Text

Informs of Congressman Dingell Request for Listed Info Re Data Base Accumulated as Result of Fastener Testing Required in NRC Bulletin 87-002
	ML19324B271
Person / Time
Issue date:	05/26/1988
From:	Bradburne J; NRC OFFICE OF GOVERNMENTAL & PUBLIC AFFAIRS (GPA)
To:	Rehm T; NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
Shared Package
ML19324A112	List: ML19324A111; ML19324A362; ML19324B258; ML19324B263; ML19324B267; ML19324B269; ML19324B270; ML19324B271;
References
	FOIA-89-334, FOIA-89-335, FOIA-89-336, FOIA-89-337 IEB-87-002, IEB-87-2, NUDOCS 8911030042
	Download: ML19324B271 (2)
	v • d • e

{{#Wiki_filter:_ h h h h h'. h h h h bhh [kNh$fh [ (IS$b N [UhTE$ NTEs? [. HUCLEAR REGULATORY COMMISSION ' p-lWg ^> 3 c ; ,35, WASHINGTON, D, C 30006. N ,t-in y h s i n May 26, 1988 i4: I, i MEMORANDUM FOR: Tom Rehm, Assistant for Operations. OEDO / FROM: John C. Bradburne, Director [ Congressional Affairs, GPA . SUB.1ECT: CONGRESSIONAL REQUESTS RE: SUBSTANDARD FASTENERS On Tuesday, May 24, representatives of CA, 01, and Vendor Branch met with the staff of Congressman Dinge11's Subcomittee on Oversight and Investigations to answer questions about the data base accum;1ated as a result of the fastener testing required in NRC Bulletin No. 87-02. During that meeting, Mr. Dinge11's staff requested the following items: For the 15 safety-related fasteners that were seriously out of specification, provide information on: (1) what the. plants have done with' the inventories that the fasteners were taken from (e.g., quarantined, disposed, etc.); (2) locations within the plants where fasteners from those inventories had actually been used; and (3) for cases where fasteners from those inventories were determined to have t been installed in the plants, whether those fasteners have been removed or left in place. Provide tne test results showing the degree of non-conformance for bolts suspected of being mismarked as to Grade 8.0 vs. 8.2 and Grade 5.0 vs. 5.2. Ai soon as it-imompleted, provii. :cpy of the "Temparm, ' Instruction" to~NRC inspactors regarding~ follow-up actions for plants with inventorics containing non-conforming fasteners. Indicate whether nuts were tested for anything other than hardness, and if so, what.- List the eight vendors that are being considered for NRC ins >ection action as a result of the informa+. ion contained in the data 3ase. Provide a computer run of licensee 50.73 reports involving fas+.ener failures over the past five years. If this is not possible, any substitute information on licensee reports involving fastener failures would be appreciated. Provide the names of nuclear power plants that are actively under construction at this :ime (as, opposed to completed plants that are awaitinglicensing). 8911030042 891030 PDR FOIA MCORATHB9-334 PDR p /,,, +

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steel bolts. This study was initiated because of a recent Industria! Fasteners f Institute research report (1) and media reports that " counterfeit" bolts were E: being used.in structural applications in the nuclear industry. Of primary concern were claims that bolts that-were marked as being hardened alloy steel' s were actually carbon steel. Hardened alloy steel bolts resist tempering, .tetain strength, and do not relax at elevated temperatures, whereas carbon steel, bolts have less temperature softening resistance. 4 1 Twenty-si:. bolts were submitted to FRC for comparative analyses. Twenty-one of thase were marked with 6 radial lines 60' apart indicating they n j conformed to the requirements for Grade 8 bolts as specified in SAE 429k (?). Two bolts.had 6 radial marks 30' apart indicating that they were Grade 3.2 of J ~k. SAE 429k. The remaining three bolts were marked "A 490" per Type 1 classificationin ASTM specification A 490 [3). As described in the following sections of this report, the bolts were subjected to the various tests requir3d by the specifications. Based upon the ? results of all these tests, several conclualons and recommendations are presented. i. t

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3 2. ANALYSES AND DISCUSSION g, 4. E 1 The bolts submitted for evaluation are listed in Table l'with the ' identification numbers assigned by the U.S. Nuclear Regulatory Conunission y* (NRC). Markings present on the heads are also noted. The mechanical antt i chemical requirements in the relevant specifications are listed in Tables 2 and 3 along with the results of the varioun tests, which are discussed below. L l 2.1 MECHANICAL REQUIREMENTS AND TESTS The mechanical requirements, test methods, and test procedures for Grades 8 and 8,2 bolts are given in SAE 429k (2), whereas the' mechanical requirements for A 490 bolts are given in ASTM' A 490 (3) and the test methods and procedures are given in ASTM F 606 [4). Since the SAE and ASTM property and . '6 methodology specifications are the same, requirements and test data for all the bolts are presented jointly in Table 2. The' standards cite the proof load, i.e., the load at or below which no permanent elongation should be incurred, and the minimum Joad at which tensile failure should occur for a bolt of given diameter, thread type, and dimen-sions. However, for a bolt with a length less than 21/4 times its diameter, proof and tensile tests are not required. Rather, hardness tests are .s. [l specified to determine conformance to the mechanical requirements of the I standards. For the bolts covered by this report, all except five--6177-1, 7;d I i 6177-2, 6177-17, 6177-23, and 6177-24--had a length greater than 2 1/4 times 4 the. diameter. ll 3 Furthermore, for any bolt of length less than 8 times the diameter and a r Sr diamwter such that the specified tensile load is less than 100,000 pounds, proof load and wedge tensile strength determinations are required to be .>y 9 conducted on the full-size sample. All of the bolts fell into this category. 9%,

l-Finally, for all of the bolts, the specifications required that core hardness

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q ,/.,, 2 - y;. F-6177-1 c-, u F .1 b-u Table 1.' Bolt Identification K..i, f W, u .q, Grade Mr.nufacturer's. Thread ~ Bolt-3 Markina(II Mark h Tm - a l 6177-1 860962792A 8 LE 3/4-16 Fine 6177-2 B B LE 3/4-16' Fine. 6177-3 860830527A 8 RT 3/4-16 Fine 6177-4 B 8 RT 3/4-16 Fine 6177-5 860912841A 8 3/8 Fine 6177-6 B 8' 3/8-24 Fine (c. 6177-7' C 8 3/8-24 Fine W g' 6177-8 D 8 3/8-24 Fine ' j - 6177-10 850431409A 8 6177-9 E 8 3/8-24 Fine 5/16 Coarse 6177-11' B 8 5/16-18 Coarse-6177-12 C 8 5/16-18 Coarse 6177-13 860859665A 8.2 KS 3/4-10 Coarse 6177-14 B 8.2 KS 3/4-10 Coarse s< 6177-15 870085789 8 CEM 9/16-12 Coarse 6177-16 870085790 8 CD1 5/8-11 Coarst 6177-17' 870085791 8 CEM 7/8-9 Coarso

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'6177-18 870085792 A 490 (2) TB 3/4-10 Coarse I 6177-19 870085793' A 490 (2) TB 3/4-10 Coarse 6177-20 870085794 A 490 (2) TB 3/4-10 Coarse 6177-21 870085795 8 LE 5/8-11 Coarse .' l. 6177-22' 870085796 8 LE 5/8-11 Coarse s 6177-23 -870085797 8 N/LE 3/4-10 Coarse w 6177-24 870085798 8 N/LE 3/4-10 Coarse j* l 6177-25' B70085799 8 N/LE 1/2-13. Coarse 6177-26 870065800 8 LE 1/2-13 Coarse .A !.h: Q I 1. According to SAE J429k for Grades 8 and 8.2 or ASTM A 490. 'L 2. Type 1, based on the absence of Type 2 or 3 markings. .8: '! +.w .;4 R t i a l)., t .'a ^ ,g i 'e i

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p > f e: f ' }.. ~, f s Q. ;, ,ggO.n.a n .i t , Q$O u .) ,w 1 x jk [, s. g,. F-6177-1 "f' i l{ c ' p. 1 From the deta in Table 2, it can be concluded that, with the exception of wc1 bolt 6177-15, all the bolts met or exceeded the specified mechanical test ) parameters. Siece the hardness of bolt 6177-15 did meet the specification. the low tensile strength in a single test may reflect experimental data i scatter, rather than an inherent low strength. 2.2 CHEMICAL REQUIREMENTS AND TESTS r, The chemical requirements for Grades 8 and 8.2 and A 490 Type 1 bolts are listed in Table 3, along with the results of the chemical analyses. These data show that there was a wide range of composition among the bolts. i Except for three groups of the Grade 8 bolts, all bolts met the relatively broad specifications called for in SAE J429k and ASTM A 490. Bolts 6177-3, 6177-4, and 6177-10 to 6177-12 had carbon contents lower than the minimum specified 'i i for Grade 8, whereas bolts 6177-5 through 6177-9 had been fabricated from I carbon steel rather than alloy steel (see footnote in Table 3 for definition of alloy steel). None of these bolts are necessarily out of specification, since, as is noted in the footnote in Table 3, for bolts of this size the substitution of carbon steel or SAE 1541 (or 1541H) steel for alloy steel in Grade 8 bolts is permissible by agreement between producer and consumer. g In the present case, i the chemical composition of bolts 6177-5 through 6177-9 does fall within the range specified for 1541 steels thus, these bolts could have been supplied to w a distributor, correctly marked as Grade 8, under a substitution agreement between the distributor and producer. ? The composition of the Grade 8 marked bolts with low carbon (6177-3, ( 6177-4, and 6177-10 to 6177-12) was very similar to that of bolts 6177-13 and 7, 6177-14, which are marked as Grade 8.2. However, all of the former bolts are h. included in the size range for which carbon steel may, under proper agreement, f be substituted for alloy steel. Furthermore, since the material in all these . g.p bolts is actually a higher alloy than a plain carbon steel, it would more than

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~} qualify as a substitute for a Grade 8 steel with slightly more carbon but less alloying. Indeed, they met the mechanical requirements because of the strengthening effect of manganese and chromium alloying additions. I 4. .-w ,_.--.-.,,-,.-r .,,.---..-..-.-_.,.-__w... . m m-m --.-...e< l. h ~ w- _.~ 4 4 m-Table 2. Bolt Strength Rgsirements and Test Data ,: 1 2,. s Ream 1. ___..it I Froof Tensile Test M 1Le e toad Proo{II 5trength Tensi Core Surface-Elongation Tens 11e Core Serface 1 1; NRC FRC (Stress) 8.oad (Stress) toad I Hardness Hardness gglt 3g]1 fasil fib) fain /ssil fain /1h1 toin/R _1 (man) 30N atPrgI Lead Nordeness Nordness g Lead fibi A_ M 1 860%2792A 6177-1 120.000 (3) 150,000 (3) 33 58.6 (3) (3) 36 4 I 8609627928 6177-2 (31 (3) (3) (3) 37 47 3 860830527A 6177-3 44.800 56.000 ' 3 8608305278 6177-4 44.800 56.000 0 64,000 35 45 7,7 860912841A 6177-5 10.500 13.200 8.00020 15.300 38 ~de 0 62.100 36 43 8609128418 6177-6 10.500 13.200 D.00020 15.440 37 51 - s = 860912841C 6177 7 10.500 13.200 0.00020 15.400 38 44 860912841D 6177-8 10.500 13.200 0.00042 14.760 36 51 . $77 .5 860912841E 6177-9 10.500 13.200 1 850431409A 6177-10 6.300 7.850 0.00036 14.840 37 52 .C 8504314098 6177-11 6.300 7.850 0 8.440 36 51 850431409C 6177-12 6.300 7.850 9.00011 8.400 36 50 860859665A 6177-13 0 8.260 35 54 ^W 40.100 50.100 s 8608956658 6177-14 40.100 50.100 61 0 57.200 38 48 0 56.200* 37 55 870085789 6177-15 21.800 27.300 4 870085790 6177-16 27.100 33.900 61 0 24.100 36 46 I 870085791 6177-17 (3) (3) (3) (3) 35 47 58.6 0 35.000 35 46 /.. 870085792 6177-18 40.100 " (4} 50.100 (5) " (6) (7) 0.0002 53.050 33 53 (33 ) } 870085793 6177-19 40.100 " (4) 50.100 (5) " (6) ' ( 71 0.0002 52.250 30 53 (33 a ) - 870085794 6177-20 40.100 " (4) 50.100 (5)

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(7) 0.0002 52.500 30 52 (33 ).( 870085795 6177-21 27.100 33.900 58.6 0 38.800 35 54 ,j 8700857 % 6177-22 27.100 33.900 i 870085797 6177-23 (3) (3) (3) (3) 34 59 ~ 2 0 38.650 37 55- = 870085798 6177-24 (3) (3) (3) (3) 34 OS ) 870085799 6177-25 17.000 21.300 870085800 6177-26 17.000 21.300 O 24.450 32 59 i O 24.750 34 OS i } 1 Length should be the same before and af ter loading within a tolerance ofFrom Table 5 in SAE 429k (for all bolts 2. i 0.0005 in. sed on belt s'ae and threod type. 3. Bolt length less than 2 1/4 times the diameter. 4 170.000 psi men. Therefore only hardness test required. 5. 56.000 lb ans. 6. 38 R man. e 7. No more than the equivalent of 3 puints R higher than herdaess 1/8 in from surface. " Unesvally rapid drop during yield. e .w 4 y-e. i ~ . 'bg$- F " ~. ' Wb j % g. 9, +, +., .,f( - ' ;QV a j1 F-6177-1 .,f ,1, m L l' 4 ' if ik Table 3. Chemical Requirements and Test Data ri nta (11 RAli c Mn P 5 8 tlin tita 211 0 tita llaa 11 tilA $C Mi IIR Grade'8. 429kII) 0.28 0.55 0.04 0.045 Grade 8.2. 429k 0.15 0.25 0.74 0.048 0.058 0.0005 ASTM A 490. Type 1(2) 0.26 0.50 . NRC FRC Roli 8411 J 860962792A 6177-1 0.43 0.67 0.011 0.012 0.24 <0.001 0.33 (0.01 0.26 8609627928 6177-2 0.43 0.64 0.012 0.012 0.26 0.001 0.32 <0.01 0.24 860830527A 6177-3 0.21 0.95 0.011 0.014 <0.01 40.001 0.21 <0.01 <0.01 8608305278 6177-4 0.21 0.95 0.015 0.012 <0.01 <0.001 0.20 (0.01 0.12 3 860912841A 6177-5 0.37 1.54 0.015 0.023 0.22 <0.001 0.07 <0.01 0.01 i 8609128418 6177-6 0.39 1.56 0.013 0.018 0.23 (0.001 0.02 <0.01 0.02 i 860912841C 6177-7 0.36 1.52 0.012 0.023 0.20 (0.001 0.12 <0.01 0.01 i 8609128410 6177-8 0.39 1.58 0.014 0.019 0.21 <0.001 0.06 <0.01 0.01 l 860912841E 6177-9 0.39 1.55 0.014 0.019 0.23 (0.001 0.07 <0.01 <0.01 8!0431409A 6177-10 0.20 1.02 0.013 0.018 0.04 0.002 0.19 <0.01 <0.01 I 8504314098 6177-11 0.20 0.99 0.014 0.017 0.03 0.002 0.23 <0.01 0.01 850431409C 6177-12 0.20 0.94 0.014 0.011 0.01 <0.001 0.19 (0.01 0.01 860859665A 6177-13 0.21 1.01 0.014 0.021 0.02 <0.001 0.17 <0.01 0.01 8608956658 6177-14 0.22 1.03 0.014 0.021 0.03 <0.001 0.19 <0.01 0.01 870085789 6177-15 0.44 0.92 0.014 0.035 0.31 L<0.001 0.99 (0.01 0.20 870085790 6177-16 0.43 0.93 0.014 0.035 0.32 <0.001 1.00 (0.01 0.20 870085791 6177-17 0.39 0.90 0.013 0.033 0.26 <0.001 1.01 <0.01 0.22 870085792 6177-18 0.39 0.87 0.011 0.022 0.27 <0.0005 0.95 <0.01 0.17 870085793 6177-19 0.39 0.86 0.014 0.025 0.28 <0.0005 0.94 <0.01 0.16 870085794 6177-20 0.38 0.87 0.011 0.025 0.28 <0.0005 0.97 (0.01 0.16 8700B5795 6177-21 0.38 0.61 0.011 0.015 0.22 0.0007 0.30 <0.01 0.17 870085796 6177-22 0.39 0.63 0.011 0.016 0.22 0.0006 0.27 (0.01 0.13 870085797 6177-23 0.40 0.58 0.014 0.010 0.26 0.0007 0.32 <0.01 0.14 870085798 6177-24 0.40 0.60 0.011 0.011 0.27 0.0005 0.33 (0.01 0.15 870085799 6177-25 0.36 0.95 0.011 0.012 0.23 0.0005 0.54 <0.01 0.02 I 870085B00 6177-26 0.37 0.92 0.011 0.013 0.21 0.0005 0.54 <0.01 0.03 l-1 Medium carbon alloy steel with no specified alloy content. " Carbon Steel may be used by agreement between producer and consumer, for sites 1/4 - 3/4 in diameter products. oli quenched and tempered may be used at the option of the producer for products 7/16 in nominalSAE 1541 diameter and smaller." 5AE J429k 2. Alloy steel with no specified alloy content. " Note 4 - $tetl is considered to be alloy. by the Q American Iron and Steel Institute. when the mu imum of the range given for the content of alloying elements exceeds one or more of the f ollowing limits: manganese. 1.65%; silicon. 0.60%; copper. i O.60%; or in which a definite range or a definite minimum quantity of any of the following elements is specified or required within the limits of the recognized field of constructional alloy steels: aluminum, chromium up to 3.991, cobalt. columblum, molybdenum. nickel titanium, tungsten. vanadium. l af ronium, or any other alloying elements added to obtain a desired alloying ef fect." ASTM A 490. I 4 s o -l L 1 l 1 <.s : Je U f.q '% [(Q. 'Ys' N ..c - ] ' [ i p,] F-6177-1 1 v i Accordingly, the determination of whether or not these bolts are out of .g specification,-l'.e., mismarked, depends on whether or not the steel-substitution.was in accordance with an agreemen'c between a purchaser (a 'gj l- < i distributor or an end user) and the peoducer. From the above findings, it is clear that if the end user does not purchase directly from the producer, but from a distributor, he may not be.

4 aware that he has purchased carbon steel rather than alloy steel Grade 8 bolts.

In many cases, this will present no problem, since both materials would behave similarly except at high and low temperatures. At low tempera-tures, the carbon steel would be expected to exhibit a higher ductile to { brittle transition temperature and a lower shelf impact energy than an alloy 3 - steel. Furthermore, at ele'vated temperatures, the carbon steel would soften at a lower temperature or in shorter times than the alloy steel. i ~ 's There is also the possibility that bolts with carbon content lower than specified in Grade 8 could have high temperature characteristics superior to -those of a Grade 8 bolt with specified carbon because of different alloying additions. Thus, when specific temperature / property characteristics are x required, testing of sample bolts is necessary to assure adequate service i performance. .g l-As further evaluation of the quality of the low carbon and the 1541 steel bolts, the microstructures of bolts 6177-3, 6177-4, and 6177-10 to 6177-12 V L were analyzed in longitudinal cross sections. A uniform, fine-grained l martensitic microstructure was present in all the bolts studied, as shown in 1 the micrographs in Figures 1 through 4. Thus, consistent with the mechanical properties, none of these bolts can be considered poor quality, and whether or l' not any of them can be classified as having been mismarked would depend on i 1 whether or not compositional substitutions had been agreed upon during the p 9 original purchase from the fabricator. S 1 1 ' n: o e 1 7- -..-.,.-----..-,.,m . ~ _ _ _ - - _,. -.. _ -,.,. m ~_. -., -. _ _,. -. - _ -,. .-..-o.mm.- n;f;N h,%# [W a> s C , c., A @ ,,. 4 - z.)?

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~~ B. Bolt 6177-12 100 X Figure 3. Micrographs showing a uniform, fine-grained, terepered martensitic microstructure in two bolts with carbon cor.tu.it lower than l specified (without agreed upon substitution) for Grade 8. A higher magnification micrograph of bolt 6177-12 is given in Figure 4. ' 1 1 m, .s . l,1 + c: Y @cfy, , gw., / - yf',_v:Q;/, p.~2 -,' ff.j 4.,m yn % q p q p e.,g,w h.y.p p tw y8t w

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,l$9.;... : s."... ;. ', _ p ?. ? '.,';.,.. ',&.... , h.,.. '] '3' g, -g ta.. B, Bolt 6177-12 500 X l l l l l l Figure 4. Micrograph showing, at a higher magnification than in Figure 3, the I uniform, fine microstructure in a carbon steel bolt with a Grade 8 marking. i l l 1 j 4 4 . ~.- ha n b. E

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, a c'Q) {, ~ Q- ~" d J g. ([ ~F-6177-1 y G y a ~ ~ _, t g, .v g 3. CONCLUSIONS AND RECOMMENDATIONS ]r [ Based on the above' analyses and discussions, the following conclusions cy. r M.C and recomunendations are presented: .~ k, I '. All bolts except one met or exceeded the mechanical property .'] requirements in the relevant specifications. The one bolt (6177-15) that had a slightly low tensile strength did meet the hardness specification and, thus, the single test may reflect inherent experimental scatter. 2. Some of the bolts marked as Grade 8 per SAE J492k were out of ' specification with regard to chemical composition. However, if these bolts had been supplied by a producer under agreed-upon composition t substitutions, they would not be in violation of the broad y composition range' permissible in J429k. Thus, the bolts cannot be J. considered mismarked or " counterfeit" unless it can be shown that an f agreement for substitution had not been made in conjunction with ]- their original fabrication and purchase. .9 All bolts which would have been outside of Grade 8 composition 3. requirements, in the absence of agreed-upon substitutions, exhibited i unifom, fine microstructures, consistent with the mechanical ' properties. 'Thus, the overall quality of these bolts is not in question. .l 4. If-the end user of high strength bolts purchases them from a distributor, who'in turn purchased them from a producer with agreed L.tj upon composition substitutions, he may not be aware that he has l carbon rather than alloy steel bolts. Thus, the end user must 'y, L, qualify his order of Grade 8 bolts, if they are between 1/4 and 3/4 !~ l in diameter, as to the type of steel, if an alloy steel is deemed . gf I necessary for the intended application. i L Jg LI S. When specific service conditions require retention of strength at ~~Q i' high temperature or require low temperature toughness, testing of f bolt samples should be performed to assure that bolts will have M. necessary characteristics. Grade specifications in and of themselves el are so broad that they assure room temperatura properties only. ~ ,, ~. - l .Qf D f l s, .4 " - - ' - ' - - ' ' ~ ~ * ' ' " ' ' * ' ' ' ' ' " " ~ ~ " " " ' ' " ' ~ ~ ~ ~ ~ ~ ' ' ~~ WE, i. [) * ,e,,t r.,, c,. ~ .c. ] ~ ~ y 6177-1 N .iq j if - .) y 4. REFERDfCES ?,? ' l 1. False Grade 8 Engineering Performance Marks on Bolting and Improper f Marking of Grade 8 Nuts, Industrial Fastener Institute Research Report,. ','py Cleveland, ON, April 4, 1986 ~ - 7 2. FAE J429k: Standard Mechanical and Material Requirements for Externally ' k Threaded Fasteners, Society of Automotive Engineers, Warrendale, PA,1980 l .6 3.. -ASTM A 490 Heat Treated Steel Structural Bolts,150 kai Minimum Tensile j Strength, American Society for Testing and Materials, Philadelphia, PA, ..g 1985 4. ASTM F 606: Conducting Tests to Determine the Mechanical Properties of' j Externally and Internally Threaded Fasteners, Washers, and Rivets, American Society for Testing and Materials,, Philadelphia, PA, 1986 I l s I j r T e

t

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n v,7 .'W ? ELEC1 ' %. 4. {y(;n.. ,s ?- ., a .4 . ',-.x -., ;y i; -r, 3 s y, q ') s '. $.., 0 1 ', ( CHARLES CENTER

P. 0. 80X 1478 s

} .'.Q:$ / ' .w. Jwas ueeot.o ,j t WANAotst n avewa s so v. css oe.A tw~t } i i September 30, 1987 3 4 U. S. Nuclear Regulatory Commission Washington, DC 20555, ATTENTION: Document Control Desk N

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2: Docket Nos. 50-327 & 50-318 Commercial Oustitv Meehsniest Fa'stener Evaluation

REFERENCE:

(a) Letter from Mr. J. A. Tiernan (BG&E) to NRC Document Control Desk.. dated May 11, 1987, L*se of Mechanical Parts Purchased Commercial Quality in ASME Section XI Class 1, 2 and 3 Systems i 1 (b),Teleconference ' between Mr. A. R. Thorntos (BG&E) and' Mr. L. E. Tripp (NRC), on September 15, 1987, same subject Gentlemen: s In Reference (a) we. stated our intentions to remove, test and evaluate specific mechanical fasteners in ASME Section XI Code Class Systems. Since that time, we have wruked repdily and committed considerable, resources in complete the testh n and ., ev4luation in s timely manner. This letter provides the results of our eve.jhtmu ar...

f the actions we have taken and plan to take as discussed in Reference (b).

L n Evaluation Results

i We have tested individually 1539 fastener components or pieces, where a piece is a N l-stud, nut or bolt. Each has received a surface examination, a hardness test and a chemical analysis. Approximately 150 pieces we removed from the plant which we do not L

plan to test. Of these, 50 pieces were misplaced or mislabeled when they were removed i from the plant. 'Approximately 100 pieces cannot be decontaminated without the .t L expenditure of significant additional resources and radiation exposure. We do not believe the information we would receive from testing those 100 pieces would justify the resources and exposures that would be required. We also feel the remaining 1539 fasteaers are representative of those not tested. 1: s AM

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usa 39 x..m : }g.. + ,(

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, s.. m a - c. ,,u .o ' / 'l '. * " Doc:me:t CIntrol Desk - , September 30, 1987. g,f Page 2 J 3., D d' m 3: d [. { .c specifications to determine whether they were adequate to have perfo All 1539 pieces have been compared to the applicable chemistry and hardness material V i function. Initially, 399 pieces yielded test results that were out 'of. specificatloa. E The chemical composition for :74 of the 399 pieces differed alightly from the material requirements,. but the hardness was within specification. For these it. was clear that the pieces were of the correct matet:al and that the critical property - strength as determined from hardness measurements - was adequate. We therefore determined that Ml these were adequate to have performed their design function. ] . A number of other pieces had the chemical compositions within the specification range or only slightly out of range, but the hardness was just, beyond the specified range. Based upon engineering judgment, we determined that fasteners with hardness within 10% of the specified. strength were adequate. This meant reducing the minimum hardness for B7 studs from 26 HRC to 23 HRC and,2H nuts from 24 HRC to 22 HRC. We found 40 pieces were acceptable with this. criteria. This engineering judgment was substantiated by - the evaluation performed on the remaining 185 pieces. The remaining 185 pieces come from 26 different locations within the plant. An evaluation specific to each location we.s performed to determine if the pieces had adequate strength. We analyzed each of these ISS pieces in a manner consistent with the class of each item and found that in all cases the actual material properties were adequate to ensure the structural integrity of the system. Data relating to these results are listed in Attachment 1. j 1. T. Conclusion From the above, we conclude that although a significant number of pieces did not meet + their originally specified requirements, all would have functioned to ensure the structural integrity of their system. Because our testing _ and evaluations of the 1539 m-L fasteners yielded adequate results, we are confident that the use of commercial quality' ' *, fasteners in our Class I, 2 and 3 systems never posed an.anreviewed safety question, y, e immediate Preventive Actions q In early June 1987, BG&E initiated a comprehensive investigation to identify the root Y l cause of the mechanical fastener traceability situation that had arisen at Calvert s. l Cliffs. Several issues were identified for which corrective action was felt to be -R.' j prudent, but the primary causes were found to be (1) inadequate awareness of the / I material quality and traceability requirements for mechanical fasteners used in the J maintenance of AShfE Class I, 2 and 3 systems, and (2) the absence of formal easy-to-use ;p }h documentation to assist our personnel in the identification of code coundaries during maintenance planning activities. To correct these problems, maintenance personnel and quality control inspectors were given special training and instruction on the code requirements that apply to fasteners in Class 1. 2 and 3 systems, in addition, formal guidance documents were provided to maintenance personnel to' facilitate the identification of code boundaries during routine maintenance planning activities. These actions ensure that present-day maintenance activities affecting Class 1. 2 or 3 systems are identified as such when l

,a . ; W QW ; & W- ' yy Q, o, ur e

m: .

_u '3 . Dccuser,t Control Desk - i-Me W{' . ' + . ;,j[ Septenber 30,1987 L. Page 3 p e i o. s.,. ( V n the maintenance: order is written and that appropriate replacement fastener materials l.; are specified eccordingly on the maintenance order form. To monitor the performance of 7:p', individual maintenance work activities in the field, quality control inspections are C conducted in accordance ~ with existing QA program requirements. y $gnolemental' Actions ) i The immediate actions described above provide reasonable assurance that-all applicable i P material quality and traceability standards will be maintained in current and future maintenacce activities at Calvert Cliffs. Nonetheless, a number of supplemental actions are presently under consideration which would simplify and further improve l procedures for controlling the procurement, storage, and use of mechanical fasteners. The objective of these supplemental initiatives is to make the overall maintenance process more effective' and thereby less prone to error. Examples of these initiatives include: o Replacement of the commercial quality (72/78 series) fastener stock inventory with Nuclear Class I fasteners; o implementation of 'a fastener standardization program for all fastener applications in the plant; 9 o Development of a comprehensive computer database for use by engineers, maintenance planners, and purchasing personnel in ideetifying specific code requirements and allowable procurement methods for each piece of mechanical l equipment ; and b -) Upgrade of the material descriptions in the material management system (MMS) o computer. database to improve consistency in stock item descriptions and to provide more flexibility in the types of computer sorts that can be

7 L

l performed. L i [ Should you have further questions regarding this matter, we will be pleased to discuss them with you. Very truly yours. f 4:a; u l1 [ , ', 'd.'. t. ( IN ,,:jfjh WJL./SRC dlm M, Attachment di i cc: D. A. Brune, Esquire J. E. Silberg, Esquire l R. A.Capra, NRC l S. A. McNeil, NRC W. T. Russell, NRC l T. Foley/D. C. Trimble, NRC 1

1 f: a gga, .. g.s. ,. s,y.; -, ~,. c;.. . s,,. y ..o ..v. /.. ~ ' ~- @ - .e 4*.'i,- hat CMI Desk ; j ' F Septenber 30,"1987 ' - f' y.: Page4' ey

g l

, u

~ :. :L (' o.vz.,, bee:. J. A. Tiernan -4 ' R. F. Ash /Ri C. L. Olson -

'i '

C. H. Cruse /P. E. Katz 1 R. E. Denton/J. A. Mihalcik . R. M. Douglass/S. E. Jones, Jr. T. N. Pritchett/M. Gavrilas/E. I. Bauereis J. R. Lemons /R. P. Heibel W. J. Lippold/A, R. Thornton 'j F. J. Munno R. B." Pond /R. E. Cantrell L.' B. Russell /J. T. Carroll R. E. Lapp j C. M. Rice R. G. Staker ) W. R. Hortacher, III D. L. Shaw, Jr. L. S. Larragoite S. R. Cowne. P. E. McGrane M. E. Bowman /L. E. Saiyards 'f 9 g. 3 >s e s q'. .A$ y' ---w-, -%w ,.vy,- --,,,,yy c.._, ,.9 y_ -N-- y

mew-r =

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hF.:..M,U-l;&M..(. [>Y.nw - @p39 $. 4 A '4 NmL w/. .p g .o.,j,.; % 3.- , e i ATTACHMENT 1 ,.WW' ti jc, e s.. X: y; 3 r ,2 ,1- '. L MCQ FASTENER STRENGTH EVALUATION i _3 p i' f .l

4, ny Dese.- l-- Spec.

Comuneat $g } p ( T Hardness Strength (KSi) A O ~* MO s' Piece # .g.: r;q l 590A. .1 f 'S MS. B7 22 HRC 112' Chemistry OK I[. E Forging Lap 2 <f 4; J ' 494 A ' 6 N $. 2H e '651 A'. 6 'N Tii 2H 10.3 HRC 90 Chemistry OK $ l: 1564 A-1 -7.- S B7 90 HRB 89 - Stainless Steel 3 n. 564A. ' 14,15,16 N-2H 90 HRB 89 Stainless Steel 4] 781A 1-12 B SAE 2.5 HRC 80 Low Carbon Steel Grade 5 ai > c: 1 781A 15-20 B 16 SAE 5.0 HRC 86 Low Carbon Steel / Grade 5 ~! g\\q # I8-781A 21-40 N. 2H 5.4 HRC 86 Low Carbon Steet ) 667A 21-52 N 2H 88 HRB 85 Low Carbon Steel' Forging lap. $98D 6' N 2H ) .585A

9-24 N

2H 10 HRC 90 Low Carbon Steet j 607A '3 B B7 88 HRB-85 Low Carbon Steel ' 607A 4 B B7 80 HRB 72 Low Carbon Steel"~ < a 607A 5 N 2H 72.7 HRB 65 Low Carbon Steel ~ s $M6B-3'b N W. 2H 20 HRC 106 Cnermstry OK g 1' 302A 21 N 2H 20 HRC 108 Chemistry OK ",. s. i 850A. 9-24 N 2H 88 HRB 89 Low Carbon Steel. -(*22)

~

I, ~. IL YJJ, L, 797A 2,4 S HB B7 22 HRC 11 Chemistry OK 4 [ 646A 3 S B7 75 HRB 68 Low Carbon Steelp 2H 10.3 HRB 90 Low Carbon Stee " 7(4 850A 9,10,12 N (*21) 14-23 670A 2 N 2H 15 HRC 94 Low Carbon Steel i 1-

. sl ,j, Q :h.. 4 W ;Jlru. e. .;O x.. ? ;; i:' ; m.? : ?.&MtW ? . d4,. ,7,7 pg. .s .. a y. (..,.,./,',.f.e-ATTACHMENT I '6,. i q e. l.<..yy MCQ FASTENER STRENGTH EVALUATION . L, 7 >y J,;; g!. ..1 ' ' t...g t. s 4 7.g l MOe Piece # Desc. Spec. Hardness Strength (KSi) Counment

{

. w. 76tA 1,2,4,5 5 B7. 90 HRB 89 Low Carbon Steel ' 76tA 6 S B7 22 HRC 112 Chemistry OK 761A 10 16,19-21 N 2H 92 HRB 93 Low Carbon Steel ~ ' ~718A. I B B7 16.5 HRC 95 Chemistry OK 588A '4 'B $ B7 71.4 HRB - 62 Low Carbon Steel' 588A 8 N 2H 86 HRB 81 Low Carbon Steel-77tA 17 S B7 21HRC 110 Chemistry OK 601A 5 S B7 21HRC 110. Carbon Slightly Low 850A-4 S B7 21 HRC ' 110 Chemistry OK (=23) i I 850A 9-24 N 2H 90 HRB 89 Low Carbon Steel 1 837A 4 B SAE 19.5 HRC 106 Chemistry OK .i Grade 5 837A 10 - N-2H 90 HRB 89 Low Carbon Steet... 768A 1 B A325 Forging Lap l 696A 4,5,10-13 N 2H 70 HRB 62 Stainless Steel ', Y, 757A 21 N TS 2H Forging Lap t: ~s \\; l jf, i dh'$. N = Nut - - 1 S = Stud ... ch B = Bolt q.,, l 1 ,.ls. I' Chemical composition was in specification. 2 Indications that were found by NDE. 3 Piece was composed of stainless steel. 4 Piece was composed of Low Carbon Steel. 1i1 L 2

4 [f. E' .. j 'i i f f '. p f J t e $ p 1 e , - ,j '/ ~ Y ! f g M W,' < + j'f. Tj g [ V l ~~ A 7 Q 7, ,17 c.*, .g ,j.i EALTIMOME i ':k M. Jc . O AS AND " C' > i ELECTRIC 3 .v ry:, u i CHARLES CENTER

R O,toX 1475
BALTIMORE. MARYLAND 21203

,w . JoscPM A.TitRNAN vice Passionat + Nue w a t=.., f May 12,1988 L U. S.' Nuclear Regulatory Commission Washington,' DC 20555 ATTENTION: Document Controf Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant m Unit Nos.-l & 2; Docket Nos. 50-317 & 50-318 Fastener Testine . Gentlemen: 3 . On November 5,1987, our Project. Manager, Scott McNeil, selected ten bolts and two nuts from our warehouse with the -intention of testing them to determine their physical properties. We selected an equal number of fasteners from the same bins and tested them at our material testing facility. ~ 'At Mr. McNeil's request, we hase attached a table summarizing the results of our testing. Please send us the results of your testing in a format similar to the attachec table. We = found three minor discrepancies with the specification requirements, J s [1 tat Discrenancy r '72-175(1) Hardness was 0.3 HRC (or 1.2%) below the minimum hardness of 25 HRC. 72-175(2) Hardness was 0.4 HRC (or 1.4%) below the minimum ^7 hardness of 25 HRC. e 72-229(2) Hardness was 1.5 HRC (or 4.4%) above the maximum hardness of 34 HRC. <j These hardness variations are minor and, based on past experience, would not adversely affect the strength or ductility of the material.

'E e .m e g.p ge p]:. 4 ,. P . K t 4.!.ygT ,3 . Document'CoCtro1 Desk w. ..i . May.12,1988

Page 2 -

7 v 2 y' {. 'j E 2 i Mr. McNeil also requested a list of vendors that BG&E purchases fasteners from, or have. 'y i (' purchased fasteners from in the ' past. We have attached such a list. It is not j Intended to.be all-inclusive, but it does represent our principal vendors. AM. t: Shoulf you have any additional questions regarding fasteners used at Calvert Cliffs. e j please do not hesitate to contact us. Very truly yours, / (&V& t i. / s. i.' k JAT/ WPM / dim ' Attachment cc: D. A. Brune, Esquire F J. E. Silberg, Esquire R. A.Capra, NRC S. A.McNeil NRC W. T. Russell, NRC D. C.Trimble, NRC P p l n k 'i}p M .n.e. 4 ,e .e p ..n----

w w 'q ~ A a 4 'A 1 ELSMENTAL WEIGitT PERCENT. ^ IIARDNESS PART ID MARKINGS SIZE C Mn P S-Si Cr Mo (HRC)_. 72-155(1) KS Grade 5 5/8" x 1" 0.375 0.973 0.025 0.025 0.222 0.089 0.02 30.1 i j 72-155(2) FM Grade 5 5/8" x 1" 0.324 0.911 0.012 0.017 0.230 0.072 0.02

30.2 s

72-165 FM Grade 5 9/16" x 3" 0.303 0.876 0.013 0.017 0.252 0.106-0.01 26.1 72-175(1) Grade 5 3/8" x 3" 0.384 0.824 0.015 0.018 0.242_ 0.066 0.01 24.7 72-175(2) Grade 5 3/8" x 3" O.451 0.830 0.015 0.020 0.259 0.063 0.01-24.6 i 72-218(1) KS Grade 5 5/16" x 1 0.464 0.801 0.023 0.024 0.237 0.084 0.02 27.3 72-218(2) KS Grade 5 5/16" x 1 0.401 0.832 0.023 0.022 0.236 0.084 0.02 26.2 i 72-226 J Grade 5 3/8" x 1" 0.399 0.882 0.016 0.015 0.035 0.269 0.00 25.7 72-229(1) KS Grade 5 1/2" x 3" 0.357 0.906 0.014 0.016 0.240 0.079 0.01 33.7 72-229(2) KS Grade 5 1/2" x 3" 0.358 0.868 0.014 0.017 0.249 0.080 0.01 35.5 l 445767(1) (-)2It AME ut 1 1,'3" 0.448 0.839 0.026 0.017 0.237 0.130 0.01 25.4 ,u 445767(2) (-)21t AME Nut 1 1 8" 0.399 0.925 0.026 0.023 0.239 0.153 0.02 26.0' '( / w.. .M iy i Table No. 1: Chemistry and Ilardness Results a ,s

N

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f.h O % v -j, m.. - of 8 f }4 BGAE Fasteners j g,+ FQ l .( l.- A&G Engineering Company j: 4640 East LaPalma Avenue i, Anaheim, CA 92806 Tet (800) 242.6587 ~,- ' 2. Leonard Jed, Company 1301 Covin8 ton Street i + Baltimore, MD 21230 Tel: (301) 685 1482 l c 3. Kenneth O. Lilly Fasteners t P. O. Box 6005 l Tel: -(302) 366 7640 Newark DE 19711 4 Standard Nut & Bolt Abbott & Hatch Streets Cumberland, RI 02864 Tel: (401) 722-6700 f 5. Sta-Put Fastener Manufacturing Company 3900 Vero Road - i Baltimore, MD 21227 Tel: (301) 247-5500 6. Vincent Brass and Aluminum Charlotte, NC 28230 Tel: (800) 438-6914 m 7. Mil Spec Fasteners s Route 30 Box 59A Hampstead, MD 21074 l Tet (301) 239 7761 3 4 8. A & A Bolt & Screw b 1110 Batavia Farm Road ';Y Baltimore, MD 21237 Q> Tek (301) 687-8831

v1 9.

C-S Metal Services, Inc. 4' I l: 7325 Washington Boulevard l Baltimore, MD 21227 W Tet (301) 796-5661 { p l-l' I l.. e ~..

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'f p-g' a .s,. j } ff. Es. 88WC444R eetWhafgev eensensMi h,I l!lj gl A8Peeste east age pinseggs l' LICENSEE EVENT REPORT (LER) 4C448TV Isaast ni Doest? - A W. su ig .Calvert Cliffs Unit 1 e s l e le i e l 31117 1 lorl01 ( { h'"

Use of Fasteners (Bolts, Studs, Threaded Rod & Huts) in A$NB Class 1, 2, & L Systems vfthout Proper Certification, Special NDE, or Special Marking.

l

, a, i.i u..n et....m., e. 3 =,. ae::e, en i.o.,t. o, ..mi..a e .ec.. i. Calvert Cliffs, Unit 2 e is le g e t s l 3 il 13 0l4 2l3 8 7 8 l7 0 l0 l 9 0l2 0l2 0l3 8l 8 e isle ie i ei g i ~ ~ ] vae ni.on, e sve.mio ev w=, to T neavinewsm e, se een a <c ,, en. ""*8 se semi se es i w,s.nen parine ~~ ~ in n==.nuw um nu m m.ien. tmw 'W' ~ ~ ~ ~ 1 l0 se me=uum w ss iei es tmismei on.ea ts +. 4 n assi.iones es vs.imuu es tsi ien.muAs 5 " * #*** **# #*" ~ ~ ~ s n essanuo.i 1 se ts ion.i se to.ian simi n.e. iiu... .m ie., n n.ien.. ticiases co= tact eon tas um nai 'itwt TIsee one arvenesa .aga coot Bruce Montgomerv. Senior Enrineer 31011 21610l-l 3191416 cowtate o= ti= een saca cowo e=t saisvas oncaiseo in two me.oes na ";3;'t "$'o%,'jf

y;'t-aig*lp,jgg civis i,it s.

co - o=== cavn i,trou co-o=ent he l l I i l 1 l I I t l l 1 I n. I I I I I I I I I I i 1 I l at ~ Sv.ptlut=1 6 htoont t aptcTtD tier t arta ca. v8AA eve..m.o., sti (99 ree semoeer 12.ttelo Sugecrgsoo= ce tte =o l l l aest a act <t . > =.,.. .~,. n , ne, 3 On April 23, 1987, with the unit in cold shutdown, we determined there were instanc4unere cocarcial-wality fasteners without tne requisite material - :.1i. traceability and certification had been installed in ASME Section XI Class 1, 2, and 3 systems. There are no similar events previously reported in an LER. We h' reviewed all maintenance work performed on ASME Section XI syctems since initial plant operation (approximately 40,000 maintenance requests, or MRs, were involved) and found that commercial quality fasteners had been inappropriately ? used in 61 cases. These fasteners, totalling over 1600 studs, bolts, and nuts, j were removed and replaced with properly certified fasteners. The removed fasteners were tested for strength and chemistry. The testing revealed only 16 fasteners were judged to fail ASTM specifications. However, the results showed that 115 of the fasteners were made of a material different from the unterial grade that was specified for the locations they were installed. Engineering i N analyses showed that in all cases the fasteners would havet performed their intended functions under accident conditions. The causes of this event have been identified and corrective action has been taken to prevent recurrenc's. ~q _..

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( ;,. s, s. ,,g, n t essa sea US tsWCLlat Decutattav eg.ameses, ) UCENSEE EVENT REPOR7 (LERI TEXT CONTINUAT90N aa =oveo ein no om-eim M ' enmee see 9 1 .aseksTV esaans sie B2Cattemme64 et sta antasete see . Paes can "!MP ll'3G y Calvert Cliffs. Unit 1 e is le 18 le 131117 8 17 0l0l9 0l2 0l2 or 0l8 ventn e ancamuwim On April 23, 1987, with the unit in cold shutdown, we determined there were 1 instances where commercial quality fasteners without the requisite material I traceability and certification had been installed in ASME Section XI Class 1, 2, ) and 3 systems. There are no simi)ar events previously reported in an LER. We reviewed all maintenance work performed on ASME Section XI systems since initial plant operation (approximately 40,000 maintenance requests, or MRs, were involved) and found that commercial quality fasteners had been inappropriately used in 61 cases. These fasteners, totalling over 1600 studs, bolts, and nuts, were removed and replaced with properly certified fastenors. The removed fasteners were set aside for subsequent testing. The test results are' summarized in this report. In our earlier reports, LERS 87-009 000 and 87 009 001, we concluded that this event was caused by: inadequate precautions placed on repair and replacement planning activities regarding the use of safety related fasteners purchased by the commercial qualf ty method, an overall lack of awareness of the material quality and traceability requirements for mechanical fasteners used i within ASME Section XI boundaries, and the absence of formal, easy to use documentacion to assist our persor.nel in the identification of code boundaries during maintenance planning activities. While these were the primary causes of the event, we now conclude that two additional conditions existed which contributed substantially to the event's y severity. The first condition was a la:k of specific written instruction to mechanics regarding the proper material grade of fasteners to use on a job. The second condition was the presence of a " free stock" supply of fasteners inside the plant which had a composition that was hishly conducive to error in the selection of fasteners. The purpose of this Aupplemental report is to identify: the causes 'and i iniplications of this event and to describe the actions taken to prevent recurrence. A total of 1689 uncertified fasteners (studs, bolts and nuts) were removed from ASME Section XI Class 1, 2, and 3 systems and were bagged and tagged for 4 testing. of these, 50 pieces were misplaced or mislabeled and 100 pieces could not be decontaminated. Consequently, there 150 fasteners could not be tested. The remaining 1539 fasteners were tested to determine their physical and chemical properties relative to the strength and material composition requirements ~, specified for the systems in which they were installed. The results of this testing program are summarized in Table 1. _ g.3...,. ,,e o. ~. a & ~

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J (1) Each piece received a surface examination, l: a hardness test and a chemical analysis, j il Bolt heads and studs also received a magnetic particle test. Test results were compared against the ASTM standard applicable to the system or component the piece was removed 4 from. In the majority of cases the applicable standard was ASTM 193, Crade B7 for studs i and bolts, and ASTM 194, Crade 2H for nuts, s. (2) Most of these bore no markings. ] A EOS I@OM MO g y $ N ONNh. M c4BI ..,. -...... ~. - - _... - -. - -. -. -. ~...... -. - _ _ - _ _. _ _ - _ _ _ _ _ _ - _ - - -.. - - _ - - - -. - - - - - -

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.amn, - n, ees..,.... unver,n =r!teg ,g Q l oft 01 2 0l 4 or 010l9 Calvert Cliffs, Unit 1 o lslel ole l3l h 7 8l7 von n.-. a - anc a an.wm H 4, The 131 pieces which did not meet specification had been installed in 25 j different locations within the plant. Using the measured strength of each piece, j an engineering evaluation specific to each location was performed to determine whether system scructural integrity had been compromised. In all cases the actual material strength properties were more than adequate to assure systen integrity. Because the unit had operated across its full range (0 1003 power), including transients, these fasteners were subjected to the full range of l operating conditions. Additionally, the analyses that were performed indicate that the fasteners would have performed their intended function under accident conditions. Therefore, there is no safety significance associated with this event. -A detailed investigation was conducted to determine the specific circumstances.which led to 131 pieces being out of specification (0.0.S.). Each piece was visually re examined for markings or any other physical attributes that are characteristic of material grade. The chemistry and hardness test results were also closely re examined. Based on this re evaluation it was determined that.the majority of the 131 fasteners in question were out of-specification because they were made from a different material. Whereas ASTM-193 87/ ASTM 194 2H (for bolts / nuts, respectively) was normally the material specified for use, these pieces were predominantly ASTM-307 8/ ASTM 563 A material. The results of this evaluation are presented in Table 2. TAB 12 2 RE-EVAIDATION OF 131 0.0.5. FASTENERS 8 DEVIATION NUM111.l M CATEGORY IIEN QF PIECES a. Other Material Stainless Steel Studs 8 Nuts 9 ? ASTH 307 5 Studs / 2 Bolts ASTM 563 A Nuts 96 TOTAL 115 1 .v s om iseo+e 4. san,4e'e geonw me

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other (possible Bolts / 12 Studs j. manufacturing _ ' process deficien. L - cies) L TOTAL 1ft {' I GRAND TOTAL .J1L Iw; l During this review a very strong correlation was found between the presence R 'of ASTM grade markings and passing test results. The only exceptions to this L were the four forging laps and 12 failures attributed to possible manufacturing l process deficiencies. An even stronger correlation was found to exist between D i-pieces that bore no markings and those that were determined to be l; ' ASTM 307 B/ ASTM 563 A saterial (mostly A 563 nuts). This should not be unexpected as the ASTM standard does not specify any unique marking for this G M j; aclass of. low carbon steel,' and it is normal and customary iridustry piact" ace tu j supply this material without markings. A-307/A 563 material is a low carbon steel with a lower tensile strength e relative to A-193/A 194 (which is a medium alloy steel), and ts normally } l specified for use at Calvert Cliffs in lower stress bolting applications. These l: i L applications include flanged connections in certain low pressure fluid systems, y g 'some piping supports, aiscellaneous structural applications, etc. These

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UCENSEE EVENT REPORT ILER) TEXT CONTINUATION 1 sense w e k j i amu" unas m oneen musse ei ue,,um ,, s .'m m W-oft 010l 9 0 11 0[ 6 os Calvert Cliffs, Unit 1 oIslejojel3lh7 8l7 Another investigation was then conducted to determine how A 307/A+S63 / material became instslied in systems where A 193/A 194 material was specified. We reviewed the original maintenance orders under which these particular fasteners were installed, and found in virtually all of them that instructions r*5arding fasteners were either insufficient or absent. In many cases the maintenance planner focused on providing guidancs for other aspects of the job and may have assumed that the nochanic would know which fasteners to use. In other cases, such as with the simple replacement of gaskets, the planner apparently did not foresee the possibility that new fasteners could be needed. In each of these cases, the mechanic was left without specific written guidance, and apparently the mechanic did not request that this guidance be provided before starting the job. To determine the source of A 307/A 563 fasteners, the warehouse inventory was checked and we found that safety related A 563 nuts were commonly stocked in significant quantities and in 19 different sizes. A 307 studs and bolts, on the i other hand, were found to be stocked in rather limited quantities. An inspection of the commercial quality, safety related " free stock" staging area in the plant machine shop revealed that A 563 nuts were readily available to mechanics in all 19 sizes. These nuts were stored in bins adjacent to bins containing A 194 2H nuts. The bins, while marked with size and material stock number, were not marked with the ASTM' grade. For cases where mechanics were not given specific instructions on either the applicable ISI Class or material grade, the above situation was highly conducive to the chance use of A 563 fasteners. It shouId be noted that none of the fasteners (neither the A 194 nor the A 563 nuts) obtained from the free-stock storage area were appropriate for use in 4; ASME Section XI systems. This is because they were procured by the ~ commercial quality safety related method and therefore did not have the ' *inoividuai starerial traceability required for use within Section XI boundaries. , t' l The main reason they were mistakenly used was a perception on the part of some of our personnel that these fasteners, because they were safety related, were qualified for use in any safety related application. Once this error was made and fasteners were drawn from the free stock area, there was a good chance that

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012 01 7 or 0 1 I p; 01019 Calvert Cliffs, Unit 1 o ls lo le j o 13l1l 7 81 7 ven e-. a aac wan.wim y Based on the investigation findings summarized above, the following statements can be made regarding the implications of this event: l 1. Procurement control or receipt inspection practices did not contribute to this event; 2. No underlying trends were found in the test results to indicate that any manufacturars were supplying substandard, missarked or fraudulent fasteners. In fact, the test results suggest a consistently high level i of material quality; 3. All causes identified were internal to BC6E and pertain to the administrative controls governing the selection and use of fasteners in maintenance work; and i 4. No evidence exists that the structural integrity of any safety systems has been compromised by this event. The following actions have been taken to prevent recurrence of this event i and to ensure that mechanical fasteners used in maintenance activities conform to applicable ASME and ASTM requirements: 1. Maintenance planners have been instructed to clearly identify the applicable code class on each maintenance order and to specifically q; identify any spare parts that may be needed to complete the job. 43; Tasteners are specified by grade. and mechanics have been instructed to check fasteners for proper grade parkings prior to use. M. 2. A color coded set of PGID's were developed showing ASME Section XI .fi Class 1, 2, and 3 system boundaries. These P&ID's'are used by the 4 maintenance planners to confirm the applicability of code requirements s on each job. This will ensure that ASME repair and replacement program 9% requirements are properly applied to maintenance work. u. 3. An approved repair and replacement program complying with ASME Section [k XI, Addenda through Summer 1983, has been implemented. Appropriate engineering, maintenance and quality assurance personnel have been D, trained on the program.

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All A-563 nuts were removed from the " free-stock" supply area in the plant and returned to the Calvert Cliffs warehouse. This will eliminate the possibility of further errors in the use of A 563 g material. .u e o.o w m..md

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=. "MMt' =trrr Calvert Cliffs. Unit 1 e [e le je le ! 311] 7 01 2 018 oe 018 47 010l9 1 we e .ac w an.. in The actions described above provida reasonable assurance that material quality and traceability standards applicable to fasteners will be maintair.eu in current and future maintenance activities at Calvert C11tfe. Additional actions will be implemented during 1988 that will greatly simplify and improve control 1 over fastener procurement, storage, and use. These measures will further reduce j the potential for error, and will reduce overall costs. They include the development of a standardized fastener program which substantially consolidates the Calvert Cliffs fastener inventory both in terms of quality level and material grade; performing a review of all mechanical procurement specifications to J identify original construction code requirements with the (,bjective of extending i the benefits of lessons learned from this event to oth w mechanical compenents besides fasteners; consolidating all mechanical maintenance and spare parts related information within a comprehensive computer datab.;se for use by maintenance planners and engineering personnel; and improving our spare parts inventory database to clearly identify the code class for which parts are qualified, l l l t l % \\\\ t .v me w. .E . _, ~ _ _ _, _ _ _., _ _. _. _ - _ _ _,.. _ _ _ _ _. _ _ _ _ _ _ _. _ _ _ _. _ _ _ - -

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t NUCL RA c=w.E,AR o, PEve.a.te0.N.S DE.PARTMENT

. m m.a i w, .c.e 'i. W P i Tebruary 3,1988 U. S. Nuclear Regulatory Ccomission Docket No. 50-318 Docunent Control Desk License No. DPR 69 Washirgton, D. C. 20555 l r

Dear Sirs:

'!he attached revision to IIR 87-09 is beirg forwarded to you for your j infomation. i Should you have any questiors regardirg this report, we would be pleased to ciscuss them with you. l Very truly yours, f og' !J. R. bs ~ L (- Mana er - Nuc1 car Operations Departnent at [ H,.. i JKL: 1:wm 4,., . [ t

rm cc: William T. Russell Director, Office of Management Infornation

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\\s[3, ' " ' [ ,s 'f4: f o o 64 ifl y* d, 4 r/J {; i, 8:y ; ' t s f. . ;i* j l d. i l FRANKLIN RESEARCH CENTER DIVISION OF ARVIN/CALSPAN l l i I i 6 ANALYSES or SA-193 AND SA-325 TASTENERS i FRC PRCUECT $896-018 l t I i USNRC Contract NRC-05-83-216 Task Order No. TA-N-220 l Prepared for i Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission ( j Warbington, DC 20555 .~ i bt NRC Project Officer: P. Cortland FRC Engineer L. Leonard 1 ( l ( .~ s i j f { Noven.ber 18, 1986 /! l at This report was prepared as an account of work sponsored try an opency of the United States h i, Government. Neither the United States Government not any agency thereof, or any of their 1,8 i employees. makes any warranty, empressed of implied, of assumes any legal liabilty er jM responsibility for any third party a use. or the results of such 000, of any information, appe. . {. t ratus, product or process disclosed in this report, or represents that its use by such third l' . party would not infringe privately owned rights. .f l l>b. l Prepared by: Moviewed by: Approved by: f AA 2% U1,~ f/W Principal Author ( " epartment Iredor osie:Wu oeio:/.xu os,e ro 20TH & RAC( sTRr[Ts PHILADELPHLA. PA is103 Twit 710.s70-1sse TEL (216)44s 1000 I f A//

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,,.,;p,- 4 ]L, ~j s 's ^ 7 y., 1 1 no,6-le .. e )l Jg 4 ,d. .cg a. . ; t. + CONTENTS-4 ?7 Sect (on 71 tie ?,agg 1 INTRODUCTION 1 2 ANALYSES AND DISCUSSION 3 '2.1 Chemical Analyses, 3 3 I 2.2 Hardness Testing a',, 2.3 ' Macroscopic Characterisation 6 g 2.4 Microstructure e 3 CONCLUSIONS. 9 4 RETERENCES. 10 3 i i I 't k I g b a , 9 e4*k.I i 6 .j $I t b l iii 2 1 4

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) l y; F5896-18 9 4 o t 9, 1 ";. ; 1 f '-{ 1. INTE CUCTION ..? -l i r The Tranklin Research Center (TRC) conducted a series of analyses in ..~ order to characterise a group of high strength studs and bolts that were j .c ' I representative of stock in supply bins in nuclear power plants. In particu-1 !ar, it was of interest to determine if the bolts met the specifications 1 i required by their markings. This investigation was undertaken as a direct result of a recent Industrial rastenere Institute research report (1) which cited extensive evidence of falso markings on Grade 8 bolts. i Three different grades or classes of bolts and stud fasteners were submitted to TRC by NRC Region I personnel. Table 1 lists these fasteners in { groups in accordance with imprinted markings and by numbers assigned by the i NRC. The markings on eight fasteners indicated they complied with ASE SA-193,57 [2] requirements, four to ASE SA-325 [3), Type 1, and one to ASE l L SA-193,B8 [2]. j i As discussed below, samples from each of these fasteners were subjected to chtmical, hardness, macroscopic, and microscopic analyses to check for { compliance with the relevant specification as well as to characterise the uniformity and general quality of each fastener. l P P i L I ^ i ? r

l 1, I, . -.,z..... p a.i, e_, z,, y,,.q 4 .- m <..s o + F5896-18 2' b ' M' - Table 1. Bolt Identification o u x,hi e Sanele Sise Ssig Grade I~ f' ?l 1A Stud 5/8x4 SA193 57 5A Bolt 1/2x4 [~ 6A Stud 1/2x4 1/2 4 7A Bolt 5/8x3 3/4 i j 9A Bolt 3/8x3 a 10A Stud 3/8x4 1/2 12A Bolt 5/8x4 l 13A Bolt 1/2x2 3/4 i; i-L 2A Bolt 5/8x4 SA325 1 4A Bolt 1/2x3/6 8A Bolt 7/8x2 1/2 11A Bolt 7/8x2.1/2 r 3A Bolt 5/8x3 1/2 SA193 BS kl. .. s i v,, f 5 4 l-2-

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2.

ANALYSES AND DISCUSSION V-,!

i l i 3 w: 2.1 CHD(ICAL ANALYSES <l The results of the chemical analyses, along with the specified chen r ' ;l'.s'.-l

L

- } istries, are presented in Table 2. For the SA-193,37 fasteners, it is evident } that, with the exception of a slightly low carbon content for bolt 5A and a high molybdenum content for bolt 7A, all the chemistries were within the f limits of the spircifications. The deviations for 5A and 7A would not be l expected to compromise their service performance, i Although bolts 2A, 4A, 8A, and 11A contained boron, they nevertheless g were correctly marked as Type 1, based on their carbon contents. While boron is required in Type 2 fasteners, it is neither required nor forbidden in Type 1. 3 L Finally, bolt 3A's chemistry complied with the SA-193,B8 specification. f i The mismarking of Grade 8 bolts reported in Reference 1 primarily involved the substitution of plain carbon, boron steels, which should have f been marked as Crade 8.2 under SAE J429k (4), for medium carbon alloy steels. l Tor the fasteners tested by TRC, a comparable situation would be an SA-193,87 l marking on an SA-325 material bolt or stud. From the data in Table 1, it is clear that there was no such mismarking on the samples studied. i i f 2.2 IO.RDNESS TESTING Hardness testing was carried out on the as-received outside diameter (OD) l surface of the shank of each bult, on a finely ground transverse cross section j j of each fastener, and on a metallographically prepared longitudinal cross section of each fastener. In the latter case, micro-as well as macrohardness [ testing was conducted to obtain data nearer to the 00 surface, i.e., near the l threads. The averaged results of these tests are given in Table 3, along with f specified hardnesses. In addition, the approximate tensile strength of each I bolt, based on the average hardness data, is tabulated along with the g specified tensile strength requirements. With the exception of some low readings on the as-received OD surfaces (likely reflecting the inherent errors in testing on a curved, rough surface), all b.ntdnesses (and hence, the approximate tensile strengths) for the l - -- -

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? e. a Table 2. Chemical Data for Bolt Evaluation . '..I, - ~ Chemistry Sample Spec Grade C Mn P S E _ Cr __ No. Ni _3 SA193 B7 0.37/ 0.65/ 0.035 0.040 0.15/ 0.75/ 0.15/ 0.49 1.10 Max. Max. 0.35 1.20 0.25 '- 1A Stud 0.40 0.92 0.014 0.017 0.25 1.04 0.16 5A Stud (0.35 0.91 0.018 0.013 0.33 0.98 0.16' 6A Stud 0.42 0.97 0.010 0.015 0.27 1.00 0.17 7A Bolt 0.42 0.62 0.019 0.013 0.26 0.93 65D' 9A Bolt 0.39 0.91 0.021 0.018 0.25 1.00 0.15 10A Stud 0.43 0.97 0.022 0.014 0.30 0.91 0.17 12A Bolt 0.43 0.83 0.018 0.018 0.28 1.05 0.18 13A Bolt 0.40 0.90 0.024 0.013 0.27 0.91 0.16 e. f4 ' 7 SA325 1 0.27 0.47 0.048 0.058 ~C Min. Min. Max. Max. i SA325(1) 2 0.13/ 0.67 0.048 0.058 0.0005 m. 0.37 Min. Max. Max. Min. 2A Bolt 0.42 0.71 0.010 0.021 0.002 4A Bolt 0.37 0.71 0.017 0.012 0.002 ? 8A Bolt 0.34 1.00 0.17 0.026 0.001 11A Bolt 0.40 0.78 0.018 0.020 0.001 SA193 B8 0.08 2.00 0.045 0.030 1.00 18.0/ 8.0/ Max. Max. Nr. Max. Mer. 20.0 10.50 3A Bolt 0.06 0.99 0.03 0.013 0.64 18.48 10.0 1. Although the bolts in this group were merked as Type 1, the chemical requirements for Type 2 are included boomene h boron, which is not defined in Type 1 requirements, was present in the bolts.

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~ ~ ~~ _,_ - _, _q .} .a- . _. n _ Table 3. Hardness Data for Bolt Evaluation i Macroherdness Microherdness(4) Tensile j Mid W NeerI3I St @ (3) ~ semple Spec Grade Sarface(I) h (2) Radius Center (2) Center (3) Center (3) Throeds (ksi) SA193 B7 26RC Min. (based on 125 ksi Tensile Min.) 125 Min. j IA Stud 29RC 30RC 29RC 26RC 23RC 28 132 ,~ SA Bolt 27RC 33 32 31 31 -31 142

^

6A Stud 32 28 31 28 30 136 ~" 7A Bolt 26 31 29 30 28 30 136 C I 9A Bolt 28 30 30 30 27 29 136 a 10A Stud 29 29 30 27 26 132 12A Bolt 26 32 31 142 j 13A Bolt 24 30 32 136 I ~ SA325 1 24-35NC 120 Min. SA325 2(7) 24-35R 120 Min. C j 2A Bolt 27 32 33 32 32 30 29 142 4A Bolt 18 27 23 22 21 19 29 118 8A Bolt 28 32 33 31 30 30 142 l 11A Bolt 20 31 30 29 26 35 136 1 1 l l SA193 38 Class 1: 96Rg Max.(6) (82Rg Min. based on 75 kai Tensile Min.) 75 Min. j Class 2(8): 35RC Max. (27RC Min. based on 125 kei Min.) 125 Min. l 3A Bolt 85Ng ISRC 19RC 19#C 100Rg 37 35 106 1. Hardnese measurements on the as-received outside surface of the shank. l 2. Hardness measurements on transverse cross sections. 3. Hardness measurements on longitudinal cross sections. j 4. RC or Rg converted from Knoop readings. h[, 5. Approximate tensile strength based on average hardness. -g*, 6. For sine 3/4 inch diameter and smaller, a maximum of 100 R B is permitted. ei 7. Type 2 specification requirement included per Note 1 in Table 2. E i 8. Specifications for Class 2 are included for comperison, since test hardness values were at the uppec lianit j of Class 1 requirements. ilC

T [ g; f [ e e n.,s-1. n: c;g \\ [ I A c $A-193,87 fasteners met or exceeded those required in the specifications. The low carbon in bolt SA and the high molybdenum content in bolt 7A did not H adversely affect the hardnesses of these bolts, j j one of the SA-325 bolts, 4A, had slightly lower hardness (and hence, j slightly lower approximate tensile strength) than required. Tensile testing would be required as a critical check on compliance, since actual tensile data 1 l takes precedence over hardness data in determining compliance, or lack thereof, with the specification. I The macrohardness of bolt 3A was at the maximum specified in SA-193,88 j Class 1, but was less than the requirement for Class 2. The microhardness l readings were significantly higher than the macrohardness, likely becaut,e of i i the greater influence of the rapid work hardening characteristics of 18-8 type stainless steels on microhardness indentations than on macrohardness indentations. 2.3 MACROSCOPIC CHARACTER 12AT10N The transverse cross sections of all fasteners except I?A and 13A, and longitudinal cross sections of heads and shanks of all of the bolts were i f macroetched to evaluate whether any gross inhomogeneities existed. Macro-graphs of the samples are presented in rigures 1 and 2, and a summary of the observations is included in Table 4. J I The transverse cross sections exhibited macroscopically uniform etching f characteristics. There was some pitting on a microscopic level, indicating { e carbon segregation and/or inclusion stringers. Macroetching of longitudinal bolt sections revealed desirable material flow lines in the heads of all bolts i except 7A. This latter bolt head had clearly been machined, which leads to a bolt with lower resistance to bolt head failures than a bolt with an upset i + f formed head. Neverthelcss, since specifications SA-193 and SA-325 state j l material requirements, but not bolt or stud manufacturing processes, the machined bolt is not in conflict with the specification. t Also, as indicated in Table 4, the threads on all fasteners except 7A had been rolled. Again, although such machined threads are not in violation of SA-193, rolled threads are generally considered to be preferable for service performance, particularly in fastener sizes below 3/4 in diameter [4).

.- c ~ r m q: ~. Table 4. Bolt Evaluation Data l I l Macroetching Sanple Spec Grade. temaitudinal Transverse Threads Microstructure ..~ { SA193 B7 Uniform Rolled Gross carbon bending segrepetion 1A Stud } SA Bolt, Forged Head Uniform Rolled, Irregular Uniform l 6A Stud Uniform Rolled Moderate carbon bending segregation 7A Bolt Machined Head Uniform Machined Rough Pronounced carbon bending segregation 9A Bolt Forged Head Uniform Rolled Moderate carbon bending segregation Uniform Rolled Uniform l 10A Stud 12A Bolt Forged Head Uniform Ro'. led Minor carbon bending segregation, 13A Bolt Forged Head Uniform Rolled Minor carbon bending segregation

l l

SA325 1 2A Bolt Forged Head Uniform Rolled Uniform l GA Bolt Forged Head Uniform Rolled Mostly uniform, j some grain boundary ferrite l 1 8A Bolt Forged Need Uniform Rolled Uniform i 11A Bolt Forged Head Uniform Rolled Uniform, minor h of free ferrite l SA193 38 f 3A Bolt Forged Need Uniforn Rolled Anneeled in conter Cold droun at (2,1/4 to 3/8 in doey 2-3- { 1 e j i NY r r

gjl ~ [,, F5896-10 !Jq g{g.a et 1 a i 2.4 NICR0 STRUCTURE l The espected microstructures for SA-193,87 and SA-325 fasteners would be g's j guenched and tempered martensite, whereas that for SA-193,58 would be either

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carbide solution treated, i.e., ennealed, for Class 1 or cold worked for Class 2. As can be seen from the data in Table 4 and the micrographs in Figures 3 ) through 16, the microstructure in all the samples except 3A (austenitic steel) I was, indeed, quenched and tempered mortensite. However, in some SA-193,87 samples, the degree of carbon banding segregation was significant, with the l worst case being bolt 1A (Tigure 3), in which tends of free ferrite were 'f present. Such a nonuniform microstructure is undesirable since low strength l l ferrite can be a crack intiation site, particularly under fatigue loading conditions. Accordingly, although the SA-193 specification does not define any limits on segregation or microstructural uniformity, it is reasonable to recomend that bolts with marked carbon segregation should be considered as questionable for use in critical applications, unless tensile and impact tests can demonstrate adequate anticipated service performance. l None of the fasteners exhibited excessive inclusions or decarburisation of the threads which would compromise their service behavior. i The microstructure of bolt 3A, shown in rigures 15 and 16, was r.onuniform f rom the OD to the center, in that the center was annenlad and the outer f periphery had been worked, most likely from thread rolling. This is consistent with SA-193 which states that "where practical, all threads shall be forred after heat treatment." Since the specification covers the material prior to thread rolling, the deformation can help explairi why the hardness 'f (see Section 2.2) was at the upper limit specified in SA-193,BB for Class 1 t material. Accordingly, the bolt is clearly within the Class 1 specification, l j assuming all the deformation had, indeed, been incurred during thread rolling. (Deformation of the stock material to strengthen it would have 7 required that the B8 marking be underlined to identify the strain hardened swterial as Class 2 grade BB.) l l -B-

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.,f (. 3. CONCLUSIONS yf.. .i N' i Based upon the analyses conducted, the following conclusions can be i stated: i. 1 l 1. None of the fasteners had been improper 2y marked with regard to i classification. 2. The carbon content of bolt SA was slightly lower and the molybdenum j content of bolt 7A was higher than required by SA-193. These l deviations should not adversely affect service behavior. j 3. The' hardness of bolt 4A was slightly below that specified by SA-325. J Tensile testing would be required to determine whether such a bolt - should have been rejected as being out of specification. 4. One bolt,:?A, had machined threads and head. Although this ( fabrication method does not violate thJ requirements imposed by the { B7 merking, the bolt could be inferior in service performance t (depending on the service conditions) to a bolt with upset head and rolled threads. 1 5. The microstructure on several B7 bolts exhibited undesirable carbon segregation, which can negatively affect service performance. Since such a characteristic is not specifically addressed in SA-193, compliance with the specification does not necessarily assure a high quality fastener. 1 i l a r e i 1 I l 9

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4. REFERENCES 'jd 4 1. False Grade 8 Engineering performance Marks on Bolting and Improper ^3 Marking of Grade 8 Units, Industrial Fastener Institute Research Report, April 4, 1986 2. SA-193: Specification for M1oy Steel and Stainless Steel Bolting Material for High-Temperature Service, American Society of Mechanical j Engineers, 1986 3. SA-325: Specification for High Strength Bolts for Structural Steel Joints, American Society of Mechanical Engineers, 1986 4. SAE J429k: Standard Mechanical and Material Requirements for Externally l Threaded Fasteners, Society of Automotive Engineers, 1980 li' e 4 1 1 I l I i 1 i l t .. - -,,. ~, _.

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. 2 A ". c' ~ ;:y.,."p . ~ p. 1A 1 I f i B 2X l I'igure 1. Macrographs showing macroetched transverse cross sections of the fasteners. There were no pronounced inhomogeneities or defects. (Hardness indentations are evident on some samples.)

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[ ~ p. o 5 / l i I.' , s' t i s i i 'r ' B. Bolt 7 500X I'igure 6. Micrographs showing a quenched and tempered microstructure with pronounced carbon banding segregation in a longitudinal cross section. ,. l

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B. Solt 9 500X Tigure 7. Micrographs showing a quenched and tempered microstructure with some minor carbon banding in a longitudinal cross section. .ig_ i -r

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( 4., 8 ' i '. f. ,I$ p A. Bolt BA 100X 3 4 I { l l f i f.- B. Bolt 8A 500X l Figure 13. Micrographs showing a quenched and tempered (or normalized and e, tempered) microstructure with a little grain boundary ferrite in a longitudinal cross section. l . l b e mes 4 ew-2. m e- .-?

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' 'g.) # a > dQ R '. l i c ' ,pi l' J.>.h:, kg w;.p.;.u 4f+g'ien, p.t [ p $n.a,&..yi%Q&-%ee.....g%, A s -c r.. We dw

3

.o A. Bolt 3A, center 100X ,ii 'I j.....--. u s 1: ....n .x ? 'l 4.'* ' r . 7 m >m.,, f '. ;g 1 g. j... Td 4 g ty f, :' ,y<.,a 2.. 't.y + ; d. y. s a s l .. c -~ s.i

y. _

q-S. 7 s - m 9 3...

" '; ^

?, ^ n +,, - .s p, '. ' .., ; ',...*n. ,.. y;,[ ;.,a y, ~,,. :~ f' .. y-C.. e ,4 ,t t j 3 3 w... B. Bolt 3A, center 500X 4r+e l'igure 15. Micrographs showing an annealed austenite microstructure in the center of a longitudinal cross section. J...--...

,... ~ r.. .:-..-~~7.------- + - - - - - - - - - ~ y ] lo i, p . 3 :;; yp f ' w,M o? I'5896-18 .Q/. l "d,..'.. 5 ,t. ,4 pW.6 f4) s ,'-a do d. i T;c,1 p + e: w s f m, ? t w N .- 3 ,.e v 3 _r A, r ' ~

w

, (- W e,_

p...

4 p ~ ~ s j + m, ,e

1 t

r _s < -,. r. i .. 3 - 4 v s ... 3 . a,,* .,. tw:. - p# (,\\#.. k.* 'f ,s L,, s & '*,V ( 0g .'.l, O 's% 3 . 1- ,, o i ,. s.% f, *.i f.j. ' f N,_ b,.y '. + g [ I ) d., A. Bolt 3A, near OD 100X lI l ...I' ?. gf., ,, s.3 p l '.:. ;',, \\.g W. 1 1 x. (..y rw.- ~. 1 ?'

p'.jd(I, s,Q

.4 ~ - V:'. ., f_k., f.. q ... y '.,.: } j'.. ?,> [ ^ l' I x, .-lf,,hg

' >;syp.L i-5 b-;g y r;

..m-,'* ~ L, w-

',(,,.

kk 4 N'* ' N l.1, s M, + ,,g v.;,,f ;{'l,;. ',.? ., gj- . 4 s. f - [' p,' '.. (, \\,4%{ yI "*;.4 F.1 -[p..,i. : i' ' L .i % - i <' r l ? N, W,?!' 'f ? ? . l B. Bolt 3A, near OD 500X Figure 16. Micrographs showing a cold worked austenite microstructure near the OD of a longitudinal cross section... ._ - _, _ _. _}}

ML19324B271

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