAL SLEEVE. Location 2, Figure 3-3.
1 3 i}iD 6.s N \\ s / .2 yI FIGURE 3-3. DIACRAM OF REPRESENTATIVE SECTION TilROUGli TilERMAL SLEEVE ATTACllMENT AREA. 5X G
20 N DN 9,9[#' n,h,q(+k Mh.,..w.N[. n.c[.R$. ~M. 45r,ho...,ne wyd. s s.v ?, + '4 (w;s, p. 9 y.. < - m. p: ~..
Q,b l.,W, ;z?gz,Q':i Ngsj.p&,k Q,..y
~~_.? ,%}',y,y, ,A&.- lY] c ,.5 s .x- ,v. N F' r. ~ x , ~. * . e ', 7 (., [ p t*%,%, g . ;.,f . ', Y[y*c*. o'. ^p 2 '....... :w.. s 3 ;,. y.v. /' % ,,, /., e x. E' (~~
i
~~h. g,.~~
~~s. #,,,. ~ %~, .,w..... ,.c n .,,,m...... ..,; -. e.... x ,i+ Q,.,, ~ ,~1. &u~;.p /,^.n.o - ,w< s;. s g- ( m, v...,, +..; < = - . 3. . v'~~
~~.v w.~~
~~. w,. s i. 'h .f m;~~
~~y. m. s a~~
~~', py A, f ---;. f..-y T.g_ *g f, y ;y,, $.% ~ 'N ' f %- y ..h 4-p;.t~n w. q, [. _ yl t, - e.? -. y \\., t- /.x. r,- 4, ; g z.;, - ~), ::; m ,/ (.gy~~
~~h.;~~
~~G'- ..N J' ,g.~~
m..5

3..&
~~~ x, e s -~ M .,8-'$-~<,. .__ J j k, - , _./'..;"'t :, h@ g[ I~~
~~\\,., w w % p ;.-~~
~~y I~~
~~~ - -~~
~~uy [A g v' pm.s 1 - ---...c . :).. ) ~ ,. 3,%x.. e c <..s. . [,._ J.,_.: ~, ~. - - - -. ( -r- -cm > q f -e,:.. f,. sy g 3. p ..~. s { Q~~
~~W'.~~
l [ ^ w? 5 h.,$ . :. r' ^ ss,. - s-\\ f t .,/. ,.\\. u.. w ka , /,! \\. .. N,, ..,N J r,, \\ A q A. e e ~ .s Y g E ,s ., 'w s-: _,- \\ ~,- g y5 x p n: / 2-3!.398-399 FIGURE 3-l.. MICRCSTRUCT"RZ OF MZ A: RI? AIR.G R. Lcca:icn 3, Figure 3-3. E chant: 10T; Nital, electrolytic. 200X
21 m m w m.o...., .n.,ii.,, u,mmu enuu c u - m q 3, ^ h,, h n ~.m.; ; ;
~~t u~~
~~_. y a,t.. q - -v.,g y %.,w.v* ...Q,) g ,,f~~
~~s e.~~
~~(~ w.t 3 3 n.~ ~ds .%. x ~ n ~ . m a ? ,s ~~~
~~Af v~~
~~. jg:. 'd *a,:y; ,.a s Le J 1 .m-+ X k.~~
~~- r,:. -~~
~~-_w ,' ' s. r os_,. pc an. c,y.. - + ~,,en.4 v.,,. m~~
~~u yJ. -~~
~~, =.R p. m. d. - -,._ w~ ..m,. % _ if,.\\,;r." . N-; <s,,, ': gs*., i >g .Qi ?; m. q _ -.. q > ' g y, ;. 4 g:: 9, t ~, a h c.. ., 4.r _, ? ;,.;~~
s
~~..- w, %,- - p ,.... w~~
~~' y-'~~
~~, w...~~
~~n..~~
~~s f ' ,,, : Me:, ~. ,,. 7 as. c;, -+ - lpM'[N' k,;i. fl' 4 0 P.;. ~ ?g (JQ Rf l -gg s Athrq 1 a :_ N.4 t.~~
~~. q e,<~~
~~, f ^8 , c, r w., y, n: &.~~
~~w$^ f~~
~~. e nA + -y 5 ,/> p gy;,,.i : w. O w. ~;: ~~ nM M :L, in f/ g, ,c 3.g. 9 psp s o, , g. .. K) e .e.; e~~
~~. ~.~~
x \\ ,g ,:.y, . ;h,, y. -m. ( f,y. jp. z , ~m u; w. >. y,, i 1 U;t e-w1 4 y: y' #- <Q, :; ~_ ~' .. ?' Q m?,,ym "Q N,,fy?.fy, ..JQ- . ' ;p. -;;. >' . s.. VA;f; x.i_ \\r 's hQ.; ',1..% tq4Q:' ~$' g. ' q ? ~.; ' + ' j 'U" :N,_ mk ,i @;;&.*+ Q.. \\, cy>v.e.n .s^. 4 0. +G,O - < y- -%w y: g i-v s., s* ' ' r< 5 %G ' a :-Wb,. J,... r?? s.v., s' A a .J,.g .m W r_q e ,t g. m a m m-n y g w;. m.> m e w p wrg g;f.* yp.4 y; 1ks '%N yb s,. o e, t* w fi,,,'.. ;.~;.. ". '; i K.%, y; ; ; ;,.-. g. 7 - O
~~% pm e~~
Vy,,9;.e;+ll ?.'u % ',_ y, a y gQ. c w -,w. v : ^ Q .y v, n. 4 g:. >m,. s,r . r f p%.p.: w 'v. q. 4 r.- , ns <. '),3. J$@(('N,' ^0cfM[ $u s' y+ Tdig g : 4y $ N Y, .Y \\d I . d 2W '-M M, t w>A iat p ~m y. NEMit i, $ + 'I i $20&$ i PC$$:' W !g^ srw?s;4. tp?y?.., ha_ a b ~gp -}q t* -fQ..-; - -4 p. .a , :,,, mA..g a p;..,x,gyyve, N -.o e;~ wn cp. u. 7,g v,v, . s:..;,,a,4 u s u., a ;~ f, w;3 s $':g L'm u . n. ;. 3,; DrQ : '.. g ;N -. % ] *n, ?$ 9. 4 f ~ -lN;gn. \\ ia
~~^ '& W,t c<_~~
$'ob,iRKW s I6p ilst+bfi ' _n S/yca ! MiVif 2-34396-397 FIGURE 3-5. MICROSTRUCTURE OF HAZ AT REPAIR WELD. Location 4, Figure 3-3. Etchant: 10% Nital, electrolytic. 200X
22 in any welding of Inconel 600 and subsequent stress relieving would serve to enhance any earlier sensitization. The microecructure at locations 0.03 in, from the fusion line and beyond is comparable to that observed at locatic.is remote f rom the weld [ compare Figures 3-1(b) and 3-4]. The microstructural features within the HAZ are consistent with normal welding procedures and techniques. The microstructure midway along the line of closest approach of the repair weld and the thermal sleeve attachment celd is shown in Figure 3-6(a). This structure is comparable to that at remote locations [ compare with Figure 3-1(b)] indicating that the repair welding operation did not alter the microstructure in the vicinity of the thermal sleeve attachment. The HAZ at the thermal sleeve attachment weld is shown in Figure 3-6(b). The microstructural features are similar to those of the repair weld HAZ and are normal for this situatiot.. This zone was not involved in the cracking but the normal microstrtcture serves to indicate normal welding practice. Microhardness measurements were made within the safe-end base metal, thermal sleeve base metal, welds and heat affected zones on Section 5-5. The particular locations of the traverses are indicated in Appendix C, Figure C-1. All measurements were made employing a Knoop elongated pyramid indentor with a 200 g load. The results of these measurements are plotted as Knoop Hardness Number (KHN) vs distance in Figures C-2 through C-6. The zones marked "HAZ" in these figures represent the heat-affected-zones that are visually evident in photomicrographs of the metallographic seciton. In general, the hardness values measured near the weld fusion lines were noticeably higher than those for base metal (KHN 240-280 vs KHN 184-191). At each weld, the hardness in the HAZ decreased fairly uniformly with distance from the fusion line. The range of hardness beyond the visible HAZ for all traverses was KHN 200-240. This range of hardness is somewhat higher than that measured for safe-end base metal at points remote from the weld.
23 1 y - ,.. w. R' 7 9 3- ----.y 7W"t * '**W".T ': W S.
~~a. ;. j~. e p., c y"'y~~
~~-T r, c,y o n.. .s 3 N, - z j,. . ' f,. _ewyc%j.A - f tR -{ }.' ~ '~~
r<
-r ,...a m.' -Q &f,, w i&[ -. ' ' ~ ' t. A ..Nff f] .n ~ es '>{- / X 3 t, ' dW*
~~$f.~~
~~ri ' [* b 4.e,~~
~~. y ; j ;r<-~~
~~m. y'h f f ~ *. % . j. -; ; ' ' ' (' g p ?y-._. ? s' op y u, . _ _,.s hs.,,m-f e~~
~~y..~~
~~wf.. r e a ~.6. ~, y.- 3< R.nf"s:W L 4-a ,g, q f; ,2. , q,,.;> 7;;~~
9

s

J.>..
~~y ~) .,1. &s s e Q&v . ' "} Cy 't Q., a -,s y.- g s + y?, e= j., y., v, 4 p' p.. e WM :. -.M'c g ' **.; e ,n~~
~~t u~~
~~'t ? ,y . ' n ;< 'g-5 L "%g 'k.M ~;bh(tM % : S 'M~ N n <h lFh.f - I NE%:A ~~~
~~u ?s-J '* ' z p _,-7 37.*.. q a g.v a. C y t~~
~~~7'h; ;1;;- W c-.,c d.-1 la .3 -W Q% ' '- ' 9 j :: p.; [% y 1 - ~> 4 , "?Q 2 C !} r , f, s $, f .j;? x) lJ '); ,. Q.,~~~
~~M' n~~
~~-Y, .\\.;: 4S%y.j;j, u~~
~~f..~~
' 'v_ ibm 3"* . %. ad-t 4 9;w. y a J e'. C , 'v 'M d n Q v' : L 4 / 4 .W u p.r.r ; e, 6,.0 .y 4-t /% } ifr* MV '+.fm, I ie );33 . q h= 24 Q M ~, .,:;n., +~ p 4 M W M WfjGE*Y W %9h % %@DN!dj[@.MSN"S$$+% fN 35 x N. bu ?tt we 2 n Ew5.' Web.& 3 : 'i % QQn:Sq k Q Mh w.h,*,b h brM r 3 [ e* 5 Q W"; W*g.w., o.I . m....~., .m:s AM..N.w'pht. s; 3.. ., V. <e 4f"*_t,e * #, 3%*X.. (%,%yv).s, M e=- .>~ t. i k'.s C. y 8k, s. ,M%*g, t/- J,,, g ,y '.4 [-?h ** swr..-]:?'}.%)*;-ThTlW.-u*-7*NR*T a W 92.p.-; u. 'S+Q: 'Nn;.,%p.yg,$.%' L Wy.{.k'M ; g.v..QgM,+W'.%g-L.f:?,,2 Q'.,,.*rr?.? -Q g. 4 O>w =< 'df.W sdf yco t. W;. y M .? O ': u.; O r - t** Q w.d Y
~~5 I' '~~
~~5" Y .'. A,m.y a. w. m.d IA 't!',h's."T A4 wM.. 4y*,N. s..+.'~~
m
~~.a = = .A gy: . ;.M..'.*:f. 0 s..~~
~~.a,.?..y'E h t. *l>:d, g.y%, %,..,s.,ts$'U*g. J.*9, Q.~~
~~~ =. *,'c ('*. Lf..g s,..,W ',., :h. a (. *s.,A >, .,,p ?W7 '.-i~~
~~";7 r..p'f g.~~
~~.d w 'Z f - W. . - j.. q *M. s-e ~ ? fi'.rf.Jfp V.S[Q/Wsg*M;,V.C,.k;..g;g.g+X-O' ..v . n;~~
~~4; 55h s, py, a~~
~~cua . r,.0 g x.;n.wLw.~.*.[am.s.w...n.nph( .e. H: m=- . lY .kf hY $Y k ha ~.? 5h h.,. < q, . j..* :q. ; ~.~,,. Yj,.- t._:,g,.$Q u s..S. $, Q** Q. T W..s &.a >c p : r. May.~~
.w
=
';*. i,.. s. g'

'st
~. A;a~ '%'.., / %,s. . 4 n> ..Cf =n!.4 q,; -y f.Q,)ch) ~ o, .;fl $'*5 Y.s's (c M: , W -; r:,, M . s w y> J s: q.. -.m @- n$ e.;.3'.. s.u. f '.' S - $ ...y v N,W' O. ' EM., f,.s % , ' D, - t9 e" e 3 .% ' e & g s i z vf5.p k-
~~W *e~~
~~- W15: ~:'* hh'"3 5 N N~~
*d,'
e v 1 . h !. :. 't. U.'$ s%.'.t.s.W.. X.l ...e..% Q>a,a ~ M + ] w_
24 These hardness traverses indicate that the welding optrations have resulted in a general hardening effect in the vicinity of the thermal sleeve attachment. However, the indicated increase is not considered sufficient to markedly influence the toughness or crack susceptibility of the safe-end material.
25 4.0 CHiRACTERIZATION OF CRACKING 4.1 Microstructural Features Metallographic examinations of selected sections through the thermal sleeve attachment area were performed to establish the micro-structural features of the zone in which cracking occurred. Micrographs illustrating the features observed are shown in Figures 4-1 through 4-7 and in Appendix D. The heat-affected zone of the root-pass veld head is evident in each section as a zone with noticeably fewer matrix carbide precipi-tates than the unaffected base metal and with a different grain boundary etching response. At most locations ti ^ material immediately adjacent to the fusion line is essentially devo'.a of matrix carbides, and the amount of these precipitates increases with distance from tle funica line (Figures 4-2, 4-3 and 4-6). A varying degree of grain boundary carbide precipitation is also evident within the HAZ. In generai, the grain boundaries of the wrought material immediately adjacent to the fusion line are lightly etched indicating limited carbide precipitation. In each section a narrow region of heavily-etched grain boundaries is evident. The grain boundaries within this region generally exhibit more extensive carbide precipitation than the furnace-sensitized base metal. All of these features are the result of rersolution of pre-existing carbidea during welding and subsequent carbide precipitation within the HAZ during cooling. The extc0* and distribution of the precipitated carbides vary with distance from the fusion line depending on the peak temperature reached and the particular cooling rate. Fnnor differences in the nature of the HAZ noted among the sections are attributed to normal variations in heat input and cooling rates over the circumference of the weld. In all sections examined the crack path is completely intergranular with extensive branching. The intersection of the crack with the inside sur-face of the safe-end (surface of tight crevice) occurred at a point within the HAZ some distance away from the tip of the tight crevice. The fact that this condition exists completely around the circumference indicates that crack initiation occurred witnin the HAZ. The early stages of crack propagation generally followed a path parallel to the root pass fusian line. In the
26 i/*
~~r e~~
~~/ / g:\\,1,~~
~~,4:fl; ej.&lRiQ a J Y- .;~ n>f A ~ u-6 .~~
~~w $,plb%,~~
~~-/: i ,^4.W.Uo,y,.:. N:?llf a. ;., pA r f,~~
~~g-e~~
~~...fyN ,. V;'v &'~~
~~s e~~
~~- p*,*, f;4 c .e~~, qf'eq'V}a b a,'# /b (- 'p\\,~~~~
)
~~~~^f, 4 p j y -l /~~~~
g
~~~~.w%4>~.*M.ky&e9lllW s ) $l~~~~
~~~~C.0u~~~~
~~~~,s 3 N',jc'y.m% '. 4~~~~
i
%e 2 k, 795i &,;, P,',t#*?p.e.,: [% 's ' ,,t. l o '.> ;e i .o %%9Ql tg(g,t nk*). o b \\,,' o i /* I" /r'eq: y* q %u /l N u M, y g 4' t'0 s 4.9f" * 'V;- 99 a, 4 * '#g, o. e s,,i f .y ?,', n Vl. "nt R x.7 k '*lk, #,,s'p ',' * : p ;f s;:ayW:;h'.Ra > 30{j a p 'o e ; / ,.d**,s /e 9
~~~~$a-~~~~
~~~~'s,l lt y~~~~
e- .c P l;;g,;y[-. ap* p% *~ Ve e/# ' l ';/* +;v', a, .c V-h\\ N> %/ih ) 5/ + 6 g eac)j %4py &+6 'w,, 4 q+$ gs, h e, vh, vR#O hv c,$ e# x
Vut <b y\\ .} -S*? 3 M '^ Js \\ N; c .h'- ").%, g,. x
~~~~a. - -~~~~
~~~~\\'. s N, - N age,. .~_~~2 r-f g s 4 { - , _,,.~~~~
~~~~f -t '~~~~
~~~~'M,,.M " l-j v, 6Je;.~~~~
~~~~+..~~~~
~~~~l ____- s m %.- r 9' %4,~~~~
~~~~3-e.,",.;.S.m~~~~
/ 1 x; ,s / ',,.~; }'
== s l x @,, ;s : x i 2-344'.0,-441 ..,. ' '., -l.t ; '.'.... C*. e s. o. s*. r s) z 4 = . f ~.. -a m .:) i r ..~., \\
~~~~g...::.-~~~~
~~~~j%. -f. i;.:1.- ..v,.' ' fe', J.: ;,' m.- \\ .s i ..y.s. ...K...,.,-. .. :. i- _.yi:. w. q% .y ., %.f'. f%/ ..a ._/,'~~~~
t
' \\ ;- R / v.- i s. s - s i .o-+. "IGURE 4-2. <ICRCSTRUCTURE iT POI:,TS 0:. OPPOSITE SIDES OF CRACK. Section 1-1, nocation 1, Figure 0-1. Etchant: S:1 Phosphoric acid. 500X
28 so st 1 (9:n, k)n.,> r *m f.,k ' s ..~ 7 b M.. W[k h,b' g.IANd ib 4 ~
~~~~4 Myt M,;);.,"1,*n~~~~
~~~~9 WM G(*i:cD Q'. p.n:~~~~
~~~~~* W q+>:r qQ. $..f :p G. j b .7 37 %e&.i M ..~Ma p :N.cs,fn; M.W$$[ m.N.T'h, 8.,u. .a .g p. J, A gy~~~~
~~~~4. sM.acN.. '* gP~~~~
~~~~-A., J $, r,> p M N,.h.' M.".[w.a. N.4 e- .tw;y:d:Jfdhkl. h J M, W: hr ', e b .W. t .g(;yp cu p</g;L:. s~~~~
',:. ;.; n.:.. n. 7

, >. g y. 9
~~~~..j.gt.y.) Jg {','{, ( f,. i.'& '.%s. m,.'{;[{:.y n.., ;,f; t..%..f.p. ou g,.3,t q';g,r. w.,,.,O,.hm ,.,....f. &.~~~~
Y
~~~~$ & }, a . n... n.,4 4 ,..a,..J.m..,;r.. x oco c. ~.. m.1. 1 ,' n... ~., y o6 ., a - - m. m, m q q. > e p'W,.. _s lyff'.g.l.t::lig,Q gg y, y, w p g. g e. u @ g. g hl.Ml,,, ~~~~~
~~~~p...m~~~~
~~~~. ;.' t y.,.y ,i b,4 J% v.y . ag. gg b~~~~
~~~~.x; pe.y.p>4 p c,;~~~~
~~~~p. ,e~~~~
~~~~3 3. g.~~~~
~~~~y ,ggf.p.. d.. 4,.w y,3y.s.r y.. Va p y 'q. ;y,g'.y;;,c..,g.. n .),, _ ' a.- .p,..~~~~
~~~~'q.~~~~
~~~~Gg '.s. u g ...; g ; - 4 y. ;;*,*gg y.QIteq.~~~~
~~~~. i l,'k'f,,.,.m ;n, 3.x:. y.a., -:w e p..~~~~
~~~~,, ;, 4...~~~~
~~~~a n~~~~
~~~~zau m c p,.4-.- p... ..m g*s,I ,c (!+e 'j.l ' f. ,pg..~~~~
f:
~~~~,'?f jl:... -.,;hlh ef n '(. 'p'; h {p {g d .$' ::.,,% y>;.n,/m.c,.y$..<f,a V.. c j .3, . s {c.q.* ,e t,;.h *?, w. w. uu -av. a a%' y,'~~~~
~~~~..Om Vj'~sh..W **%,,;%e x. c..s;y..~~~~
g-
~~~~o.,,~~~~
~~~~m,.:,y?. g,' s te ~..~,,m y ).,.;", M5 '- .< e ; .v i + V. . t. ~ *?i,* p& @ i". 'l N ,$';<'&;yt,g:.' q g, m, g -i ',,,.., 7 j~~~~
~~~~i y.. w.., p a..m.r.? p a.mv<) M.c g,3~~~~
~~~~[ f. n pw. a;: Ls ..: eyo S.. a~3o =V?**.. '~ ,,y..$p..,e o o~~~~
~~~~%u.. w.. i 3~~~~
~~~~f...., s m c o u, ~. 4 .., ~ ;~x~- ' t,, g; x;.cs.,**;@. 'h ~ Q;Q.s.qr...p;.;,; i%g(s s,..,:. / , O?oy *.:rg* q., 9,,.z., f. u o p. .s.: l >Q 4l 5 V OI.Q :,, v1.a - + Q,~~~~
~~~~Q y? _..~~~~
~~~~t...=h',m.,._%..g/$dff:'.'%p's,. :;u.r..h o u.c yV., a o~~~~
~~~~, ;,l ?. n'v) w ' %n,. n. M. ~,.-lr -n* u o u.o Meu-s. ..Qg<.,-y,e 'r;~~~~
~~~~','%..y s:Y;,,".}~~~~
~~~~yjQg~~~~
~~~~t. -~~~~
~~~~+ r. a M .Q .T Q '- .s~~~~
~~~~,j L~~~~
~~~~(Z m. .m. >...p. 2,s. r}t,, w.. u w.~, p. y 4.c,.a.,%. .p. 9 M..,, 3... 3.a~:s,f,. + --s 0 +-.c F r3:. r s.. o y.< y. O. p ;.' %'. M,.,,t n. 3. y- ).. y'. .o ...cn : n~~~~
,s. s, n N,..Q

Qh;,%,.F 3.%.,
~~~~,a .. q.. pt. c.3 u ;p%..k3 p .1~~~~
~~~~p.$n~~~~
~~~~+. - ~. Q. f4 ;+. .[- s. l.~~~~
~~~~~~~'~m y ;;lk <-~~~~
~~~~h,,M. o; opy L: H ,,r ,,,n . e 3gs,,g;n,,.;*.e g y " ; c.,4.g,, y3,;,a. g*,... ".f. ? s p.. te ; ,s, y, ,4...,,s.i.a..,.;, J. ..>v..:c,..y. 4...... g,m.~~~~
~~~~'y. t y ?.w v"~~~~
~~~~n s, en w r ~. .f*:a.,";f~~~~
~~~~~e s q.'. ' n *C' ?,G.V t 'g M,. 6..s.~ < p.. s A.~~~~
~~~~f -r+ i .;;; e,:~~~~
~~~~y..~~~~
.t; ,.. f c, ..g _T ').- ..f^*.:f13) 4 m.,..I,M/, *l"R;' L '.s.'.;'h. - r 9 G,, * ?.O 1 LW:. ..r.%. ~ ~, g, y B..,..u.;T.*w..io.,.,a.tls 1,.v,;. m w. A..,., g. =+ t.,,f> ;. -(*a.s.,.,. ('.[.s f.., s. y. - 4 e g-g.. i ;..-l;}% v. Q (p,. S.idlQ, ' df. 's_*
~~~~3 bT~~~~
~~~~"'. 3 'N' I.. a .ay.,/. ,. T*t C.3,[ if aw a + 'y. g.. I ?vf y,t.g* e. I g,...J,...,.f. Q '..*,7, ' a.; -.~~~~
~~~~r e A, c.j ^'~~~~
~~~~7.i; 3 *. - i "b . 4.',.( .- %s f 4, t,' s. + ..;( .s;*,.l7 -i( -.. i, J. 1; n. %;/'.~~~~
~~~~i.;.~$I:Ef' %,~~~~
~~~~o fe -.. 'f,' f,G,.,Q'y.'.,'M',' q; ;i~~~~
~~~~M[.,.,~~~~
W l AG. .,. 4 [.% Q,. g..;c..p,,., a,.. T W; % h!., i ' ',' ' '.4. ';.1 G > . t ce.5 i:;V, ' J f. 4.. b. N s e sc,, is ; y.. ', '9.,$N'j;~.h,.f,.- .*w ,a /.c.,,, *
~~~~h,'Ifa h;,,., i q:. r.l~.l. a~~~~
~~~~'} 9 .:. i ,s . ;*',.j/,,l.'..,,li.r#':] e;;~~~~
~~~~,f'y;;.... ;~~~~
s. 4: .*.q ; i.. ., -., p, .. )..:..... :.. < ~ n. .,q.. . r,[.. ,r a.. [ g[ .I... p' T bf b.*N ? kI ') . h.,'/[g,.g. <:q. . v,. a.... k. ; r.....s s a - r {'. b.' :'f yxh //., II. -. ..... u : / M.v*,;; b].x:' * *.t.' }. *j .I p us-a:-
29 h; lai .;. Y ~t m,, g~:., pv,. , - wx + 2 c.< - ..,1 a .,s ,' M' - y @h;, m. p, - 1 o,,.- o. m ,.y - - < h., ', o,& ...,. -x 3 q s M o
~~~~v. &., n Wl L{s.NY,~~~~
'T & ^ \\,f t . W,,,.:...Qq:. :. ; c'yo.;& N:. q,:*,:2.o s ,';;w. g.,9 y y <,/\\- 4 t tp. A. ,..t. < t : v..o ; 3 a y-tv%; V s. c% :7 m.f. . ;. +) ?~.? .M y-. y' y?. m > :.v u -,n a w ..,.K'.>-_s. - -' s. y * : :m:g.,. ~ \\ c._.- m.;s < ~,. _. y \\,, 8; _, + n,,y ..% (w NG.- m7. ::. : ef. y.J.',. *'^ ip
~~~~q.wy~~~~
~~~~.d ,7 .;o ,4.,. y,.,p y+ e : .\\. m W, .s.,..9. 4 >7 t -$$$. GOOD.:.AQ%. -\\ \\- j:ib-e&nmww;s2s":b. n3:' %:. ynw ~A-~~~~
~~~~=nu.:@~~~~
+~2 L M m.? 7). n, A,,.,,,. .. u.,n_U. ;.. : c y m. ;@=r = nw { - .n W 3 ~ ' f. N *p'Q,% Q)p{' &. %;y y. '., f,: /:~,. .'W,;.x 4 AT 4 y g/. ,;, v-h f,%&:. .;~. -%>.. ' W::. p .w %,.;; ::, s;: ss i. D.g:, p. w -M.,&gyg(y 4.,,,x. - w w 3 u.p. .l: ....p.m,, . g p .y: y y;{ /; ; 7, p " Q; $ n c Ai. " y.}. . j" [F... .Q 3 Ms a,"
g
~~~~? .\\ . )... ,.. 4y .--r. 4 e. w.7 tyg ; r .p~~~~
~~~~y. - n pg;~~~~
~~~~.~m z- ~.;g-g u. y %f.,,3,h.g[3:v'w..p(hf,lv lJ,$:fI.;ia l * ^ l y*y ,- :,1 ~.. _j.& /fg;' 'f' )9 s w g. v..f,,,. 3.i Lyr. _,e.qp .. ru .x .... <\\ s, ( g jg [U %r -[N DdkkIh[,'[f[,'[.)'}%.h %[~~~~
y (,. 3

,y,; @y#, s.;w y) g -
~~~~g-yg y3 mw e . y.. r.~~~~
~~~~s. R ',.~~~~
~~~~r ~, y-a y%*- -. 4 . p *. v -... & _ % :p ;.y x.':..; 4 ;. . y% a& - y.1 y y a..;-; f x. d fA T&_m. -.,AB 02NRdhb $;Gd$w'15 s~~~~
~~~~$ N T~~~~
~~~~f . v., w,4,...-%_ N w s; y -.un g .a. v- .a, Y, /, i, O ' ',{w m .N . "?N 2-34894 2 2-34864,-366 \\ 3e~~~~
~~~~r u n n,w~,f.~~~~
~~~~+ m' .Y ,8 s W N..- w ; %. g,,a m sq'g~.,;y~~~~
r, r*
~~~~_A %- ( 4*\\~~~~
~~~~3. s~~~~
~~~~,s s r. -y s .s h ,,/ A r @'--@y,f.ye P bf L ~,~~~~
~~~~j ',;, E'~~~~
< r"- ,s 4.qh.. li. gu-I n O x r x 3-r. 6 f {y,,,. L +Q$.'N,s M'.:\\ 1 M . )l ; x' .s i 's l 'N ? F g.=;r% a,[~', .." ~% % a.
y.
[ ~nt 7f, s v ' if$' c; y(s,: (6 j, N i, L~ +,, x e y- ,'..;. f m L w %._. } y. s <m fy ~~^3* 34 ~ iu FIGURE 4-4 SECTION THROUGH THERMAL SLEEVE ATTACHMENT AREA. Section 2-2, Figure 1-4. Etchant: 8:1 Phosphoric acid. 100 X
30 q M 1 -4 e 1 i
}
~~~~v a 5 5' w .~ s d, 3 r x c, .p. y , ~; - a~~~~
1 f, a a

j
~~~~.,:f .3 ~id:* '; 4. s, . /: s. 5 .s 1 [, f y -h v i E3, ~, ~i y' t w .. p / s . z. \\ t '\\'- N: s.s~~~~
~~~~2...~~~~
~~~~s .v- . -. w x i. ;... v s i. .,;.~ c.s., .. /y.~~~~
}
~~~~v' [,.,.D a~~~~
~~~~. b ',-!l'. _j. s~~~~
~~~~o. o~~~~
~~~~... < N. _.. '. e i)>t 2-34479,_zg3 .c~r- .a s 1 ~ ,y ,:X mL.i ' _'~$2$ - r,.....: ,. ~.. m.Q: q w~~~~
~~~~s. ;-.~~~~
,sa 'eg M,,. %e. r.kJUo ] + . m . n x %;Q'y FIGURE 4-5. SECTION THROUGH THERIAL ' y u w a s. x.,'r,.n. M<, >yf@f,j il*; ? 2 SLEEVE ATTACH'fENT AREA. h.;5').[T.,4-Y; SkjNM Section 5 s, Figure 1-4' 5 E'(h;h,f7@ r.- ,_. *c, ce3Ln Etchant: 8:1 phosphoric r c w.g acid. 50X w/ V <g a -, ,c- ~ MO seg g-pv> - 4.~.< mm; v-wgr pp .t-w ' ' C 4. ~ N * '; -*Aa ,qGW.., s.,a g e r e2...R,,a,a-A.. .gQqq
31 g g g g p, g[ g '.s,y ~ ' *q ; ' -.j f]f. 5 " ; y;7vep.y h.*?,4 '- g/ d $/.% ;b Q.
1

5. m., @g.2+,*.,:.;.0. v 4. n
.s. %%.,Q ,%'. h- '4 w,,&.A. . u,+. ~ s-o.,,.. . ',.. 1., A.,. .~ o .N 9 fr g*.N g * ?s a >h,. . t 4 kl*.f.5 fy s G dy&m'?'r[.c':f.(_.k Mel ,e' i. ye. - (V W; r y es Q .k, ;* b.N . k* Y f k, [h.*,[:YhU*[* N ~,-" e r Q.2 Q &s >7
~~~~f*** g - ie(', a.* >* d.w e(~~~~
~~~~(YJ,,*** ^ 1 ' *for~~~~
~~~~m.,u j~~~~
~~~~r 1 ..,,i g C. td '^ t. y, s )w,*.d w= ~ m := M'8"-).;. M l*.*r. ydo . v e ~ r .a..,.. p m.., e,~~~~
~~~~m,',.n.b..v...-e' r y)?.#..~~~~
l
3,.'.p, t.*;;M,.3.& e,A p- <... a.

o.. r.~y<:R..,p.s >tq.% ;
~~~~v .a g%;,.....,v. /.*'., v. = s 4 3 .,s o @, e. . pl ~a ., '.. s,.. g.,, 4 W.. N. m,-y-gr $' Q, m M.v. M:. m,' *y.,s.f .d,n c -;(. t. -~~~~
~~~~cs.~~~~
~~~~r .f-U v . s....... # y. y/. ,*?,<,'. .Q .,r. '.,.*.s,'/ t. a.., 7. -f. 1.?,r,.s, Z,.hm.. '.<.,. 4,.,.. y M y 4, v. - se,. f,.,< ".~~~~
~~~~i s. > * -~~~~
~~~~.p, , s_7 O + r.'.(N,, ', 4. ;.,, r.;.j...ws..,k.g,7Xs' W).e c'4. P T. 8' y r.M. s . ( *.,- $ -u 4.s' t~~~~
~~~~.g.~~~~
~~~~^'., 7.4 4JJt2* . .e f... r%.s j'..v. A, y..f.<.. .'9 ? eg....?.< i..: s.;4 ] -l*y.. ,g h,. v.. r..,.?, y~.R,,> a. 4.fn. ..e. + =W A u .... *.~~~~
9,
~~~~~. , - 4.. ; 1 e. us.". - h s. ,n u .[-* p. -g, ? y, y e ;, \\..,.s ,*4.,..,.p;, 3, s. .W. . t.. ;s ( f f S '. sg ',f y f,, '.11' _ h.s- ) M. i s @ N. %,'.*,. p,,. ;. $.,g.:g ' \\~~~~
~~~~. :ve,T.4?.y 9_..m 1.,,.~~~~
~~~~% j- <. - .-.A ;,s y %. w."* A ?. 4)e, l a e ,.., e.-...< - g. s -,.-.-s. y \\ ;p.g.C =. . f.~. i*'%>,4 ). :.~~~~
~~~~s U~~~~
~~~~\\a. * -;" p > .',(.. ' ' ; g.*.h'. '. J.,..;~~~~
~~~~. f ^-~~~~
~~~~S';;. \\ y "l,rv .-4 * "* * ' s' d' yO ".~./, w ./. ,4 t *.. ^e g ,../ e. ,'r ? ..",s g . A.. ?! Oe, 1:'.~ e~ H ^ ',~~~~
~~~~&J W.~~~~
~~~~= ~ - ?.. g- % P 'st.~~~~
~~~~"fA a~~~~
~~~~.<,n j i,. y;'"l,.1.e;r ;qs -@ q , b'.- - G*., f, ,m [.S.e : s,., o m a r~~~~
~~~~3, s~~~~
~~~~U ., ; d-,2 M.. s..".~~~~
~~~~y '-~~~~
*g ?.. * -
~~~~-a '"=' 3 .',I'I; &] D Q*.] (*4 e~~~~
t
~~~~, ^ ',, q h q i. w.. ..i m r u. t~~~~
\\
~~~~.O S 1.=$ s i,.. Nc d, # 1:;,t. m a m, m.s.W N.,f, N'f; p > v ~.i . N - N._ .,. g ;. e As.,s-M "'-* awe. m ^ ' '.f '.,.l,.7, P s...,~,, . # ;=%~~~~
~~~~y.. d,,4 t~~~~
e s _-;.J e .I'., - !.,') ~., e.!..s.,>.F'.', 's, m .t si, . 4 ,F = s. ~ . g J T ,.7 . * ? ',, ' '.g% .'4 *.,.w, e t _- e. g,.,,_s'_,, g -s c' y.y., N.. t *, ,.p...,...*6: ' s..,. 3. .*, e., a m 1 n s + :._. 'N.~~ I ,o,*:f ; eP,s:~..w i ~ y ','.a r e,,,$; .,,Q. -'m,,f. V + . s s . e, N
~~~~c s~~~~
~~~~u y '-.*s*- s~~~~
{,
~~~~.b, s.~ h M ew f ( a Ow w i A 3 O ~,0 w a >A = e E"* C~~~~
J
~~~~= .J ,/ -- J U~~~~
~~~~V3, >:~~~~
h \\ O MC Q i c %( >m.n , (. g .= Z e U2 . L.} f f =. C C 2 '.a O "':.s M / F ^ ~* .M_, 'u-* U U t. . ~ ~ i ~s)p-C b U U C [ oq -p. s U U C y y .i. U => V: 'v "V Q e L s /- U L O ./ C e. .= ~f n- =***. O y.,,, x N. 2U t;: e m U $_ D C
r.
~~~~s.s C ~e. g ~~ s.- c.--, r '%,-.t.'e.,i., ~ lN $ 9 a .1 p'j y - - 4: a e g1 E Cp y e 2 ,.j w ru;, :,.?%+ / ~w w E o,~~~~
(
x.: 9 4 .w v ....../; y 's [ ? Y s l '. as 4f h.,,. 4 b .m. ,b! e Y,, [W,.d k $k . $g' m m
32 ,m. m.. y;,q.,.,. (my-7 3;,.- ~ ,%e- .O
d'
~~~~.,s y ' ' k ;, :- + >> p, ,g - +j,. . w. m' - e}.;._ q.vn w, e.. , ~~~~~
y
~~~~, p,p _. q;w .xq ,.,s c_ .. L3 n ~ - n,.. ;~~~~
~~~~x n.- n n "J~~~~
~~~~-,. ny n .+ w , ' r t. w J.,. %,p), '., ;%.. Qg~~~~
~~~~N.%.; n.~~~~
7
~
~~~~h,.a~~~~
~~~~.. L,m,.. ,_.,, ~.., e. c y.- z s. s a,;g. 9 wp n E h. -.~ - ,..i n. 8, 3 i< . Er [. '^t 4 ]1~~~~
/
R
~~~~- $ p} d]~~~~
j
2 e

v... - f y
j
~~~~M. c.~~~~
~~~~,N ... c.e, ;;yrp .\\ [n 1 D .o h,c-y ~).x4 <).. -).,,~~~~
~~~~.i.,,~~~~
~~~~--,....*g 5...,y, ,y ( <,x '.3'A .+ \\. ' p:N s . V: -- :fppF ,q.. f,. D - ' g,q n'e j P J~~~~
~~~~Wv s n.~~~~
~~~~{- t~~~~
~~~~W.'.'...s.~~~~
~~~~./.,['.' ./ ,',-/ . e, V,., j- 'f i ;s .,<,j 6 _ .- m'. 's p, ,, c r.! E+ + l s~~~~
~~~~,.,., 7 'e P y..,-~~~~
~~~~W. : c. '.f.- m.e, e ,a ow .s v. + ~. <. : r. _ - ;~~~~
~~~~s )-tvR ; CM $ c._~~~~
~~~~"i* Vll' ff.M, e'w-i.y ', WN. y : ' ^ ' Y 3~~~~
~~~~7. z ce~.;.-. r; ;,~~~~
~~~~f' ps. -. ?,p e ^a Q. y / '. l.'.' A,. ..,. _,, * '..,,,., ' ',g, m';g Q' n p . 7 9.'r' w. ....g-'B,~~~~
~~~~[,,~~~~
~~~~'5 f,~~~~
~~~~a. e #~~~~
~~~~g .g .s,.~~~~
~~~~c.. ;, ~f A..,,.~~~~
~~~~,yy *; y L,..,~~~~
~.
~~~~.~ . W. ? m. -. w. .... p.., i 1 . f>. - a ~ -.. r: s.; +, t ~ v,. : ;;"~a e. g~~~~
~~~~v..,.. ;-.c.....~~~~
~~~~- a .~a .. Ap c?, *.u.. ' '+ y..n. w~~~~
~~~~m..+~~~~
~~~~-. t o.%y.,.,e,:.,.... e... w,. n - i. v= r. .;', s. . {l '. T 4.. ry.~~~~
~~~~.^, y' e,, :mp y,;~~~~
. -. 5.~m s:;. n.:~n s:n..%-*e* .v' u m i. p '. k o l w-. p'....,..*y... T-Q.m.s c '.n - =<. l.. .,' ' l. .. :. n., I < =.*y r+n, +. a s$*. ?. f/ , ; ir %. i *.. u,r;,, 7 -.9 ' t *,u:. T. i.,&. ly. - +^* .t* "4'
~~~~e.,M~~~~
~~~~= '--'t , P.n. 9.g,, y y..v; c.,.-,,o-'-- y p.,7 <, & . a~~~~
~~~~p. p ?. -.~~~~
~~~~.._ - c,:,ng i .. -- n ; y. ~., s.- _, g..._z23.v.. u 3 n ' j.. ;- ,,,s, ' y 6- ,,./., ge. ^ -,-g [..Qy'-~~~~
~~~~-*U d'.Z 2:.~~~~
' O ~ f l 3:,: f:)'l k Q h l!!; W<<.3,;&@dP w w^>2" ,,. r $&. {in 3:.d4% pfm'y:,.+blk Q 7 ~ m#y 3 ~ 7,*( Qjkj ~W;l,.n ! e; MQ.J{lWl l l4% jp f h 5 h;ynnJ~f_;. y & ,,4 y .a.n -<y y tn ?~%q :g s- .V 7- . d pg{ :2Cg f n, lMMl.k &, /$)~. N^ lf y* f;,& h'{ $1 3 J w M<.SM w W W.% Wf ~. Q ~ g@l-f gi. y- &, a, '.4 {[ &s ~l;(l' f & ) Q. ~- ~w G a pf; %)y? 4.Rj h: m. m,.p%9a c ,9 g. p.,.fsh) ; p.y# - w.4. w;s - c Q., - r. m--y,.....J 3, ,4 cx 1 ,M ',s3 [., I ~h J.k'w$'[' M.i A yN[ D O +,. j,.V, 2 Al)/ 1 'O 4 ' T 7~* ~ \\~'YT 3 / ge Y / j FIGURE 4-7. SECTION THROUGH THERMAL SLEEVE ATTACHMENT AREA. Section 11-11, Figure 1-4. Etchant: 8:1 Phosphoric acid. 75X
33 later stages of propagation the crack diverts from the thermal sleeve attachment veld into unaffected base metal, see Figures 4-5, D-3 and D-5. The location of the initial portion of the crack path within the heat-affected zone varied around the circumference. At Section 1-1 crack initiation and early propagation occurred within the carbide free zone between the fusion line and the zone of heaviest grain boundary carbide pre-cipitation, sea Figure 4-1. At other sections crack initiation occurred within the region of heaviest grain boundary precipitation,and in some cases the initial stage of cracking extended across this region into unaffected base metal, Figurec 4-4 and 4-5. The configuration of the safe-end and thermal sleeve is such that the attachment weld forms the closure of the tight crevice. At Section 1-1, Figure 4-1, fusion of both components is complete, forming a relatively blunt crevice tip. Fasion was also essentially complete at Sections 4-4 and 5-5 (Figures 4-5 and D-1). At the other sectioits, lack of fusion was evident, forming a tight, irregular extension of the crevice into the attachment wcld, see Figures 4-4, 4-7, D-3 and D-4. This lack of fusion extended approximately 0.02 to 0.04 in, from the fusion line. Such a feature is not uncommon for the joint configuration employed in this case. The significance of the lack-of-fusion defect depends on the type of weld intended in the initial design. If a full-penetration weld was not specified, tiais lack of fusion cannot be considered as significant. In any case, the feature is not related to the cracking problem, since it was observed that crack initiation occurred in the HAZ away from the crevice tip. The entire length of the tight ctevice was examined in each metallographic section. In each case, cracking was observed only at a single location,(intersecting the inside surface within the attachment weld HAZ), and there was no evidence of any other intergranular attack or incipient cracking along the crevice. .crographs at the tip of the crack in Section 4-4 where the crack approaches the repair weld are shown in Appendix D, Figure D-2. At this location, crack propagation has continued within unaffected base metal in spite of the proximity of the more heavily sensitized HAZ.
34 4.2 Fractographic Features Three specinens were cut fro: the therral sleeve attach:ent area of the safe-end sa:ple and broken open to expose the crack surfaces. These specirens are designated as Nos.1, 2 and 4 in Figure 1-4 The specimens were decontaminated by washing and brushing or by ultrasonic cleaning in a detergent solution, and examined in the scanning electron ricroscope (SEM) to establish the topographic features of the crack sur-face. iberographs of the crack surfaces are shewn in Figure 4-8 and SEM fractographs illustrating the fine-scale topographic features observed are shown in Figures 4-9 through 4-12 and in Appendix E. The crack surfaces of all three specinens were characterized by distinct intergranular facets at all locations exanined. Figure s 4-9, E-1 and E-4 are representative of the f ractographic features observed at the intersection of the crack surface with the inside surface of the sa f e-end. The crack surface was co:pletely intergranular along this edge and there were no features to identify any discrete initiation sites. The features of the crack front, at locations where partial penetration occurred are shown in Figures E-3 and E-5. The transition f ro: the service-induced crack to the laboratory overload fracture is apparent and in each case, intergranular features are evident at the extrenities of the crack. Specinen 50. 1 wLs taken frc: a location where the fital stages of cracking passed through the repair weld. A transition in surface topography, =arking the line of intersection of the crack with the repair veld is apparent in Figure 4-S(a). The fine-scale features at this transition are shown in Figure 4-11 and fractographs f ro: the crack sur-face within the repair veld are shown in Figure 4-12. Distinct inter-granular features are evident in the portion of the surface corresponding to crack propagation in basr retal. The features of that portion of the surface corresponding to the repair weld demonstrate that crack propagation in this zone occurred in an intercolu=nar code. The trans-ition in surface topography at the intersection of the crack with the repair weld is strictly due to the dif ferent nicrostructures characteristic of the weld retal and the base recal.
35 wr .-:,,yy n1.-
~~~~b. m "5~~~~
7 p 4 ? b ' -(*? '.2 }g *^ g yM hh ,,j l?l < Q: , DM;;4 M;3 t r g/;w c4 s w.:gs. os,4 ( )4;tu{ ? d,' ~ 4,. t, : F z = R,f 's = t'E '+, {[ ? >, f ?g V' . sA. ::: g$ld hg .4 '; I.j ss ' )' $,, st < ~ ? y g%?y%ly. , ; Lh+$ Mf)f [ ;h = vi" h){s 8,h-Tft N \\
~~~~Q, AI;~~~~
~~~~~ m$t ]N{ 1$.a p? ~ l am n m m E .. w.. -'1. ~. =w: _ ,. bM D-Q P.., g 7; k5 e wy%f' -L C 2.;,, " Z wk Qk. l; ^ 2-a.-- + cQ-Nf+ ~?. 5.__ "::.:Q[nDirb 531~~~~~
~~~~p,,~~~~
~~~~.5 %~L z 7YT~~~~
~~~~.V.. n-u L.,~~~~
~~~~1 +WO;.1:rs tt L , I 3' 5 g.t * ! ' " -~~~~
i
~~~~'~ w 5'EE C.Z[M V 5[ .I '^ ~c = - N.n.... s l C~. ~ z - an' %A-M$>'% p ~ h.i'; '- 5 - - b MWh ? "A ~ ~ - - - - m 3 l ki m:,% ?l g~~~~
~~~~e 575E[$~~~~
e, r I< Wee= 2
36 ,; w4 " s &a' p y % l ph sag r E g y gpf ' s y'pg#[" g#p:,sw.g.f Mj krfk# %g.ijdte&/k/ p% : .,). ez = 3 og + ~ ' v' 5~ ? %Wg%!n,;+s M 8 >" h ?k y~. v f>> .f (b. i \\ k k k l h } ),yw::sskea;ww%W kd f s n w &iME M f: w '3na n , \\t et :A m M h a= ~ uE 9.- ,A JJ Wh, sit , t w). ., u. % us k % n1 + .e :-, = u.- Y ' f ; Y 'k $h, a viht k A,z ggg4g,i i = ~ ni wgg O ..q gyg o
37 RTN%% 3N~.F + 5.pw"w r + + *kj.a, _ a ".,; e% ' ^ N 5*; J ~ 'r w LO 2-174 (a) Location 2. 100X . ay,, ~~ -- ,r - ~;,, ~; 5W t w.. t E%" 2s- ,.e = A V y., e. v.. r~ ,x: < s AIf,',:5 s INS 2-117 (b) Location 3. 150X FIGURE 4-10. SDI FEACTOGR>PHS FRC ! CRACK SURFACE. Specimen 50. 1. See Figure '.-3 ( a ) for locations.
38 ??8 o
~~~~f. ' ?-~~~~
~~~~. w,, *\\.i,~~~~
~~~~..,j-fY~~~~
~~~~' {liY. ' ';y _ < 3 2 - ) l 1 Sb$E.'!?*'tlbl ;',~~~~
~~~~!*;_ N~~~~
~~~~!Q ^ ty .r g.c - ~ g y --,. ,gs .,F *) f; 7; ^ er %t hbd ..h4 .,s a; 93 p9m kdb, -' e s +., ,Y ? -( ~;~~~~
t
^ ~ 3,,. 9 2-120 150X FIGURE 4-11. SDI FRACTOGRAPHS FROM CRACK SURFACE. Specimen No. 1, Location 4, Figure 4-8(a).
39 p'.- y pyy
~~~~v. r~~~~
~~~~,$} l T-j I ll ti f .::l ...h,;3 s g' l. ' g 1, $fh kl~~~~
~~~~':0 V5\\.~~~~
~~~~'g<~~~~
~~~~.L%~~~~
~~~~Np !S s vu u 2-191 50X WT&;;~~f';r T;,;- +3~~~~
~~~~,,. V~~~~~
~~~~.1 %;.. % p > p%,,. l_ r, y, n ;, 4. 3 ,:v .y j 0 ; ? l_ _ y. g.. (R.4:- _hk y..p: _'A f% ^ ?f Y p ;.3_ q 7 f;~ :'~~~~
q:. 3 +

a-j
~~~~,. m .<; \\ _.,. yy _ In . y?i % Q Q g"*h'._p?-g; . \\ _.f l9 fp W-f ./~~~~
}{
w 11 1h - y;ieth 5 L .i W J ; y _,.uyc aW W 'b'f;Q.dg *6 . &, T15.,s;t ~. ? y :g,~; p ,c y', b..- \\1. $ ':t*fo,..9,3) t jh 5 I. 1 .y> -,e% . n_ f., A;_ _ .i ,_ y sp_ j -- re 2-192 300X GURE 4-12. SEM FRACTOGRAPHS FROM CRACK SURFACE. Specimen No. 1, Location 5, Figure 4-8(a).
40 The fractop raphic features at the particular points described above, together with those at locations in the central portion of the crack surface (Figures 4-10, 4-11 and E-2) demonstrate that the cracking was completely intergranular. No evidence of any form of step-wise crack propagation was observed in the fractographic examination.
i 41 5.0 SURFACE DEPOSIT ANALYSIS In the examination of the various crack surface specimens, deposits were evident on the intergranular crack surfaces and on the crevice surfaces. Distinctly crystalline deposits, such as shown in Figure 5-1, and a fibrous appearing materials, Figure 5-2, were noted at several locations on the crack surfaces. The particular examples, shown in Figures 5-1 and 5-2, represent small amounts of deposit materials remaining on the crack surface of fractographic Specimen No.1 af ter decontamination by gentle washing and brushing. X-ray energy spectra for these particular surface deposits are compared with the spectrum from a clean area in Figure 5-3. Pertinent features of these spectra are as follows: 1. Indicated iron content at location of crystalline deposit is higher than for base metal. [ Compare Cr:Fe peak intensity ratios in Figures 5-1(a) and 5-3(c)]. 2. Presence of sulfur is indicated at location of fibrous deposit, Figure 5-3(b). Four crack surface specimens were specifically examined to establish the character of the surface deposits and their distribution. These spect-mens were cut from the safe-end sample and broken open to expose the crack surface and crevice surface. The exposed surfacc: rcre eyqmined in the SEM both in the original condition and af ter ultrasonic cleaning. Energy dis-persive x-ray spectroscopy was employed to provide in situ, qualitative analysis of the deposit materials *. EDS data and SEM fractographs from Specimen No. 6, representative of all four specimens, are presented in Appendix F. The results of these examinations are summarized as follows: 1. The fibrous type material (Figure 5-2) was the only recognizable deposit evident in examinations of crack surfaces in the ori-ginal condition. This deposit material was particularly evident at points remote from the crevice and was not present at locations in the immediate vicinity of the crevice.
The EDS analyses of specimens in the original condition (no decontamination) were performed at the Argonne National Laboratory where facilities for SEM examination of radioactively contaminated materials are available.
~~~~42 f' e M 7 m%,*Prfjsh; jp 5 eg' W G v.'f + N yle.r%q n g' S 'ig; ., &.? : f ' ;1.. nag 3, ~ r - Ab M i&?*I~~~~
~~~~1.,~~~~
g
~~~~d l~~~~
~~~~+ -,,, ;,,. :.%;nn%5%,e%%V~~~~
. y 7 9 -'

f=::p.Qygg_ rv -
~~~~u"% 'i;;fa,cy t.7 :t ':9i ~.m $gspy h9yb,dcfT s%49 ' -r , & kecep.se s%v&. N d [ M., h~~~~
]
~~~~0, ' R~~~~
~~~~l&mp$m.f. ~hf{c+%..~~~~
~~~~l a gu V kg d 82 U N.;g 6[W, e. g'-hkiAf: I~~~~
~
~~~~jk. <! [ 5-g,.~~~~
~~~~3. g n ~.~~~~
~~~~.n - m~~~~
~~~~~ '" : ?~~~~
M
~~~~" ' ~~~~~
~~~~$, _g x\\~~~~
~~~~,f'".- 'A'. g\\ s se h.{h S '! f~~~~
N%
~~~~. AC80$$215;.QYJ.%.W-Z.E'..?;A x-t a,. 2-175 300X Y L=i' a ~~ s y',. 's I 7.a:E w J J1 ..Jtyj: ~ w:1 - @Q / ~ q n r: @.,pn,{ -+ f~ h "k cf+%llv..h{[-..g T .w y e~~~~
~~~~d 4~~~~
q SFlc.. M').% o-2-178 1000/10,000X FIGURE 5-1. DEPOSIT C: CRACK SURFACE. SEM fraccographs. Specimen !o. 1. Location 6, Figure -S(a).
43 v y- -T k',99 ; k' T[ 3.n jlY i (',.'-$ a ,3 ~ . - - vg'.~jfg - 73, ,s - ' W in..., _,
~~~~,=j/j~~~~
~~~~,j{j?M.YY ' ' ggy;g. - v u 4g~,. f. M, C.-; giv ~ g 4~~~~
Q
~~~~~ q i +p-w g sea ~'~ 4 i< 2-187 200/1000x %,+ -.., x ~ g r, .? s +. s k' %~~~~
~~~~' s~~~~
^ E 'g, bP, 3 .g[" -;-{' ~, -) e, 4- .e.. .,'S-. t-j .-P [. 2-189 200/1000X FIG W 5-2. DEPOSIT ON CPACK SUPSACE. SF'! fractographs-Specinen ,o. 1. Locatica 4' o Figure 4-3(a).
-_.L-_mus-44 '.? * ' ' oI d, g,, - ~ * -7 m m - t ;';. ....: % ~. a ? L. 1,t.,y '-PU-n ;y e' UC -
i*
~~~~sg.g pt.. p%d 'i. g. - - ""'t f. f? j 4.~~~~
~~~~) oh) j'.~~~~
~~~~? *;.2~~~~
~~~~l* '~~~~
~~~~' _'~~~~
~~~~7 - \\.~~~~
~~~~.. kA . N.k ' -r 7 c.a., 4 - -a 9 . :.k. y - 3s, s .m n, c ._E~~~~
(
~~~~g 6 f%~~~~
~~~~-Q5 1 --l.~~~~
~~~~y 4.~~~~
~~~~e ..< j, ; ' ", ' ' * 'g ...g'V' / j. y',=.g.* ] .-%,., * $.4,.,; * %,+ ] s s ..s_ e 'Y . A t v ; h y p - . '.e.i~~~~
~~~~a*.~~~~
~~~~.:.4) c#~~~~
C
.,J 3 ki c : ,;,%,.g ~ x.
~~~~-e4 s,,~~~~
~~~~"a -f ,9; *,[ i i.. ' ,p ['. c 1. E. " ' t % 5h. 8 d~~~~
., 1 7 d~ W.."
~~~~[ 'O f g. 1 A gw :.. nh h, 'i $ h.' W y.w ( , k,- ._t.- ) e g. w* ,:.l + 1 - :., y 3~~~~
~~~~4 d [,~~~~
~~~~, j;*, ' ) - r.f. W. .,: *. M.? .s u m.- t.y 's.Mg : ~ .Y U \\, ', J. - -- i ,,+. ?,* y ~. J P. l. _) . +. ~ 9. [ .c. z,,... ,4 g + o,"-~~~~
~~~~s y~~~~
~~~~.s., 3 A J ~ ' n e.,:. ? a .. ~ 2,~~~~
~~~~f; j~~~~
~~~~k".. y(, ...g m, j - i U qs .7 r..-. f. ,e u. 9, .. g. p '. -I .9 - m p 4 A A p. ( . F, w.7\\~~~~
~~~~- ("~~~~
~~~~li 3 g E c n_..-.y Q%gyg ? a i n.,, y, ^ >: n +. 1 1$', 4 4,'g l i~~~~
~~~~( ~p )(-@f6~~~~
[* ^4 4' . ; ? 4.,*4 q%. s, ;4 . ,.. N'.y. '. q i g.1 fM <* - -~E [ ( .. g. : N l.% 1 g:. r: - '- ' '. w..-...'._.s g.w: ?'m x ". r a 4 _,,,y .. +.,.. -...: . $g,'-IO,, %,. Q, . M g, y'*i F, *['.y% E&, [ha t, p h s j i . ga.. s k .. g
~~~~gs 4.,j.-~~~~
~~~~s sn , y o,, .s.4 1 a N ...C,- c !., y ?g g... s p- ~ 4.- 4 y ".~i g;*4 s .. % Ci' d'r;, f(#~~~~
~~~~f' g~~~~
~~~~a6 e c 3% m.'., .,A, 4 'o. .~. f ~. e 9 -J f t-- M'f f A- ' yx. L' a 1gi O % U 5., . ' E sk=. '. an. -.~~~~
~~~~-a a~~~~
~~~~l Wig :. . ~.- ~~~~~
~~~~s. N,'~~~~
~~~~v C ~s$n ' y 'A ss r' f., %. q. w 'i a ,, z f 'A a -'hh I'l { f ' d' y,,. g Q } .7 C w:, . l Z' aa e~~~~
,R
~~~~,) k. s f ; (.. .r ~- 4 t- }% ... R-4' s ':g. (; ,. - - ~ .f. 7,f-* g Z c 7.'- qp. =~~~~
~~~~4 z 3~~~~
~~~~A \\ .w .i. $,w $p $u~~~~
u-
~~~~>= /.4 ww..-.. ( ~ a .x.. . n e A '. ';,* wj, ' ' D' ~~ ~ I i.# a XUZ x. e, ,_ 7. " p% %. 'd ' ~y >s '9 en L. +n .,1 G = m. M 4 %,;%>.-. y e g ', 8. 4 C~~~~
~~~~. p~~~~
~ e i V -s 3 Z 'T" ,g' . m M w m =; s --J C s ns m l ' 7. :. =.w.~p. a 3.
45 2. The crystalline deposit material on the crack surfaces was evident only after partial cleaning. 3. The fibrous deposit material on the crack surface contained sulfur. 4. The crystalline deposit material on the crack surface is iron-rich compared to the base metal. 5. Iron was the predominant element detected in the crack surface deposits near the crevice. No sulfur was detected in this material. 6. Deposits on the crevice surface presented a distinctly dif ferent appearance from those on the crack surface. 7. Iron was the predoninant element detected in the deposit material on the crevice surface. No sulfur was detected in these deposits. 8. The presence of chlorine was indicated at one location on the crevice surface. SEM examination of the portion of the crevice surface contained in the fractographic specimens, (Specimen Nos. 1, 2, 3 and 4, Figure 1-4) revealed an essentially as-machined condition (original machining marks evident) over the majority of the area. Evidence of limited corrosive attack was noted in a few localized regions. SEM micrographs illustrating the condition of the crevice surface are shown in Figure 5-4.
46 .,,k. WNh:Y$N ~ _. mim21.2..:.;MM-' ' w!'-'W!~&. L.*m.-n -. - -#Mg%
~~~~j. i &. : r~~~~
'2 a ,.. s. ,- e.~.w mf...% e-:; m,. g,,.,.-..a >.x a <=a m :: ga '~ w - m., ew m.~. . r e.,L m.,,,,w m.,~,~w .n--,<- .u...e - .....,m y.;,w ~..,eJ G y u ,:9 g.,;3,.agarz.w s-- 5 v EdQ.,_ 3 ~ ~ - x..,,..s-.-- _ __. - _u. u tenamey __._,_-- :.,:~.:.., a.,..mm .:,,gis;;is:Ernm wgg.<-g < s_- Leg -.,._, a _ _ __ sz =: : s,;;.;.:._ w _ ;_.a r x .._,Q y z.u mA y% g g y r g %,~*Jw w ? - ms-m - -,... --_: w...- -- - m -, - -... ~ 5m.. lY'~, ~ ...gr $ _ ".i l l A WMn_ &y;4%y** *.f;,4M:M:K, ~A.'e*.: . 2
~~~~.,.a m.~~~~
~~~~m ,.c.. mar g, -.cqg s~ - ~. _ - -, -M=~~.',,f ., g :- ^ m - ^~_-- _w, _ _ ;-~ ~.L.. -,.. --~~~~
~~~~-a---,~~~~
s ~. --- w :*.::.- ~.rx:;~;vw. y 3%3 a;. p p.. .2-243 (a) Typical condition $,.2 e$$,-m?x- -w.pr- .4,M)~La?.ffP:' R8.L ~ j Q~ a $ fi5'% 4 Kf4 6.%+;: iL ? y-2 22 2 ' # W M - %. y ;. q pgR$y n <.3 ga*=. - b. . N~ ht 5@M k-?s:Sm[M NN46-sww.s5%;32..- V f **.. p p~ i g '
~~~~P,' / g m :" %~k 2 s v ; 2 %~~~~
~~~~pv yim 3~~~~
w
~~~~'y-T '.C 5~Q'&fif7.r$ ??"~Y~,.eannEE(*;Qpae 4. -N~~~~
~~~~%~'<f$"6.~~~~
$s C % W( $' $ h W Y S ' l '= W 5f6? ',5v$ W M: & ? neW3f 2-265 (b) Localized region of corrosive attack FIGURE 5-4 SEM MICR0 GRAPHS FROM SURFACE OF TIGHT CREVICE. Specimen No. 4, Figure 1-4. 100X
47 6.0
~~~~SUMMARY~~~~
AND CONCLUSIONS The observations made to date in this investigation may be summarized as follows. 1. Significant cracking occurred on tha inside surface of the safe-end over a full 360* of circumference. 2. All cracking initiated in the immediate vicinity of the tip of the tight crevice between the thermal sleeve and the safe-end. 3. Cracking occurred completely within the safe-end forgiag, except for the later stages at some locations, where the crack propagated through the repair veld. 4. Crack initiation and the early stages of crack propagation occurred within the heat-af fected-zone of the thermal sleeve attachment weld. 5. Cracking occurred at a single location within the HAZ at all sections examined. No multiple cracking along the crevice surface was observed. 6. Funor corrosive attack of the safe-end occurred at some locations on the crevice surface,but no significant inter-granular attack or incipient cracking was observed along the crevice surfsce outside of the HAZ. 7. The cracking was completely intergranular at all locations examined. 8. No evidence of any step-wise crack propagation was observed. Also, there are no fractographic features to indicate discrete initiation sites around the periphery of the crack. 9. The deposits present on the crack surfaces at locations corresponding to the later stages of crack propagation con-tained significant amounts of sulfur. The specific form of the sulfur, i.e., S0", S, S", etc. was not determined. No
48 evidence of any other extraneous contaminant species on the crack surface was observed. Sulfur was not detected on the surface of the tight crevice. Chlorine was present on the crevice surface at one location. 10. The deposits on the crevice surface and on the crack surface near the crevice consisted of an iron-rich material. 11. Both the safe-end material and the thermal sleeve material are in a sensitized con /.ition. This condition is considered normal for this particular case in view of the post-weld stress-relieving treatment, applicable specifications, and usual mill practice. 12. The chemical compositions of the safe-end material and the thermal sleeve material conform to ASME Specification SB 166. 13. The weld deposit chemistry for both welds conforms to AWS-5.11-76, except for a minor variation in Mn content. 14. The repair welding operation on the outside of the safe-end did not result in any significant modification of the microstructure within the zone of cracking. The metallographic and fractographic characteristics of the cracking (completely intergranular with no significant direct corrosive attack) serve to identify the cracking mechanf sm as intergranular stress-corrosion cracking (IGSCC). Laboratory studies have shown Incone] 600 to be susceptible to such cracking in high-purity water environments in certain circumstances. A survey of the literature pertaining to the stress-corrosion cracking sus-ceptibility of Inconel 500 is given in Appendix G. In general, the pumlished results of laboratory studies indicate that relatively high stresses are necessary for IGSCC in Inconel 600. Stress-corrosion cracking has been observed in uncreviced specimens at stresses as low as the 0.5% of fset yield stress, but no cracking has been reported for stress levels below the yield strength. On the basis of reported data, IGSCC of Inconci 600 in BWR environments is not likely unless stresses exceed the yield strength. One factor indicated by the published data is that the metallurgical condition of Inconel 600, i.e., sensitized vs solution annealed, does not
49 significantly influence susceptibility to IGSCC. In the case of a weld in Inconci 600, the heat-af fected zone will consist of resolution-treai i (or lightly sensitized) material adjacent to the fusion line and a heavily sensitized region some distance from the fusion line regardless of the initial condition of the base catarial. In this investigation cracking was observed to occur in both regions of the RAZ. Also, the crack path diverted from the HAZ into unaf fected base metal in the early stages of cracking. In view of these factors, and the fact that no inherent microstructural defects or abnormalities were apparent, the furnace-sensitized condition of the safe-end forging is not considered as a significant contributing factor to the cracking problem. In many material / environment combinations the presence of a tight crevice can result in severe localized corrosive attack or stress-corrosion c racking. Thus, attention must te directed to the possible role of the tight crevice in IGSCC of Inconel 600 in reactor water environments. It is not likely that the classical differential aeration cell would develop at a crevice in the uniform bigh-purity water environment, but such regicas could entrap air during outages, causing locally high oxygen levels on start-up. Also, if any anionic contaminant is present, acidification of the crevice could develop. Such a condition is known to enhance the susceptibility of Inconel 600 to IGSCC. It has been demonstrated that the presence of a crevice significantly accelerates cracking in low pH and high oxygen content solutions, and GE data indicates that crevices enhance susceptibility to IGSCC in BWR environments. In view of these factors, it is likely that the presence of the crevice is a principal contributing factor to the present cracking problem. Analysis of deposits on the crack surface identified sulfur as a constituent of one of the deposit materials. The only other elements detected within the crack were the principal base metal constituents (Ni, Cr, Fe). The particular identity of the sulfur-bearing materials and the particular form of the sulfur were not determined. The deposit materials on the surface of the tight crevice were identified as iron-rich, and sulfur was not detected in these deposits.
50 The presence of sulfur in the crack surface depot..:s could be associated with the composition of the base metal or result from progres sive concentration of a contaminant species within the crack. If significant amounts of sulfur had segregated to grain boundaries during the stress re-lieving operation, corrosion products formed during IGSCC would contain sulfur *. In the absence of evidence of sulfur on the crevice surface, no definite conclusion can be drawn concerning the source of the sulfur on the basis of the EDS data alone. The EDS analysis identified chlorine on the crevice surface. A significant quantity was indicated, but evidence of the presence of this element was confined to a single location on one of the specimens examined. In view of this limited evidence,no definite conclusion can be drawn con-cerning possible chlorine accumulation within the crevice during service. The results of the EDS analysis performed in this investigation can only be considered as indicating the possibility of sulfur and/or chlorine contamination within the tight crevice. If either species were entrapped from the environment their presence could Icad to acidification of the crevice and contribu a to cracking as discussed above and in Appendix G. The obser-vation of limited corrosive attack of the crevice surface is an indication that such acidification could have occurred in service. Further investi-gation of the nature of the deposit materials, employing other techniques such as electron diffrac tion or Auger spectroscopy, would be nece: sary to resolve the question of possible contamination in the thermal sleeve attachment area. Consideration must be given to the source of stresses in the thermal sleeve attachment region which contributed to IGSCC. It is evident that the stresses in the vicinity of the tip of the crevice are the result of applied stresses associated with service loading and residual stresses associated with the attachment weld. The primary stresses (bending + membrane) due to service loading were calculated by GE to be 787. of the yic34 m roneth*'. _n--
~~~~In some laboratory investigatiena cignificant ammmts of sulfur have been observed on intergranular crack surfaces of a similar Ni-base alloy (Inconel X750) after testing in high-purity water.~~~~
~~~~See Ref. 10, Appendix G.~~~~
~~~~Reference 27, Appendix G, pg. G-8.~~~~
51 lt is generally recognized that typical butt welds in piping components result in tensile residual stresses on the order of the yield strength of the material. Therefore, residual stresses of this magnitude must be considered to exist at the thermal sleeve attachment weld. Residual stress analyses of the thermal sleeve attachment veld, performed at Battelle-Columbus Labora-tories, predict yield-level tensile residual stresses over the entire length of the tight crevice *. Thus, the combined applied and residual stresses result in a net ef fective stress substantially above the yield strength in the immediate vicinity of the attachment weld. The fact that multiple cracking did not occur along the crevice is significant. The distribution of the applied and residual stresses in the thermal sleeve attachment area would result in c :- wH an t in the combined tensile stress with the peak stress level at a position on tue crevice surface near the fusion line of the attachment veld. The occurrence of cracking only at a single location along the crevice is evidence that the combination of applied and residual stresses to produce an effective peak stress well above the yield strength 7s a necessary condition for the cracking. Residual stresses associated with the thermal sleeve attachment weld would be relieved by the occurrence of cracking at that location. As a result, the residual stresses are likely to be involved in crack initiation and in the early stages of crack propagation but would have little or no influence on the later stages of crack propagation. Ac the inside surface of the safe-end, the cracking was located at an esseatially constant distance from the fusion line of the attachment weld. This factor, together with the fact that cracking occurred completely around the inside surface is evidence that residual stresses in the region of the thermal sleeve attachment weld were a significant factor contributing to the cracking problem. The existence of significant residual stresses in the crack initiation zone due to the repair weld has not been demonstrated. However, consideration of 6cncial principles concerning tenidual str:ccca dsveloped from welding ope rat ions it.dicates that the repair wcld would have resulted in compressive
~~~~Reference 27, Appendix G, pg. C-8.~~~~
52 hoop stresses and corapressive axial stresses at the thermal sleeve attachment location which would not favor IGSCC. Regardless of the nature of the initial residual stresses associated with the repair weld, such stresses would be altered by subsequent machining and welding. The welding operation performed to attach the thermal sleeve would completely relieve all pre-existing stresses in the vicinity of the crevice tip. Therefore, the final state of stress at tae location of eventual crack initiation would be completely con-trolled by the thermal sleeve attachment weld. In view of these factors, it is not likel; that residual stresses from the weld repair contributed to crack initiation or the early stages of propagation. In view of the factors discussed above, the information and data obtained in this investigation support the following conclusions: 1. The cracking and eventual leakage encountered in the safe-end occurred by intergranular stress-corrosion cracking under the combined influence of stresses in excess of the yield strength (applied + residual) and environmental conditions associated with the tight crevice between the thermal sleeve and the safe-end. 2. There is a possibility that sulfur-bearing and/or chlorine-bearing contaminant species contributed to crack initiation and propagation. This factor was not completely resolved in this investigation, but the presence of a contamiaant species is neither a necessary nor a sufficient condition for inter-granular stress-corrosion cracking. 3. The furnace-sensitized condition of the safe-end material was not a contributing factor to the cracking problem. 4. The cracking was not associated with any microstructural abnormalities or inherent defects in the safe-end forging or in the thermal sleeve attachment weld. 5. There is no evidence to indicate that the existence of the repair weld on the outside of the safe-end contributed to crack initiation or the early stages of crack propagation.
A-1 APPENDIX A RADIOGRAPHS
\\ c. r, A-2
~~~~..'.n.',,~~~~
~~~~(. ^ - Th. +- - ~., ,.. Oh [jh_ ,a $h l ? s:. 4,. v#. c ....; ye a k ,.n.9_,,~~~~
g
%A pp 7 :s { ~ r ?9"'gi.'., f e .g', '. q f ~,3 '., J - ~-fs v4 Nw O - ' " QhQ #y^;rn 3 = h. 7,gg - f., .3 - 4 ,3 a 64 c. .C. U" 2.,.f t ' Qf .) .h, .* y. R y, y $ },l .f ?, t 1 m x gV .. k<. <a e 'g c ,j ,. + uo , - ;.; g. 4. (p., -r Cm .1 3 W-4 4.Q ,*l ... [.' j {
~~~~ftl' w u~~~~
~~~~) Ar, U "' l y . ;, =.; k~~~~
~~~~t e~~~~
~~~~~ Q~~~~
~~~~.. n~~~~
~~~~~ 4 ..t s- . -., g w . - p# . s u .,C~~~~
~~~~,_.,:.y.,~~~~
~~~~f ? 7 j' g 3 '; wd~~~~
~~~~.i.~~~~
~~~~.,gh;, 4~~~~
~~~~c 4~~~~
~~~~../,g. g. g > w -. - e ,s.g,,.y - u. s. r . v. 4 ..gf.: j 'egw. . g. r-. g ; -., : g,, g.r., ea . g., 3': g.; _.w s, p. m. w.p _<~~~~
~~~~c. '~~~~
~~~~.%j. M9/ g A O i.Cs -a 5 ,a .J C <..i.-~~~~
~'
~~~~d e ei .-). .. s # b. m n. . ' ' ;t' . c -sh ; r.C~~~~
~~~~g'. y -~~~~
~~~~g.. -15~~~~
~~~~yp g, ' ". -~~~~
~~~~g ' ', & = .k ?. mea ,;)~~~~
~~~~7 e g~~~~
~~~~y4 x g '#g.9 : 7 K f g ik'S S, Y> ' 3, .k/. '^ $ E I~ t 4#. ^..s . 14.... " s a (,. s 1.> 57 rm ;. t. J : 3-r~~~~
~~~~rs Aq -~~~~
~~~~c u~~~~
1
~~~~' *., e.x' e)gQ ;, .5'-~~~~
~~~~y. %~~~~
~~~~yqt,; y c~~~~
~~~~y g;'-~~~~
~~~~i oo; ~~~~~
~~~~4 o&>.s. ',, y^~~~~
~~~~s u~~~~
~~~~o .v ~ '.? +i r* u L. =, q. p q' t.".sn .u ? . L ,,f,.4~~~~
~~~~':J y b>;~~~~
~~~~m .f ' d [1 M[ 'M..xi$ 'k . 'y f i,Y ^. ; _ g w- >v ag xa o M. ,M5\\g ,-s ' ). T A .f C C A o u 'a y, n ; y s s a h ; ".hWN E' R$'. .).. ;g m~~~~
~~~~mat, oir oy r.~~~~
~~~~.w&~~~~
~~~~A ' 'l.p g %~~~~
~~~~s _., $. F,a a .y,g;.g,; 79 (wy" f%c.~~~~
~~~~g 'w, }~~~~
~~~~J y. m >, u e.-s o ,... v 3. e u c, % .y j '}4) # . s. M O 'e4 (.c',' _ ~ l,y ' * - f., e. 's .~ l ? y, 'f yg9 mu% Eg [;;r-c . y ;']4F~~~~
~~~~h,y~~~~
~~~~~ A JM g g ^^tf +g, ]a'- '. " j x J, g s I < D.". ' ? y.lh gh.J lRi Q - Q4...~~~~
* ~

U y
~~~~>g A . c..,, y' - ,,, mu Yk.., %. ;~~~~
~~~~m gy a.p~~~~
~~~~'.: :. g ir.t' ' -.g jy s- ~ g$. '^1~~~~
~~~~y[h~~~~
~~~~..-)-a 7,l,..g ^h,s, j~ q e's p., = c "1'. f 4 g..y, 'q .Q r. Ty .e* U j' l. f'2l l; fh. W . 5 n m. .~ m3. a, e c. m,..,, 7 =, z - wLs %.~~~~
~~~~.t c.x eA4~~~~
~~~~.-?s".9. m % 3g.?, ;e (gs-h h k... p ? c:' n o~~~~
~~~~v. Tg.n ' -,.-~~~~
ct
s
~~~~h. z wl yg. e .cm~~~~
~~~~s. -~~~~
~~~~a 1.,#}sWn a s~ s .. ; g 3.s , f. y::e~~~~
w
~~~~W ., -..w. .z y. .. '.' 4 u~~~~
W'
~~~~? h %y sd 4r +p,s i.n., +,', h. u%. j.. e.? %:,~.. m c. v v;. g; g ~" ~..,, p% v" er ~.,.~~~~
~~~~a p 7. j%.S./.:,. 5 :, %.wh y is.,'A s% f'; m.~~~~
~~~~A. .,j .4 .e k n.; r. ' -. y'. - *:i 'n ' ;~) - m f .x t 1/}f - J. s v- ~... v .c~~~~
~~~~,a u~~~~
~~~~> W- : . n-. m "n s i.~~~~
~~~~Q^ y.yfR~~~~
~~~~!.,: /,,,i;.. s '. ~ f,r _,. Y'.f " ;1,, 9$. f..f M j ' g + p.~~~~
e..,

f f..,> -M.. g ' ; i. c 9 4 7 ? _,., :[....,-
~~~~p .+, . O ~ l$, v~~~~
~~~~s.,~~~~
~~~~w p: c .s~ m,.y;. ),..."r~~~~
~~~~4%,..* 7~~~~
~~~~~ ,#. o V J m n. ; y..%. 4 y.1 p.;.._: y. / ;;;. ' u. ..._nw.. ,n. .t ga,w ^ g<., ;m ~- _.'T ~ j[ r p., 4, ~ 4.- .',g w g. (I ' ^ Y"' y : w., ' , y,f.l Q ' v. [~~~~
~~~~1. [ Y5s"6lJ;r'Y-gy %pg y-Q, Q_ y~~~~
_ f, gh't} Q+ ; <g y,L&.my$ g. ) g.,, h,_ w_ g, y-.;x 4_l.g$. w. *' u + c, 1 .e 4 ' uj. ~5 .: q g "%.. xt... p Ayg s t_. - g c r r *;. k,.lQ l c;p; j fo n r_ f. e - a _, u '.l.. y. f .,n. 2% -- m x, :. w: 0.m-
~~~~w " V '. s_~~~~
~~~~h ' f.l;', [ ~ f... :.k x. ~ k, G, 9..)c NA f g:N h .}f._.g &": g. sy L ;ff.,.. .I. bt .}g ~ t hw. s. e .. 4 L t. ymvsA. s ;^. "'; y.. x ..W gL g. kp;> . gic h. g 4.3#:%~~~~
~~~~A&%Q.Y&}_spyQ g%; & gli f, p. ( G_.~~~~
~~~~Me., .,g.,w. - c m w.~~~~
~~~~p ? : ) E.? -?, L. 3: ; '..~~~~
~~~~~ k, '~ y. Q 3. ' 4 ) Ag..y Q-4 ,9 .l. c,. A Q;:& l 2'. , h1 ' + l] h J.M,y 4 3%._ $.::,,,/di k M &\\a9M M~~~~
~~~~2. %~~~~
~~~~x y; Q.._ y ; . f. . e %; y., &g,g.c c ? x.% g." ^ :..~~~~
~~~~;' J..~~~~
~~~~J.& & u.& (f$ 1 ;., ..f Q p &,,$:?~~~~
~~~~t3 a~~~~
~~~~.c + 1-S; g g _ .( ' 7, '? +. ~ \\,.>, l%?'?~~~~
. ; + ;- ^ f. [; w* *. ~.Q

.V.

-
~~~~s_- g s, a. +*uye . '..:u e.v r - t,. +~~~~
~~~~y.,Q ~ l* i;.~~~~
~~~~-. g.... V, :.. O ( 6...n&~;6 ',, [ j.;~*: :. .',.]. e %.. Ls ..~.,;. + m/ ,%'.:r s -~~~~
~~~~- w -~~~~
~~~~c':- " _. .wv: ;; .y ;'!* ;>. g.% . + ,gi4, s. 's, g *:~~~~
4
,.A y,_ - J 4 t v % _. i w a: ' 2.:. %':,_y a L Q } . ;.3_; _LJ y..f. ; '. _ _ _ _ _, z. _ f 7. L 2-34466 FIGURE A-2. SAFE-END RADIOGRAPH. Stations 7 to 10. See Figure 1-4 for location. Section markers indicate location of metallographic sections. Block arrow indicates direction toward vessel. a La
A-4 ',l; &$llE??.OlkW j&Qf $ h% $*. @ lb sl. [ _ / ^ .L ll y-f"-' e 'v " i..p e A y 'sl '\\l l W ,g' ': s_. _ ;.;.: l ^ : f! ( u J
~~~~, q.~~~~
~~~~- ;,... 9,, w c . d b]. ,.S% ='.., - 4 u ., a,, *,.~~~~
~~~~t w~~~~
m 's . 'y g y .E e-4 C x g CC y a, y . +- 1.. ,2 q_ : ~~x j CC C ~,- s-g ~ '1 e4 E "O .g. % ' g. a r,-' ** a p p. =- W O 3 G-pk N N O% C g Q . ~. o ,d Q *,* y. ag ecu % y. .,e 4 c ? g* ",,, y. a. .,C M~~
~~~~1.., #,,~~~~
~~~~mu o ^. u., i cnm f& * , = s' oy u ... + -b.. -s ~~~~~
~~~~4 O U J. %~~~~
~~~~.; s um o~~~~
~~~~l.' :F a.~~~~
~~~~es ,. ? ~ ' 3 a c W +7 u 0 -4 a, b U1 a =c = ~^.,~~~~
~~~~A - -.~~~~
~~~~+- '. -3 .x. 4..,- w c 1 x..; 4 (- .: pgg e w+; e' ' y cc . w g w , s, ' ,,_,,.n u 40 c.;.. - ' j ' ' g6, w %,*,, a}*' r e, A cc 4, ,.T i*i nu <=; w y =~~~~
g.
~~~~g I 7~~~~
]
~~~~CJ CC~~~~
3
,.,f ", 4m. J 2 +..._-__....,e,,, f< O ugc g - y j w ,=" QL <f cg ,. ~ 7 ' 9 :, ~',- S,i* 9 <:: W 3 5 =. a. ;, ' a3 + q M cO 'Ci, W E h 2 ,.=y " y*. /..; / 4 L o y m 3-r,* [. :t i Z C C q,' L ' L- [ y., y, a =. /S. [ lr.1 u u g g r J, d.o g- = ^ ~. p ,4 .4 3 I i-ey +. gg,4&hQ r y e <r o m ,*.j. C. %s4/g' $@y g, N U O i [ ,.i t ' h.. f; " ?,y U2 U3 c:2
.o
- O.- A _ g ;,Q ij" gg '* * * - N, ",,. m s a -3 .q ;;kr ' k -ye , b e K,afg("w4mt..'" <=, "r - h, 4 u; -.m s 1t.w. Ax f -4o,k"."'.eJ., , " A Qr mb. .~, M ',N p .,4 ,3, 3 w 4..- 1'( p" L e - ?.e g. f,y g p, tr. 9.: riig.y ~ , r. w f 4 ,a
~~~~s.,~~~~
~~~~+, 9,, -. ,[~~~~
-)
~~~~ypf( - f,' f 4 g g ,4 j gP-e ggy c*,,. S ,J . p,. - 4 -4 N E" kl ,y a + 'g 9 a.a.. a 4 . ~..._.y. m '_,,.s, ' 5,, e j M b g g U"h h...~~~~
~~~~".g N~~~~
t'%.A. ;; ^,.,
B-1 APPENDIX B MACROGRAPHS OF METALL0 GRAPHIC SECTIONS
3-2 'A, {',. . A'$ . ' vk, w . %. f %.
~~~~e. v.,}T n.e~~~~
~~~~,Pg,- ~l W t ' ' t-N 'n' -t. u ;. u v ~ .r i i W W % ; g &g y & yan i %nk 5,,; s~~~~
~~~~s. wwgg~~~~
= 2 v.s. w x e& %, e e : n i k. w - = e 3 . wy %w pc?> e.u. oh > t,[ m# e - 3 1 w .m, WT A 't M+g,wt,W 8 d,he ?..]s 2 g g y5 Mg ~' -t 7 y%. p4 wy as y v a,. 7 e ' U7 5N?' g f g t f,A)"? c w. .y m? f. ,. u' y 'i a., p+..y;ff, Q 1 '+ , y,m~.e.;v.&pp.y gM j-3 i . g:,.r a,e w gwe 4 g
~~~~s. " -~~~~
~~~~n ., b,,Q~ ? ycv.,.:.. . ~., ,,,,.. m $ P vs .w.. wn ~ c /. J!a ' Gts.v. ! fl. 7~~~~
~~~~! ',;';%G.e -Q,.~~~~
~~~~- - - -.A 7 ~ m l k Z L +., 3 - ep - t + +j. ,c. n i; Z Z J r ,I h *,, v %'A l ;u ' f, c ,. e- .LJ s.w. - ss~~~~
f

-
~~~~s 9;? - yp p T ~:Q:.~ k Ie; ljj~~~~
~~~~h jp@~~~~
~~~~^; 1. 74' '3~~~~
~~~~9j zs..~~~~
~~~~w -- H s N[h. - -,, ' ' f a e a h 0#' A- ;;;f a.'., % '4 f~~~~
~~~~4' T~~~~
-B-g !l#:.+' m. '?l ~ E 'C. - ) E2 f *- kg, 6 9' RQ+ s; "-t a, -} E' s ~ ^ * ~ [' K ?[* Q f_- Q I' \\y s s e [ ~ + ^ ,, [ 4 E ld,,. ~ ~ ' -I f '~ e%.: Q 1 ~s',, -- "C I g,- '@ i m, e -~t' e,, e.. 3 2 y_ !* ' A .L5 'x
~~~~y%-, y; o - _~~~~
4 -5 S i a. ~' -' $ Ek w ~, l.sne1 . U,? s
B-3 p7s'gMM,,g IT ~e-T#@F@j4, %. " ' "-~ m:,wn g. h' ? J- '[h ;, ' d.t c. 3 A...*d. + I ; hhf" q - 1 Mj.
~~~~,'st %g v.ff. '~~~~
~~~~W ' ; *, 'W' _S U.i }.~~~~
~~~~! Y..:.. [c w %. .s f te a. c . n ; b '. Q L " -..K 3: y, J %..Y:y;c*9g..\\f1*'[l'3.,_......, a c (..4 . ~ -Q t. _ ;,'f <t. ..,. p)L -' }.. ; - - y --- v % w' f b.. 9 . m.~~~~
~~~~L._;.,, ( g t %, p y :g '.~~~~
~~~~,.g ,L ' ' g j ^* s :F :& g.;. .,.qJ ':j.')(.g, f;[ j.]Q j..y }s-[3 ~_.}]3 ,c p- .f . sg w. ..:y.f.~~~~
3.
e
~~~~- ' y~~~~
....,s ' - .,,. ; + y. ; :, ; :... ~y s. +. .n a:v... - .5c' }i r. m,-%.. .ga k 'I'4 McMfgh ; % a ,, - : g,.. .'+cL c 2-34465 (a) Section 7-7. Lapito's etch SX n-r a-s.. m m- ~ l :. t,; s.,g g, , y,. _ c. m a ~ %z,ig.f j' / - ' ' l; - g, ...,..; g 7.: ,y y 4 e Nys..;- g, .t .w -d
~~~~r f;,~~~~
~~~~. : 4:yr3 k ,.s - e. e. s 4. /s a : p %.. 's , pry: , g fr. . $ ~. '. (:Q %.y f.. ~ - g,p ? ; - .c3g$ j r~~~~
~~~~')<.~~~~
. h, t - : J-l, }..p( -- l.., ;. '~ .n. g z ? 8.*
~~~~i e., l~~~~
~~~~,y% gg h L,~~~~
~~~~t..~~~~
~~~~M w.;y,,$.ga f. w. .~i.- . a - $-> .q..J , ;;x r n "q p I j'yh i Y n_ '.' '[ 7~~~~
+p y....

g' K
~~~~O- : v~~~~
~~~~f ; +~~~~
' l; f~' l*? Y '' '. L ~ % g:.} r n . yr. y' _..s? ,J w. -1 + a m '; w.- [ D -Q ?'Y?' - ~ g e. '.p.;, D 7 '. i..,Q. '*s T4 j. y _;q s,.e, ... ; e s g... -. q% r..e_, u. y '; y _a .u-:, . [Q lW,' ' D 2 ,'* 44 *' - i.2 enmW. ,a VQW,%'* g fW gt .A. w. e, i,- , y q. 7,; ; ,'.& ' &r..
~~~~.c c,~~~~
G. '?. .(4 +# 'N q:*: _l + m - :. c r' 2-34871 (b) Section 10-10. Etchant: 2-34330 (c) section 11-11. E chant: 8:1 Phosphoric acid. 7X 3:1 Phosphoric acid. 7X FIGL*RE B-2. LONGITL*DINAL SECTIONS AT THEDLAL SLEE'lE ATTACHMENT. See Figure 1 ' for locations.
C-1 APPENDIX C Microhardness Data
10 5 / '] yg N N 5 S' N I N2 " T T ' ~ k~ 4 f 2 9 )f x &- m FIGURE C-1. DIAGRAM OF REPRESENTATIVE SECTION THROUGH THERML SLEEVE ATTACHMENT AREA. Numbered circles indicate metallographic locations. Dashed lines indicate hardness traverses. s,
4 ?w v 4 0 5 0 5 r B0 B9 B9 B8 R 1 R R R I' t a ,i It M" i '~h 1 E. l la_. 4,- .i l3 d n ~ / r '~ -N
~~~~"'t e~~~~
~~~~'s. .! /Ft :t ) {! f 1'~~~~
~~~~4 t-[,.~~~~
~~~~- i l e 1 Iiij.i: it / ~ f a L=~~~~
~~~~tt[..-~~~~
jI
~~~~n. '~~~~
~~~~s j.t. [ i 't 1i ,. r4-d;. . j. 1 '{ t. ii ' r. v\\ o ..-.m..:_-. 'AO[:_ - a ": y,,,. - t ~, \\ .9,} ' 11r f'<: l . ~. ' ~~~~~
~~~~-l h~~~~

~~~~.r / d d.n. l 1, U '" - a ..a. i.. c w L mm i.. .i L ii. .n, itg4 mt { .. ; + e ..4.I. " l. - E - g} l2 e [.i 'b. v n-~~~~
~~~~i..~~~~
~~~~P'. A l e L.~~~~
h0

M s
~~~~f l~~~~
~
~~~~'t .+y g. f r ^ s. a i = i l U ~~ a !'t.' r .c: t ;.. "c. ,~~~~~
~~~~C.. ' "..~~~~
~~~~.2. l.f i ~ f. hf. e m j t {; -. a.- .i- .n .q. l h l i. .: s *: a. (g I. T l. .i~~~~
~~~~d..'m.~~~~
~~~~[ = ,g n.. '. m p: E g.- 5 4mI {3 f.l~~~~
~~~~i r~~~~
~~~~m 5~~~~
i
~~~~.g1.. : ~ i.f. :l, n . k .y .g. .Vi -.m-: i t. d~~~~
.~
~~~~l' p,. I [' l;. ga.. *. '13' o .a. 1 e i c l ... m c t~~~~
f..

C
~~~~.=: H.- l 1' [r! j4 q t S t -[. n c. 3 !..n. t a eh i 1 s a . ;h"r. .a i p . r r-l h D~~~~
~~~~d.. -~~~~
~~~~. - 4.e; } 3'~~~~
~~~~J.:~~~~
~~~~. +: c d. 1 k i l. j.r~~~~
~
or
~~~~2. -~~~~
i.. Nc ..+m.+ I 1 l. ,p ! i: t j l Uf,.. E s 2 . ~ a. j I j.. S s J R o = ti...ti l i{. . }p1l f. !.t.;t t-E r V c j[ i. -.~ 1..- 1j ' [ :. {tr' .i 0 A a I h.a, bf 'l ~ .t4..e R Tl i . (( .j-m* ~ 1 4: t j* }' a .t- _, dm t. i.
~~~~i. : -~~~~
~~~~S t S e . rr-9[A _- l. f...{- l, }. [. E m .i p N .r T i;g R s [ I~~~~
t:
~~~~i f. f t }' D e .= A a .= 'I .t I b tL' I ~ l;;~~~~
i:
~~~~l1!l' '..a a I (!}i p'.~~~~
~~~~i. 3~~~~
~~~~. ~ !,I i i i.;* .2 q 1, 2 r.- h j}' p r= : .o. - g 1.;; i i .t, L_ !L. 7 t 4. t +{+" f.1*! C E f], c.- [,. E ti, L_; I .l' l, ,i I1 R _ m.. f. - _ t i4 >.tg Itt-G U~~~~
~~~~4 ti J.~~~~
I r3 F - l l'- k-1! -l t *f 0 0 0 0 0 0 0 0 0 8 6 4 2 0 8 6 3 2 2 2 2 2 1 1 S0 ,h,? :c:r:,8s
= '. ? c-0 5 0 5 B0 B9 B9 B8 R 1 R R ~ ~ l. j-1tI
~~~~1 i1~~~~
~~~~.t' l l4 7 u d I 3 n 1 e ~ 1 ~ 1tt +l l 4! l~~~~
i
~~~~!u j j ~ :. _. ' 4 ij 1 l ~. e f a J' j_ 1 + s .~ .~~~~~
~~~~i..;~~~~
~~~~jI ~. * +1 l i . n_ . ' ~ ~ t p A.. I l i o i t i ,!l H :r ~ ~- d ..h.. i Aj i ' j) t { J. f 1.. !.l:. I' ' t_ l I: l ..~ " 13.. ~ i!)'. fj ~ + I."- e~~~~
~
~~~~w _~ i,ip.'~~~~
~~~~- 1 j~~~~
~~~~u. e iaI n' 1q {+ v [ /_ .a.- E_ " 4 e I2 e 5 1~~~~
~~~~s l~~~~
~~~~~ s I ~ %{.. fI {~.i+ ..-tt C r.. i.- .,7 ~ a. g 9 iI1 l j.- ~ .= +~~~~
~~~~i.. -~~~~
~~~~la .H . ~ .~ J/< .u n.; m~~~~
2
~~~~~~- ~ ' 2 .1 f;~~~~
~~~~${j r~~~~
~~~~. 'z. i ~ ~ + f. ~ l "{.. A- .t e . a. ~~~~~
.^
~~~~1 h ~ i T \\.. 2 } : n. ~ ~ .+ ~ t. i;. 1 T.i.~~~~
g4
~~~~.E .~ .- A 3{ 5 1 ~ 1 E m 5 .u .t ,2 @' g n m~~~~
~~~~g. --~~~~
~~~~Fu$' i.,;. 4. T ,i q'~~~~
~~~~.a n~~~~
~~~~.,7 ! 2f }t j .^ t L: 1.1 4; o .!i. 1, 1[u ~ m u i / .s. .o l1 e t j [ i t. . {'t t ~ ~ !lI 1- /i~~~~
~~~~, i.n.~~~~
~~~~1 { . $u1 Ei c c . 6 ,n 1: n e a S i ir ~ N t s i .e i i i {.igl {,j . :+.' j i } . y D 2 c~~~~
~~~~4. g;:. t'I i. a' t. }~~~~
~~~~F!k t.,]. i..a a. ~ i . g. .i.. c r .v u Oe n 3't !. t. !. L:_ ;: g! u. i. I] ] j Nr 9l. . I c l..' iqr~~~~
~~~~t_ q E~~~~
~~~~1 J. C; .u. A S g Rn ~\\'a !=~ E o ~ 14_.; .] ~ .jY r Vl~~~~
'i
~~~~,i i' !a .t !'I. 43 t ~ { 5: Aa ~~ i 0 R I N, ~ Tl~~~~
~~~~i. ~~~~~
~~~~j ,tg~~~~
i

,t, j1
~~~~/. - i i a_. ' .t ipp St~~~~
~~~~t A 7i a~~~~
~~~~~ Ig S e } l 4: l Em ~~ N .a. ~ j,..' l1} 4 y De ~ t { ). i._ i i,a. :- i 3: !ji 4,. ;. - i 4, ;- !i. ~A s' Rs b IAa 8 b 2; l.1 I . g t }g.~~~~
~~~~,a.~~~~
~~~~.I ia_1~~~~
u..' '.t.:

t_ j j;
~~~~k. i ~.. ~ 3 f A { ,j~~~~
+
.uI .,2 - i: 7-7;' L.. C j 3-n - E il jl !i l1 R 2-T U ii ft, t1 ,. _t t ig G '_^ I _~ ~ F - ~ f9 t! 0 0 0 0 0 0 0 0 0 8 6 4 2 0 8 6 3 2 2 2 2 2 1 1 u 2,Eax m $ c 2 3.- co Cx
oIw 0 0 5 B0 B B9 38 R R - R_ R _1 .^ ~ .~
~~~~i. d-~~~~
~~~~~ = .-.:u...,. .a iLl-f Ft .u I L @y ... f'aT {- ij9 [ ,' { '~~~~
~~~~4. I 1l'~~~~
~~~~+' H, r-; ~ * - E_ = l l 3 a ~ T m ~ }-t t.. l3, ' p,' ,i,']'~~~~
i
~~~~~ .2~ 7 r 11_ ! f. e iR d' h e j i t ~ aD {, .{ j7, _T!T l [. o h.t' j l.~~~~
~~~~i. i itl lw ^"~~~~
~~~~j i t l i l d il ~ u,. i: a ~ t' i l f4 l 4 ^~~~~
~~~~... [~~~~
~~~~{44 [ .t' 1 ~ l e 4 J i w h i g' p E e l d;- .... @b .. Ei i j n' ^ ] .A~~~~
~~~~4. ::~~~~
~~~~E i j3 [ jtp 1 .t 5.-. - v 1" .p. f-i. e r i e e i l2 l i. E s 5h:t ~ E yw - o l d' .} e j ' 3.t,, A- +. ~ ijg" - E a u .c m E r I Bi -.M. N I h ~ ~ b e L2 {- f 4 .^ .j j I ta I !:B-i~~~~
~~~~o. 'A, N~~~~
~~~~T u - H \\ ~ .-: E M l j 1, E b. E .g(,, ~ 5 i g + i it i o .1 . Y 1t,, f. a. "' , /a - .h.M E l m i i f l+ M. M 5 JT N m n r-ii E.N r , rw_ L i E .2. 2 {~~~~
~~~~e@"~~~~
~~~~. b o g h.4f19 l 7} \\':.u{-, l .;2i2 l i f .o j i t i j ^ a~~~~
~~~~4 n~~~~
~~~~l.d n !a. ' m.' 1 e c t 4 g 2 .K :ai l~~~~
~~~~M:d~~~~
~~~~' W.' a ..n N c e 3.:, ~ .i N i a - ~ '. m. "E f k: ! t2t{ n S P .!'T p-1. T l t 7: s i s UE - ~ 4 3 ng "p KH ii ~ 4 i ~ . n ( M::"-.$ r.. D !i. 1 l i 1 .t.: ? h .,t + = o 1 4;g. ' N~~~~
~~~~i...~~~~
~~~~bU ..'.t {'p.-4 iE li= O . - 4 ~ .r _i,.." ii ~ j 3-E El i lt* Fi ~ k .f F l $. ~ .d '{. !.e _ q i c i. 3 S a u. i Rt c\\ . w~~~~
~~~~n E e~~~~
~~~~+O [ 1 .l 41 i/ ~ T . }U } i i l~~~~
M{

{
l AVm 7 i 1 / y !T1: f / 'A M. R e 31 l 0 Ts ~ a C;... }- [* -. I't ~ . "b,'h"{ L I*
~~~~1 l~~~~
~~~~i r 1,; [ S Sb } l i1 i .I,,t i ~ - N v l E e Re D e t[d 1 E' I'. -. g4q i Hs iJ ;. 1 t;: Al [ k.7d. {. gi. i i. ' x : I i~~~~
~~~~.n_ '~~~~
~~~~[h.'- t .{ a ,1 [. i !i f,..!; Ft.I t I' i. IJ-1 j I .I e l s 4 .u" ^ r C . 4"; p E2 1 4f b. j = .n : N-3:~~~~
~~~~h. {.:.:.: f N.1 l,.:~~~~
~~~~E 1 4-~~~~
~~~~i. i; n:~~~~
~~~~..t I: i p j< i i l' i" u R q ~ 1 U . ~ i.~~~~
~~~~7:.,. T M;'4. d ~~~~~
I. Il,,. > ji d G i Ij J.- I ^ i F b. ~ f m l: Ji t 0 0 0 0 0 0 0 0 0 2 0 8 6 4 2 0 8 6 3 3 2 2 2 2 1 1 ygogS ow gus* p, ocg t
1 .r :J...... ~~~ 'h, j J .p 32n-ik -2I-- ~ -N: {
I
~~~~-N ~ I U-2- i-h, .t .g.. r-- 3 i~~~~
.g

f;:
~~~~i$,- l i I y~~~~
p:
~~~~} l l ..I.. 4:. ._.4._. ug. _. [-. .j- -j~~~~
L.
~~~~t J i. i I t-c.w: {- - l ..L: ] 300 __... _ . i. Rpdir Weh~~~~
~~~~i. ::-~~~~
~~~~... p g a q:. ; u.. -- g -. 3 - j-- m .m 1~~~~
j.
~~~~..j:; a: ~.. ""f-i ^~ ~ ~ ~. ' " i' ~ "~ ~{"~ l" ~ ~"[- ~f~ T['!~ "~ ^ ~~ ~~ ~ ~~ ~ B - " ' ~ ~ ~ ti 100 l. ;;: . q 2 8 0 ~--*.-: ~--E 5A i i .l l 4'- "Themdl4Lucv fi~~~~
i:
~~~~.. i:. -1 SiA~~~~
~~~~a:_~~~~
~~~~7 .t - .t--~~~~
~~~~h.:~~~~
~~~~w1.t ..: b:. . l.d.. g._ i.;. ..i: ..p: .;p l l I l 8 1 4 j l l' ..,'i~~~~
[
~~~~[ -- }~ . ~ ! } ~l% i:m 5- -T > tr-4su~ , 30_ ._ # wia F um I -. f- . i, 1 o... t- -;F T: ]- a n.-- +a : i-- - L1 _.j. a. y 7 i-t y y i~~~~
'h
~~~~~ ~~ ~ ~ ~~i~ M ~ ~~ ~h f T h"i'~~~~
~~~~J::l M~~~~
~~~~-7 [ Nf~~~~
~~
~~~~~ ' ' ~ ^*- ~ -~ -- ? +. - - -- ---} - - - - ~ 5 1 F4 j " g-- A h; ""y @ 240 .,j, [ ii-h. J-~~~~
~~~~4"-+ih~~~~
~~~~-.. r-- g.\\ .[: ' ~,-i - ' ~ ~ ~~ ^;{. t ~ ~-~~~~
~~~~i '~~~~
~~~~~{- ? _....._ b .j-3 l - ) ..r - I t ... -'[.. a: E-pra g h-- 5 -b 4 'h- ~~ ~- "r~ ~" ~ ' ~ -~ a R i j B .!; A g. 1 g 220 - -r 'I-- p- ,r - 1 l 90 L mt-- .s .J - . a.-...m - p a-~~~~
~~~~- 99~~~~
~~~~-j - 2 -t.a - r i .j. r ci. .-7,.. AW-t~~~~
}'

g-
~~~~.y i i f. Z.1 ;_ .{ _]- p j": -" ~ e" J.tu i .+- .p ~~ -h; - .y ]. 1 --+ 200 i 1 i '"i~7 --'th- " T-- m % er n smi 1 / R .l-l gj~~~~
q

-6 B
~~~~.~ aai u-F----- -{- ~ ~~ ~" h ~ ~- ,-~ .hi 2 ---.J - --f-O- A -f ! -h !!= a FF F =- - }- m s gp .l.. j. "r-~ } i.O ..l.. q. ..j .p uh.....,:; :-y-- j-- 94h ."tM I',' E h. + g .h,- _ l h.h.~~~~
~~~~j ; -+}- yli-~~~~
~~~~-j ' - r;" y ~h'-~~~~
[~
~~~~a --.1-u .p F .-i.~~~~
~~~~1..~~~~
t. ~ . g.:p: 3 l f Q g l l l 'l l l i 2 3 4 5 6 1 0 4 Distance - mm FIGURE C-5. HARDNESS TRAVERSE NO. 4. Section 5-5. Repair weld to thermal sleeve weld. E
n" 0 0 5 B0 B9 B8 1 R R ~ i. 7 5 a1, 1 li. l 5 4 ~ tth2 -t I ,J l r 1, Tl ,ii t 9i i u , ~ T 8
~~~~f T~~~~
7 i! i ~-. i ~ ~ ~ ~ ~ [ ~ t N ~ T ~ a t ~ t fi l j . i 7 a ~ f- ~ l4 t 3'i i ~7 +~ i! i. ~ 5 e ~ ~ m ~ l7t e s ~ ~ ' L- ~ a 2Y ~ b i { t e d ~ I n t':]s1 U ~ e f T' Tt j1 ~ 'I._ ~ ~ e ~ f a ~ 2 ~ s iIj! 3; 1j! ~ ~ ~ ~ ~ o l3 t ~ .N . ~ !I' 3i 1;+.h . ~ ~ d f, N l . ~ e 1 . ~ w i yt a.I }* i r j l p a -I h l3 j e i'- +3 ft1i. R [ s ~ E . m j ~~ m- ~ m5 8k .i . ~ hc ,a 5 -7 t eo C m j2-n !iT-- h;- ^ a, nt 1 ci ac ,1 ' / t e i i l
[;
~~~~fi - f I i sS Y ~ 1 ~ I D jj ,2p: ~ i:_ 5 lj O ,f3 N [ 1j L1 N k.l-t1 g ! {"* ~ j, E I J- ~ l1 R T 2 + S ^ ~ E j I i ,j. 'bJ [' l I1;.Y ~ V ~ ~ l. A 'b k4 T ~ R ~ 4) - ~ S ~ f ~ Il - I; ,1_ i~~~~
~~~~h. i~~~~
~~~~!;3_ I S l f. l E . ~ N ~ ~ ~ i [ j'f.; t+ ! I' DR A H ~ ^ !f i I' i l~~~~
~~~~!a i.~~~~
~~~~~ ~ 6 -.t' - j ~ _k_. ): M.. 0 ~ C [ }.f !!iii E~~~~
~~~~t U}~~~~
~~~~~ R 9[t } f U G f.; ~ i~~~~
1*
~~~~F I 1i :f ~ 8 . ~ r i i { ,3 f^ h. . 7 {1 a d p-i ~~ e d. ~ Y y; i{ .1~~~~
~~~~r2 i!'~~~~
~~~~k j R ~- 1 -Ill I l1 I.~~~~
~~~~+ - '~~~~
f 'g Jij ~ Al-i; 0 0 0 0 0 0 0 0 2 0 8 6 4 2 8 6 3 3 2 2 2 2 1 1 j mhm @8x
D-1 APPENDIX D Micrographs from Sections through Thermal Sleeve Attachment Area
4 A e' a 9 ,Y L a e r y 'A f \\ ,,;[' ([\\, 9 ~ 4 k
l~
r J yp /'* 3 7 ,/ i % ',g \\ e-qO' 9's-956, 4# se 9 ch4$$?;,55$t - .b 4t* \\ \\ 4 %.s go+f# 1 ~ rI N .I r f; C2,Qi pe' ,f .3 ' A =* 4 f', ,,. 5 v m
M D-3 myym w.- w [{ < -. o.- s f r y pk,Y ~' 4^ 4 J/' A-, *\\._ 7, 3 ', s."",., s 4 g .g ? !.^ 3 E'dr -; -yg V.. 1, {;f A ,..r 3 V.u;; - ' j r
~
~~~~,,4: -~~~~
~~~~e 4~~~~
.f6, h.l- __, v); - j[(R a'l '\\- . c.. .4.m h,[.l "a' -L_gN ~~ k:. :sm:,,.s fq-;- y'e -.- ,a ; x 1-j e,. 4 = a e ps_ n; :7 g k . chf % b~ q '! [:. h ~ld:k.. 'f ' / m 3: %N 2 =J W $,%.lt$.4 S ::$ %. .~ ~ s ' f:' - jx ~ U a
~~~~La a :~~~~
~~~~.. f.,. s,, c$. M g~~~~
~~~~w w,~~~~
~~~~n - y-> w ..~ g'4[ V~' y_~~~~
~~~~-{f;s O j~~~~
~~~~a; jj.. e - p% ~ y f.. [,f 4 N f~~~~
~~~~/. <~~~~
~~~~$w:.'~T& >s, _ ' h,' k,.. J. s, = . y L_$f. [^k Y,YS k.~~~~
~~~~f.-,,~~~~
~~~~f ~ N U~ r1 , s,. e.,f. c, s. A,,,, ti.,-_. ,, ~ ' ,-. !a s '; J. y < h =s J., hN%;) 3ArW'. y, eh > <...' ? .'l Db u:,*:d. ' b m ~; Q Ykb; w t %N O D = H 01 U " U J = L. -e % 0 L.~~~~
~~~~A C~~~~
~~~~'J2 ~.: OA L O U U C EZL I e N l2 i.. x X 3 U x O 2. r IL' a (g., = V s i i 1 t I, A~~~~
~~~~e Y &,, h o~~~~
%s q s k 6' h P .s e N. I b':>< N .t- _..?- + q 2'4 Ai . Jer . M J.d'
D-4 % :u gr. m. O,5.-3f q ;_9,m ~; w :,;4 ?n~*rynT 7nwv wp's . ~)Ej:,d?f2W y y <l
~~~~NkDya Q~~~~
~~~~w hb;$$g.J.4;f(.%"%K.6hhs'.n.,,$,c..f, &.&._gg!,f 31 n M:$f't5y$- ~1d.s$h.Ns ? c T$new--M Q f M M<> M~~~~
~~~~E{'M ?f, : c,.m m.. - :l,. J.4 v.o c, R 4 g,r t~~~~
~~~~g4.- w jo - ;,. y y: Q^"f.g$' - w n h i.~~~~
~~~~&.". %;gs)~~~~
~~~~-?' f ? .r %mes* W< w I n % w "p >vi % y a s y, =,t%,bc u ws4..- g,2w A. *k +a. gg : m mo y,, t..: s.v. %n g.e# w g e %. : n.n-. + ..p.dgsc3;p s. w ; ,., ; e ya~~~~
~~~~g..Jv u,gu; net s t~~~~
~~~~-,e.aru s o-R$p..~~~~
~~~~N O Q% ^'*ft fd:A.~~~~
Wk
~'
~~~~re 8,s.O 'y& k?NYU Y'%w.n v..:.; &e m. -.., X m,t:na rn - ,v y4 w , ~ c,' xl +.. 7 s w f. M s. h ;;<,<*)- ^ ty Qg. a j.c r f ryg ;~~~~
~~~~e. r~~~~
,~ ,p-w ..y g,p ;qn ,'_.y.6 a v >, Q't y A, ~ wf m Qu.s'. :!::ny R'Mg:as Q J - e. .\\.g. ,. _ @ 1),y>:N,.pnt ydA q .'..c..'1<v g i e5-e 9 %w' / '(~-{.'._., , [ff,5 kh.z f 1 . ~: ;:Q9y 'I x*u > ym.;.;a;%y_ .+. .i, g 9 -A
~~~~s%.,~.s~ y,~~~~~
'a-- r ~).- J>-g] s - ~ ,r y %. 4 g( h, K..a., g'f yg \\Q' ' = y .. q .,3 - ^., p\\ tq) . o. L, :M. ,pQl'j n. l c y I 1 q; _ v.a N /s V,-,. ' s' fj ). ',t (, 3^._ 7,rv/. mg%{ Y , - S$ y,. , $ _f ,j ) %. _,7 r - w ; d i. o. r;v L. / s< .3 s. a' NA
p.
~~~~'\\.,.A .i / v. + v. ll4 5 j .y i- ,;. sng. - > . m, / - %y/f ' " ~ " ' r i./~~~~
?
~~~~L/ t p Ac / ~ Z;;r~~~~
~~~~l. A.'~~~~
~~~~y' / s.- r s .8 - :. - ', y, ~ '[ y ,, 3 :~ - . / b, ~, .s - 3 \\- hJ' q u GMf w. M, * ~ 'n ,/ 8 3W~~~~
E.
~~~~.y [ w g'^ g 4 .u m n .,~ h;m;~;~4 g ~' '==,'~~~~
~~~~~n-x~~~~
y
+. ^- ..;, yysp y. ir 9 r ( ev . < up %M' v \\ m.g h.% . v N;;.% s , \\ A., a', s,o 4 FIGURE D-3. SECTION THROUGH THER>iAL SLEEVE ATTACIDIENT AREA. Section 9-9, Figure 1-4. Etchant: 8:1 Phosphoric acid. 75X
D-5 a y m 3. m x. m p.=g s yg-<, m g 3 59gqz g c;9 >gmm:-p., mggg~y:3 9:s'Ky v7{ < v v. 1.,,. .0 . s v.e. ~, ; < ~ e r -., ,.. s x v, ::a .5$$.; $$..' m$i}:W:,. '.:;$5$$l. 'OWY.l a y ;{Yk, & b$0$s??u{NN $y* h 4l'*l:Y 5 m;nt.,,S. p. - - m:w .& % e %f.%. n se m.
~~~~o w < y e~~~~
~~~~\\.%. w. aw~;. m-a.y g,,h.,s ; ' i-h.. uy~~~~
~~~~y.,~~~~
~~~~. f: ~ >f 3:. t1 .g.. Q J)Li. v.-'s a ;?;If R,. i ?m' Q, .f]'~ hQ ' ~3 + Y'-l'):.l.:.*\\^Ql' f.% -. 'i Q:f. b t M t & A # w;n~~~~
~~~~W.Q&: 3 o: rc.~~~~
Oi I M. >^ & :Y. A %,&,. w.W,.,m- @<;ca.y. h.e&m &L W ;.,< /+- ,s. a.- .c 3~ 9,1 M. %.e;c.s.y,._s.sg,9y.p ur.. m, .a ; . h.. ~ .. gh ~ 1-j e. a y N' m y,..*. D i w]W,d it.',.h;dh.- .--4,p A.- -.3 't 7/. '- w::.,bd-- w m.; #>& ,~.
' %

r zI^
r?'1 ' s y i ~& h9...u4,, s + . r x y ym;tw. kmcuwg. @5=% %'r, 7' ..<I L s I g f ^* e br/. ~~J i +- Q '. / ~ \\ b%,,.. ...h., x x. \\ ( v. \\ / N,' W#,VM ;SW 4.A..W./ s ' Ju% ,Y'Y b .N. - rjg rq y _ N:*'.. k:h(hi@# /[.
~~~~f..~~~~
~~~~q D [ ~.., M x < / %.:/ r.s,y :e, ;- .a s. y , ~ -., A(n .s .,,y , - -. ~~~~~
~~~~3.. s.ym.,~~~~
1 x ,4 ~ -. w ,,.8 w. - r, a:. c:..Mw;-., K~%) f - . ~, L < <. M ,W- - w. .c. p Ci - - ~ ' pd,f g.<l:'" A)J f't. a AR: WT*i ... ~ Q 3, p l$.& s'w %~' M ~ WSP,'iifgg,pWTbr"bl 1 gd&Qh /,-$f;', $gi &Whl-f$h;d$k6p 1 t 'Jn W:% = N. ' yx[3. ~j ' y '(: [ f [dy' [f j,/ h h f, w.d_,. k };Q8$m$$$n%.sy::sg,g-gg[y' Q (> p %k' c -M y w&{g '".' qN ~y Q.. :-z.yq'Q%m e%.> y* x M[I' , ' *f%;:.y S,g g h,s her-c'1 ) f' . +. 4 . ys +.- o _ ~.r-w p. A g,L ~ m.
~~~~4.,,4 K'M: u..e,3 =,,.. -v. w A, d'Qq,w?lEM.~~~~
~~..w. w. q'; s ' s .m. a. -- w-y,,w w- - s s M,1,.] - fg.-- _'- hw#C s, t G v N. #. w# >Qe,;9c,;f.y . 3 c se % q%,. 93. b : Q Qg.,'~,g.y.Ms.;.~,yN,a 4.,; g. w ~_ ;,, c y mMQN '- - y,;2 ..q c s s~~
~~~~h. 3l J--ig,f~~~~
~~~~.g m 'igp Q g.1. ' 3 ;',~, TA.g.g.yp,x... y(4,$. g1; Mg 4,; N. d m~~~~
~~~~c. g Aw% 4.a,. g.1 s g;.~~~~
~~~~y. 3.. - - a ; 4,s..e..... s s .yso .W w :p 3 u,,x. .fm%>, + q,T'\\. A s g~~~~
~~~~g r~~~~
~~~~c E' i~~~~
~~~~'$ g%.WS~~~~
~~~~-dA.:bn ;,m eK y ,s (, 2-34872,-873 2-343S9,-890~~~~
~~~~5. C., s.~~~~
~~~~... t, L.,.......r.,, L. x-1 a.. aC..y,n.. .:2 un.:u c~~~~
. Ov ar c s.uo

c....
AF.E.A. Section 12-10, Fipre 1 I: chant 3:1 P'.ospheric acid. 100 X
D-6 p.- , -d_ < ~wmx-m y,,,
rm wc~,,n-ww

n., -
~~~~r W.,,' y~~~~
~~~~n,m~~~~
~~~~-m u.r ' d,3 W ..,i.. zi ' * ~ ' Jk.A ~~~~~
~~~~y.,,~~~~
~~~~.u . y l ~a ;, e. n . ~* 's ^~3 y pi 3.._ -(k ',_ m~~~~
L
~~~~., Q, ,.s j S . ' ~.. w. ~x -v. ~ n ' 'J A'.N 'M vf. ,s.__. n y ..m u v. ~.. .A ~. p .;c u s,. .7 .j ..c. n r, ._y._ g 3.h 3 2 ' n. i + 3~~~~
~~~~'p%~~~~~
~~~~c + ip.g. ): ,2 gn. ,.c s M U, P. T.. t ' < M: .t i N7)P.5 X..l w;.u - s e M ~~~~~
~~~~<m nu ^~~~~
~~~~W. ?hf.d.,x' ? ? ^ pA _,.k, h,ny :G. :M. eh. l$ < __ ~J W h.M,T. a w -~~~~
~~~~ma.~~~~
~~~~g c 4 .mqfk c .a. -...>~) v .s n,,a.<, m s /:m x~DMlW S Y ~ 'i n 1 O. ' W.. - ~,. c M~ (; l' p w,m.., y,p" v? '\\ , h! .a p f} 7 .. e,i {lll'h~~~~
~~~~Sh' s hc'^ >'$.,h(WW x u< yr. R.,q$" :.L W ;.,. -. Y' s~~~~
~~~~^* ' - ) 4f y' v k.' M , +. ~ k,k. -v-~-~ . r ph y ' r%:... - epi.wh, s ~. ~n a.o.,e - v n~~~~
~~~~3. s,~~~~
~~~~~, g,g/, ~ ~ g V'~~~~
~~~~.j^,,p.s 4~~~~
s.
y,
~~~~r.\\,' p, ,9.. o . w As'y4y,.n.,,.*.',c4 % ' -',~N ,m: ,.a w. ffn r m W l % w m u w m M:"$ +l?OQhi-QN;fi .Wy A .y ' A 2MlbpR.. f _~~~~
~~~~. 7 m;ab e-l (m,p; d [ f ~~- r W~~~~
~~~~~ 9 .&we d' A~~~~
~~~~,, x.r.. a~~~~
~~.,. a isw,_q e x N 7 ;t:. W M k sN .G.. W,,aWydn,".s o.f mm. ,~ : y . ~. -, *. ~. r .a n y, u. ~q1m,... n- + ~-f ~ /_ Tf.Y .} ?.{l + 4 .,,,y-es r .m y r. y v .s,, w /e_ g -a if J.n$ eM.v s r n.. ,v~~
' e.g 7 @ R.-

.. 41
~~~~, f,. e. ,- p; g 6 y M, gpF'%y+.4 s. p.cm y . w ~--~~~~
r3
_. c4 5 m m.g' , d.Q. '%p.Q ..,y..'. 's (w,. ~ -( &v.i Q .i A 3n . f- .y i Q.. xn. m mk:Y;.%.;,m m';< vm wm zD*.s. 2. A b> ;y,1X' A ".y.~ N., 4 C. <-n p %e.k v'19 '..<33... g' * .4 .. g ;,p 4 = r- . ' L.3 . 4 e g.3
~~~~i.;.v v$ u, 'c X w~~~~
~~~~-? %%g.;" ?' d $ '? r #., s 4 o ..t ,f JTy~~~~
~~~~it - '~~~~
~~~~e d < y %w$.r%v.r,QNJ.?)iU' %M"W7... M e %u a TQ - / h w art. < s j, s + e,p(.-~~~~
~~~~(.>e~~~~
~~~~,g. Wa n;@.4Sk: 3,0 -L,,. -v'e f.. g %e p,a., 3.. d e. y y, : n , a/ b <J, .- d;,w: , m Gy, gg.~ y w. w A. r-x,... r-m y why.y.3~~~~
~~~~x. m/.~~~~
~~~~-i o y 4~~~~
~~~~:',' 'g g 3,,m y g h r~~~~
~~~~Q,g;f %a '&.. u.y b:-7 @y +,;ygf!. 3r s...~~~~
~~~~-*p ay~~~~
~~~~.u% g 4.u, p v.iW E MJ M ;l4 ' '" M " c.4 AD [7,* %.M ~~ .t-v- \\ kd,~~~~
7.D f

Q2NJNeQGMg q Q,,w &. L+9
&;,9 +14 j % s,,- n w ow.,. M. . ac%;> ~ma NM '4ri@hf1 Masdr4 CuN " 'MJ' E DI4'is"% Ap FIGURE D-5. SECTION THROUGH THERMAL SLEEVE ATTACHMENT AREA. Section 11-11, Figure 1-4. See Figure 4-7. Etchant: 8:1 Phosphoric acid. 37.5X
E-1 APPENDIX E Selected SDI Fractographs
E-2 ---,3r, :: y r,.;<yg, y m u ,e A si s,
~~~~7).~~~~
~ LL ,y, /*/ s y'r g ,_ ' t. 9y, w m" = ie ,Je C 'O A. ~ g 4 Y: 5 Q 4 E ~ I i f lll sa i. M '~ I 4 58 I r fn c; ei 'g e ., i 2 $Y, 't .pi;ga:: 1 1g Cg j? ' '3 E.h i =r; ry -#4 ~ kf5 N-5 i E 3, 4 b
E-3 ?v 'b 2 'z 3 ?-',9 - %,.,*,. 7,' ,,, s )$ 4 6. s.' ~ ,*q 1 ? M h*.. e .o ..s. 2-247 100X i i = I '~ i., ,f ~' ; . f' l / ?; qPj %,f',,, I ' 1 ' -u] 2-210 1000X FIGURE E-2. SEM FFACT0 GRAPHS FROM CRACK SURFACE. Specimen No. 2, Location 2, Figure 4-9(b).
E-4 ~. (f?Ci,C*l, f,fy'.'%&* df&p.g'oSN.' 3 .g 'J- -Ahw . '* O ^ Q $\\ %' 6~4 -6 .c. - yp. s:n ~, 41{% ? K_ a; V. .:s ., A C2 J %q. k,' /Ls 'y y a _ ';- ; b - ~'.gA a s (Q% i-"' e 5' f 2-253 100X ~- w v,g g % s as.:- y -_ - .,q M, J'N)wFBR!rsiiD2dhp)'D- .,, - : -l?' ' [ DIG.:,Agap%y% na [t*TDadkhs-[ ~ (-ph A s.;. m --q
~~~~[ & @lh a & W~~~~
!A ~ ~ ~ f f. ,, "h. ' S ~ f l 2-254 300X FIGURE E-3. SEM FMCTOGRAPHS FROM CRACK SURFACE. Specimen No. 2, Location 3, Figure 4-9(b).
zV r. 9 %r

~~~~memwn m~~~~

~~~~m. m m.m. e e rWe4, ::. v.wf u.: ?Y'.': r! # Aj,y,,.4, 4 tN, .,y x 4.-. e, ozo W e?,'. a.,. ? %. -Q g j i $!/g2~~~~
~~~~esEQ 4r mis a~~~~
~~~~(Ag}};1ihigggg;s.-: r1 4 E TJ r =.4 ;c w,;.,c gyp g g,3 T'k['yk,'hj i ,Y I b S*a m,g.: 'n' @4,. vg wf9 'i.fg., 3,g y n.: o sw waf,a:g e p =, y.., t =03~~~~
s,
~~~~0.+ a<m i,3 ..c r-i' ed .9 i x Si a~~~~
~~~~y,i U,n?r>~~~~
7. ;.g,< c b.

a a a an1- ?d;k

M. m,-
~~~~0 ..M, $$ / sE f I O ll % m] % ". 8 m wyn g 4gy%$ ? 164"$g$e.%,c6% T i Wh89G~~~~
~~~~n ar m as m. h~~~~
~~~~,2 h q pus e c, s -o ~ y:*t %jli I hf[. , ~$$ fM!h,!g~9ih l kh kWyg _/ 1 f33 t. .N' a fa s i 1 2 s y. 1 v ) L 'i ( Y % l 3, g g \\. 3 ., l ? ~ ~~~~~
~~~~~.-~~~~
>~ / R ~ 7 o a .Ai ~ ~
E-6 f $j; ~ 3 .<y .e; ~l[ g ' llt{ ' %;' ;p >h ^ y?. ![b^ ' h,h
~~~~hf:.4a,.,~~~~
2
~~~~^ '%+;*h$. = e t < sis c. +gQ,.,:,1. < ~ v. J a, ,fh, hl~ $ '1 V h !hf 73 M.,. - -i j - ,j k 'h i n1%d.- .I 2-216 30/30GX '.QgM ,y. \\ T g 4., ~?g~~~~
~~~~. 7~~~~
~~~~...% g . s ? ' re k 4 n, t kh f):b~k $h5' k iT 4 ?..~~~~
~~~~f,I~~~~
~~~~l i ik b ? %,f 'e.s ~~~~~
Vw. g $.h l .;?,> b% 2-218 1000/5000X FIGURE E-5. SEM FRACT0 GRAPHS FROM CRACK SURFACE. Specimen No. 5, Location 3, Figure 4-9 (c).
F-1 APPENDIX F SURFACE DEPOSIT ANALYSIS DATA
F-2
~~~~SUMMARY~~~~
NOTES ON EDS DATA Crack Surface Location E 1. High Fe and small S peak in overall spectrum [F-2(a)]. 2. Particle at A is Cr rich [F-2(b)]. 3. Deposit cluster at B is Fe rich [F-2(c)]. 4. Fe decreased, S peak remains after ultrasonic cleaning [F-3(a)]. 5. Small crystalline particles remain after ultrasonic cleaning [F-3(b)]. Location F 1. X-ray spectra for original and cleaned condition same as for Location E. Location G 1. Fibrous deposit present [ F-4 (b) ]. 2. Sulfur present before cleaning [F-4(a)]. 3. Deposit removed by ultransonic cleaning [F-4(c)]. 4. No sulfur after ultrasonic cleaning [F-4(c)]. 5. Fe/Cr ratio unchanged by removal of deposit material [F-4(a) and F-4(c)]. Location H 1. Distinct S peak in overall x-ray spectrum [F-5(a)]. 2. Sulfur uniformly distributed [F-5(b)]. 3. Fe/Cr ratio comparable to base metal.
F-3 Location I 1. Major S indication in overall x-ray spectrum. Highest S/Cr ratio noted [F-6(a)]. 2. Sulfur uniformly distributed over intergranular facets [F-6(b), F-7(c)]. 3. Fibrous deposit [F-7(a)]. 4. oluster of fibrous deposit material shows high S [F-7(a)]. 5. Fe/Cr ratio comparable to base metal. Location J 1. Major S indication in overall spectrum [F-8(a)]. 2. Fibrous deposit on crack surface in repair weld as well as on crack surface in base metal [F-8(c)i. 3. Sulfur uniformly distributed on intergranular facets in base metal and repair weld areas [F-8(b)]. Crevice Surface Location A 1. Fe preFent in surfPce deposit [F-9(b)]. Location B 1. Fe/Cr >1, Fe/Ni > 1 in overall spectrum. Cr/Ni ratio higher than for base metal [F-10(a)]. 2. Fe/Cr >> 1, Fe/Ni >> 1 in cluster of deposit material, Cr/Ni : 1 [F-10(b)]. 3. Fe is predominant element in deposit material. Deposit material contains Cr. Location C r /Cr 21 in overall spectrum [F-ll(a)]. 1. e 2, Fe/Cr ard Fe/Ni >> 1 in area of heavier deposit { F-ll(b) ]. 3. Fe is predominant element in deposit material,
F-4 Location D 1. Fe/Cr : 1 in overall spectrum [F-12(a)]. 2. Major Cl peak in overall spectrum. Note only indication of C1 among all locations examined.
FRACTURE ,~ v y ( an' , k f4' $[' g%.\\
~~~~c. sf:s g s.~~~~
t) : .:;fn, Ly _. i + 'f 7,2,<*1'. i~'[ ...f-},,"'. .s. ,d Sp ..a e.. gy. ig,.O'.l- .rl * '-. pr ~ ~ &..M 'La. E' ' ..s -~; = l s.,- Y.h C REVIC E 3mm FIGURE F-1. CRACK SURFACE AND CREVICE SURFACE - SPECIMEN NO. 6. See Figure 1-4 for location.
F-6 -r< n/ ?.~ ~ w ; y. r.w rv -,, m- 'Mf? f 's-M*r; %w:- ('g-+' UB,cW.}ph 'N sf i, h, T* j k Q4 h h[o. P H ', il llH !HHl' ! IHldi > 0 5t pg ' 'ylg', 2fff?+ '9 M? T im m tonc;1ni ,T %+ *'k
~~~~pp,,~~~~
.pli il H[.. HHUd D' 4 i ;. 1 ,1.LL_ S N#d,{ b,+., '. h h Mi, b jd,, J. H "' h " !" h ~. yJ'{h[f[M[N,fs, 4b g +7 9I' 3 $ q,j-3 hl S 4 4 ""Ni U J " f..e@ %n:u; g?N $,. 34 % A ir M7 s' .1A _. UEd 6 .jd y L .., f HHn if(r 6 -D Yh fyJ lit {H HiHI i!- ('y. k S. M f; j f y;guj ;
~~~~$.jk~~~~
,U i l g; talub . ^:e - c y 3t s c p, ng (a) 120X l lllIliH'i-d'Higl,ij,$ HINT _E 1],I I,p H lHi4;:i '] I11til IHHIN ' l. _Huu.' -,I a,u 1_. lH H'""" jeu 1 _; i,.y :n o Hu^ E IH Ii i 1J,3: .I l. I JJ 3 i Hii. E i g I t, ' If I ' { g i llH!idiE [ g I th i l. l } [ ] ! jliUW U to i.in y g 1pw nL 4p % [Wmy),jjjly, l } l {10 t b j, j; f!ing n u sti ,e tu tau.1 C3E y L L_ Cr Fe Nt Ce Ye Ni (b) Point A in (a) (c) Point 3 in (a) FIGl'RE F-2. LOCATIO'i E.
F-7 - llh:l. ~ ~ y,.. -
~~~~w t, (*-~~~~
'{ R 'll K ) T [1,' l1 s< s c-ne at (a) Location E. Sane area as F-2(a). 120X ~ s$ ?d , - _,, A h Vf .52. S (b) Location F. 2000X FIGURE F-3. LOCATIO:;S E A!a F. After ultrasonic cleaning.
F-8 p ' l. -4.,,..g - ',. g f,.:2 '. _..... - ,m. f/- e af, 1 ,7', ..,+-g- -:7 w--~g kd, ' -.(.? .[ y ,.3, s ,.a "? %,' l ";. <. ' kl ' )" J ;. _ ' g _, 6-_ . ~
~~~~p-l%~~~~
( p,. s =g . - g,. ' 3 4. $ , s ,i, j,Al, l fw i - A 'I g.? ( (, -. l M., g. (.- p...,, C ? .. M p, -: ' g* h e q ; 4 'z Li %0 y .r ~ '*
~~~~.g4,r.6 ;,~~~~
~~~~y -y l " ", y r, A~~~~
.(
~~~~.; s g'~~~~
~~~~.4 ' ' / '" b '. ;- z: l.: . 'P---' Eh f "[ j e C W .o .;; *.,g. g m p p-m v .. - 5 g'- _I =~~~~
~~~~r. u _~~~~
~~~~h.':.. t ~ w s~~~~
~~~~- -- - s.~~~~
~~~~Y 44 g - o 4, ..,s.,, s. m C n - ka 5 y* 9:7' ') 5 ,4 g~~~~
~~~~].~.~~~~
~~~~e._. asu /- , ; I 3,,,, ; .w..- j y._~~~~
~~~~, - - y.~~~~
a g g w 7 3, . ~. -4 y y w i c ~~ 3 -3 g 9.. 9. 6 4 4 I-3 N O' 9-h, ~ T 4 e.J .p I,...I "f ~ ];] d. g ,,,,s "ND' f .__...p- = % > >b "... ;;.,,.y e u ' '.,~, l g, '] u x -2 g -- 4 _j.g._, ,] c 5 - r '_4-_ U v gy 3' w ,[, ~ ' 4 r I, 1 +Z ' f ?? .. } r f,Vr~~ y 'i O k,.. '.. U 3
'o
~~~~.i, p V .,' 4, D L' (y l l$ 9.' ~ h~ d ., 4(.- l 12~. 1 l;<.- ..+ t _, + , %.. #) J.. 3 3 3, . gso.. Joe, _..g,, r ,3 l y j /l "- [, ..( h.,: '~~~~
[,
q. ~ 'j ~ .r.,Q,,..;?\\' s .~ .... 1s ' ,)f. y,,.. . N. N b '...s_.._ j v .. w...g.f., ' .y 1. _4 c zy _. j 5 '.Yd'. C si r. $8 y );*- C 7{ w ; ( s -u s h. N /1 O .6 ha W WN M fg. sv [ i e' '/ 1 e N l...b 4'f r.j, e. = 1 .o [ i.
F-9 h5 [ j.~ '[ $ f;,,, .,b % U f!! UIUII f b ,,r.y .h ~ w;,$. ,,.. j%4 ' I' I }lUfllHill!!ih;' ll ; t h 'ig'g ~ - .p ~, j., M%, *t ~ I 1M ' ' S I }l dl !U N Hi I r de .I.Mdd I N . g$ . ni ni i m'. y rw upd.,. 9A .l .1M Litu. _1_ ys nu utt j i u i <c e 1 y r-g_ .r MEE3EE'N -- T Cr Fe 14 (a) 150X i i J 4
~~~~u.,,~~~~
q e (b) Element distribution map for S. 150X FIGURE F-5. LOCATION 11.
F-10 zi.~,: v. v ' 'X ~ . fY 's,. I ll ll!!ll'll fl!!i ' JJl T l i ljllil liiil i'- I lI III!!!' lil!Ilh ,j i l Q't. ! hill i IH!"
~~~~k. ~'~~~~
I _C f11 Jil:DhIEEUE m. ~ j } j $ i ll!Hli, A M I U* E ~ o, Lt ll ! l ,j I 'Ib :i E Uli L( lj, ), j [ lid!il E 6 IC S TV Ce Fe. N (, i ~ (a) 150X 4 i 5 36 ~ j g,j (b) Element distribution map for S. 150X FIGURE F-6. LOCATION I.
F-11 A m pkNk%-d' -f l l lll { { H!H4!ll J'* Odihflj :. l lll l lt Hi!nliil 'l"hjkyi' fI 1 HI i Unmq E s Lx:: -g^$ v -g$&29 s { 'llllll"l 1 E }- 'v d,. ' R 4... m ii .'e4 B C3lE-S Cv-F. Ni (a) 1500X (b) Point A in (a) ? e (c) Element distribution map for S. 1500X FIGL*RE F-7. LOCATION 1
~ q nr i i u pl F-12 !] " # dI. l l 'll pH ;ipt!!; W j e-I I i ![g: e I ,j l l l l }lilh I li' .,1.f s, [Il llIlHH i i.Mi i 4 ir ;, M.. $ l l [ jun! : g w: u-k !' M "l in, MP i ) 1 'l' [ l s., + ..., y e - f" d %6lg'd ty Fe HL (a) 100X e,;p >g l, ; lj_.\\}j;; y pq_f ),. ] d' y *.. }l. '.
~~~~W i '. ~ ~. ',~~~~
~~~~' i %hK8-[ 4 6 f^ "gg/h2 ,;, ' t,.? $ ^$O 'h % lpW;k ~ $, '. j y:x. { w, -,9 = t . A'f, :;1 w# po. . !?. . ( '(',^ If ' f'h 4., jf 4 3 r. ?' j p.:..._. ~, ~ g. w. .3 f.c..Q f ',, %,' a ?:~~~~
['f^. [g} l.,_,,. i..fkfY

y..
+. )).; *, _ .f.* s-g a.J ;. j ' *:4 ig h 'y i .;v...; y - (b) Element distribution (c) Po int A in (a). 1000X nap for S. 100X FIGURE F-8. LOCATIOS J.
F-13 $,M, _T g.., fy-.p..c. g,. p.,..., c.,. 4. ; ;p-4 ?' ". dd
~~~~5. 4~~~~
~~~~, ';g q.. __y. . ;- + g ': - p,.4 - .f. x -. i $ ;;:p,."' .i s.3~~~~
~~~~+-&.,~~~~
~~~~4 ~. ~; ~ ] )7 n~~~~
~~~~J W,Y 'legj[.., ;j2kr~ ~}' x:d,q~~~~
~~~~~ .f );i !!$g~~~~
R'%74a'~,-. ciW+,'

1. ) ;;
~~~~1 j ELI -,7 :. .,.T~~~~
~~~~'fy;7~~~~
~~~~.g'y e. ,p t;g;):};./(%:syp;ig- "w p;:f;:-l;yy - t%;. 's. ;.3 4 ;. -f fi h N gy t.~~~~
~~~~ngmp fex gm w3~~~~
' h. N [ d;?; W f} [ d/m.4 % _' l ~,j-y. ..:. :9 i -' ' '2 ,5 k ,n '. A.$ :;~/M'%.,' - Qt*.:t '%G O. , 4 ~. e. l .'.[. ;; j. ,1 i 6.1 ..',u if -?, ;( 6 .. wa - 7:,, s gg g y .. _ $ O!idh.f \\[ t i.. [f 3 M (a) 25X (b) Element distribution i map f o r Fe. 25X FIGURE F-9. LOCATION A. Crevice surface.
F-14 h$- );. js l lll l,fl ll!!'!9! ll ll!!iil'i l l lli!'!N: l l!!"i! .,~.. l l iHw, lli!ilil i tilli!i y..,. t ,'O ' l Uhii i I j linit g.o cr Fe P4 C (a) 150X ((l l!!!!!i':lH MIll llli, !!llill li' M { l lll!} !I! !6 i: it' il l il Elin _E l Il I lil I iti-E 'l \\ l [ { llh 'l U I 11 I Ilh! [E l { lI } !lIU.' E .fl-l . h;,'I,tt,I li g B vaug 6 I C3IEW C, Fe, P4 C (b) Point A in (a) FIGURE F-10. LOCATION B. Crevice surface.
F-15 $$$$$I$hihlN9n@ k. wo.. ny!'gg spere w ma a a 4 T M 4, h ff .MI 48-IN lfhh$ I 'k~g'dW'YM*I.Ndd$ffe ER hh"ch E 2 N 1L T!!!um, O n' f,w ~Q s l l n ,g,;+, x-
{,
~~~~4 < w n.w%geps 1 C* Fe t4 C (a) 150X 5 .+ fgnlhYko..e v.e x,4 Y %4~~~~
~~~~n"W Wm. m?~~~~
~~~~i1 ^ A ~ew ..me ~t ' ; ; % gg. 1 y i fk E'* lll-l ! '!IMHH fI'IMD F ' 4 I d p.kry%{$fE tj$}[ Of.j[ ', f n'll"ljl!;E j et ..E O.* 1%j kl v; I hl IH!! U h!' l~~~~
~~~~=4 w)x,s., %- Qt w,,-- 3y:yp.,~~~~
j
~~~~p %~~~~
e, m a 3 b qs : '} l m s++.n i I [' / ' d' i l l f jpif;$iMdtfN-49 $,2[~ijk1 $nd 3 i (:3 4Q = + (b) 1500X FIGl'RE F-11. LOCATION C. Crevice surface.
F-16 p, Y.....
~~~~y>.. ',.~~~~
_. +g-,t y ~-a'~' . p fd,. k w-s, p.,5. Q M, y.,;. . o. .s. 3..... m 1 g. ,s. su nevex... ns. 2.r.,c. g 4-U 9HillH IHHH5H55 .- 4.+.,. - nHE ElllIDHIlllEl Illitilill8ER 311111111511115 5 W,,, <' *,:7 -'. c. 4 ~?g ;~* tttftRRERU .ii.ylligmt lHilllll e4
~~~~ty piping~~~~
,4- ^ i ,0 3.[f [.. f ~.; $-I IldlOl .:a i .n.%y,~ r ; '. V.c gemt , i..'g..,..s. .y 4 16, $. 's -..? ! '.s. ; *~ ci e, cr v u s. s FIGURE F-12. LOCATION D. Crevice surface.
G-1 APPENDIX G STRESS CORROSION CRACKING SUSCEPTIBILITY OF INCONEL 600 IN HIGH-PURITY ENVIRONMENTS Literature Review r, y -
G-2 The Strese-Corrosion Cracking of Inconel 600 in High Purity Water Environments: A Literature Review Inconel 600 is extensively used in the primary water circuits of Pressurized Water Reactors (PWRs), and its service performance has generally been good (1,2). The small number of service failures which have been re-ported can, in general, be attributed to caustic cracking (2-4). Failures have occurred at temperatures as low as 217*C (4), but contamination possible in PWR steam generator use accounts for the majority of these failures. To the author's knowledge, no failures attributable to pure water service have been reported. The purpose of this review is to discuss those factors which may affect the service performance of Inconel 600 in Boiling Water Reactor (BWR) ap-plications not involving heat t ran s fe r. In the absence of evidence of an upset in operating procedures involving an excursion in OH concentration, the performance of Inconel 600 in caustic envitvaments is not at issue, since no mechanism of caustic concentration, such as that operative on Leat transfer surfaces (5), is involved. No attecpt will,therefore,be made to include a detailed appraisal of caustic cracking, although some mention will be made of the similarities between caustic and high purity water cracking. The major object here is to give a concise account of the expected influence of a) Environment, b)
~~~~Geometry, c)~~~~
Stress Level, and d) Metallurgical Condition on service performance. It must be realized that the major use of Inconel 600 has been in PWRs, so that much of the data discussed has been collected at temperatures in excess of the normal operating temperatures of BWRs (290*C, 550*F). The compilation of Cowan 6 Gordon (2) shows that increasing tempera-ture does increase susceptibility, but there is sufficient evidence of cracking at 290*C to suggest that the data derived at higher temperatures, up to 350*C, should be considered pertinent to the case in hand. Coriou and coworkers (10) considea the performance at 300 C to be similar to that at 350 C. Effect of Environment As early as 1959, laboratory studies shoved that Inconel 600 was susceptible to intergranular stress-corrosion c cacking (SCC) when exposed at high stress levels to high-purity water (8). Since that time, numerous workers have duplicated these results in pure water with oxygen contents ranging from the detection limit (< 3 ppb) to levels above those experienced during normal BWR operation (i.e. 100-200 ppb) (8-17, 25, 27). There can now be no doubt that Inconel 600 can be cracked in water of a purity level typical of BWR 2 service without the introduction of contaminants such as Pb + or OH~. Although
G-3 cracking can be produced at oxygen 1cvels approaching zero (9,10, 27), it is well documented that high oxygen contents accelerate attack (2,13-17). Various contaminants, apart from oxygen, are also of pertinence. Lead additions have been shown to accelerate the SCC of Inconel 600 and to cause a transition to transgranular fracture (13, 15). Contamination by halides (Cl and F-) is also a common concern. Hydrofluoric acid is a constituent in e unuuu n ly spivycd jiickling batha, ou that outty-ovet is a possibilitya Chloride ions are known to have been involved in several service failures of stainless steels (1). Performance of Inconel 600 is not greatly influenced by Cl and F contamination (9, 10, 13, 15), although some pitting may occur. However, the observation that cracking is favored by acidic conditions (13, 14, 20) raises the question of the role these anionic species, which facilitate pit and crevice acidification, might play in in-service cracking. The existence of a crevice geometry, in combination with halide contamination, could conceivably accelerate SCC. The role of electrochemical potential in the SCC of Inconel 600 is not well understood. Experimental evidence strongly supports the view that cracking isacceleratedunderoxidizingconditions(lg+-17,20),andthuscontamination by oxidizing species, such as 0, H0 r Cr , may be expected to be detri-2 22 mental. Of major interest in regard to operating sys tems is the observation (1) that coupling with a type 304 alloy does not appear to significantly in-fluence cracking behavior. Coupling is only of concern in practice on a local basis, since the high impedance (typically > 1CM cm-1) of the solution pro-hibits long range galvanic ef fects. In summary, the published data indicates that Inconel 600, when stressed to a sufficiently high level, is susceptible to intergranular SCC in typical FWR environment s. No out-of-control conditions are necessary to cause SCC, although highly oxidizing conditions and low pH will probably stimulate the reactions causing SCC. The Eff-ct of Geometry Two different geometric configtrations deserve consideration, the occluded cell and the clean surface. The presence of an occluded region, such as a crevice, pit or lap, can sig. ificantly accelerate corrosive attack by concentrating aggressive species. In addition, such geometries act as points of stress concentration, increasing the local stress and thus favoring stress-corrosion cracking. It has been conclusively shown that the presence of crevices (produced either by grain boundary attack or by specimen geometry) greatly accelerates the intergranular SCC of Inconel 600, particularly in the presence of high o:, gen content and low pH solutions (2, 13-15). Results obtained by CE also clearly indicate that crevices are detrimental in pure water containing 200 ppb 0, typical of reactor environments (27). 2
G-4 The mechanism of the crevice effect is not completely clear. In the low conductivity, low oxygen content solutions of interest, the conventional mechanism of crevice attack is of questionable relevance. It is highly un-likely that the classical deacration cell can operate, since the high IR drop effectively isolates the interior and exterior of the crevice. It is, perhaps, instructive to note that during plant shutdown oxygen concentration will rise to 8 ppm, and some workers claim that levels of 100 ppm can be found in occluded regions such as the anular gap between the thermal sleeve and safe-end (1b1 These high 1cycla could accelerate corrosion in such regions, SO =) in the and lead to the concentration of anionic species (e.g., Cl, F, 4 crevice, with the accompanying decrease in pH caused by hydrolysis of the dissolved metal ions. Since the concentration of anionic species in reactor water is very low, the classical scheme, of hydrolysis within the crevice and inward dif fusion of anionic species to maintain charge neuirality, would be extremely sluggish. Once initiated,however, crevice corrosion would proceed, just as it does in the classical case, essentially independent of the bulk solution. The Effect of Stress Although some workers (27) have had difficulty cracking smooth specimens of Incone] 600 at stresses well above the yield stress, failures have been reported in uncreviced geometries at stresses as low as the 0.5% proof stress (7, 9, 10). Thus, it seems likely that the threshold stress lies near the yield stress. This parallels the behavior of sensitized type 304 stainless steel under similar conditions (21). The cracking of Inconel 600 is, there-fore, not likely in BWR environments unless stresses exceed the yield stress. The Effect of Metallurgical Condition The familiar problems associated with the use of austenitic stainless steels in the sensitized condition has contributed to a wide suspicion of all alloys which may develop a similar condition. The Ni-Cr-Fe alloys also depend to a large extent on a passive chromium-based spinel for corrosion and oxi-dation resistance. The precipitation of carbides, particularly at grain boundaries, is therefore a potential source of problems, since this causes depletion of the (local) chromium level. Cause for concern is heightened, as the equilibrium solubility of carbon in Inconel 600 is significantly below that in iron-based austenitic alloys such as 304 (6, 24). Hence the matrix chromium content in equilibrium with carbides at any temperature is less than that in 304. A large effort has,therefore,been expended in the study of the effect of sensitization on the behavior of Inconel 600 in high purity water. Mill-annealed Inconel 600 is generally in the seasitized condition, since practicable cooling rates for mill processes. and for large forged parts, are too slow to prevent carbide precipitation. Additional carbide precipitation can result f rom stress relieving heat treatment applied to pressure vessel components after fabrication. It should be pointed out that this treatment, commonly 1150-1200 F for several hours, is not a stress relief anneal of Inconel 600, but of the associated steel pressure-vessel components. Only slight stress relief of Inconel 600 results af ter heating to 1200 F or lower (23).
G-5 There is no evidence that a stress-relief sensitization treatment is detrimental to the stress-corrosion cracking resistance of Inconel 600 exposed to either high-purity water or caustic solutions. Coriou and co-workers (9, 10) have conclusively shown that lowering the carbon content and eliminatica of intergranular carbide precipitation have no apparent af fect on the mechanism of cracking in high-purity water. Subsequently, others (11, 12, 14, 15) have shown that furnace sensitization of commercial Inconel 600 appears to increase resistance to SCC, both in high-purity water and in caustic solutions. However, as with the austenitic stainless steels, low sensitization temperatures are potentially more deleterious, since the equilibrium chromium and carbon levels are lower, and the dif fusion rate is less, than at high temperatures. Therefore, prolonged aging at service temperatures could conceivably enhance chromium depletion. The effect of enhanced depletion is unknown. Alloys with increased chromium content (-30%) are known to be superior to Inconel 600 in high-purity water (10,15, 26), but a simultaneous reduction in the nickel level, to ~60%, could be the main factor in improving resistance. The failure of sensitization at 1100-1200 F to reduce SCC performance of Inconel 600 suggests that low temperature aging may have little effect, despite fears to the contrary (3). The above discussion is pertinent to the present failure, since welding produces zones of carbide re-solution and partial re-solution. On cooling, the region near the weld may be in a solution annealed or lightly sensitized con-dition. "urther from the weld, a zone of heavier sensitization will be produced, regardless of the initial condition of the base metal. In initially solution-annealid base material the structure will, therefore, go through the transition from solution annealed (or slightly sensitized) near the fusion line to heavily sensitized in the heat-affected zone (HAZ), and back to the solution-treated condition. In base material which is initially sensitized, the degree of sensitization may be increased J-the HAZ, because of the ef fect of the zone in which partial re-solution c. che carbides has occurred (28). However, the structure will still consist of a solution annealed (or lightly sensitized) region at the fusion line and a heavily sensitized zone further out in the HAZ. Thus, the prior condition of the base material (sensitized or fully solution annealed) is not expected to have a significant effect on service performance. The ef fects of welding and cold working have nst been extensively investigated. The behavior of weld metal does not appear to be appreciably different f rom that of heat-af fected zone of the base metal. The heat-affected zone may be slightly more resistant than the base material, but inaufficient data is available to be positive (14, 15). The results of work investigating the ef fect of cold-work are conflicting, so it is unlikely that cold-work has a significant effect (2). In conclusion, a literature review has established that: 1) Inconel 600 is susceptible to IGSCC in high purity water typical of BWR environments at stress levels above the yield strength.
yr-G-6 2) The previous heat treatment is not critical in determining susceptibility. Specifically, sensitization associated with typical stress relief treatments is not detrimental. 3) The presence of a crevice can enhance the susceptibility to cracking at normal and above-normal oxygen levels. 4) Although contamination is not necessary to cause cracking of Inconel 600, caustic concentration, oxidizing agent concen-t.ation or acidification within a crevice could enhance failure. 5) Weld metal is not more susceptible to SCC than is the base metal.
G-7 REFERENCES 1. S. H. Bush and R. L. Dillon, " Stress-Corrosion Cracking and Hydrogen Embrittlement of Iron-Base Alloys," p 61, NACE, Houston (1977). 2. R. L. Cowan, II and C. M. Gordon, " Stress-Corrosion Cracking and Hydrogen Embrittlement of Iron-Base Alloys," p 1023, NACE, Houston (1977). 3. J. Weber and P. Sury, Fbteriala Performance, 15, 34 (1976). 4. B. Gronwall, L. Ljungberg, W. Hubner and W. Stuart, Nuclear Eng., 6, p 383 (1967). 5. R. E. Hall, Trans. ASME, 66,, p 457 (1944). 6. C. H. Wagner, H. Spahn and H. Schenk, Discussion of Ref. 25, p 1200. 7. H. Coriou, L. Grall, C. Mahieu and M. Pelas, Corrosion, 22,, p 280 (1966). 8. H. Coriou, L. Grall, Y. L. Grall and A. Vettier, Third Metallurgy Conference on Corrosion, p 161, Saclay, North Holland Pub. Co., Amsterdam (1959). 9. H. Coriou, L. Grall, P. Olivier and H. Willermoz, " Fundamental Aspects of Stress-Corrosion Cracking," p 352, NACE, Hounton (1969). 10. J. Blanchet, H. Coriou, L. Grall, C. Mahieu, C. Otter and G. Turbuer, " Stress-Corrosion Cracking and Hydrogen Embrittlement of Iron-Base Alloys," p 1149, NACE, Houston (1977). 11. H. A. Damian, R. H. Emanuelson, L. W. Sarver, G. J. Theus and L. Katz, corrosion, 31, p 26 (1977). 12. F. W. Pement and N. A. Graham, " Corrosion Problems in Energy Conversion and Generation," The Electrochemical Society, Inc., Princeton (1974). 13. H. R. Copson and S. W. Dean, Corrosion, 21, p 1 (1965). 14. H. R. Copson and G. Economy, Corrosion, 26, 55 (1968). 15. H. R. Copson, D. van Rooyen and A. R. McIlree, " Proceedings of the Fifth International Congress on Metallic Corrosion," p 376, NACE, Houston (1974). 16. W. E. Berry, Discussion of Ref. 7, Corrosion, 22_, p 287 (1966). 17. A. R. McIlree, H. T. Michels and P. E. Morris, " Corrosion Problems in Energy Conversion and Generation," Electrochemical Society, Princeton (1974). 18. T. Kondo, Y. Ogawa and H. Nakaj ima," Corrosion Problems in Energy Conversion and Generatioa," Electrochemical Society, Princeton (1974).
G-8 REFERENCES (Continued) 19. G. J. Theus and R. W. Staehle, "The Stress-Corrosion Cracking and Hydrogen Embrittlement of Iron-Base Alloys," p 845, NACE, Houston (1977). 20. D. A. Vermilyea, Corrosion, 29_, p 442 (1973). 21. C. S. Tedmon, Jr., and D. A. Vermilyca, Corrosion, 27, p 376 (19 71). 22. I. L. Wilson and R. G. Aspden, " Stress-Corrosion Cracking and Hydrogen Embrittlement of Iron-Base Alloys," p 1189, NACE, Houston (1977). 23. "Inconel 600," Huntington Alloy Products Division data sheet. 24. G. J. Theus, Nuclear Technology, 28., p 388 (1976). 25. G. J. Theus, corrosion, 33, p 20 (19 77). Sedriks, J. W. Schultz and M. A. Cordovi, " Alloy 690 - a New 26. A. Corrosicr. Resistant Material For High Temperature Applications," Presented at the 15th INCO Power Conference, Lausanne, Switzerland, Oct 5-7 (1977). 27. " Recirculation Inlet Safe-End Repair Program - Duane Arnold Energy Center," Iowa Electric Light and Power Company Report dated December 8, (1978). 28. H. D. Solomon, Corrosion, 34, p 183, (1978).}}

ML19269C765

Contents

Text

1.0 INTRODUCTION

SUMMARY

SUMMARY

SUMMARY

Navigation menu

ML19269C765

Text

1.0 INTRODUCTION

SUMMARY

SUMMARY

SUMMARY

Navigation menu

Search