Text

Analysis of Decomposition Effects of Vinylcel Insulation on 304SST Facings in Dba
	ML17258A496
Person / Time
Site:	Ginna
Issue date:	01/15/1982
From:	Bruce M, Kimbrell M, Sweeney E; WYLE LABORATORIES
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	17490-2, NUDOCS 8202040108
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'C

'r NEq REPORT O

(Nuclear Envlronmantal Quallflcatlon)

ONYM lfOIRlEB SCIENTIFIC SERVICES AND SYSTEMS GROUP HUNTSVILLE,ALABAMA r

Rochester Gas and Electric Corporation 89 East Avenue I Rochester, New York 14649 REPORT NO.

WYLE JOB NO.

YOUR P.O. NO.

DATE 17490-2 17490

¹BU-17089 January 15, 1982 ANALYSIS OF THE DECOMPOSITION EFFECTS OF VINYLCEL INSULATION ON 304 SST FACINGS IN A DESIGN BASIS ACCIDENT STATS oFALftoafgtA)California Professional coUHTY OF NACISOH )

Engineering Reg. No; 2635 James F. Gleason deposes and says: The information contained in this report is the result of complete and carefully conducted analyses a

d is to the best of his knowledge true and correct in all SUBSCRIBEO and swor o before me this day of

,19 No ry blic in a d for the St of Alabama I

e.

u i

i

~

3

~gP/

8202040i08'20i27,<,.,'",;~'ORM 1143;"'; PDR, ADOCK;,05000244, PROJ. ENGINEER APPROVED BY WYLE Q.A.

Bru e eeney M. Kimbrell Wyle shall have no liabilityfor damages ol any kind to person or properly, lndudlng special or consequentfat damages.

resulting from Wyle's providing the services covered by this report.

0

. I

N, Report No.

17490-2 Page'No.

1 PURPOSE This analysis was prepared by Wyle Laboratories for Rochester Gas and Electric Company.

As requested by RG&E, this report provides additional analysis to sup-plement Section 8.3 of Wyle Report 17490-1.

2.0 SCOPE The scope of this investigation includes literature search and analysis of applicable data to estimate the time it would take for the 304 SST facing panels to be corroded by the decomposition of vinylcel insulation during a design basis accident at the Robert E. Ginna Nuclear Power Plant.

APPLICABLE VINYLCEL INFORMATION g

~.0 i

Further information regarding the 19-mil facing panels was provided by RG6E:

Gilbert Associates, Inc., Bill of Materials, GAI W.O. 4155 (Attachment 1).

ANALYSIS As the accident temperature declines and the total radiation dose to the vinylcel'ncreases, HCL gas will begin to evolve.

Wherever moisture is available on interior suxfaces of the 304 stainless steel facing panels, aqueous HCL will form.

Neutralization of this acid will be most effective in the areas most accessible to the containment chemical spray, that is, along panel edges and around retaining bolts.

Less accessible areas will be exposed to hydrochloric acid at pH levels that will vary depending on chemical spray penetration between the insulation and facing.

Welded areas that might be sensitized to corrosion are protected by acid-resistant paint (Attachment 3).

Reference 21; Wyle Report 17490-1, reports a corrosion rate of 10 mils per year for 304 stainless in 0.4% HCL (Gale pH = 3) at 80'F (Attachment 2).

Below about pH 4 increasing acid concentration does not greatly accelerate corrosion of carbon steel (see Section 8.2 of Wyle Report 17490-1).

Though no specific data was located, a similar insensitivity to acid concentration can be expected for the 304 stainless in acid environments.

Temperatures following a DBE at Ginna are postulated to be higher than the temperature for which a corrosion rate was given.

Corrosion at higher temperatures would be more rapid.

Because the initial transient tempera-ture phase is short (slightly over 1 day) and HCL generation will not occur until the radiation dose to the insulation has reached 5 x 10

rads, only the 150'F post-accident ambient is considered.

Reference 20 of Report 17490-1 reports that the rate of iron corrosion by HCL (at low pH) doubles for each 10'C rise above ambient temperature.,

Low pH will persist in the least accessible central section of the panels.

Assuming the acceleration WYLE LABORATORIES Huntsville Facility

Report No.

17490-2 Page No.

2 4.0 ANALYSIS (CONTINUED) factor for iron/HCL applies for 304SS/HCL and extrapolating the known 10-mil per year corrosion rate at 80'F (26.66'C) to Ginna's 150'F (65.55'C),

corrosion rates in those areas could be as high as 160 mils per year.

Penetration of the 19-mil facing could occur in 1.4 months.

Neutralizing chemical spray could then enter through these penetrations and retard or prevent further corrosion.

Along panel edges and around panel penetrations for retaining bolts, chemi-cal spray is assumed to enter behind panels and completely or partially neutralize HCL evolved from the insulation.

Fully neutralized areas would not be subject to rapid corrosion.

Slightly less accessible areas where only partial neutralization occurs would be subject to acid corrosion.

Reference 20 in Report 17490-1 indicates that corrosion by solutions of pH 4-10 is limited by oxygen diffusion and that corrosion rates approxi-mately double for each 30'C increase above ambient.

Extrapolating the known rate of 10 mils per year at 80'F to Ginna's 150'F, the expected corrosion rate, in slightly to moderately acid areas, would be about 30 mils per year.

Panel penetration could occur in about 7.5 months.

As with penetrations in lower pH areas, these areas would then become more exposed to neutralizing chemical spray and further corrosion would be inhibited.

Thus, for the panels to fall, it would take 7.5 months to penetrate the panel in the areas of the retaining bolts.

The bolts are analyzed per the following.

The chemical spray may neutra-lize the HCL in the areas of the bolts.

For purposes of this analysis, it is assumed that only partial neutralization occurs and the 30 mils per year corrosion rate applies.

The amount of corrosion of the bolts which could result in failure of the bolt due to exceeding the failure shear load is calculated as follows:

Shear stress calculations in panel mounting bolts:

Assum tions Panel is unsupported by frame work.

6 studs carry full panel weight.

Studs are in pure shear across threads.

Panel weight is evenly distributed on studs.

Given Panel size:

Insulation:

Studs:

44" x 84" x 0.019" Tp 304$ S 44" x 84" 'x lt<" density 4 lb/ft bonded 3

to panel 6 ea.

10-24, Tp 304SS WYLE LABORATORIES

'untsville Fscltlty

e Report No.

17490-2 Page No.

3 4.0 ANALYSIS (CONTINUED)

Calculations Panel-Weight:

3 Steel:

(44") (84") (0.019") (0.29 lb/in )

= 20 lb Insulation, (44>i) (84tt) ( jgttt) (1/].728 ft ) (4 lb/ft )

3 3

ll lb Total:

20 lb + 11 lb = 31 lb Per Stud:

31 lb/6 studs

= 5 lb/stud Stud Load:

Tensile stress area of stud 0.0175 in2 Shear stress v = 5 lb/0.0175 in

= 286 psi 2

Allowable stress Su/8

= (66,200 psi)(1/8)

= 8,275 psi Failure stress Sy/2

= (25,000 psi) (1/2)

= 12,500 psi Minimum Stud Area at Failure 2=:

2 A

5 lb/7 failure =. 5 3.b/12,500 lb/in.

== 0.004 in.-

--min.

. Diemerer-

-/4A/m- =-~4'l'.0004/n')

'= 0.022 in.

Original minimum diameter of 10-24 thread 0.136 in.

Depth for failure (0.136 0.022)/2

= 0.057 in.

Source for calculations:

Boiler 6 Pressure Vessel Code ASME Section III, Div. 1, Appendices, 1980 1.

Design Requirements for Bolted Joints XVII, 2460 2.

Shearing Stress of Austenitic Steels - XVII, 2461.2 Fvb ~ 0.62Su/5

~ 1/8 Su 3.

Su(200'F)

Table I-3.2 4.

T'200'F)

Table I-2.2 max The time to reduce the minimum bolt diameter by 57 mils at 30 mils per year corrosion rate is 1.9 years.

WYLE LABORATORIES Huntsville Facility

Report No.

17490-2 Page No.

4 5.0 ADDITIONAL INFORMATION Additional information was located on actual corrosion of 304 stainless in acid environments containing chlorides (see Attachments 4, 5, and 6).

Attachment 4 reports field corrosion studies for 304SS (unstressed samples) in wet scrubber systems.

General corrosion rates are not reported, but the maximum depth of pitting/crevice corrosion was 55 mils after 5.3 months in a refuse incinerator scrubber in which the process fluid contained recir-culated unneutralized hydrochloric acid.

A maximum penetration depth of 47 mils was achieved by 4 months exposure in another scrubber system which used a highly oxidized fluid at a pH of 4.5 and a 1,400 ppm chloride con-centration.

As noted in Attachment 2, acid chloride solutions (pH below 7) could induce stress corrosion cracking in austenitic steels at Ginna's 150'F ambient (residual or applied tensile stress for the steel is required).

Data from Attachment 5 indicates that if the acid is hydrochloric, general corrosion is dominant.

A solution containing 0.8%'aCL and HCL at a pH of about 2.2 and a temperature of 141'C did not show cracking for U-bend specimens after 10 days exposure.

Cracking did occur after 30 days, but may have been due to evaporation of the test solution during that period.

When the acidifying agent was phosphoric or citric acid, stress corrosion cracking and pitting/

crevice corrosion was dominant.

The effect of acidified borated chemical spray solutions containing chlor-ides on 304 stainless is presented in Attachment 6.

Increasing chloride concentration and decreasing pH were shown to promote stress corrosion cracking.

All stressed samples (U-bend) and samples "sensitized" to crack-ing by heat treatment showed cracking after exposures to spray containing 200 ppm chloride at a pH of 4.5 for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months at 285'F, 7 days at 212'F, and 2 months storage in the spray solution at 180'F.

Two (2) of four (4) welded and ground coupons (more nearly representative of panel retaining bolts at Ginna) exhibited cracking in that-environment.

At higher pH's, cracking was indicated as much less significant.

Ginna's relatively low temperature and the moderate static stress for the retaining bolts would reduce the probability of failure by stress corrosion cracking of the retaining bolts in slightly to moderately acid environments.

A neu'tral to slightly alkaline environment is more probable for the retain-ing bolts and such environment would not result in stress corrosion crack-ing or significant general corrosion rates.

6.0 CONCLUSION

The panels could experience corrosion which could penetrate the panels in 1.4 months.

The rate of continued corrosion would be slowed by the neutralization of the HCL by the chemical spray and these penetrations are most likely to occur in areas furthest from the retaining bolts.

WYLELABORATORIES Huntsville Facility

Rapport No.

17490-2 Page No.

5

6.0 CONCLUSION

(CONTINUED)

The time for the panels to fall is most probably a function of the corro-sion around the retaining bolts.

The corrosion in these areas would progress to the point of penetration of the panels in 7.5 months.

In order for a panel to fall, penetrations around retaining bolts would have to be well connected.

As a penetration developed, the chemical spray would further neutralize the HCL and retard corrosion.

The time to failure of the retaining bolts is assumed to be the time when the failure shear load is realized.

This time is predicted to be 1.9 years.

Thus, the time required after a DBE to cause falling of the panels is between 7.5 months and 1.9 years.

7.0 REFERENCES

1.

Bill of Materials for Robert E. Ginna, Unit 1, Containment Insulation, from Gilbert Associates, Inc.

(Attachment 1) 2.

Taylor, Lyman, Ed.,"Properties and Selection of Metals,"

Metals Handbook, Vol. 1, 8th Edition, American Society for

Metals, 1966 (Excerpt Attachment 2) 3.

Contact Report, M. Bruce, Wyle, with Bill Davis, Carboline, and Product Data Sheet on Vinyl Paint (Attachment 3) 4.

Anderson, D.B., "Spool Corrosion Tests in Wet Scrubber Systems," Materials Performance, Vol. 20, No.

10, October, 1981 (Attachment 4) 5.

Asphahani, A.I., "Effects of Acids on the Stress Corrosion Cracking of Stainless Materials in Dilute Chloride Solutions,"

Materials~Performance, Vol. 19, No.

11, November, 1980 (Excerpt Attachment 5) 6.

Cottrell, W.B.,

"ORNL Nuclear Safety Research and Development Program Bimonthly Report for November-December, 1970," ORNL-TM-3263, Oak Ridge National Laboratory',

March, 1971 (Excerpt Attachment 6) 7.

ASME Boiler 6 Pressure Vessel

Code,Section III, Division 1 Appendices,

July, 1980 WYLE LABORATORIES Huntsville Faclllty

Report.No.

17490-2 PaEe No.

6 GILBERT'ASSOCIATES, INC.

BILL OF MATERIALS ATTACHMENT 1 BM SYMBOL SHEET NO 380pi.',iPQD-i'LI EN TI aestinghouse Atcmic Power Division (Hochester Gas 8 H.ectric Co oration) hexTEal Znsulation and Pex~ acxo~~j Hobert ~tt Ginna Nuclear Paver Plant LOCATION

- Vnit 2o.

1 Pittsburgh, Pa.

GAI w. o.

4155 CLIENT w. 0

)gal 33PQQ ITEM NO OUANTITY OESCRIPTION OF MATERIAI ISSU OROER NO

.'D

.:.mwxori Containment insulation, Herbert Construction Corporat'on, shall include the furnishing, abric ting, delivering and installat'on of heat insula ion vi h stainless steel facing, to <<nclude M~

9 penetrations and tvo hatches reouired for the interior of the containm nt v ssel to be in accordance vith GAI Specification SP-5290.

216114 Johns-Hsnvi~ Vinlcel Insu~ation shall be applied to the..

ar as specified in the above speciPicntion as foU.ovs:

o019 Q ~

304 Znsulation to be l-l/4" th. Yinylce3. shh ts 44U x 84'.

~

ets vi3.'ave specified design routed edges og face.

Sheet face to routed edges shall 'be f'nished, with j~j/Q~~ stainless steel

//js]/Iy//gjfQ/Q6//IpjjJ/4<".// Sheets to be mounted on stain-less stce3. studs KSI$304 stainless 810-24 x 1-1/2.

A 1-1/8 dia. silver colored neoprene and stainless steel ccmbination washer villbe placed ou s'da the sheet over the stud and held in place by a self-locking stainless hex heed nut.

We sheets

'cPFn~iXCN~

~555~. ~~hase' Kei9%i%MnYFBKKorl %morat o

." If '!RWINSRW 3m&s of sheets vi"1 be routed to fit over the 3.-1/4 "

cnsnnels in the fie1d.

Sheets villbe erected. with 44" dimension vertical and vcrTic I points viMI be staggered,.

A13.

sheets vi13. be spaced app~:imately 1/3.6N apsM,,

The Joints at base of routed cdgas vil3. be taped with 3/8N wide t pe as specified.

Che appl'cd s" recommended by 'he manu-uicr o zske a

3.ush finished )oint ~

At penetrations, etc., where sheets must bc cut to fi.t around snd. butt to same, the edges shaL'. b beveled and. caulk d as described above.

2erbert Construction Corporation v'll spray on, the sheet metal f"c a 1-1/2U diameter c"rcle indica ing location of test pl gs.

'SUE NO.

OATE KDITOR I. I p KNOINKERi Uhere plates at penetration areas prospect into the vessel b~ond the noxM valne, Herbert Cons-ruction Corporation work cut acceptable. details in he f:eld, by eithex using t"."'nrer insul tior, or developing an approved overlap at the juncture point.

!Ccntinu d She. t 2) 21g68 OAI 62 RKV 5/)

Report No.

17490-2 GILBERT'ggOCI ATES, INC.

PaeN 7

BILL OF MATE,'RIALS ATTACHMENT 1 (CONTINUED) 8 M SYMBOL c...ZL'Ii: <JOD -3'~

SHEET NO.

r LocATloN:

Pittsburgh

~ Pa+

Westinghouse Atomic Power Dirsion

{Rochester Gas,k Zlec+ric Corporation i Themn1 Insulation and H

fractorJ'obert Bmaett Ginna Nuclear Power Plant Unit Ho. 1 GAI w, o.

II155 cLIENT w. 0 RH-33000 ITEM NO.

QUANTITY OESCRIPTION OF MATERIAL IS SU OROER NO.

RP-1 cont.

HEVXSX i Herbert Construction Corporation shall use electric swing scaffolds to insulate the area from 16 ft above the spring line where the insu1ation is indicated to start, to the operating floor.

Tubular scaffold shall be used, for the balance of the side walls.

216114 The metal face shaLl 'be laminated, thc sheets sha13. be face routed Bnd drilled before shipment to the job site.

Herbert Construction Corporation shall store sheets on job site in ama provided.

Herbert Construction Corporation sha11 erect a sms11 fab shop on the job site.

Herbert Construction Corporation villkeep C02 fire extinguishers on the scaffolds and in the axeas they ax'e vorking.

Herbert Construction

~

Corporation shall hang a tarp from the bottom of the swing scaffolds as a safety measure.

Herbert Construction Corooration will secure from material vendor" certificates as specified.

H rbert Construction Corporation sha11 guarantee worlaumship for a period of two years after inst~ation.

(321.5)

Mgineering and price to be in accordance vith Herbert Construction Corporation Quotation dated. January 8, 1968 and, telegrams dated January 10, 1968 and January 12, 1968 wl 1oNera dated FS~ 6, 15o8 end Such YF 1968 Delivery and Xnstal3.-

ation of Material:

On appro~ately Ifarch 1, 1968 Herbert Construction Corporation sha13. start the insulation below the operating floor, working in,conjunction with the Hech*el Engineers as to what areas should be done first, etc.

The second.

phase con-sisting of the crea abov th operating floor would 'oe don later in the year.

De2~verg x quired:

February 15, 1968 a

ISSUE NO.

OATE EDITOR

KNGINEKR.~)l (2) 3~19~06 Al 62 REV,S/c

Report No.

17490-2 Page No.

8 ATTACHMENT 2 HARL)SOAK 8th Edi/ton VOL. 1 Properties and Selection of Metals prepared under the direction of the METALS HANOBOOKCOMMITTEE TAYl.OR t.YIVIAN.Kdltor HOWARD S. BOYSR, Managing Kdltor PAUl M. UNTKRWKlBSR, Associate Kdltor QOS. S. POSTSR, Associate Kdltor JAMSS P. HONTAS, Asaociate Kdltor HKt.SN t.AWTON, Assistant Kdltor AMERICAN SOCIETY FOR METALS elk Metals Park, Ohio

RPPP<E NP rr4PD E

o RTTRCENENT 2"(CDNTTNUED)

Table 12. Corrosion by S IrN(sqs r9 Luursnnlc Compuunas Compound and

~i~ unncrnrtn'unn TEEnprrnrurv, F

Corznrion, Compound Pna mpy, ~ ouncrllrrnrlull Trmprrnruru.

CurrrNiun, F

mpy 20 ammonium STSnante..... 204 10 ammonium chloride..... 316 0.4 hydzocMOTLO add........ SO4 0.4 hyazochlorlc acid....... 216 30 manganese cMozlde...... 204 50 mnnrtnacse chlozirle...... 347 28 alcknl sulfate.......~....

304 40 soatum bLSULMe......... 204 40 soalum blsulnae......... 316 Boalag

, BOULUS 80 120 194 194 122 Borllag r Boning 5

(L 10 0.7 0.7 0.04 LA LA 20 504IUul sUIMn ~ ~ ~ ~

~ ~ ao ~ ~

20 sodium Sulnae

~ os ~ ~ ~

~ ae ~ 318 40 504LU111 $UIMe ~ ~ ~ ~ ~ ~

~ ~

~ 304 40 soaium sulaae......'....". Sle 6 sulfurous acid............

204 6 sulfurous ncla............

504 100 sulfur cMoride..........

304 Loo sulfur chlozran..........

410 Allsteels In chn nnnnnle4 conaltloa.

!cats. Teats mnae La the lnhozntozy.

120 9.1

~'so 21 Boulnrz Ld Boutag 2$

104 0.1 194 18 Boiling LD

~ ~ ~

Xl Allsolutions from CP chem-Table Ls. Corrosion by Staaunus PLUOHae Solution

~rrunsrh.

TPRISht vo r

Curzoeion, mp~

514 2LZ 2.0 15 50

~

~ ~ ~ o ~

~

35rz 09 Noae

~ ~

~ ~ ~ ~ ~

~ ~

OA Noae

, ~ ~ ~

~ ~ ~ ~ ~

LAL(~)

(a) Stained black Table 14. Corrosion hy 78% SULLUHc Acid Mixed with Salfnnatlun Products

~

~rrnEhPny mp~

SOF LLOP 20 0.6 LD 2.0 SA) 1 134..

02 Type 318

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Haszelloy B,...........

Hnstnnoy 0...."...."

MLL4 steel

~ ~ ~ ~ ~ ~ ~ ~

None Noae Table LS. Nozzoslnn hy Spent Sulfuric held aztec Sepnzaana of Sulfonatioa proauets

~ITURIon~ mp~

59 F LEO F AUor Type 318....

No. 20......

Lnconel ML14 steel...

15.12

'.94 L9~

53.6 ODL O.OS Ls rr In repaIHng equlpmeat that has beea 111 sulede service, the surface shorrld be cleaned thoroughly by abrsslve blasting before welding, to avoid weld cracking.

Stannic Chloride Types 304 and 318 have satisfactory ze5!5tance to aqUeoU5 sohr'tlon5 of stan nic chloride at temperatures to 200 P for concentrations not exceeding 1%.

316 is snore resistant than 304 and has fair resistance to solutloas of 10 to 15%

at 70 P. but Ls unsatisfactory at higher temperatures and concentrations.

Stannous Fluoride Laboratory tests made at 200 P with aqueous solutions ranging from 2 to 50%

by welghC indicate that stannous UuoHde solutions can be handled ln equipment made of the series 300 stainless steels.

A maximum rate of 3Jl mpy was obtained ln a 2% soluQon. Vyith aUowance for ex-perimental exzor. all rates either decreased or remained the same with Increasing concentrations.

No tendency toward ylt-Qng could be found, and stressed horse-shoe-type specimens of 304 and 31S tested for Stree-conosion cracking did not faU.

Table 13 sununarizcs these tests.

Sulfation and Sulfonation Products The ausbinlQc stainless steels and car-bon steeis have low corrosion rates. In oleum (fuming sulfurtc) and sulfuric acid of more than 80% coacentration at room temperature.

At 100 to 103% there Ls a distinct rise In the cozzzrsion rate with carbon steel.

Above 103%, both stainless and carbon steels have satisfactory cor-rosion rates.

Steets of the 300 sertes are satisfactory for sulfonaQon practice at zoom temperature with '18% sulfuric acid quate (5 to 15 fps) to keep all solids sus-yended.

Charring of organic matter or deposlQon of scale (such as caldum sul-fatal may result ln ylttlng and perfor-aQon.

The surfaces should be kept dena during shutdown pertods.

Corrosion FSUures.

Organic acids and traces of bsoxgaalc salts contributed to the conoslon faUuxe of welded zones In a steam-Jacketed ketQO of tyye 318 used to heat 4%

suifuHO add In methanoL The intertor surfaces of the kettle are shown In Flg. 8. This failure could have been avoided or delayed by the use of 318L or by fuUy annealing the kettle

~fter fabxicaQon.

The conoslon faUuxe of Van Stone ends (type 318) oa a continuous converter for sugar soluQons Ls showa ln Flg. 9. Crev-ice-type

~ corzoslon Ia the Banged ends was Increased by a carbonaceous deposit

. aC these points.

The solution contained sulfurtc acid at pH 1.8 and was hdd between 275 and 325 P.

Since the ends had noC been aanealed a(ter

forming, conoslon was Increased by the severe stresses developed ln the Uanged areas.

The corxoslozl could hlsve been CUrtsllcd by using ends with a CMcker wall aad an-aeaUng, aad bg deaning the deposit.

mixed with sulfonaQon pxoducts.

At 140 F conzrslon of series 300 steds Ls exces-sive.

Conosion rates at these tempera-

~..tares are reported ln Tables 14 and 15.

If accuracy of parts ls essential, as In valves and contzol lnstnunents, or lf velocity of Uquld Ls high, as In pumps or mixing operations, corzoaion tates are excessive, and steels such as CN-7M and nickel-baso alloys are needed.

The neu-traUzed pxoducts of sulfonation may separate when stagnant.

and the sertes 300 Steels can be sevezely pitted by the xesultlng diluted aclrL Sulfuric Acid

'The 18-8 varteQes of stainless steel are resl5tanC to corxosive attack by sulfuric acid within rather narzow ranges of coa-ceatratlon and temperature.

Although the stainlee stee)s may be used safely hs contact with 80 to 100%

sulfuric acid at ambient temporature (carbon steel Is ozdlnarUy used ln thts range),

they are attacked at sUghtly higher temperatures.

One to 5% sulfuric acid at ambient temperature should not be stored In vessels of molybdenum-free stainless steels.

Type 31S may be used for thts purpose; 317, with a higher zao-lybdeaum content, may be used Safely In th)s zaage of acid conceatraQon at tem-peratures as high as 150 P.

Alloys such as No. 20 and CN-7hf resist all concentxatlons of sulfuric acid at temperatures to 140 P, and to the boUlng polnC for concentrations to 10%, but do not resist all concentrations over a wide zange of temperatures.

The preceding data peztala to pure sul-furic aclrL The addition of oxidizing agents (such as nitric acid, air aad cop-per salts) will widen the range of ap-pUcabiUty of all stainless steebg reducing agents (such as hydrogen) wUI narrow the range of usefulness.

If other thea pure sulfurtc acid Is used with stainless steel. corrosion tests must be made under conditions of operation in order to evalu-ate the usefulness of the auoys.

Only those concentrations of sulfuHc acid and temperatures

'should be used that have given satisfactory results In corrosion tests.

Tests should include an-

nealed, seasiQzed (1200 P for 8 hr),

stressed and crevice-typo specimens.

Agitation and aezatioa In stainless steel equipment and the velocities of sulfuHc acid solutions In piping should be ade-Sulfurous Acid and Sulfur Dioxide Stainless No. 20. types 316. CP-85f. 317 and CN-75f have been used ln equipment for.sulfur dioxide (wet) and.sulfurous acid <<nvlxonments.

The molybdenum In these aUoys gives thc required resistance to reducing environments of sulfurous acid.

The wrought type 316 and cast CF-851 alloys are the most widely used.

Complete suspension of any solids present Ls necessary to avoid crevice-type Utlng.. Figure 10 shows pining and per-oraQon of a Van Stone danged end of 304 stainless welded to a tube of type 318: the latter did not conode.

Crevice

yockets, lapped /oints, 90'orner Inter-sections.

and simUnr obstxuctlons should be avoided, and the surfaces Should be dean and smooth.

Cold and hot working should be Umlted to minor forming operations that wUI keep the hardness of the steel below Rockwell B 96.

Stress-corrosion crack-Ing can occur in steel exposed to sulfurous acid solutions containing 100 ppm or more of metal cMorides.

-.nv4fgi:

Cay 1

~i u

QP<l rr v U% - ~

~Z Ffg. 10. 'Vars Storrc /lunge o/ type 304 that runs pi(Lcd arrd ycr/orated by xui/urous acid.

The type 316 tubing Lo u;hich it rcas u;cfdcd rcas rrot corroded.

P P 4

~

E.I I

~.

I;i

~ '%

"~

570

-.-Report No 17f(90-2 Page No. -10 SELECTION ()F S'I'AiyLESS STEEL k

ORROSIOY SERVICE IY ATTACHMENT 2 (CONTNUEi)),

CIIESIICAI. Pk<>cl Csl~<.

r

l

~

Si Table 6. Corrosion ln Formic-Acetic Acid 5(ixturcx ln the process.

destroys the passbdty o!

stainlesS steels.

1VHxtures of acetic acid

~ with other acids espcclany sulfuric. hy-drochloric and formicmay produce con-ditions more cozr(aire than acetic acid itself, particularly't high temperatures.

The data ln Table 6 emphastxe that xnght

. changes ln solution concentrations caa have a signtncsnt c(feet on corrosion rates and that suitable corrosion tests muSC be made whenever any change ln opersUng conditions Is contemplate4.

Stshticss steels are not always saUsfac-tozy for contact with hoc solutions of aceUc acid of concentrations greater than about 25% and containing 2% or more reducing agent (such as formic acid). If oxtdudng agents such as sodium dlchro-*

mate may be added to the ace(le acid. the useful Ufe of the stainless steels msy be appreciably extended.

In a stL'I handnng boning 99.59 acetic acid Uquors and vapors, the serx4ce Ufe of the heating cons of 316 varied from ten months to ave years.

corrosion tests have aho showa thaC ln boning 75@,

acetic acid vapors. both 304 and 315 werc suseePtlble Co severe PltUng corrosion, Izt some boUlng Hquors where excessive)y se-vere corrosive condlUons exist (for ex-ample. where acetic acid 15 contaminated with various chlorides) nickel-base anoys such as HasteUoy C have pzered more resistant than stain)ess steels.

and their use ls Iustlned economlcany by the longer

'fe of equipment.

The CF-SM cast anoy ls generally used with the 18-8 types of wrought steeh be-cause its zeslstance to pitting attack is greater than Chat of CF-8.

To obtain service comparable with that o! the 18-8 znolpbdenuza tppes o! svought alloys, the chrom(um content of cast SUO!e should be on the high side of the composition raage.

Casting should be tully annealed for best service.

Ammonium Sulfate Plus Free Sulfuric Acid Tppes 316 and CN-TM are used la this service.

Before these steels were avaU-able, construction was ahaost entirely of lead, which was sub/ect to fatigue crack-Ing, and occasionaHy o! 5UIcon non. which ls brittle, thus requiring continuous main-tenance.

The 18% Cr and 18% Cr-8%

Nl steels became pitted and underwent severe corrosion.

Tppe 315 ls useful when properly heat treate4 after welding; otherwise, heavy intergranular cruvoston occurs atUacenc to the welds.

When extra-low~

stainless steel ts used (type 315L) heat treatment br unnecessary and large tanks can be fabricate Such tanks have been ln service for several years with no cnrl-deace of either general corrosion or lnter-grsnular attack. CP-SM and CÃ-7M cast-ings heat treated after casting are a)so

useful, although lf the casting skin is

daznaged, corrosion may occur.

CasUngs repaired by welding must be heat Created again atter welding; otherwtse they wnl corrode lntergzanularly ad)Scent to the welds. Pretreatment 0! Che steel by passl-vatlon ls not reqtnre(L Curtn iun rnpr (a) 3 to 20 2 to 11

+18 32 (1.0 3.0 2.0 (a)

Acid runrrnr. %

Accuc Formic Trrnpr mtnrc, F

Strci 2 to 10 2 to 10 2 Colo 0

125 1M 4

4.

30 to 50 30 to 50 30 to 50 Oiscial Olactat 25 25 25 25 2$

corroded 223 223 223 200 to 230 200 to 220 220

~

220 220 220

'(a) Completely 30L 34T.

316.

317.

316.

21T.

216.

31T.

$21 ~ 34T Bromoform Type 304 generally 15 satisfactory for hsndnng bromoform. either wet or dry, at ambient temperatures; howeVer. wet bromoform wUI discolor snghtly. If a water-white product ts required, stainless steel is not suitable.

and at the Uquld levek The products of sulfation, which may retain chlorides.

cause stress corrosion and sometimes se-vere pitting.

Pipe wclds and vessels of the austenltlc steels should be fully an-

'nealed whenever th(s ls feasible.

Epichlorohydrin PSUure ln processing equipment bp'tress-corrosion cracking was cordlrmed by laboratory tests with horseshoe speci-mens at 140 P.

Types 304.

316 and 347 cracked ln a seven&ay test.

Chformated Solvents The halogen derivatives of methane,

eQume, ethylene, propane an4 bensene are widely used ln drp'leaning, metal

cleaning, vapor degreaslng aad solvent extracUOn processes, and as cheznlcal In-termediates.

The compounds of primary Interest src methylene chloride, chloro-form, carboa tet~or(de, ethylene di-

chloride, trlchloroethplene, perchloro-ethyleae.

methyl chlorofozza, propylene dich)orfde, dlchloroethyl ether.

mono-chlozobeasene and orthodlchlorobensene.

They are used lndlvlduany as chemically pure or commerc(al

grades, as mixtures, or with other compounds to control boil-ing point. freedng point, solveacy, aad nsmmabnlty of mixtures.

Stalaless steels aze noC corroded by chlorinated solvents when water ts ab-senQ but when a ~ster phase ls present, the compouads hydrolyze to form hydro-chloric acid and someUmes organic acids.

Although the presence of metanlc 'mate-zials usuaUy lacreases the rate of decom-pcrdUon, stainless steeh do not, and their use ln equlpmenC for handnng chlorlnatecl solvents Is gencraUy satisfactory. The cor-rosion rate of type 304 after 12 daps in wet chlorinated solvents at renuxlng tem-peratures ls shown ln Table '(. These data sre fzem hrbozstory CO5Cs with mixtuzca of solvent and water, ln which one third of the specimen was ln the solvent layer, one QUzd in the wsCez'ayer snd one third ln the vapor phssct ConsideraUon should be given to'he Use of types 316, 317 or No. 20 for appU-csCloas where piCClng ls encountcrecL Ia tergrsnular SCtack occurs sometlmcs at welded Joints; tests should be made.

Stress-corrosion cracking may aho be en-countered ln equipment hsndnng chlorin-ated solvents.

Chlorosulfonic Acid Although carbon steels sre'sai(sfactory for chlorosulfonlo acM below the Hqtnd leveL type 317 or higher alloys are rccom mended for wNlstaadiag the vapors above I

Fatty Acids The fatty acids of lower molecular weight, such as aceUc and forznlc. require the usc of 18-8 stainless steels (see sec-tion on Acetic held). The fonowlng dis-cussion 15 concerned with the acids o!

higher htolecular weight. such as laurlc.

myrtsUc, paUmltlc, snd stearic. which are less corrosive. ht temperatures to 150 F.

cheaper metals such as carbon steel and aluminum are moderately corrodecL but lf color and absence o! contamination of the product are important, the 18-8 steels shoUld be UserL lf Che temperature is below 350 P, aU standard 18.8 types are saU5(sCtOry; shove 350 P, type 316 is needed to avoid pitting corrosion.

Corrosion in fatty acid vapors 15 no greater than ln Hquld, except at high vapor ve)ocIUes.

Under these conditions corrosion-erosion rates have been lower ln Cppe 316 Qtan la types 304, 321 snd 347.

Pitting snd loss o! surface metal are caused by high-temperature plant proc-esses (Flg. 6).

There are ao reports 0!

straight fatty acids having caused lnter-grsnulsr fsnures tn 18 8 stainless 5teels.

Cast sUops, htcluding Cppe CN-7M, have been ssUsfsctozy.

The molybdenum-bear-ing wrought steels and the newer precipi-tation-hardening stainless steels have been used for pump and valve parts where ganlug ls a factor or where hardness of Is desirable.

High-nickel cast Iron given satisfactory service in fatty acid aC 500 P.

Patty acids mixed with,chlorides cause failures by stressworroston cracking (Flg.

7). hcidulsUoa of fatty acids by sulfuric acid produces a wide varlatlon la corro-sion rates of stainless steels.

Factors that contribute to such vsrfaUon include un-known dnution of the coacentrsted sul-furic acid, the moisture inherent ln the fatty acids, temperature, and methods of agitaUon.

Corrosion

~ rates encountered with acidulated fatty acids of higher molecular wdght with steam agitation are reported ln Table 8.

Hydrochloric Acid {Dilute) hlthough tppes S15, S17, 329 and No. 20.

aa4 the cast SHoys CN-7M snd CP 8)f and some use ln very dnute aerated hy-drochloric acid environments.

stsinles:

steels are not usuaHy zccoaunended for this service.

Solutions containing chloride salts at pm below '!.0 sre essenClany hydrochloric acid eavflonmcat8, PltUng and stze55 corrosion cracking are encountered at acid concentrations less than l~~, depending oc

~ Qle temperst~

aersUon and sgltsUoa.

BlmetalHc couples between ststnlec Loss of Type 347 F(0. 6.

Weld metal and pipe of ftrpc 31S and IIanpc of fype 347 ootterfcd bir faffy acid at 400 F

epor x o.

Page No.

11 ATTACHMENT 2 SELECTION OF STAINLESS STEEL FOR CORROSION SERVICE IN CI(ESIICAL PROCESSING (CONCLUDED) 571 and other alloys should be avoMed, since corrosion may be accelerated at Chelr JuncUon.

In such couples the stainless steel may becoxne the anode In dilute hy-dzachloric ad4 resulUng ln loss'of pas-sivity and rapid corzadon.

Corrosion Failures.

Hydrochloric acid at pH 2.0 to 4.0 and 120 to 180 P has, caused pitting and subsequent faaure of heat~changer tubing and heating coQs.

Calcareous scale has Induced piftlng fail-ures.

Activated carbon that settled out has caused pICUng of heating coQs and tank bottoms (Cype 316).

I Stress~on cracking of hea~-

changer tubes has occurred at pH 4.0 and 180 P.

Excessive stresses were Induced In the tubes when a nesting head on the heaC exchanger became "axed". Bending of tubes between baSIe supports has in-duced stress~on cracking. of tubes of 316 stainless steeL Excessive roQing of tubes Into the tube sheets. has Induced stress~on cracking of the tubes jusC

'adlacenC to the sheets.

Weld deposits of Cype 318 on sheeC of shnaar grade have

corroded, weakening tho JofnL Weld deposits using an elec-txade o! type 31T or 310-Mo have Im-proved the conaston resistance of these weld.

Weld-zone attack has been obr served In type 318 Unlngs for steel tanks handUng addined starch sluny at pH;2.0 and 120 F.

Covers and vents fram addlaed starch slurry tanks ususQy corzade rapidly. Con-densed vapors of dilute hydrochloric acid environments are usually more corrosive than the Uquld phase.

Stainless steels are usually unsatisfactory for tank covers or vent plying for such tanks.

Hydrocyanic Acid Pure hydrocyanic acM is not corrosive to most materials of construction, but when stabQIzed against polymerization at elevated temperature by the addition of acidic materials. It becomes corrosive to steel. copper and aluminum. The stralght-chxaxnlum stainless steels are not recom-mended for use with stabIUzed hydro-cyanic acid solutions.

The austenltlc stainless steels resist corrosion by hydrocyanic acid that con-tains smaU amounts of sulfur dioxide as a polymerization inhibitor, at aQ concen-traUons and temperatures to the boQlng point. Types 318 and 317, as well as CN-TM and CP-8M. have greater canaslon resistance than the stainless steels wlth-ouC molybdenum.

The unstabnlzed steels should be tully annealed to prevent lnter-granular attack ln these solutions.

Lactic Acid Types 304, 318, 317, No. 20, CN-'IM and CP-8M have Umltecl use ln lactic aci4 solutions.

The molybdenum~ntalnfng varieties generaQy have greater conaslon resistance than type 304.

Purity, concentration, temperaCure, aeration and agitation are environmental factors that determine the type of stain-less steel for use ln process equlpxnent.

The presence of chlorides or suUates In lactic acM solutions Increases the sever lty of corrosion.

Impure solutions fram which lactic acid ls ultimately separated and concentrated are usually more cor-rosive than the purUIed solutions. Stain-less steeh are not suitable for use with lactic acid above 200 P.

Heating cons or heat exchangexs for lactic acid should be designed for use with hot water or Iow-pressure steam.

Decom-position of lactic acicl with formation of carbonaceous deposit on heating cons can result In pitting encl perforation under these deposits.

Temperatures above 200 P, concentra-tions nf lactic acid ranging fram 30 to T0%o, and the presence o! chlorides or Inorganic ImpurIUes usually Increase se-verity of corrosion. Use of type 304 should be Umited to vesseh for storing pure cnluanns at temperatures below 100 F.

Dnnllsxion of Iscttc ac!d causes corzaslon'y the vapor phase, and lf lactic add esters and volatQe add lmpuxltles aze present, pitting attack wal xesult.

Corrosion FaQures.

FltUng faauzes ln

'heat exchangezs for lacUc acid sduUons have been xepozte4 One faQure of this type was Umited to surfaces covered by the Uquld, parUcularly ln the parts o! tho tubing where soUds have settled out.

Weld-zone attack and conoslon faauzes have been reported for type 304, but zare-ly for type 318. The weld-zone failures were In stainless s~ that were not of the extra-Iow-carbo.

variety and ha4 not been anneaie4 Monoethanotamine Stainless steels have exceQent resist-ance to conaslon by monoethanolamlne and by monoethanolamlne saturated with carbon dioxide plus oxygen. at tempera-tures to 200 F. Stainless steel is used ln preference to carbon steel In pzacess steps where carbon dioxide ls stripped from monoethanolamlne for example, In re-

boQers, exchangers and parts of frac-tionatlng columns.

For heat exchangers.

a conunon practice Is to specify stainless steel only for tube bundles having ISO-psl steam Inside and monoethanolamlne that Is rich In carbon dioxide outside.

Type 304 Is adequate.

Experience has been variable with stainless steel In monoethsnobsmtne solu-Uons as used ln processes for removing hydrogen suUIde or carbon dioxide fram natural and rennery gases.

Pzabably abouC one fourth of the amlne gas treat-Ing plants make some use of stainless steel piping and vessels. Remedial process changes can often be devised to avoid the use of stainless.

Nitric Acid Stainless steels, fhst used cornmerclaQy on ~ large scale In service Involving nitric acid, continue to be used In such instal-lations. These nrst appUcatlons were'of 15 to 18%o Cr steel (now type 430) and soon thereafter of 18% Cr-8% Nl steel (now type 304). The necessity for proper hest treatment to prevent aceskrated

~rzasion and Intezgxanular attack ln nitric aci4 was demonstrated at once through service faQures of Improperly heat treated and as-welded equipment.

These dlfnculties wero eUmlnated by post-fabricatlon heat treatments Involviag slow cooUng fzam about 1450 P for Cype 430.

and rapid cceUng from about 2000 P for type 304. SubsequenUy, for the austenitic

grades, the use o! stabIUzing elements (particularly columbium In type 342) and, more recently. reduction o! carbon content to 0.03%

max (type 304L) have been effective In contxanlng this pxoblem with-out the necessity for quenching fabricated equlpmenC from a high temperature heat treatment.

In the as-welded condition.

304L and 342 show satisfactory resistance to corrosion by nitric acid snd are there-tora suitable fnr neld-erecM equipment.

Where corrosion rates on equ>prnent xnusC be held to less thsn 5 mpy. types 304L and 34'I can be used with nitric add In concentrations up to about 40%, at the atmospheric boning point; 40 to 10%, to about I'l5 P; and '10 to 90%, to about 120 P. Por a conaslon rate of 50 mpy max, the conespondlng lhnlts are appxaxlmate-ly 40 to T0% concentraUon of nitric acid at the boQlng point: TO to 90% at 160 P, and 90% at 85 P. If the acid Is recircu-lated so that conaslon products accumu-late, attack In hot solutions aC tho higher concentrations Is accelerated when the chromium In the acl4 exceeds a cextaln leveL With bolUng 65% nitric acid, the Umltlng chromium content of tho so-lution ls about 0.005%, above which cor-xadon Incxeases zapldly with further In-creases of chromium In the nitric acid soluUon. Under these conditions, conasion Is lntergranular, even with tho stabnlzed or extra-low-carbon grades.

Corzosion by nitric acid In storage h sUght for concentrations to about 94%,

but the acid condensate Is of higher con-centration, and attack becomes appre-ciable on the part of the tank exposed to the condensate (Table 3). (Aluminum Is commonly used for storing 95 and 98%

nitric acid. but Its resistance decreases rapidly with decreasing concentration:

consequently, exposure to the dilute acid must be avoided.) Corzaslon data for spec-imens of 34'I snd 430 steels for various concentr'aUons of nitric acid st Tt P are coxnpared In Table 9. In hot concentratecl solutions where attack Is too severe'to be tolerated, high-sIUcon Iron can be used lf Its mechanical pxapeztles are suitable.

'n reactions under pressure and at tem-peratures consMexebly abovo the atmos-pheric boning point, corrosion rates of aQ the stainless steels increase rapidly with both temperature and concentration:

under these condlUons, only very dilute nitric acid solutions can bo handled sult-Tab!a Z. Corrosion o! Type 384 After IZ Days lu Wet Chlorinated Solvents at Reauxfus TcGlpcxstuxcs Solvent Corroeiou, mpy bfethyleue chloride....................

0.1 carbon tetrachloride..................

5.0 Methyl chlnrnfnrxu....................

10.0 Ethxleue dichloride...................

04 Fxnpyieue aichioxide..................

IT.O oua thtxa nf specimen was In solvent layer. one xhfxd in water lazar, aud oue third in vapor phase.

Table 8. Coxxnslou In Fatty Acids Acidulated with Sulfuric held (steam ssxtaaon)

Sulfueio acid.

'fo Temp, ~erosion, mp~

F 304 3I8 O.o I 0.1 5.0 io 205 15.4 335 M5 200 48.0 215 240 8.0 3.8 194 vzs 487 Ff(f. y. Stress~ass crackle(Z caused Ixs type 308 by cltrfc acfd and xaft ar 212 F

Report No.

17490-2 CINACT REPORT ATTACHMENT 3 Contact Report Of:

. Date Of

Contact:

Telephone ~

Visit Q Follow Up Date:

Agency Or Company and Address QC}it- /7 ~ 5'r Phone Person(s)

Contacted and Title Purpose Discussion ZNcroO ia

.c-.

tX r 1 /

Action.

Copies To:

549 Rev

port No. ~242G-2 prtsdttet taetat Sheet ArrAC(+AT 3. (COmzmZOy-RUSTBOND 8 HB 350 HANLEY'INDUSTRIALCOURT'oST. LOUIS,,MO..63144: 314444-1000 SELECTION DATA GENERIC TYPE: Modified vinyl.alkyd.

GENERAL PROPERTIES:

Rustbond 8 HB is excellent as a primer for bare steel and a tie coat for the followinggeneric coatings:

vinyls, catalyzed

epoxies, epoxy esters, chlori.

nated rubbers, alkyds, acrylics and acrylic latexes. Material dries quickly permitting rapid topcoating.

Provides good, weathering and corrosion resistance for a single package material.

CHEMICALRESISTANCE GUIDE:

Splash and Bxgosoro Bgiiiggo Acids Goad Alkalies Fair Solvents Fair Salt Very Good Water Very Good (with suitable topcoat)

Fumes Good Fair Good Very Good Very Good TEMPERATURE RESISTANCE:

Continuous:

160 F (71 C)

Noncontinuous:

200 F (93 C)

FLEXIBILITY:Excellent WEATHERING: Very Good ABRASfDffNESISTANCEIGood SUBSTRATE: May be applied over properly prepared steel, aluminum or others as recommended.

TOPCOAT REQUIRED: May be topcoated with acrylics, chlorinated

rubbers, vinyls, catalyzed

epoxies, alkyds or others as recommended.

RECOMMENDED USES: Developed specifically for use as a primer and universal tie coat for most generic topcoats.

=Rustbond 8 HB is an excellent shop primer. For mainte-

nance, Rustbond 8 HB permits topcoating, thereby reduc.

ing the possibility of surface contamination. This product will find applications wherever an economical, fast drying primer requiring excellent topcoat compatibility is specified.

NOT RECOMMENDED FOR: Heavily rusted or pitted sur-faces or immersion service.

COMPATIBILITYWITH OTHER COATINGS: May be applied over tightly adhering vinyls, chlorinated rubbers,

acrylics, alkyds, catalyzed epoxies or others as recom-mended. May be used over inorganic zinc primers for non-immersion, atmospheric exposures.

'NOTE: A test patch is recommended to assure adhesion of Rustbond 8 HB over other coatings or the adhesion of topcoats to Rustbond 8 HB.

SPECIFICATION DATA THEORETICAL SOLIDS CONTENT OF MIXED MA-TERIAL:

BY Voiorrrc Rustbond 8 HB 42% - 2%

RECOMMENDED DRY FILM THICKNESS PER COAT:

2-3 mils (50-75 micro ns).

THEORETICAL COVERAGE PER MIXED GALI.ON:

674 mil sq. ft. (16.8 sq. m/I 6 25 microns) 269sq. ft. at 22/2 mils (6.5sq. m/I 965 microns)

'NOTE: Material losses during mixing and application will vary and must be taken into consideration when estimating job requirements.

SHELF LIFE: 12 months minimum.

COLORS: Red, Off.White, Gray.

GLOSS: Flat.

ORDERING INFORPhATION Prices may be obtained from Carboline Sales Representative or Main Office. Terms Net 30 days.

SHIPPING WEIGHT:-

~

1's 5's Rustbond8HB 11lbs.(5.0kg) 55lbs.(25.0kg)

Polydad Thinner 9 lbs. (4.1 kg) 45 lbs. (20.4 kg)

Catboline Thinner 425 9 lbs. (4.1 kg) 45 lbs. (20.4 kg)

FLASH POINT: (Pensky-Martens Closed Cup)

Rustbond 8 HB 52 F (11 C)

Polyclad Thinner 73 F (23 C)

Carboline Thinner n25 77 F (25 C)

Oct. 80 Replaces Mar. 78 N To the best ot our knowledge the technical data contained herein are true and accurate at the dote of issuance and are subject to change without prior notice.

User must contact carboline to verity correctness before specifying or ordering. No guarantee of accuracy ls given or implied. We guarantee our products to conform to carbollne quality control. we assume no responsibility tor coverage, pertormance or injuries resulting from use. Liability, it any, is limited to replacement of products. prices and cost data if shown, are subject to change without prior notice. NO OTHER WARRANTY OR GUARANTEE OF ANY KINO IS MADE BY THE SELLER, EXPRESS OR IMPLIED.STATUTORY.

BY OPERATION OR LAW, OR OTHERWISE. INCLUOINOMERCHANTABILITYAND FITNESS FOR A PARTICUt.AR PURPOSE.

Report No.

17490-2 Page No.

14 APPLICATION INSTRUCTIONS ATTACHMENT 3 (CONCL'UD"D)ib These instructions are not intended to show product recommendations for specific service. They are issued as an aid in determining correct surface pteparatlon, mixing instructions, and application procedute. it is assumed that the properproduct recommendations have been made.

These instructions should be followed closely to obtain the maximum service from the materials.

SURFACE PREPARATION:

Remove anny oil or grease from surface to be coated with clean rags soaked in Carbo-line Thinner 42 or toluol.

Uncoated Steel: Dry abrasive blast to a Commercial Grade Finish in accordance with SSPC-SP663 to a degree of cleanliness in accordance with NACE rr3 to obtain a 1/2 to 1-1/2 mil (12.40 microns) blast profile. Note: Power Tool Clean per SSPC-SP3.63 is acceptable.

For application over existing coating, the surface must be clean, dry and free of any contaminants.

MIXING: Mix to smooth consistency before thinning. Thin up to 25% with Polyclad Thinner if necessary.

Use Carbo.

line Thinner 425 for brushing or rolling or for temperatures above 85'F (29 C).

APPLICATIONTEMPERATURES:

Material Surfaces Normal 6090 F (16-32 C) 65.85 F (18.29 C)

Minimum 45 F (7'C) 35 F (2'C)

Maximum 100 F (38'C) 150 F (66 C)

Ambient Humidity Normal 55.100 F ((330 0) 10.85%o Minimum 40'F (4 C) 0%o Maximum 120 F (49 C) 95%

Special thinning and application techniques may be re-quired above or below normal condition.

SPRAY: Use adequate air volume for, correct operation.

Use a 50% overlap with each pass of the gun. On irregular surfaces, coat the edges first, making an extra pass later.

NOTE: The following equipment has been found suitable; however, equivalent equipment may be substituted.

Conventional:

Use a 3/8" minimum I.D. material hose.

Hold gun 8-10 inches from the surface and at a right angle to the surface.

Mfr. 8( Gun Fluid Tip Binks 418 or 262 66 DeVilbiss P.MBC or JGA E

approx. 0.07" I.D.

Air Cap 66FB 704 Airless: Use a 3/8" minimum I.D. Inaterial hose. Hold gun 12-14 inches from the surface and at a right angle to the surface.

Mfr. & Gun Pump" DeVilbiss JGB-507 QFA.514 Graco 205 591 President 30:1 or Bulldog 30:1 Binks Model 500 Mercury 5C "Teflon packings are recommended and available from pump manufacturer.

Use a.018"-.022" tip with 2000 psi.

BRUSH OR ROLLER: Use natural bristle brush. Use full strokes; avoid rebrushing. Thin up to 25% in hot weather.

DRYING TIMES: 2.1/2 mils and 50%o RH Temperature To Handle To Topcoat 40'F (4'C(

6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 24 hours 50 F (10'C) 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 16 hours 60 F (16 C) 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 8 hours 75'F (24 C) 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 4 hours 90'F (32 C) 30 minutes 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months CLEAN UP: Use Carboline Thinner 42 or ketone solvent.

STORAGE CONDITIONS:

Temperature: 40 110'F (443 C)

Humidity: 0-100%

CAUTION:CONTAINS FLAMMABLESOLVENTS. KEEP AWAYFROM SPARKS AND OPEN FLAMES. IN CONFINED AREAS WORKMENMUST WEAR FRESH AIRLINERESPIRATORS. HYPERSENSITIVE PERSONS SHOULD WEAR GLOVES OR USE PROTECTIVE CREAM. ALLELECTRIC EQUIPMENT AND INSTALLATIONSSHOULD BE MADE AND GROUNDED IN ACCORDANCE WITH THE NATIONALELECTRICAL CODE. IN AREAS WHERE EXPLOSION HAEARDS EXIST. WORKMEN SHOULD BE REQUIRED TO USE NONFERROUS TOOLS AND TO WEAR CONDUCTIVE AND NONSPARKING SHOES.

350 HANLEYINDUSTRIALCOURT CcLI IbGIRLS ST LOUIS MO 63144 e 314-644-1000

An Oflicial Pub1tcatlon of Report No.

17490-2 Page No.

15 ATTACHMENT 4 r

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,MACE VOLUMETWENTY

~

OCTOBER, 1981' NUMBERTEN

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1 Report No.

17490-2 Page No.

16 ATTACHMENT 4 (CONTINUED)

Spooi Corrosion Tests in.Wet Scrubber Systems*

DAVIDB. ANDERSON Data Irom field corrosion studies in seven wet scrubber systems ere surveyed to assess environmental ellects on alloy performance. Units studied include utilityholier Ilue gas desullurizatiorI systems utilizing lime/ime.

stone, doublB alkali and sodium su/I/de as absorbents plus water scrubbers on reluse and sewage sludge in.

clneretors.

The data Illustrate the severity of corrosion problems which can occur in the variety olenvironments produced by these complex wet chemicelprocesses.

Im.

portent considerations include pH, tempereture, chio.

rides, absorbent oxidation stage, acid condensation, end alkaline seal/ng.

Unprotected carbon steel con-

. sistently shows unacceptable corrosion resistance ex-cept in areas restricted to exposure to hot, dry llue gas.

Stainless steels and more highly alloyed materials pro-vide useiul corrosion resistance but alloy selection must consider spec/lie environmental conditions. Par-ticularlycorrosive env/ronments are encountered In Inlet prescrubbers and exit duct/ng subjected to acidic con.

densates.

Corrosivity is often compounded by Introduc tlon ol high chloride levels lrom fuel sources or use of closed loop water systems.

fp./

<j'- g~~

. /i

//g NKi'IGURE 1 Corrosion test spooL Introduction within th6'guidelines outlined in ASTMStandard Recommend-WITH THE PASSAGE of strict environmental control regula.

ed Practices G474 and G1.79. Wrought alloy samples wore tlons and concurrent expansion of coal usage, Installation of prepared from 1.0 to 1.5 mm thick cold rolled strip while cast fossil fired power plant FGD scrubber systems increased from alloy samples wore machined from 50 mm diameter cast bars.

essentlallyzeroln1970to55unitswlthacomblnedcapacityof Samples were exposed without applied stresses or welds.

18,000 MWbyJune,1979.Capacity isexpectedtoexpandtoat Tight crevices were provided, however, by the small Tefiontu least 70,000 MW over the next decade.

Insulating spacers.

Wet scrubbing processes, commonly utilizing lime or Ideally, corrosion test specimens should be exposed for llmestoneslurrlestochemlcaitycaqtureSOz,rapldtyachieved three to twelve months under relatively steady state condl.

Industry dominance.

Materials engineers recognized pros-tlons with minimum process upsets. Unforlunately, this ideal pects tor severe corrosion problems introduced by a compii-is not Inharmony with typical pilot plant operation. Most of the cated wet chemical process withvariable, and often unpredict.

case histories cited In this paper meet the exposure period re-able complex conditions of pH, temperature, chlorides, oxkfa.

qulrements. However, since most of the systems studied were tlon stage, acid condensation, and alkaline scaling. Initial in early development

stages, steady state operating condl.

designs were hampered by limited guidelines for selection of,tlons were the exception rather than the rule.

t I

I lh t

ma eraswt assuranceo optimumdurablll ty Extensive field exposures have been conducted over the Case Histories past six years utilizing the established Inco corrosion test Extensive corrosion test spool exposures wore conducted spool program.'esults have provided Interesting insight into In seven wet scrubber installations to be described.

In many the corrosion characteristics of a wide range of alloys, the im.

cases, multiple spools were exposed, each including samples portant corrosion mechanisms involved, and the effects of of a wide range of corrosion resistant alloys plus mild steel.

specific operating variables.

Rather than provide a detailed review of 'all of the data gener-ated, the results presented are limited to alloys selected to II-lustrate a range of corrosion resistance and to isolate environ-Fieid Co ionize t pro in mental effects for a wide range of exposure conditions. Alloy A typical corrosion test spool utilized for this program is comPositlons are given in Tabte 1.

s mn In Figure 1. Spools w<<e assembled a"d p'ocessed Caae 7LimesfOrte pGD SySfem A five month study was conducted tn a double loop design

'Presented during corrosion/81 (paper 127), April, 1981, Tor-limestone scrubber with test spools exposed In the areas onto, Ontario.

The International Nickel Company, Inc. New York, New York.

I'ITrademark of E. I. Du pont de Nemours & Co., Inc.

0094.1492/81/000168/$ 3.00/0 October, 1981 1981, National Association of Corrosion Engineers 13

O Report No.

17490-2 Page No.

17 TABLE 1 Nominal Composition of Test Materials ATTACHMENT 4 (CONTINUED)

Percent Nl Fe Cr Mo Cu C

Mn

.Other AISI 1010 steel HSLA steel AISI 304 stainless steel AISI 316 stainless steel AISI 317 stainless steel AlloyG Alloy625 AlloyC 276 bal.

O.4 bai.

9.5 bal.

13.0 bal.

14.0 bal.

45.0 20.0 60.0 5.0 54.0 5.0 0.9

0.4 18.5 17.0 2.25 19.0 3.25 22.0 6.5 2.0 21.5 9.0 15.5 16.0 0.10 0.08 0.08 max.

0.08 max.

0.03 0.1 max.

0.02 max.

0.40 0.3 1.5 1.7 2.0 1.3 0.05 SI 2.1 Cb+ Ta 3.7 Cb+ Ta 4.0 W Inlet 4

Re ter 3

<<Make-Up Water Packed Tower

~OWW&$

1Il WI Tower 6

Tank Make.up t

We'ter I

FIGURE 2 Limestone FGD system.

Exit Gaa To Stadt shown in Figure 2. This design confines the recirculating chloride containing scrubbing solution to the first loop, Le.,

the flooded disc scrubber and the absorber area below the packed tower. Corrosion data for AISI 1010 steel and three alloys are given in Table 2.

Average corrosion rates for the carbon steel samples were an unacceptable 0.20 to 0.58 mm/y (8 to 23 mpy). AISI304 stainless steel also exhibited limited corrosion resistance, particularly in creviced areas.

The single exception was the hot gas outlet, which was presumably above the dew point.

More highly alloyed AISI316 stainless steel provided a marked Improvement in corrosion resistance In all areas, but only alloy G provided virtual corrosion immunity. It Is of significance to note that with the relatively low chloride levels in this unit, the two stainless steel alloys showed little sensitivity to the envi-ronmental differences In the scrubber and absorber tower.

Case 2Lime FGD System A three month test evaluation was conducted ln the ab-sorber section In a double marble bed lime system with ex-posures in the areas indicated In Figure 3. Corrosion data are given in Table 3. As In Case 1, carbon steel and AISI 304 stain.

less steel exhibited limited corrosion resistance except In the exit gas above the mist elimlnator whew'no condensatlon was TABLE2 Limestone FGD Scrubber Absorber Exposure Area 158days,pH ~ 57 chlorides: 2250 In scrubber 100450 in absorber Max. PlttlnglCrevlce Corrosion-mm 304 Stainless Steel 316 Stainless Steel AlloyG Average CorrosIon Rate For 1010 Steel mmiy Base of scrubber (1)

Absorber tower below nozzles (2) o.66 (kf.O~)

o.o5 0.79 (Jlii~/

0.18 0

0.34 0.25 Absorber tower

-mist eliminators (3)

Absorber tower

-gas outlet (4)

Scrubber slurry tank(5)

=

Absorber slurry tank (6) 0.28 0.25 0.18 0.15 0.05

'0 020 0.26 0.58 0.33 Materials Performance

Report No.

17490-2 Page No.18 ATTACHMENT 4 (CONTINUED)

Gas Reheater~

Gas To Stack Gas to Stack Q4 Wa share

~

0 e

s e

It Scrubber Boiler Rue ~

Gas Q1 Q3 Gss Inlet Gas Inktt Steam Btowers Ladder Vane Spray Commktutor Scrubber Overnow Sctubber Scrubber Drakt Pump

~

Booster Q2 Fsn Racy de Tank FIGURE 4 Double alkali FGD system, dilute mode.

FIGURE 3 Lime FGD scrubber.

AISI Alloy Shower Spray (1)

Above Marble Above Mist Bed (2)

Elfmlnator (3) 316 0.28 $)t0+4~e.18

<.03 0.13 317 Average corrosion rate (mm/y) 1010 steel 0

0 1.60 0.74 0'.13 TABLE3 Lime FGD Scrubber 93 days, 400600 ppm Cl, Shower Water pH ~ 4.9 Max. Pit/Crevice Corrosion-mm evident. AISI316 stainless steel (2.3% Mo) provided greatly im.

proved corrosion resistance, while AISI 317 stainless steel (3.2% Mo) was unaffected over this relatively short exposure period.

Case 3Dilute Mode Double AlkaliSystem A typical dilute mode double alkali systemrecycles highly oxidized regenerated liquor and can be expected to achieve moderate chloride concentrations. Corrosion test locations In a short term exposure program of this type are shown In Figure 4 and corrosion data are given in Table 4. The variable cor-roslvity of the process conditions in the different areas Is evidenced by corrosion rate of carbon steel, ranging from 0.35 mm/y (14 mpy) In the dry inlet gas to 3.3 mm/y(130 mpy) in the moist outlet gas. AISI 304 stainless steel again exhibited limited corrosion resistance in wet sections. AISI316 stainless provided some improvement except In the aggressive quench area where maximum chloride concentrations are expected.

Case 4Concentrated Mode Double AlkaliSystem Exposures ln a concentrated mode system were limited to two areas shown In Figure 5. Corrosion data in Table 5 show TABLE4 Double Alkali FGD System-Dilute Mode 31 Days, Slurry pH w 10.13,1000 ppm Cl Max. Pit/Crevice Corrosion-mm Alloy Flue Gas Quench Absorber Discharge Inlet (1)

Section (2)

Tray (3)

Duct (4)

AISI 304 AISI 316 AlloyG Average corrosion '.35 rate (mm/y)

AISI-1010 steel 0.10 0.10 0.53 0.20 0.39 0.28 0.05 3.31 October, 1981 15

Report No.

17490 2

Page No.19 ATTACHMENT 4 (CONTINUED)

Reheater Clean flue Gas Inlet flue Gas Venturl Recyde Venturi Scrubber Scrubber Exit Tray bsotbe Wash Tray Feed Absorber Recycle Orifice Contactor Booster Blower flue Gas flyAsh Purge 'to Pond 6

5 Absorber FIGURE 5 Double alkali FGD system, concentrated mode.

TABLE 5 Double Alkali FGD System-Concentrated Mode FIGURE 6 Sodium sulfite SOz recovery process.

4 months, pH = 45,1400 ppm Chlorides Max. PltICrevico Corrosion-mm Stack I.O. Fan Alloy AISI 304 AISI 316 AISI 317 Alloy825 AlloyG Alloy625 AlloyC.276 0.20 0

0 0

0 1.2 0.9 0.6 0.7 0.8 0

0 Absorber Above Mist Overflow (1)

Ellmlnator (2)

From Incinerator Mixing Chamber Pre-Quench Chamber 03 Mist Esmlnator Scrubber Clarifier minimal attack In the absorber overflow piping system.

However, the exposure in the outlet duct above the mist ellmlnator provides an example of the severity of corrosion which can occur In sulfurous and sulfuric acid condensatea Only nickel base alloys 625 and C-276 were resistant to attack In this area Case 5-Sodium Sullite SO, Recovery Process An extensive exposure program In the scrubberlabsorber areas of a sodium sulfite SOz recovery system Is outlined In Figure 6 with corrosion data summarized In Table 6. The com-FIGURE 7 Refuse Incinerator scrubber.

blnatlon of high temperature, uncontrolled pH, abrasive flyash, and heavy solids buildup In the venturl scrubber en-trance resulted In severe corrosion of all of the alloys evaluated.

Reduction In temperature and flyash abrasion significantly reduced corrosion at the venturl exit and ab-sorber tower bottom although clearly, high alloys are required to cope with the low pH environment containing 1200 ppm chloride. Condensate conditions above the mist ellmlnator again provided aggressive conditions while exposure to scrub.

ber solution sprays and the scrubbed flue gas caused minimal corrosion.

TABLE 6 Sodium Sulfite SO, Recovery Process 3 Months, 1200 ppm CI, p H ~ 1.5.2 Max. Pitting/Crovlco Corrosion-mm Alloy Vonturl Entrance (1)

Exit (2)

Tower Bottom (3)

Mist Ellmlnator Absorber Bolow (4)

Above (5)

Solution (6)

Scrubber Flue Gas (7)

AISI 316 AISI 317 AlloyG Alloy625 0.94(P) 0.20 0.46 0.18 0.94(p) 0.36 0.20 0.33 0.20 0.38 0.18 0.10 0

0

<0.03 0

- 0.30 0

0 0

<0.03 0

0 16 Materials Performance

EepoLr. No.

17490 Page No.20 TABLE 7 Refuse lnclnerator Scrubber 161 Day Exposure Max. Pltlcrevice Attack-mm I

I ATTACHMENT 4 (CONTXNUED)

Alloy Scrubber Inlet (1)

Scrubber Induced Oraft Roof (2)

Fan (3)

Flume (4)

Clarifier (5)

AISI 304 AISI 316 AlloyG Alloy625 Average Corrosion rate-mmfy 0.43 1.40(p)(8>1

.51 0.25 0.10 0.13 0.69 0.20 0.15 0.10 0 '.33 0.30 0

0 0

0.28 0.15 0

0 AISI 1010 steel H9LA steel p 1.3..

0.9

>1.4 0.8 1.0 0.9

>1.3

> 1.4 0.4 0.2 (p) = perforated TABLE 8 Sewage Incinerator Scrubber 15 Month Exposure Max. Pitfcrevice Attack-mm Alloy Gas inlet Scrubber Impingement Baffle(1)

Liquid(2)

Plate(3)

Exhaust Stack (4)

AISI 304 AISI 316 AISI 317 AlloyG 0.30 028 0.0&

0.03 0.46 0

0.51 0

Average corrosion ratemmlyr

-1010 steel 0.07 0.02 0.13 WATER SUPPLY GAS INLET MIST EUMINATOR IMPINGEMENT BAFFLEPLATE SPRAY NOZZLES x

INLETBAFFLE Case 6Refuse Incinerator Scrubber Day-today variations in refuse create equally variable en-vironmental conditions in refuse incinerator offices scrubbers.

Typically, the gases contain significant levels of chlorides from the burning of chlorinated plastics. Use of fresh water as a scrubbing medium produces unbuffered HCI. Corrosion test locations In a municipal system are Identified in Figure 7 and corrosion data are given in Table 7. Carbon and low alloy steels are clearly inadequate for this application with the pos-sible exception of the clarifier tank. Condensate carryover from the mist ellmlnator created a severe environment at the scrubber roof and the induced fan area with localized corro-sion developing to some extent withall of the alloys evaluated.

The corrosivity is, fn part, aggravated by the use of a recirculat-ing water system fn this plant which does not allow fordilution of neutralizatfon of the acid chlorides. The importance of this is evidenced by the signiffcantly reduced level of corrosion ob-served in a comparison incinerator operated with a once through water system.

DRAIN FIGURE 8 Sewage Incinerator scrubber.

October, 1981 Case 7Sewage Sludge Incinerator Chlorides in sewage sludge incinerators are introduced by the scrubbing water and generally do not reach the high

'evels developed in refuse incinerator systems. The corrosion

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Report No.

17490-2 Page No. 22 ATTACHMENT 5-~

Effect of Acids on the Stress Corrosion Cracking of Stainless Materials in Dilute Chloride Solutions+

A. I. ASPHAHANI Sfe//ife Division, Cabot Corporation, Kokomo, Indiana 77re chion'de stniss cracking o/ srsinless steels (304, 304L, 316. 3160 is shown ro occur in dilute 0.8 ro 4Ã sodium chloride solutions containing 0.2 to IX HSPOa or 0.5%

CHSCOOH.

While monr localized attacks (pitr(ngwrevice corrosion J sni observed in the'h/oride solution con raining scen'c ac(d, the 0.2X phosphoric acid addiri'on to 0.8% iysCf ie sulhcient to induce stress cnicking o/ the ausrenitic srain/ess steels within less than 10 cbys ofexposure at 14 f C 77ie higher nicks/ con rent ausreni tie stainless alloys (20Cb<.

825. 20.hfod/ are more resisrsnt ro the eh/bride stress cracking. However, some pitting and crevice corrosion atrsck is observed on "these alloys. except for 20hfod.

77re high perfonnance nickel base alloys (G, C276/ show exec/lent nsisrance to chloride stn.ss cracking and ro /oca/ized corro-sive attack.

The susceptibility of the srsinless stee/s to the observed srress cracking is related to the acidiry o/ ahe dilute chion'de solutions, and is exp/sined using the concept o/ the criticalporenrisl for stress corrosion cracking.

data have been reported from SCC tests in dilute chloride environments at 300 C, in chloride solutions containing H2S,

!2

~

I3 in brines simulating geothermal environments, in pure or in-hibited hydrochloric acid at room temperature, 'nd in refrigerated HCI solution.

Still, almost no data exist on the chloride stress cracking of austenitic stainless steels in dilute chloride environments containing traces of acids, specifically less than 2% phosphoric acid. These environments appear of interest in some CPI applications dealing with phosphate chemicals and to the food processing industries using phosphate compounds as preservativcs or mixtures containing table salt and weak orglnic acids, where AISI 304 and 316L stainless steels have already experienced SCC in field service.

't is the purpose of this study to present data on the SCC of several stainless materials in dgute chloride solutions containing small amounts of different acids. The effects of temperature, acid additions.

and galvanic coupling are shown'. Also, the resinance and(or susceptibility of various alloys are established and discusscrL TABLE 1 Nominal Composition of AlloysTested 6VI%)

Atbvs Fs Nl Cr Mo Mn St Cu C

AISI 304 AISI 304L AISI 3'!6 AISI 3'l6L Carpenter 20CI.3(')

tm~mr 62S(')

Haynes alloy No. 20 Mod>> )

Hanalloy alloy G( )

Haitslloy alloy C.276( )

Bal 9

Sal 12 Ssl 12 Bsl 33 30 Bal Sal 26 20 Bal

~ 5 Bal 19 19 17 17 20 21n 22 16 2(I) 2.S 2.5 2.S

,0) s 7

'I.S 16'(l)

I(l) 1(l) 1(l)

I(I) 0 S(t) 1(I) 1(l) as(I) 0.05 003(I) 0.05 0.03(1) aos aos(')

aos(')

a02(I)

(I)Ma

.Registered trademark of Carpenter Tschnologv. Corporation.

(2!

Rsgluersd trademark of Imsmstiorisl Nlckst Company, Inc.

(>)

(.Rsgiuarsd trsdsmsrk of Cabot Corporation.

(a) introduction CHLORIOE STRESS CRACKING of austenitic stainless steels has alwisys been a problem limiting the safe use of these alloys in the various chemical processing industries (CPI). This subject of stress corrosion cracking (SCC) in chloride environments is by no means a nef(iected one for researchers.

However, most of the studies have been limited to tests in hot, concentrated chloride solutions, specifically the boiling'42 to 45)S MSCI2

. A limited amount of data exists on th other aqueous solutions.

The stress containing chloride iona has been obis commented on.

Also, the effects of v I

C s+

C sos F sos H st Us M st mentioned,

examined, and sum s

Experimental Procedure Materia/s The alloys examined included several stainless steels and high performance nickel base alloys. The nominal chemical compositions and the registered trademarks are presented in Table 1.

Presented during Corrosion/79 (Paper 42), March, 1979, Atlanta.

Georgia.

November, 1980 solutions.

Specimens e SCC of stainless steels in The SCC tests were conducted on U.bend specimens or 133 x 13

~

2~

x 3 mm (5.25 x 0.5 x 0.125 inch). Each specimen was deformed cracking in sulfuric acid investigated, and around a

25 mm (1

inch) mandrel. The specimen's ends were aiious cations (e.g..

Ba

~

maintained in a parallel position with a bolt and a nut made out of

~ ~IO,I I F

Ni. Zn

) have been Hasteiloy alloy C 276. Tenon inserts were used to insulate the maritecL 'urthermore, bolt/nut from the specimen. The specimen was further stressed by straining iis enih ffightening the nut) to a finiispan of 12 mm (1/2 inch). The imposed stress depended on the yield strength of the'aterial, and no effort wss made to calculate the exact value of the 0094-1492/80/000180/$ 3.00/0 1980, National Association of Corrosion Engineers 9

. pore No'. 17s90-2, pI.Qdu~;

at@ Sheet.

r u

age. No'3.'TTACIKENT"3" (CONTINUED)"'

RUSTBOND 8 HB

~s,,

i,...350 HANLEYINDUSTRIALCOUFIT'o.ST.LOUIS; MO 63144'~31~44-'1000 me ~ ~

o SELECTION DATA GENERIC TYPE: Modified vinyl alkyd.

GENERAL PROPERTIES:

Rustbond 8 HB is excellent as a primer for bare steel and a tie coat for the followinggeneric coatings:

vinyls, catalyzed

epoxies, epoxy

cstars, chlori~

nated rubbers, alkyds, acrylics and acrylic latexes. Material dries. quickly permitting rapid topcoating.

Provides good weathering and corrosion resistance for a single package material.

CHEMICALRESISTANCE GUIDE:

Splash and Exposure Spillage Acids Good Alkalies Fair Solvents Fair Salt Very Good Water Very Good (with suitable topcoat)

Fumes Good Fair Good Very Good Very Good TEMPERATURE RESISTANCE:

Continuous:

160 F (71 C)

None'ontinuousl 200 F (93 C)

FLEXIBILITY:Excellent WEATHERING: Very Good 1

ABRASION RESISTANCE: Good SUBSTRATE: May be applied over properly prepared steel, aluminum or others as recommended.

TOPCOAT REQUIRED": Mat/ be topcoated with acrylics, chlorinated

rubbers, vinyls, catalyzed

epoxies, alkyds or others as recommended.

RECOMMENDED USES: Developed specifically for use as a primer and universal tie coat for most generic topcoats.

Rustbond 8 HB is an excellent shop primer. For mainte-

nance, Rustbond 8 HB permits topcoating, thereby reduc.

ing the possibility of surface contamination. This product will find applications wherever an economical, fast drying primer requiring excellent topcoat compatibility is specified.

NOT RECOMMENDED FOR: Heavily rusted or pitted sur-faces or immersion service.

COMPATIBILITYWITH OTHER COATINGS: May be applied over tightly adhering vinyls, chlorinated rubbers,

acrylics, alkyds, catalyzed epoxies or others as recom-mended. May be used over inorganic zinc primers for non-immersion, atmospheric exposures.

'NOTE: A test patch is recommended to assure adhesion of Rustbond 8 HB over other coatings or the adhesion of topcoats to Rustbond 8 HB.

r SPECIFICATION DATA THEORETICAL SOLIDS CONTENT OF MIXED MA-TERIAL:

Sy Volume Rustbond 8 HB dta SS RECOMMENDED DRY FILM THICKNESS PER COAT:

2-3 mils (50.75 microns)

~

THEORETICAL COVERAGE PER MIXED GALLON":

674 mil sq. ft. (16.8 sq. m/I 6 25 microns) 269 sq. ft. at 2)rs mils (6.5 sq. m/I 8 65 microns)

'NOTE:,Material losses during mixing and application will vary and must be taken into consideration when estimating job requirements.

SHELF LIFE: 12 months minimum.

COLORS: Red, Off-White, Gray.

GLOSS: Flat.

ORDERING INFORMATIQN Prices may be obtained from Carboline Sales Representative or Main Office. Terms Net 30 days.

SHIPPING WEIGHT:

1's 5's Rustbond 8 HB

=

11lbs. (5.0 kg) 55lbs. (25.0 kg)

Polyclad Thinner 9.lbs. (4.1 kg) 45 lbs. (20.4 kg)

Cafboline Thinner y/25 9 lbs. (4.1 kg) 45 lbs. (20.4 kg)

FLASH POINT: (Pensky Martens Closed Cup)

Rustbond 8 HB 52 F (11 C)

Polyclad Thinner 73 F (23 C)

Carboline Thinner y25 77 F (25 C)

Oct. 80 Replaces Mar. 78.N To the best of our knowledge the technical data contained herein are true and accurate at the date of issuance snd are subject to change without prior notice. User must contact csrboline to verity correctness before specifying or ordering. No guarantee of accuracy is given or Implied. We guarantee our products to contorm to Carbollne quality control. We assume no responsibility ior coverage, performance or injuries resulting from use. I.isbility, if any, is limited to replacement of products. prices and cost data if shown, sre subject to change without prior

'otice:

NO OTHER WARRANTY OR GUARANTEE OF ANY KINO IS MAOE BY THE SELLER, EXPRESS OR IMPLIED,STATUTORY, BY OPERATION OR I.AW, OR OTHERWISE, INCLUDINGMERCHANTABILITYANO FITNESS FOR A PARTICULARPURPOSE.

t

~

Report No.

17490-2 Page No.

14 ATTACHMENT 3 (CONCLUD D)

APPLICATION INSTRUCTIONS Mfr. & Gun Fluid Tip Binks ~~18or %2 66 OeVilbiss P MBC or JGA E

approx. 0.07" I.D Mfr.& Gun Pump" OeVilbiss JGB.507 QFA.514 Graco 205.591 President 30:1 or Bulldog 30:1 Binks Model 500 Mercury 5C "Teflon packings are recommended and available from pump manufacturer.

Use a.018"-.022" tip with 2000 psi.

BRUSH OR ROLLER: Use natural bristle brush. Use full strokes; avoid rebrushing. Thin up to 25% in hot weather.

DRYING TIMES: 2-1/2 mils and 50% RH Temperature To Handle To Topcoat 40'F (4'C) 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 24 hours 50 F (10 C) 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 16 hours 60 F (16'C) 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 8 hours 75 F (24 C) 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 4 hours 90 F (32 C) 30 minutes 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months CLEAN UP: Use Carboline Thinner 3"2 or ketone solvent.

STORAGE CONDITIONS:

Temperature: 40-110 F (443 C)

Humidity: 0-1 00%

SPRAY: Use adequate air volume forcorrect operation.

Use a 50%o overlap with each pass of the gun. On irregular surfaces, coat the edges first, making an extra pass later.

NOTE: The following equipment has been found suitable; however, equivalent equipment may be substituted.

These instructions are not intended to show product recommendations for specific service. They are issued as an aid in determining correct surface preparation, mixing instructions, and application procedu(e. It is assumed that the proper product recommendations have been made.

These instructions should be followed closely to obtain the maximum service from the materia(s.

SURFACE PREPARATION:

Remove any oil or grease Conventional:

Use a 3/8" minimum I.D. material hose.

from surface to be coated with clean rags soaked in Carbo.

Hold gun 8.10 inches from the surface and at a right angle line Thinner tf2 or toluol.

to the surface.

Uncoated Steel: Dry abrasive blast to a Commercial Grade Air Cap Finish in accordance with SSPC-SP6 63 to'a degree of cleanliness in accordance with NACE g3 to obtain a 1/2 to 66PB 1-1/2 mil (12.40 microns) blast profile. Note: Power Tool Clean per SSPC.SP3 63 is acceptable.

For aPPlication over existing coating, the surface must be Airless. Use a 3/8' minimum I.D. material hose. Hold gun clean, dry and free of any contaminants.

12.14 inches from the surface and at a right angle to the MIXING:Mix to smooth consistency before thinning. Thin surface.

up to 25% with Polyclad Thinner if necessary.

Use Carbo-line Thinner 425 for brushing or rolling or for temperatures above 85 F (29 C).

APPLICATIONTEMPERATURES:

Material Surfaces Normal 60.90'F (16.32'C) 65.85'F (18.29 C)

Minimum 45'F (7 C) 35 F (2 C)

Maximum 100 F (38 C) 150'F (66'C)

Amhieee Humidity Normal 55.(00 F ((335 0) 10-85%

Minimum 40'F (4'C) 0%a Maximum 120 F (49'C) 95%

Special thinning and application techniques may be re-quired above or below normal condition.

-r CAUTION:CONTAINS FLAMMABLESOLVENTS. KEEP AWAYFROM SPARKS AND OPEN FLAMES. IN CONFINED AREAS WORKMENMUST WEAR FRESH AIRLINERESPIRATORS. HYPERSENSITIVE PERSONS SHOULD WEAR GLOVES OR USE PROTECTIVE CREAM.ALLELECTRIC EQUIPMENT AND INSTALLATIONSSHOULD SE MADE AND GROUNDED IN ACCORDANCE WITH THE NATIONALELECTRICAL CODE. IN AREAS WHERE EXPLOSION HAZARDS EXIST, WORKMEN SHOULD SE REQUIRED TO USE NONFERROUS TOOLS AND TO WEAR CONDUCTIVE AND NONSPARKING SHOES.

350 HANLEYINDUSTRIALCOURT Cs BI h)QIIFl&

ST. LOUIS, MO. 63144

~ 314-644-1000

An Offlclal Publlcstlon of Report No.

17490-2 Page No.

ATTACHMENT 4 f'4'<

NAC 6 VOLUMETWENTY

~

OCTO BER) 1981

~

NUMBER TEN

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N 3AV 3NUAOS13W 008 l 3UOOW 3 3 lVO h

Report No.

17490-2 Page No.

16 ATTACHMENT 4 (CONTEiGJED)

Spool Corrosion Tests in.Wet ScrUbber Systems*

DAVIDB. ANDERSON Date froin field corrosion studies in seven wet scrubber systems are surveyed lo essess environmental effects on alloy performance. Units studied include utilityholler flue ges desulfurizatiorj systems ulillzlng IIInelime-stone, double alkali and sodium sulfide es absorbents plus water scrubbers on reluse and sewage sludge in.

clnerators.

The data illustrate the severity of corrosion problems which can occur In the variety olenvironments produced by these complex wet chemicafprocesses.

Im-portent considerations include pH, temperature, chio.

rides, absorbent oxidation stage, acid condensation, and alkaline scaling.

Unprolecled carbon steel con.

. slstently shows unacceptable corrosion resistance ex.

cept in areas'estricted Io exposure to hot, dry liveges.

Stainless steels and more highly alloyed materials pro-vide useful corrosion resistance but alloy selection must consider specific environmental conditions. Per.

tlculerlycorrosive environments ere encountered In Inlet prescrubbers and exit 'ducting subjected to acidic con-densetes.

Corrosivity Is ollen compounded by inlroduc tlon of h/gh chloride levels lrom fuel sources or use of closed loop water systems.

~jr.;<@

-",.:.. 7 pep r

r FIGURE 1 Corrosion test s pooL introduction WITH THE PASSAGE of strict environmental control regula-tions and concurrent expansion of coat usage, Installation of fossil fired power plant FGQ scrubber systems Increased from essentially zero In 1970 to 55 units with a combined capacity of 18,000 MWby June, 1979. Capacity Is expected to expand to at feast 70,000 MW over the next decade.

Wet scrubbing processes, commonly utilizing lime or limestone slurries to chemically capture SOz, rapidly achieved industry dominance.

Materials engineers recognized pros-pects for severe corrosion problems introduced by a compli-cated wet chemical process withvariable, and oftenunpredict-able complex conditions of pH, temperature, chlorides, oxida-tion stage, acid condensation, and alkaline scaling. Initial designs were hampered by limited guideiines for selection of materials with assurance of optimum durability.

Extensive field exposures have been conducted over the past six years utilizing the established Inco corrosion test spool program.'esults have provided Interesting insight into the corrosion characteristics of a wide range of alloys, the Im-portant corrosion mechanisms Involved, and the elfects of s peciflc operating variables.

within the guidelines outlined in ASTM Standard Recommend-ed Practices G4.74 and Gl-79. Wrought alloy samples were prepared from 1.0 to 1S mm thick cold rolled strip while cast alloy samples were machined from 50 mm diameter cast bass.

Samples were exposed without applied stresses or weids.

Tight crevices were provided, however, by the small Tefionpi insulating spacers.

Ideally, corrosion test specimens should be exposed for three to twelve months under relatively steady state condi-tions with minimum process upsets. Unfortunately, this Ideal Is not inharmony with typical pilot plant operation. Most of the case histories cited in this paper meet the exposure period re.

quirements. However, since most of the systems studied were in early development

stages, steady state operating condi-tions were the exception rather than the rule.

Case Histories Extensive corrosion test spool exposures were conducted In seven wet scrubber Installations to be described.

In many cases, muitipie spools were exposed, each including samples of a wide range of corrosion resistant alloys plus mild steel.

Rather than provide a detailed review of ail of the data gener-ated, the results presented are Iimited to alloys selected to II-lustrate a range of corrosion resistance and to isolate environ-mental effects for a wide range of exposure conditions. Alloy compositions are given In Table 1.

Field Corrosion Test Program A typical corrosion test spool utilized for this program Is shown in Figure 1. Spools were assembled and processed Case tLimestone FGD System A five month study was conductedln a double loop design

'Presented during Corrosion/81 (paper 127), April, 1981, Tor-Iimestone scrubber with test spools exposed In the areas

'nto, Ontario.

The International Nickel Company, Inc. New York, New York.

I'ITrademark of E I. Du Pont de Nemours & Co., tnc.

0094.1492I81I000168IS3.00/0 October, 1981 1981, National Association of Corrosion Engineers 13

Report No.

17490-'2 Page No.

17 TABLE 1 Nominal Composition of Test Materials Percent ATTACHMENT 4 (CONTINUED)

Nl 'e Cr Mo Cu C

Mn

.Other AISI 1010 steel HSLA steel AISI 304 stainless steel AISI 316 stainless steel AISI 317 stainless steel AlloyG Alloy625 AlloyC.276 bal.

0.4 bal.

0.9

0.4 9.5 bal.

18.5 13.0 bal.

17.0 2.25 14.0 bal.

19.0 3.25 45.0 20.0 220 6.5 2.0 60.0 5.0 21.5 9.0 54.0 5.0 15.5 16.0 0.10 0.08 0.08 max.

0.08 max.

0.03 0.1 max.

0.02 max.

0.40 0.3 1.5 1.7 2.0 1.3 0.05 SI 2.1 Cb+ Ta 3.7 Cb+ Ta 4.0 W Rs ter

~~~~Make.up Water Pecked Tower IiI WW W SWM Make up t

Water I

Tower 6

Tank Scrubber Stutry Tank FIGURE 2 Limestone FGD system.

Exit Gss To Stock shown in Figure

2. This design confines the recirculating chloride containing scrubbing solution to the first loop, l.e.,

the flooded disc scrubber and the absorber area below the packed tower. Corrosion data for AISI 1010 steel and three alloys are given in Table 2.

Average corrosion rates for the carbon steel samples were an unacceptable 0.20 to 0.58 mmly (8 to 23 mpy). AISI304 stainless steel also exhibited limited corrosion resistance, particularly in crevlced areas.

The single exception was the hot gas outlet, which was presumably above the dew point.

More highly alloyed AISI316 stainless steel provided a marked improvement In corrosion resistance in all areas, but only alloy G provided virtual corrosion immunity. It Is of significance to note that with the relatively low chloride levels in this unit, the two stainless steel alloys showed little sensitivity to the envl ~

ronmental differences in the scrubber and absorber tower.

Case 2Lime FGD System A three month test evaluation was conducted In the ab-sorber section in a double marble bed lime system with ex.

posures in the areas indicated In Figure 3. Corrosion data are given In Table 3. As In Case 1, carbon steel and AISI304 stain.

less steel exhibited limited corrosion resistance except In the exit gas above the mist ellminator where'no condensatlon was TABLE2 Limestone FGD Scrubber Absorber Exposure Area 158days,pH w 57 chloddes: 2250 In scrubber 100850 ln absorber Max. P IttlnglCrevlce Corrosion-mm 304 Stainless Steel 316 Stainless Steel AlloyG Average CorrosIon Rate For 1010 Steel mmly Base of scrubber (1)

I 0.66 (R(s.0~)

0.05 0

Absorber tower below nozzles (2) 0.79 (8I.l~)

0.18 0.34 0.25 Absorber tower mist eliminators (3)

Absorber tower

-gas outlet (4)

Scrubber slurry tank (5)

Absorber slurry tank (6) 0.28 0.25 0.18 0.15 0.05 0.03

'0 020 0.26 0.58 0.33

, Materials Perfo;mance

Report No.

17490-2 Page No.18 ATTACHMENT 4 (CONTINUED)

Gss Reheat sr~

Gae To Stadt Gsa to Stack Q4 Wa share t

e s

e e

e Booster Fsn Scrubber Boiler Rue ~

Gas Q1 Q3 Gss inlet Gss Inlet Steam tao were Ladder Vane Spray Comminutor Saub bar Over/tow Boo t Q2 Fsn Recyde Tank Scrubber Scrubber Drain pump FIGURE 3 Lime FGD scrubber.

AISI Alloy Shower Spray (1)

Above Ms*le Above Mist Bed (2)

Ellminator (3) 316 317 Average corrosion rate (mm/y)

-1010 steel 0>6 () 9~$.16

(.03 0.13 0

0 1.60 0.74 0.13 TABLE 3 Lime FGD Scrubber 93 days, 400 600 ppm Cl, Shower Water pH ~ 4.9 Max. Pit/Crevice Corrosion-mm FIGURE 4 Double alkali FGD system, dilute mode.

evident. AISI316 stainless steel (2.3% Mo) provided greatly Im-proved corrosion resistance, while AISI 317 stainless steel (3.2% Mo) was unaffected over this relatively short exposure period.

Case 3Dilute Mode Double AlkaliSystem A typical dilute mode double alkali system recycles highly oxidized regenerated liquor and can be expected to achieve moderate chloride concentrations. Corrosion test locations In a short term exposure program of this type are shown in Figure 4 and corrosion data are given In Table 4. The varfable cor-roslvity of the process conditions In the different areas Is evidenced by corrosion rate of carbon steel, ranging from 0.35 mm/y (14 mpy) In the dry fnlet gas to 3.3 mm/y (130 mpy) in the moist outlet gas.

AISI 304 stainless steel again exhibited limited corrosion resistance In wet sections. AISI316 stainless provided some improvement except In the aggressive quench area where maximum chloride concentrations are expected.

Case 4Concentrated Mode Double AlkaliSystem Exposures In a concentrated mode system were limited to two areas shown In Figure 5. Corrosion data in Table 5 show TABLE 4 Double Alkali FGD System-Dilute Mode 31 Days, Slurry pH m 10.13, 1000 ppm Cl Max. Pit/Crevice Conoslon-mm Alloy Flue Gas Inlet (1)

Quench Absorber Discharge Section (2)

Tray (3)

Duct (4)

AISI 304 0

0.10 0.20 0.26 AISI 316 Alloy G Average corrosion 0.35 rate (mm/y)

AISI-1010 steel 0.10 0.53 0.39 0.05 3.31 October, 1981 15

Report No.

17490~2 Page No.19 ATTACHMENT 4 (CONTINUED)

~ L, Rehester Creen Rue Gss Inlet Rue Gss Ventuit Recycte Venturl Scrubber Scrubber Exit Trey bso Wssh Trsv Feed Absorber Recycte Orifice Contsctor Booster Sower Rue Gss Ry Ash Purge to Pond 6

5 Absorber FIGURE 5 Double alkali FGD system, concontratod mode.

TABLE5 Double Alkali FGD System-Concentrated Mode FIGURE 6 Sodium sulfite SOz recovery process.

4 months, pH ~ 4.5, 1400 ppm Chlorides Stsck Alloy AISI 304 AISI 316 AISI 317 Alloy825 AlloyG Alloy625 AlloyC-276 Max. Pltlcrevice Corrosion-mm 0.20 0

0 0

0 1.2 0.9 0.6 0.7 0.8 0

0 Absorber Above Mist Overflow (1)

Elimlnator (2)

From Indnerstor Pre.Quench Mixing Chsmber Chsmber I.O. Fsn 03 Mist Bimlnstor Scrubber Cbiriiier 5

minimal attack In the absorber overflow piping system.

However, the exposure in the outlet duct above the mist ellminator provides an example of the severity of corrosion which can occur In sulfurous and sulfuric acid condensates.

Only nickel base alloys 625 and C-276 were resistant to attack in this area Case 5Sodium Sulllte SO, Recovery Process An extensive exposure program In the scrubber/absorber areas of a sodium sulfite SO> recovery system is outlined In Figure 6 with corrosion data summarized in Table 6. The corn.

FIGURE 7 Refuse incinerator scntbbor.

blnatlon of high temperature, uncontrolled pH, abrasive flyash, and heavy solids buildup in the vonturl scrubber en-trance resulted in severe corrosion of all of the alloys evaluated.

Reduction In temperature and flyash abrasion significantly reduced,corrosion at the venturl exit and ab-sorber tower bottom although clearly, high alloys are required to cope with the low pH environmont containing 1200 ppm chloride. Condensate conditions above the mist elimlnator again provided aggressive conditions while exposure to scrub-ber solution sprays and the scrubbed flue gas caused minimal corrosion.

TABLE 6 Sodium Sulfite So, Recovery Process 3 Months, 1200 ppm CI, pH ~ 1.5.2 Max. Pitting/Crovlco Corrosion-mm Alloy Venturl

'ntrance (1)

Exit (2)

Tower Bottom (3)

Mist Ellminator Below (4)

Above (5)

Absorber Solution (6)

Scrubber Flue Gas (7)

AISI 316 0.94(p)

AISI 317 0.36

. AlloyG 0.18 Alloy625 0.30 0.20 0.46 0.18

~

0.94(p) 0.20

~

0.33

. 0.20 0.38 0.10 0

0 0

0

<0.03 0

0

<0.03 0

Materials Performance

Report No.

17490-2 Page No.20 TABLE7 Refuse Incinerator Scrubber P,~RULC~

4 (CONTIÃKD)

'61 Oay Exposure Max. Pltlcrevlce Attack-mm Alloy AISI 304 AISI 316 AlloyG Alloy625 Average Corrosion rate-mmly Scrubber Scrubber Induced Oraft inlet (1)

Roof (2)

Fan (3)

Flume (4)

Clarifier (5) 0.43 1.40(p) ( 8 >~

.51 0.25 0.10 0.13 0.69 0.20 0.15 0.10 0 '.33 0.30 0

0 0

0.28 0.15 0

0 AISI 1010 steel H9LA steel p 1.3.,

0.9

>1.4 0.8 1.0 0.9

> 1.3

>1.4 0.4 0.2 (p) = perforated TABLE 8 Sewage Incinerator Scrubber 15 Month Exposure Max. Pit/Crevice Attack-mm Alloy Gas Inlet Baffle (1)

Scrubber Impingement Exhaust Lfquid (2)

Plate (3)

Stack (4)

AISI 304 AISI 316 AISI 317 AlloyG Average corrosion rate-mmlyr 1010 steel 0

0.30 0.28 0.08 0.03 0.46 0.5'I 0

0.07 0.02 0.13 WATER suppLY GAS INLET MIST UMINATOR IMPINGEMENT BAFFLE PLATE'PRAY NOZZLES 1

INLETBAFFLE Case 6Refuse Incinerator Scrubber Oay.today variations in refuse create equally variable en-vironmental conditions in refuse incinerator off~as scrubbers.

Typically, the gases contain significant levels of chlorides from the burning of chlorinated plastics. Use of fresh water as a scrubbing medium produces unbuffered HCI. Corrosion test locations in a municipal system are Identified in Figure 7 and corrosion data are given in Table 7. Carbon and low alloy steels are clearly inadequate for this application with the pos.

sible exception of the clariHer tank. Condensate carryover from the mist eliminator created a severe environment at the scrubber roof and the Induced fan area with localized corro-sion developing to some extent withall of the alloys evaluated.

The corrosivlty Is, ln part, aggravated by the use of a recirculat-ing water system in this plant which does not allow fordilution of neutralization of the acid chlorides. The importance of this Is evidenced by the significantly reduced level of corrosion ob.

served in a comparison incinerator operated with a once through water system.

ORAIN FIGURE 8 Sewage Incinerator scrubber.

October, 1981 Case 7Sewage Sludge incinerator Chlorides in sewage sludge incinerators are introduced by the scrubbing water and generally do not reach the high levels developed in refuse incinerator systems. The corrosion

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Report No.

17490-2 Page No. 22 ATTACHMENT 5.v.

i Effect of Acids on the Stress Corrosion Cracking of Stainless Materials in Dilute Chloride Solutions+

A. I. ASPHAHANI Sfe//ife Division, Cabot Corporation, Kokomo, Indiana 77ie chlorid stress cracking of stainless steels /304, 304L, 31b, 318LJ is shown ro occur in dilute 0.8 ro 4)f sodium chlonde solutions containing 0.2 to fsi HSPO4 or 0.5)S CH>COON.

While monr localized attacks fpirrlngwrcvice conosion/

snr observed in the'chlorid solurion conraining scarc acid, the OQX phosphoric acid addition to 0.82( iyaCf is sufhcient to induce stress cracking of the austenitic srainless steels within less than 10 days ofexposure at 141 C.

77nr higher nickel content austeniric srainless alloys /20COD.

825 2O.IVfod/ are more resisrsnt to the chlbride stress cracking. However, some pitting and crevice corrosion attack is observed on these alloys, except for 20-iyiod. 7he high perfomMnce nickel base alloys /G. C276/ show excellent resistance ro chloride stress cracking snd ro localized corro-sive errack.

77se suscepribi)ity of the stainless steels to the observed stress cracking is re/ared ro the acidity of the dilute chloride soluti'ons, and is explained using the concept of the criricsl potential forstress corrosion cracking.

data have been reported from SCC tests in dilute chloride environments at 300 C, in chloride solutions containing H2S, t2

~

l3 in brines simulating geothermal environments, in pure or in-hibited hydrochloric acid at room temperature, 'nd in refrigerated HCI solution.

Still, almost no data exist on the chloride stress cracking of austenitic stainless steels in dilute chloride environmentscontaining traces of acids, specifically less than 2)S phosphoric acid; 'ihese environments appear of interestsin some CPI applications dealing with phosphate chemicals and to the food processing industries using phosphate compounds as preseivativcs or mixtures containing taMe salt and weak orgsnic

acids, where AISI 304 and 316L stainless steels have already experienced SCC in field service.

't is the purpose of this study to present data on the SCC of several stainless materials in dilute chloride solutions containing small amounts of different acids. The effects of temperature, acid additions, and galvanic coupling are shown. Also, the resistance and/or susceptibility of various alloys are established and discussctL TABLE 1 Nominal Composition of Alloys Tested (WtX)

Alloys Fs Nl Cr Mo Mn SI Cu C

A IS I 304 Bal AISI 304L Bsl AISl316 Bal AISI 3 l6L Bal C q ~tv 2OCbo(2)

Bas Ineoioy 625( )

30 Haynes alloy No. 2OMod>> )

Bal Hsssst icy snoy 6 20 Hasseiloyanov C276( )

i 5 9

19 9

19 12 17 12 17 33 20 Bal 21 26 22 Bal 22 Bsl 16 2(s) 2(l) 2.5'.5 2

2.5 1(t) 2 5(t) 7 1.5 16'(')

I(')

1(I) 10) 1(I) as<')

1(t) 1(t) aa(')

0.05 0.03(')

0.05 0 CI(l) 0.04 0.04 aos(')

aos(')

0.02(I)

)Rstaiisisd trademark of Carpenter Tseliiieiogy. Corporation.

(2!

( )Rselstvsd trsdvnvk ot Imsmstional Niekd Compsivl, Inc.

Rsgiuersd trademark of Cabot Corporation.

(4) lnaodu ction CHLORIOE STRESS CRACKING of austenitic stainless steels has always been a problem limiting the safe usc of these alloys in thc various chemical processing industries (CPI). This subject of stress corrosion cracking (SCC) in chloride environments is by no means a neglected one for researchers.

However. most of the studies have been limited to tests in hot. concentrated chtoride solutions, specifically the booing 42 to 45)S MgCI2

. A limited amount of data exists on th other aqueous solutions.

The stress containing chloride sons hcs been ob commented on.

Also, the effects of v 4

C vs

~ass p ssa H ss Us ~as mentioned.

examined, and sum Experimental Procedure

/Ifaferiais The alloys examined included several stainless steels and high performance nickel base alloys. The nominal chemical compositions and the registered trademarks are presented in Table 1.

Presented during Corrosion/79 (P~cr 42), March, 1979, Atlanta, Georgia.

Novembar, 1980 Specimens e SCC of stainless steels in The SCC tests were conducted on U.bend specimens ~ 133 x 13 cracking in sulfuric acid cd I.

~

2~

x 3 mm (5.25 x 0.5 x 0.125 inch). Each specimen was deformed

served, investigated, and around a 25 mm lt inch) mandrel. The specimen's ends were afious casions (eg.

Ba

~

maintained in a parallel position with a bolt and a nut made out of

~so,s I Ni

. Zn have been HsstHloy alloy C276.

TcAon inserts were used to insulate the mar ized.

'urthermore.

bolt/nut from the specimen. The specimen wss further stressed bY straining its ends (tightening the nut) to a finilspan of 12 mm ll/2 inch). The imposed stress depended on thc yield strength of the material. and no effort was made to calculate the exact value of the 0094.1492/80/000180/53.00/0 1980, National Association of Corrosion Engineers 9

~,

Report No.

Page No.

17490-'2 23 r

ATTACHMENT 5 (CONTINUED)

~lied stress.

However, all specimens were stressed the same way, g.~., the same straining of 12 mm (1/2 inch) final span was imposed on every specimen.

When studying the effects of galvanic coupling, small strip specimens having os45 x 5 x I mm (1.75 x 0.19 x 0.04 inchl dimensions were used. They were strained by bending into a C-shape and fining into a slotted holder with a 39 mm (1.50 inch) opening, and held at a constant plastic strain (e os 7%). Galvanic couples were achieved through making the holders out of various dissimilar materials. This type of specimen/holder has been found practical in studying the environmental stress cracking of high performance and 20,21 stainless alloys.

~

r Containers and Solutions The SCC tests at 82 C (180 F) and thc tests at boiling temperature were conducted in glass vessels. The tests at 141 C (285 F) were conducted in sealed Hastelloy alloy C-276 autoclaves. The test solutions were prepared from distilled water and reagent grade chemicals.

The specimen(

were checked af(er 7 to 10 days of exposure.

The failed specimens were then removed, and the tests were resumed on thc remaining specimens.

The tests were finally stopped after a total of 30 days of exposure. Visual examination at 30X was used to determine the presence/absence of stress corrosion cracks. Occasionally, specimens were polished and examined metal-lographically at 100X.

'4 ~ s Results Effect of Phosphoric AcidAddition The data on stress cracking tests conducted in 4% NaQ + 1%

Hspoe solution at 141 C (285 Fl are summarized in Table 2 and TABLE2-Upend Specimens (Two of Each Allay)

One Month Exposures 4% NaCI+1% HsPOe at 141 C (285 F)

Corrosksn Rate Localized Stress Corrosion Atloys mm/y mpy Corrosion

~

Creckine 304 304L 318 316L 2OCba 825 20 Mod G

0 276 0.16 6.1 0.13 5.4 0.1'I 4.4 0.04 1.8 IL07,3 (0.01 (0.1 (0.01 (0.1 (0.01 (0.1 (o.ot oz Crevice Corrosion Crevice Corrosion Crevice Corrosion Slight Attack Pitting-Severe Crevice Corrosion Slight Attack No Attack No Attack No Attack No Yes Yes Yes Ya No indicate that weight losses as well as localized crevice corrosion attack (the areas beneath the bolt/nut) occurred on the 304, 304!

316, and 316L specimens.

Also, dl these stainless steds sutfcrcd SCC. The cracks were of the "branching transgranular type (Figure

'll, which is similar to the classical chloride stress cracking ot these steds encountered in the boiling magnesium chloride tesL No SCC was obser'ved on the rest of the alloys testesL However. alloy 20Cb3 suffered severe localized attack (pittingercvice corrosion) after the 30 day exposure in the 4% NaQ + 1% HsPO4 solution, while alloy 20 Mod showed much better resistance (Figure 2). Slight crevice corrosion attack was observed on alloy 825; however, alloys G and C.276 showed no attack at all.

It should be noted that SCC of the stainless steels was observed at 141 C (285 F) only in the chloride solution containing the phosphoric aci* No SCC occurred in the sodium chloride solution (without HsPoe) nor in the boiling phosphoric acid (without NaQ),

as indicated by the data surmnarized in Tables 3 and 4. It ss appreciated that the test reported in Table 2 was in 4% NaQ + 1%

HSPO4 at 141', while in Table 3, the medium was 2% (not 4%)

NaQ at 141 C, and in,Table 4 it was 2% (not 1%) Hspoe at 102 C (not 141 C). These variations were dictated by a customer problem being worked on. However, I believe the condusions are valid since

~

b FIGURE 1 Stress corrosion cracks; 4% NaCI + 1% HSPO4

~t 141 C (285 F) ~ (a) AISI 304 stainless steel; 50X, and (b)

AISI 316L stainless steel; 50X.

Table 5 shows SCC of the 300 series stainless steels in 0.8% NaCI +

0.2% HSPO4 at 141 C. Pitting attack was observed on the 304 and 304L specimens in the hot sodium chloride solution.

The SCC of the stainless steels in the Cl

+ PO4 solution did not appear to be dependent on the Q or the PO4 concentrations, within the dilute concentration range of 0.1 to 5 weight percent.

Tests conducted in 0.8% NaQ + 0.2% HSPO4 solution at 141 C (285 F) showed that 304,304L,316, and 316L specimens failed by SCC within 10 days of exposure. Tbe data, summarized in Table 5, indicated that alloys 20Cb3 and 825 suffered localized attack while alloys 2@Mod, G, and C-276 showed no anack.

Effect of Temperature Tests werc also conducted In2he 4% NaQ+ 1% HSPO4 solution at 82 C (180 F). Even at this lower temperature, thc stainless steel.

specimens failed by SCC, as indicated In Table 6. Again, no attack was observed on alloys 20.Mod, G, or C.276.

Effects ofAcetic Acidand Hydrochloric Acid The results from similar tests conducted in an 0.8% NaQ + 0.5%

CHsCOOH solution (data summarized in Table 7) indicated that SCC of the 304, 304L, 316, and 316L stainless steds was not limited only to the ch1oride solutions containing phosphoric aekL The typical branching transgranular stress corrosion cracks were observed on, the stainless sted specimens (Figure 3). However, pitting associated with the cracks was more evident on the specimens tested in the 0.8% NeQ solution containing the acetic Mslsolletc rsat4ae~

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ro Report No.

17490'-2 Page No.

25 ATTACHMENT 5 (CONTIN[]ED),

that addition of any of the acids investigated (phosphoric, acetic, and hydrochloric) causes SCC of the stainless steels in sodium chiorkfe solutions. However, some ditferences between the overall effects of these acids should be mentioned.

The features of the corrosive attack vary from one acid addition to another. Acetic acid was more severe in inducing pitting corrosion of the stainless steels than phosphoric (Figure 4) or hydrochloric acids, within the same pH range of 1.7 to 2.2. However, the phosphoric acid addition was much more severe than acetic acid addition in causing piningcrevice corrosion type attack on alloys 20Cb3 and 825 (Tables 5and 7).

As to the special effect of the hydrochloric acid addition, general dissolution with uniform thinning was the predominant form of corrosive attack observed during the tirst 10 days of testing.

{Contrary to the localized anack and SCC observed on the stainless

,iteels within the same period of tening in the NaQ solutions containing phosphoric acid or acetic acid.) Furthermore.

due to solution evaporation, it is not detinite that the observed SCC is representative of an aqueous p.B)t NaQ + HCI sotutioi) ttt 141 C (285 F).

Still, it is most interesting that phosphoric or acetic acids cause localized corrosion and SCC of stainless steels in dilute chloride solutions.

Phosphates or acetates have been known to inhibit corrosion and SCC. For example, 1% NaHzPO4 addition to boiling 3% NaCI solution (pH adjusted to 6.4) is reported to inhibit the SCC of high strength low alloy steel.

Similarly, 2% CH3COONa addition to boiling MgQz solution has been proven effective in

'Vinhibiting the SCC of 18.8 stainless steel.

Yet, the data presented zs herein clearly indicate that the presence of "PO4" or "CH3COO" compounds in acidic dilute chloride solutions was the cause ot the

~ stress cracking of the 304,304L, 316, and 316L specimens. The role of the 'O'Oa" or "CH3COO" compounds in inhibiting or causing SCC can be explained through their et!acts on the critical potential for SCC, t.e., f [critical, SCC) as defined by Uhlig. 'he small phosphoric acid addition (as well as the small acetic acid addition) shihed the free corrosion potential to more noble values, pre sumably above the p [critical, SCC] and within the potential range

~ where SCC occurred in the hot, dilute chloride solutions. Therefore, alloys susceptible to chloride SCC {304, 304I 316, and 316L stainless steels) may not fail by SCC in the dilute NaQ solution where the free corrosion potential lies below (I) [critical, SCC].

However, these stainless steds do fail by SCC upon the addition of compounds that alter the relative position of the corrosion potential "A'earls" the critical potential for SCC. On the other hend, and as expected, the SCC resistance of the high performance nickel base alloys (with very noble or nonexistent (I) [critical, SCC], e.g., alloys G or C-276) will not be aftected by any addition of 'PO4" or "CHaCOO" compounds to the chloride environment.

In this respect, the etfects of the various galvanic couples can be explainecL Coupling 316L to less nobte metals (carbon steel, copper, alloys 200, 400, and 304) polarizes them to a more active potential, presumably below the /[critical, SCC] and away from the SCC potential range; However, coupling 316L to alloys dose in perform-ance or morc noble {304L316,20', G, and 25) shifts their free corrosion potendal to more noble values above the I)I (critical, SCC]

and within the susceptible potential range for cracking.

Finally, as expected, no degradatlon of any kind was observed on the high performance nickel base alloys. These materials, due to their high nickel and htgh molybdenum contents lalloys G and C.276), are not susceptibte to chloride SCC in the classical MgQz test.

They remain resistant to SCC through the various tests summarized above. However, one point of interest is the behavior of the highly alloyed stainless materials, /.e alloys 20Cba. 825,and 20 Mod. While carbon content and molybdenum addition do not improve the performance of the "300 series of stainless

steels, increasing the molybdenum content of the high chromium, high nickd stainless alloys l20Cb3. 825. and 20 Mod) plays a detinite rde in improving their resinance to localized attack. Alloy 20.Mod (5% Mo) showed no pitting attack and consistently outpertormed alloy 20CbG (2.5'%o) and alloy 825 (3)t Mo) which suffered pining and crevice corrosion in hot dilute NaQ solutions containing

~ smail amount ot Hzpoa.

Conclusion

1. The presence of less than 1% acid induces stress corrosion cracking of austenitic stainless steels ln dilute chloride solutions at temperatures as low as 82 C (180 F).

2. AISI 304, 304L, 316, and 316L stainless steels readily fail by chloride stress cracking in O.tati NaCI solution containing 0.2y, H3PO4 or 0.5)f CHz COOH or naces of HQ at p H oi 2 2.

. 3. Carpenter 20Cb3 and Incoloy 825 are not susceptible to SCC

)n the aforementioned environments.

Howeverr zhese two alloys suffer severe pining and crevice conosion attack.

4. Under the same testing conditions, Haynes altoy No. 20 Mod is resistan't to SCC. Also, presumably due to its high molybdenum content, this alloy shows excellent resinance to pitting and crevice corrosion.

5. Hastelloy alloys G and C-276 do not suffer corrosion of any type under the conditions of the tests conducted.

References

l. Acello, S. J., Greene, N. D. Corrosion, Vol. 18, p. 286t (1962).

2. Harston, J. D., Scully, Jr C. Corrosion, Vol. 25, p. 493 {1969).

3. Ogura, S., Sugimoto, K., Sawada, Y. Corrosion Science, Vol.

16, p. 323 tl976).

4. Staehle, R. W. The Theory of Stress Corrosion Cracking in Alloys, edited by J.

C. Scully, NATO publication, p. 223, Brussels, 1971.

5. Logan, H:4-The Stress Corrosion of Metals, John Wiley and Sons, Inc., p. 107 (1966).

6. Franks, R., Binder. W., Brown, C. M. Symposium on Stress Corrosion Cracking of Metals. ASTM-AIME411 (1944).

7. Loginow, A. W.,

Bates, J.

F.,

Mathay, W. L Materials Protection and Performance, Vol. 11, No. 5, p. 35 (1972).

L Truman, J. E. Corrosion Science, Vd. 17, p. 737 {1977).

9. Bednar, L. Corrosion, Vol. 33, p. 321 {1977h

10. Latanision, R. M., Staehte, R. W. Fundamental Aspects of Stress Corrosion Cracking, edited by Staehle, Forty, and Van Rooyen, NACE publication, p. 214 ll969).

11. Dean, S. W., Jr. ASTM.STP 610, p.308 (1976).

12. Kowaka, M., Nagano, H., Kobayashi, T., Harada, M. The Surnitomo Search, No. 16, p. 64 (1976) November.

13. Takernura, S.. Onoyama, M., Ooka, T. ASTM.STP 610, p. 338 (1976).

14. The LLL Geothermal Energy Program Status Report, The Lawrence Livermore Labonnory, UC66, p. 11'I, April, 1977.

15. Zucchi, F., Trabanelli, G., Frignani, A., Zucchini, M. Corrosion Science, Vol. 18, p. 87 {1978).

16. Lafranconi. G., Mazza. F Sivierl, E., Torchlo, S. Corrosion

'cience, Vol. 18, p. 617 (1978).

17. Nielsen, N. A. Journal of Materials, Vd. 5, p. 794 (1970).

1L Druelles.

P.,

Blanchard, F. Aciers Speciaux, No. 36,'p.

16 (1976).

19. Davison, R. M. The Journal of Motybdenum Metallurgy, Vol.3, No. 2, p. 17 {1978).

20. Asphahani, A. I., Hodge, F. G. Unpublhhed data {1977).

21. Vhlig, H. H., Asphahani, A. I. Corrosion Behavior of Cobalt

'ase Alloys in Aqueous Media, submitted for publication, 197L

22. Uhlig, H. H., Uncoln, John, Jr.J. Electrochemical Society, Vol.

105, p. 325 (1958).

23. Newberg, R. T Uhlig, H. H. J. Electrochemical Society, Vol.

119, p. 981 l1972).

24. Asphahani, A. I., Uhlig, H. H. J. Electrochemical Society, Vol.

122, p. 174 (1975).

25. Uhlig, H. H.. Cook. E. W., Jr. J. Electrochemical Society, Vol.

116. p. 173 (1969).

26. Vhlig, H. H. Corrosion and Corrosion Control, Second Edition, John Wiley and Sons, Inc

p. 139 (1971).

27. Vhlig, H. H. Applying Critical Potential Data to Avoid Stress Corrosion Cracking of Metals, submined for publication, 197L Materials Performance

0 Report No.

17490-2 Page No.

26 ATTACEKNT 6 OlQiL-I?l-3263 Contract No. M-7405-eng-26 ORNL NUCLEAR SAFETY RESEARCH AND DEVELOPMENT PROGRAM BIMONTHLY REPORT FOR NOVQQ~ECEMBER 1970 Qa.

B. Cottzell L ~ O*L lIOTIC~

~ ~~~ ~ g~~ ~~i, Maths ths Vattel States ooc the tJsttal States Atosdc Energy Cceoorteetoo, aoc aoy of their employees, aoc aay of thsh oootractocs, eahcootractore, cc their eetptoyesa, rashes aay wecraoty, aaynes oc~ oc aesaioes aay least tahtttty oc nsyoorthItty foc ths accoracyi con oc ~fataen of aoy lafornattoo. ayysrataa, pgygggg oc process dbg5Mod, oc reynesota that tts rie wooht sot tafttsye yttacety swot rtahts MARCH 1971 OAK RIDCE NATIONAL LABORATORY Oak Ridge, Tepnesaee operated by UNION CARBIDE CORPORATION fot'he Ur Sr ATOMIC ENERGY COMMISSION

Report No.

17490 2

Page No.

27 ATTACHMENT 6 (CONTINUED)

~

- Table 3.3.

Effect of NaVOz on Radiolytic Hz in Distilled HzO

!.c Test solutions:

A distilled HzO, B 2 x 10-H NaVOI Cai-to-liquid ratio!

0.5 Cover gas.

air Total dosez 5 x 10 rad Test modes radiation loop Pumping speedz that required for average residence time in radia-tion capsule of 1 to 2 min Test Solution Temperature

('c)

Hz

~

(vol. Z)~

h h

B B

65 95, 65 95 32 23 3.7 2.6 Established by gas chromatograph after system reached steady state, as evidenced by constant pressure.

3~5 CORROSION STUDIES IN SPRAY SOLUTIONS (AEC Activity 04 60 80 01 1)

J.

C. Griess G. E. Creek h program to investigate the corrosive effects of 1ov~H (4.5 to 7.5) spray solutions on materials of construction +as initiated, and eix seta of types 304 and 316 stainless steel specimens have been treated in the spray loop.

h set of specimens usually consisted of wetal coupons de scribed as follovs!

l.

mill-annealed U-bead coupons, eeasitised U-bead coupons, 3e Seaeitised and pickled U-bend coupons, 4,

aLll annealed double U-bend coupons, veldsd end Nround etreiihC oouponi,

Report No.

Page No.

28 ATTACEKNT 6 (CONTINUED):~

6.

vsldad and ground Upend coupons, 7.

vsldsd and ground pickled U-bend coupons, 8.

velded and ground double Ubend coupons, 9

C-shaped specimens formed from tubing, IO.

voided pipe Tha U-bend specimens vere formed by bending thin rectangular (3 by 5/8-in.) strips having a 1/4-in. hole in each end into the form of a U and then draWng the legs of the U parallel by means of a bolt through the 1/4-in. holes.

Qelded specimens vere formed by butt velding tvo sheets ot the same metal vith a seam voider in an inert gas atmosphere and cutting coupons from the velded sheet so that the veld bisected the ma)or axis of the specimens in the middle.

C-shsped specimens were formed by cutting a slot from a short (1/2-in.) piece of tubing to form a C.

The edges of the C vere then pulled together by means of a penetrating bolt until the tubing vas stressed to tvo-thirds its yield strength.

Pipe specimens vere made by butt welding tvo pieces of pipe together.

In each loop cycle, four samples from each of the first eight types listed vere in the spray and four in the solution; also two C shaped speci-mens and two butt~elded pipe samples vere in each region.

The 'loop vas

.operated at 285'P for 24 hr and then at 212 P for 168 hr.

ht the end of the 168-hr period, all samples vere transferred to another container and submerged in a solution (same composition as that in the loop) for en additional tvo months et 180'P.

The solution composition and pH for each of the loop nms are listed in Table 3.4 Specimens from the first four experiments have completed the total exposure.

A preliminary examination of these specimens indicates that

.":~4'.="-'~. the tvo months at 180 P apparently did not add to tha corrosion deILage, C

.4@~'

specimens from the first four experiments vers examined usually, and

'". ".-4~ '.+ seas instances additional dya-penetrant examinations vere employed.

s of the examinations ara givsn in Tables 3.~ and 3

, -.Ls f.$ partafns to those samples that vera in the spray roaioa

>+~ "> ~i ~

ha 4'ychs.

the porcontaio o! those oatLploI in which orate

~~ fo j.Sotod viLh ths chloride ooaoontratfoo og She ooluCioa.

~ 5

'~

< "c.

'g~ I

Report No.

17490-2 Page No.29 0

ATTACHMENT 6 (CONTINUE Table 3.4.

Solution Coayosition and ps for Corrosion Experimeats Boron as Chloride as Experiment (pp )

(ppm) 1 2

3 5

6a 4.5 4.5

~ 4.5 4.5 7.5 6.5 200 5

50 20 200 20 2 ppm of io.'ine added to the solution.

Table 3.6 contains similar information to that in Table 3.5 ~ except that it concerns those samples that vere immersed ia the solution during the loop cycle.

The data presented in Tables 3.5 and 3.6 indicates that seasitising (1250'P for 1 hr) increases stress-corrosion cracking, vith the type 304 stainless steel evincing greater damage than the type 316 stainless

steel, and stress-corrosion crackiag increases with chloride concentration.

The type 316 stainless steel C specimens fraca the first four experiments vere free frvm cracking..

Ia experiment 3 (50 ppm Cl), one of the type 304 stainless steel C specimens cracked.

In experiment 1 (200 ppm Cl)~ all the type 304 stainless steel C specimens cracked.

Ia the butt-welded pipe samples~

cracking was found in only oae speci-men.

The cracked specimen was type 304 stainless steel snd vas part of the set of experiment 3 (50 ppm Cl).

The specimens in the fifth and sixth runs vere visually examined after chair removal from the loop and prior to the tvo-month storage at 180't.

Assumiag that the storage doss not significantly add to the corrosion 4aa-

age, che stress cracking in experiments 5 and 6 will be about the saae aa chat in the secoad experiment (5 ppm Cl, SNO ppa b, pH of 4.5) with the seasicisad type 504 stainless steel U-bend samples beini the only aequi chat s4wad crockinoe

~o 3.5.

The Effect of Chloride Concentration on Stress-Corrosion Cracking ot Stainless Steel Speciaens Exposed to a Spray Solution at a pH of 4.5 Containing 3000 ppe B Type of Stainless Steel Percentage of Pour Ssaples That Cracked 5 ppa Cl 20 ppa Cl 50 ppa Cl 200 ppa Cl Sanaitised Upend Seesitized and pickled doable ~d Selded and ground a~Pt coupon 8elded and ground U-bend ikalded and ground pickled lH~

Raided and ground double Mxmd 304 316 304 316 304 316 304 316 304 316 304 316 304 316 304 316 0

0 100 0

0 0

50 0

1M 100 50 0

25 0

0 0

100 100 0

0 50 50 1M 0

100 100 100 0

100 0

0 0

100 100 25 50 100 50 100 0

100 100 75 0

75 0

50 50 100 75 75 0

1M 75 lD'0 W 0 00 rt (D

R 0 Q

~

4) V O 4 O

I g~iiien treataent!

24 hr at 285'P and 7 days at 21P in loop; 2 aoatha at 1N'P in storage.

i!,

A O

Ha

table 3.6.

The Effect of Chloride Concentration on Stress-Corrosion Crackiag of Stainless Steel Specimens Exposed in a Solution at a pH of 4.5 Containing 3000 ppa h Speci%en Type of Stainless Steel Percentage of Pour Sasples That Cracked 5 ppa Cl 20 ppa Cl 50 ppa Cl 200 ppa Cl Sensitised U-bend Seositised and pickled Doable U-bead iiehhed aad ground straight coupon Qelded and grouad U-bend Sclded aad ground pickled

&bcmf i a1ded aad ground double lbkead 304 316 304 316 304 316 304 316 304 316 304 316 304 316 304 316 0

0 100 0

0 0

25 0

50 0

100 100 0

0 0

0 75 25 0

0 25 0

50 0

100 100 75 0

25 0

0 0

25 25 25 0

100 75 75 0

0 0,

0 25 25 0

0 0

100 0

Speciimen treataent!

24 hr at 285'P aad 7 days at 212'F in 1oop; 2 aoaths at 180'P ia storage.

,. pi~~ ii~~ g,~.g),~g

\\

Report No.

17490-2 Page No.

32

~r

<',g ATTACfBKNT 6 (CONCLUDED) t Re fe rence 1.

J. C. Criase end g. L. ~ca~ll Dec~a Conaiderationa of Reactor Coataimaant Spray Syateea Part XXX.

The Corroaion of Materiala in SPray Solutiooa, USAEC Report ~IN-2412, Part XXX, Oak Ridge KL-tiona1 Laboratory.

I

ML17258A496

Contents

Text

6.0 CONCLUSION

6.0 CONCLUSION

7.0 REFERENCES

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