Text

Interim Deficiency Rept Re Low Alloy Quenched & Tempered Bolting 1 1/2 Inches & Greater in Support of safety-related Sys.Suspect Bolting Will Be Replaced or Acceptability of Matl Will Be Verified.Next Rept Will Be Submitted by 840316
	ML20082P711
Person / Time
Site:	Midland
Issue date:	12/02/1983
From:	Jackie Cook; CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	James Keppler; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
	10CFR-050.55E, 10CFR-50.55E, 26594, 80-09-#12, 80-9-#12, NUDOCS 8312090147
	Download: ML20082P711 (84)
	v • d • e

_-

Consumets Power J m w cook Vice President - Projects, Engineering and Construction General offices: 1945 West Parnali Road, Jackson, Mt 49201 * (517) 788-0453

-December 2, 1983 80-09 112 50' 30-9 60mM Mr J.G Keppler, Regional Administrator US Nuclear Regulatory Commission Region III

-799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND NUCLEAR ENERGY CENTER DOCKET NOS 50-329 AND 50-330 LOW ALLOY QUENC'iED AND TEMPERED BOLTING 135 INCHES

'AND GREATER IN SUPPORT OF SAFETY RELATED SYSTEMS FILE:.0.4.9.46 SERIAL:

26594

References:

J W Cook letters to J G Keppler, Same.

Subject:

(1) Serial 10996, dated January 9, 1981 (2) Serial 11526, dated March 31, 1981-s (3)

Serial 13690, dated September 29, 1981 (4)

Serial 14666, dated January 15, 1982 (5) Serial 16149, dated April 2, 1982 (6) Serial 17354, dated May 17, 1982 (7)

Serial 17542, dated July 9, 1982 (8) Serial 19085, dated October 29, 1982 (9) Serial 20711, dated February 22, 1983 (10) Serial 20747, dated April 5, 1983 (11) Serial 23774, dated August 19, 1983 This letter, as were the referenced letters, is an interim 10CFR50.55(e) report concerning the subject bolting. Attachment 1 provides a current status and the details of the LAQTS material evaluation that is currently taking place.

~

'Another. report, either interim or final will be sent on or before Mcrch 16,'1984.

s.m. c.aa u 8312090147 831202 JWC/WRB/cd PDR ADOCK 05000329 S

PDR

'OC1283-0001A-MP01 5

%W I Tidf j

2

' Serial:23774 80-09 #12 Att'achment 1: MCAR 45A, Final Report: Revised November. 18, 1983

.MCAR 45B, Interim Report 10, dated November 29, 1983 1

Attachment 2: :APTECH Report, #AES 8010220,." Evaluation Procedure for Low-

~

' Alloy Quenched'and Tempered Bolting / Component Support

~

' Applications" CC RJCook,-NRC Resident'Insnector Midland-Nuclear Plant HRDenton, NRC Office of NRR -

Document Control Deak, NRC

-Washington, DC INPO Records Center I

0M/0L SERVICE LIST Mr Frank J Kelley Atomic Safety & Licensing p

Attorney General'of the Appeal Board l State of. Michigan U S Nuclear Regulatory Commission Ms Carole~Steinberg, Esq

~ Washington, DC 20555 L

Assistant: Attorney General Environmental Protection Division-Mr C R Stephens (3)

"720 Law Building.

Chief, DocketinF; & Services.

Lansing, MI'48913.

U S Nuclear Regislatory. Commission Office of the Secretary-Washington, DC 20555 Mr Myron M Cherry, Esq L

Suite.3700 Ms Mary Sinclair L

1Three First National Plaza 5711 Summerset Street l

Chicago,-IL 60602 Midland, MI 48640~

-Mr Wendell H Marshall.

Mr William D Paton, Esq RFD"10 Counsel for the NRC Staff I~

Midland, MI 48640i

.U S Nuclear Regulatory Commission Washington, DC 20555 Mr Charles Bechhoefer,.Esq LAtomic Safety & Licensing Atomic Safety & Licensing

' Board Panel

. Board Panel U S NuclearfRegulatory Commission U S Nuclear Regulatory Commission 1,

Washington, DC 20555 Washington, DC 20555 Dr Frederick P Cowan Ms Barbara Stamiris

-6152 N Verde Trail 5795 North River Road

- Apt B-125-Rt 3' rBoca Raton,;FL.33433-Freeland, MI 48623

0C1283-0001A-MP01

, - ~

3 Serial 23774 80-09 #12 Mr Fred.C Williams Mr Jerry Harbour Isham,' Lincoln & Beale Atomic Safety & Licensing 1120 Connecticut Ave, NW, Suite 325 Board Panel

-Washington, DC 20036 U S Nuclear Regulatory Commission Washington, DC 20555 Mr James E Brunner, Esq Mr M I Miller, Esq Consumers Power Company Isham, Lincoln & Beale 212 West Michigan Avenue Three First National Plaza Jackson,.MI 49201 52nd Floor Chicago, IL uG602 Mr D F Judd Mr John Demeester, Esq Babcock & Wilcox Dow Chemical Building

. P.0 Box 1260 Michigau Division Lynchburg, VA 24505 Midland, MI 48640

Mr Steve Gadler, Esq.

Ms Lynne Bernabei 2120 Carter Avenue Government Accountability Project St Paul, MN 55108-1901 Q Street,.NW Washington, DC 20009 l

s l

l

'OC1283-0001A-MP01'

[.

+.

I35860 serial 26594 Bechtel Associates ProfessionalCorporation 135

_8 I3 777 East Eisenhower Parkway Ann Arbor. Michigan m Aaams P.O. Box 1000. Ann Arbor. Micnigan 48106

SUBJECT:

MCAR 45A Final Report MCAR 458. Interim Report 10 DATE:

November 29, 1983 g

PROJECT:

Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Introduction T

2 The discrepancies discussed in this report concern the hardness values of the anchor and connecting studs for the reactor coolant pump (RCP) snubbers.

MCAR 45A was issued as a Final Report on August 5, 1982. The MCAR 45A report has been reissued as an attachment to this report and will be carried as an attachr.ent until this MCAR is complete.

Backaround NCAR 45A: Final Report (see attachment) l MCAR 45B On November 26, 1980, Consumers Power Company expanded the 10 CFR 50.55(e) report to include, as potentially reportable, all low-alloy quenched and tempered steel (LAQTS) bolting materials 1-1/2 inches in diameter and larger used in support of safety-related systems.

In NCAR 45B, dated December 17, 1980, this scope was expanded to include review of 7/8-inch and larger safety-related LAQTS bolting material.

Investimative Action NCAR 45A: Final Report (see attachment)

MCAk 45B Consumers Power Company is leading the investigation required by this NCAR.

Cosumonwealth Associates, Incorporated (CAI) of Jackson, Michigan, which is under contract to Consumers Power Company, has reviewed safety-related purchase orders and identified those purchase orders for LAQTS bolting and/or component support material. CAI has also gathered data that will be used in evaluating the LAQTS materials.

1 j

Most of the review being conducted on the LAQTS bolting and component support materials consists of field hardness testing. This testing is being performed by consumers Power Company and CAI.

.s 0159u

I35860

~

Bechtel Associates Professional Corporation

[35i56 MCAR 45A, Final Report NCAR 45B, Interim Report 10 page 2 Science Applications Incorporated (SAI) of palo Alto, California, has been retained and has developed a sampling plan to determine the quantity of items to be tested. SAI has revised the sampling plan as a result of the additional materials identified by CAI.

Aptech Engineering Services has been retained to assist in evaluating the LAQTS materials purchased by identifying which materials are LAQTS and require testing. Aptech has developed a generic evaluation methodology (Report AES-8010220, dated July 1983) that establishes hardness limits for LAQTS materials. For bolting materials that exceed the established hardness limits, the methodology provides allowable stresses for preventing stress corrosion crack growth and brittle fracture.

Guidelines are also given for evaluation of soft material for tensile-ductile failure.

l Based on preliminary hardness test results, approximately 30 bolting material purchases were identified that appeared to contain material considerably softer than the hardness limits established by Aptech.

i Further evaluation and testing on a portion of these materials by the Consumers power company laboratory indicated that the bolting materials were actually within the acceptable hardness limits. The differences were determined to be due to the existence of a decarburized layer that j

had not been completely removed during field testing. The hardness test procedure has been modified to prevent future difficulties due to erroneous data. The retesting of the remaining portions of these 30 bolting material purchases with the decarburized layer removed has been completed.

The discovery of the erroneous hardness data resulting from decarburization raised the following two concerns for previously collected hardness data.

a.

Bolting materials that had been tested and appeared to be below established hardness limits may actually be within the limits.

l b.

Bolting materials that had been tested and appeared to be above or within established hardness limits may actually be harder than l

the first hardness tests indicated.

l As a result of these concerns, a retest sampling program was developed I

with SAI to identify previously collected hardness data that are suspect, including data for the RCp snubber anchor bolts. This retesting sampling program is complete and the results'are currently being evaluated. The retest sampling program will identify bolting material purchases that l

require retesting to correct data errors due to decarburization.

l 0159u

I 3 5 8 6 0 Bechtel Associates Professional Corporation NCAR 45A, Final Report l[}g NCAR 45B, Interim Report 10 Page 3 Preliminary review of hardness test data indicates that, of 494 unique material deliveries that have been hardness tested to date, 247 contain material of hardness outside the ranges established by Aptech. These material deliveries have been identified on a nonconformance report and are being placed on hold pending final evaluation of test data and implementation of corrective action. The majority of the hardness testing has been completed. However, some purchases of bolting material have not been located for hardness testing. To ensure location and testing of these items, a program is being developed to inventory all relevant applications that use bolting materials 7/8 inch in diameter or larger. The completed inventory lists will be used to identify safety-related locations of bolting requiring hardness testing. The inventory lists will also be used to locate remaining portions of safety-related materials tested that do not meet the established hardness limits. Corrective Action l MCAR 45A: Final Report (see attachment) MCAR 45B The recommended corrective action for the bolting deliveries described I under Investigative Action is to locate and replace the suspect bolting or verify by evaluation the acceptability of the material for each specific installation. This effort is being tracked under CPCo l NCR N01-9-3-289. I Quality control receipt inspection includes hardness testing of LAQTS bolting / component support materials to preclude the use of defective materials. Fafety Impilcations I NCAR 45A: Final Report (see attachment) MCAR 45B Bolting purchases have been identified that contain material that hardness tested outside the ranges established by Aptech. Therefore, it must be assumed that these bolting materials could fall during operating or accident conditions. The disposition of the suspect materials will preclude any adverse safety implications. 0159u

i35860 Bechtel Associates Professional Corporation MCAR 45A, Final Report MCAR 45B, Interim Report 10 i35758 Page 4 Reportability This condition relative to the RCP snubber studs was identified as "potentially reportable" by Consumers Power Ccapany to the NRC under 10 CFR 50.55(e) on November 25, 1980. MCAR 45B Submitted by: 'GIL. Richardson Approved by: E.B. Poser Project Engineering Manager Concurrence by: 4 \\ E.H. Smith ~ Engineering Manager Concurrence by: 2Mi ferM.A.Dietrip Pro,#act Quality Assurance Engineer PYR/AVD/beb8(C)

Attachment:

MCAR ASA Final Report 0159u

Bechtel Associates ProfessionalCorporation i35860 777 East Eisenhower Parkway I35758 Ann Arbor, Michigan W Adeess. P.O. Box 1000. Ann Arbor. Machgan 48106

SUBJECT:

MCAR 45A Final Report j DATE: August 5, 1983 (Reformatted and resigned November 18, 1983) PROJECT: Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Introduction i The discrepancies discussed in this report concern the hardness values of the anchor and connecting studs for the reactor coolant pump (kCP) snubbers. Backaround The RCP snubber anchor studs are 2-1/4, 2-1/2, 3, and 3-1/2 inches in diameter and vary in length from 3 feet, 5 inches to 7 feet, 1 inch. They are embedded in the secondary shield wall and the refueling canal well. Also included are 2-inch and 2-1/4-inch-diameter connecting studs approximately 1 foot, 10 inches long that connect the snubbers to a structural steel transition piece. The anchor studs are in place. The 4 snubbers restrain the RCPs during seismic and/or loss-of-coolant accident (LOCA) events. The studs were purchased from various vendors during 1977 and 1978 by Bechtel construction in accordance with either ASTM A 354, Grade BD, or ASTM A 540, Grade B23, Class 3. They were intended to be tensioned to a preload up to 96 kai to maintain the specified snubber spring rates under all loading conditions. Prior to tensioning, to ascertain that the studs could withstand long-term loads of this . magnitude without becoming susceptible to stress corrosion cracking, Consumers P,ower Company requested Teledyne Engineering Services (TES) to l conduct hardness tests on the exposed end of the embedded'and connecting studs. TBS conducted these hardness tests from November 21 through November 23, 1980. The test results showed that 207 studs of 384 tested are outside the range of hardness specified by the ASTM specifications. Investimative Action Aptech Engineering Services of Palto Alto, California, was retained by Consumers Power Company to review the hardness data taken by TES, and to evaluate the effect of the measured hardnesses on the ability of the studs to withstand preload, operating, and accident loadings. Based on preliminary Aptech evaluations, it was decided to lower the required stud preload (to a maximum of 12 ksi) to preclude failure because of stress corrosion cracking. Subsequently, Aptech has provided Report AES-81-08-79 (which was transmitted to the NRC via Consumers Power Company letter, serial 17354, 5/17/83). In the development of a generic evaluation methodology (in support of MCAR 45B), it was found that AES-81-08-79 was unconservative (by about 6%) in that development of fracture toughness limited allowable stresses; therefore, the allowable preload 0494u

Bechtel Associates Professional Corporation NCAR 45A, Final Report I35860 t58 Page 2 and accident stresses of AES-81-08-79 have been reevaluated. Based on this reevaluation of allowable stresses, the lowest maximum allowable preload for any of the RCB snubber anchor bolts is 42.9 ksi. Therefore, the required 12 ksi preload is less than the allowables in the Aptech report and is acceptable. Instructions were issued to construction to preload the studs to 9 ksi, a value lower than the maximum permissible. A tolerance of 13 ksi is allowed. This preload value, when reduced by temperature and relaxation losses, exceeds 3 ksi, a value in excess of the minimum preload of 1.5 ksi required by Babcock & Wilcox (B&W) during operation. New spring rates have been submitted by Bechtel to B&W. B&W is proceeding with the new seismic and LOCA analysis of the reactor coolant system. ITT Grinnell, supplier of the snubbers, has also been informed of the change in the preload. Grinnell stated the.t there is no effect on the snubbers or on the spring rate of the snubbers themselves. The Aptech report noted above also contains an assessment of the allowable accident stresses of the RCP snubber anchor bolts. Based on this report and on the reevaluated allowable accident stresses, the allowable stress limits for operation and short-duration loading are available. Calculations have been prepared and the results indicate that the bolt stresses, based upon the capacity of the snubbers, are acceptable when compared to the Aptech allowables. l Procurement documentation packages for these studs have been reviewed. All necessary corrective action was completed and a report issued. No additional action is required. Corrective Action Construction has been instructed to preload the snubber studs to 9 i 3 ksi. A procedure was developed 5y B&W construction to ensure that the studs are tensioned as required. This work has been completed for Units 1 and 2. Engineering has made a comparison of the calculated anchor bolt stresses with the Aptech allowable stresses. These stresses, based on the capacity of the snubber, which limits the loading on the studs, are within the Aptech allowable limits. All corrective actions under NCAR 45A are considered to be complete. Safety Implications If the subject studs were tensioned according to the original design requirements, there may have been a safety deficiency in that some of the studs could have failed because of stress corrosion cracking. If uncorrected, this deficiency could have adversely affected the safety of Midland plant operations during the expected life of the plant. ( I 0494u

Bechtel Associates Professional Corporation MCAR 45A, Final Report I35860 l50 30 Page 3 Reportability This condition relative to the RCP snubber studs was identified as "potentially reportable" by Consucers Power Company to the NRC under 10 CFR 50.55(e) on November 25, 1980. Submitted by: [ _ d 'p

M g P.V. Regupathy civil Group Supervisor Approved b E'.B. Poser Project Engineering Manager

. _ ~# / y y Concurrence by: A T.E. M nson Chief civil Engineer LC Concurrence by: E.H. Smith Engineering Manager Concurrence by: 6rM.A.Dietrig Project Quality Assurance Engineer PVR/AVD/beb8(C) 0494u

I i ? ] 1 ,a i 1 y , T[ ^"' p

--rr.

g. = 1. .' i, 'q r? ~% f' C.,,-. ..r L*1 :l jf> O#. EVALUATION PROCEDURE FOR LOW ALLOY I k g .C %kg/ QUENCHED AND TEMPERED BOLTING /COM.PONENT . rji g. S' ?fi SUPPORT APPLICATIONS - 3,, h.?$, y.g.; ~K' ., T,,, h '.w vtT m t '1.y q.d,,*;,g.a m WUMSPt3W.-- ~ .$u../,:M 2 /_,N $7f.;-r77APTECH I 2T "%,3 w w, ?. ~a i a ps,~ +- m 1 ,*s m.- ~ a w. a., '2?.?/L, $ Wi$09 l$$f Oh' ~ '

O,

. f:, y5~ f' 'f.!QYtpfh ~Qyu-.. N f t ( y ( t f, D C.. I ds && _v- ~ 3 s v w a s m' n;YM,.; .m f.ag ' ,i .,$y/- '..,.y }9 . IN.~ii.. 1 <~ .m ,.,g 3 -= r - nQ * ~&. ,{i h .V ' ' ' - - * - ^('{- $y,[ ' y;E['i@.&fc

t f

sl?4.Y [, M a T fjfM7N W" 4.- Ig;hnh RMp. p' a ~ gysf.. [ d4 A[%"%.. ilmke. r t 'ic. a gz. ~ 3.g'. hi m f ( y ..% E* N ,$g e .s ... ity;ffl_.,l.* -}. Q(,'t} rd ' ~ fy }%g.;,y} r.2n;, f;W. y x ,s.pA: _q%'p t.m 4:n.,a 2ees. ( . ee!q A.

n

. n 5: y p res san Automo noan. pno nya,ca,4xn. .g ). hY 2 ja g ]&g, gig gyp.'i (s '

AES 8010220 o n, $OQ OS$f OQ /$f ($/, OC ENGINEERING CONSULTANTS 795 SAN ANTONIO ROAD. PALO ALTO. CALIFORNIA 943o3 (415)858 2863 EVALUATION PROCEDURE FOR LOW ALLOY QUENCHED AND TEMPERED BOLTING / COMPONENT SUPPORT APPLICATIONS Prepared by Russell C. Cipolla Steve R. Paterson Aptech Engineering Services, Inc. 795 San Antonio Road Palo Alto, California 94303 i Prepared for Consumers Power Company 1945 W. Parnall Road Jackson, Michigan 49201 l ATTENTION: James A. Pastor Harvey W. Slager July 1983 Sarvices in Mechanical and Metallurgical Engineering. Welding, Corrosion, Fracture Mecha nics, Stress Analysis

e QUALITY ASSURANCE VERIFICATION RECORD SHEET

Title:

" Evaluation Procedure For Low Alloy Quenched and Tempered Bolting / Component Support Applications" (AES 8010220) (( g/J/[f3 Originated by: fa Russell C. I f /df b / Approved and Verified by: f Geoffrey R k n 3 !O3 Quality Assurance Review by: Jeffrey D. Byron Quality Assurance Approval:

b. O.

Je frey D. Byron l l l l l l

TABLE OF CONTENTS Section Page Abstract i Nomenclature 11 1 INTRODUCTION 1 2 EVALUATION METHOD 2 Strategy 2 8-Assumptions 2 Outline of Procedure 5 Description 5 Part 1 - Establishment of the Hardness Limits 5 Part 2 - Estimation of Material Properties 7 Part 3 - Determination of K 9 Part 4 - Calculation of Allowable Bolt Load Based on SCC 12 Part 5 - Calculation of Allowable Bolt Loads Based on 14 Fracture Guidelines For Determining Material Acceptance 15 3 ANALYSIS ASSUMPTIONS AND RESTRICTIONS 18 Introduction 18 Failure Modes 18 Materials 19 Chemistry and Heat Treatment 19 Ratio of Yield to Ultimate Strength Correlation 20 Environment 20 Stress Corrosion Cracking 20 Fracture Toughness 21 Yield and Ultimate Strength 22 Bolt Geometry 22 Thread-Root Region 22 Head-to-Shank Region 25 Shear Pins 25 26 Loadings 4 LIMITATIONS OF THE PRESENT HETHODOLOGY 28 General Overview 28 Application For Other Component Supports 29 i 5

SUMMARY

31 REFERENCES 32 l l l

0 0 (TABLE OF CONTENTS - Continued) Section Page APPENDIX I - Bolting Evaluation Form 34 APPENDIX II - Recommended Hardness Limits For Satisfyin9 37 ASTM /ASM Specifications APPENDIX III - Tabulation of Stress Intensity Factors.(i ) 51 g APPENDIX IV - Effect of Temperature on the Threshold Stress 57 Corrosion Cracking Stress Intensity values of Low Alloy Quenched and Tempered Steels I O I

o o TABLES Table Page 1 Reduction in Yield Strength Due to Temperature 23 ILLUSTRATIONS Figure Page 1 Strategy of Evaluation Methodology 3 2 Yield Strength Versus Hardness For LAQT Steels 8 3 Lower Bound Threshold Versus Strength 10 4 Lower Bound Fracture Toughness Versus Hardness 11

ABSTRACT A procedure for avsluating low alloy, quenched, and tempered materials is presented. The procedure utilizes the principles of fracture mechanics to assess the performance of potentially variable materials in environments and loading situations that may cause stress corrosion cracking or fracture. The output of the procedure are allowable stresses for preventing stress corrosion crack growth and brittle fracture. Guidelines are also presented in the evaluation of materials that may be sof t and the concern for tensile-ductile f ailure becomes important. The procedures are straightforward and are primarily focused on botting applications. Guidelines for evaluating non-bolting applicatfore are also includad. The major analytical assumptions are discussed, and the technical basis and justification for the Input parameters are presented. A form for completing the evaluation 'In an organized asnner is provided in the appe ndices. 1 e ..n _.,.-y_-,_w...m _-yr-.c.,,,,, w.. -.m, - -,..,.., -.., - _ _,--.3 . - +. ,yy<--

Y 11 NOMENCLATURE Symbol Definition a Crack depth a Critical crack depth c a Crack depth for a postulated " reference" flaw r-a/1 Crack aspect ratio A Cross-sectional (shank) area A Net tensile area or " stress" area 3 C Yield strength reduction factor for temperature f D Nominal (major) diameter d Minor diameter F Specified minimum yield strength y F Specified minimum ultimate tensile strength u h Hardness h,,x Statistically based maximum hardness limit h Statistically based minimum hardness limit min K Stress intensity factor K Stress intensity factor for Mode I loading for a unit stress y K Stress intensity factor for Mode II loading for a unit stress yy K Plane strain fracture toughness for Mode I loading Ic K Plane strain fracture toughness for Mode II loading y Kic Conservative bound to K data Ic Threshold stress intensity factor for crack propagation by stress KIscc corrosion cracking data K Conservative bound to KIscc sec K Stress concentration factor t

iii Symbol Definition i Crack length L Leeb-scale units for hardness n Number of threads per inch p Thread pitch (p = 1/n) 4 P Axial load it P Allowable tensiin load for long-term (normal) loading condi-a tions st Allowable tension load for short-term (accident) loading condi-Pa tions R Rockwell-B scale units for hardness (also HRB) b R Rockwell-C scale units for hardness (also HRC) c S Specified minimum yield strength (ASME Code) y S Specified minimum ultimate tensile strength (ASME Code) y o Nominal applied stress Allowable stress o, f Allowable stress based on fracture toughness o oj Allowable stress based on strength scc Allowable st'ress based on stress corrosion cracking e o,tt Allowable stress for long-term loading conditions st Allowable stress for short-term (accident) loading condition e ~ c Yield strength y o Minimum yield strength p Maximum yield strength limit based on h c,,, max y Minimum yield strength limit based on hmin - oymin Ultimate tensile strength ou Minimum ultimate tensile strength oum Maximum tensile strength limit based on h,,x c,,x y

iy Symbol Definition o Minimum tensile strength limit based on hmin umin Nominal applied shear stress 7 Allowable shear stress T, T{ Allowable shear stress based on fracture toughness 5 T Allowable shear stress based on strength T Allowable shear stress based on stress corrosion cracking scc it Allowable shear stress based on long-term (normal) loading con-Ta ditions V,# Allowable shear load based on fracture s V ce Allowable shear load 'oased on stress corrosion cracking V,tt Allowable shear load for long-term (normal) loading conditions Vst Allowable shear load for short-term (accident) loading condi-a tions I i O l

~---a

Section 1 INTRCOUCTION In May 1982, Aptoch Engineering Services, Inc., issued a report (1) that presented the results of an Integrity evaluation for the reactor coolant pump (RCP) snubber anchor studs (SAS) for the Midland Project of Consmers Power Company (CPCo). The objective of that evaluation was to assess the structural Integrity for both long-term and short-term loading situations. Specif ical ly, the assessment involved detailed computations to: (1) Determine the potential for stress corrosion cracking (SCC) In the materials purchased (2) Evaluate the of facts of low toughness properties (3) Evaluate the potential for ductile f a.Ilure for the situation when the material may be sof t (4) Calculate the allowable loads under long-and short-term loading conditions The purpose of this report is to present an evaluation procedure for general application to bolting and component supports that are f abricated f rom low alloy, quenched, and tempered (LAQT) materials. Where possible, this report has expanded the work presented in (1) in order to allow for general use. For completeness, alI of the basic asseptions and description of the input parameters are presented herein.

r 2 t Section 2 EVALUATION METHOD 2.1 STRATEGY t The basic approach of the evaluation method is sunmarized in this section. It is the Intent to outline an evaluation procedure in a generic f ashion to allow for a uniform or standardized approach for which the completed RCP-SAS I evaluation would be a subset. The precedure employs fracture mechanics l concepts to quantify the allowable bolt loads based on the fracture properties of the material. In addition, the minimum strength of the material is estimated in order to compare with the design requirements based on strength. A flowchart showing the Integration of the coquired input Information with the calculational steps is shown in Figure 1. In applying the principles of linear elastic f racture mechanics (LEFM), a philosophy has been adopted which Involves the use of a ' reference flew" to calculate the allowable bolt loads. in the assessment strategy, this reference flew is postulated at the thread root and represents a flew which is large enough to be unlikely to exist in a The material behavior (i.e., mechanical strength, f racture resistance, bolt. and SCC resistance) are estimated f rom an analysis of the field hardness Hence, a key step in the evaluation is the determination of the meas urements. hardness for the material for a reasonable sample size so that statistical Once the material properties are established, the limits can be established. remaining calculational steps are straightforward and simple. 2.2 ASSUMPTIONS The important Many ' assumptions were made in establishing the procedures. For assunptions are discussed in detall in the RCP-SAS Report (1). 1 completeness, the major assumptions and areas of conservatism are outlined below: .,,-,-n,,,,,,_ -,,..c.,--, --n,-,,-,-w,en,.,,--.-e .,,,v-n,--,,.. ,.7,,,,, --,r r-,,-

i i Hardness Measurements j t i Statistically Based Hardness Limits 1 I w J a Estimation Estimation Detemination of of Strength of Toughness Stress Factor Properties Properties Intensity I I Design Allowable Loads Allowable Loads Allowable Loads Load Based on Based on Stress Based on limits Strength Corrosion Cracking Fracture Figure 1 - Strategy of Evaluation Methodology. I n I

4 (1) A flav with a depth of 0.02 inches with an aspect ratio, a#, of 1-to-4 Is assumed to exist at the thread root (2) A lower bound curve to fracture toughness data was used to esta-blIsh K for the material (3) A lower bound curve to threshold stress intensity factor data was used to estabiIsh K for the material (4) The variability in hardness within a component (e.g., bolt) was assumed to be no better than the variability in hardness within the heat (5) A 90% probability of occurrence with 955 confidence was used as the statistical criterion for determining the tolerance limits for the bolt population Some' of the assumptions above have the potential of being very conservative. Future improvements or refInoments may be warranted for materials that cannot meet these criteria and are dif ficult to replace. The areas where this potential exists are summarized below: (1) The assumption that the material variability within a component is equal to the material variablilty determined for the entire heat may be very unrealistic especially for short bolts. The varies bility in hardness with respect to axial position could be quanti-l fled by testing. (2) Lower bound curves for K and K could be very conser-Ic Iscc ' vative. Statistically based curves may provide Improvements. l (3) The 0.02 Inch flaw depth assumed as the " reference flaw" was exces-sive when compared to the flaw sizes which have t,esn observed to initiate the failures in component support bolting summarized in 4

5 (1). In fact, failure enalyses for theso instances did not iden-tify pre-existing flaws which Initiated SCC. 2.3 OUTLINE OF PRO DURE 2.3.1 Description The outline presented below sunmarizes the steps required to perform Tne evaluation. The strategy shown in Figure 1 is divided into five parts es follows: Part 1 - Determination of Hardness Limits Part 2 - Estimation of Material Properties Part 3 - Determination of K Part 4 - Calculation of Allowable Bolt Loads Based on Stress Corrosion Cracking (Long-Term Conditions) Part 5 - Calculation of Allowable Bolt Loads Based on Fracture (Short-Term Condiffons) Each analysis part is described in detail in the subsections that follow. A calculational form is provided in Appendix I that outlines each analysis step. There is space provided on the form for all relevant Information wiTh regard to the evaluation as well as recording the results. l l 2.3.2 Part 1 - Establishment of the Hardness Limits The minimum and maximum hardness i nmits for tne lot of bolts must be estabilshed to provide a quantitative estimate of material properties. To determine the minimum and maximum limits, hardness testing is required to establish a data base for the lot. For statistical purposes, we will def ine l

6 this bolt lot a stratum, if possible, the lot of bolts should be defined as an Individual heat of material or a single size of bolt. The following steps should then be followed: (1) Establish a date base of hardness measurements by stratum, by reple-menting a suitable test sampling plan. (2) Establish the probability f unction that best represents the frequency of the data. A normal distribution f unction may provide a reasonable fit for hardness data directly or when the hardness data have been fIrst converted to their equivalent value in tensile strength units in eccordance with ASTM A370 (2) and the normal f unction is applied to the tensile strength data set. If a suf ficient neber of data points exist, a nonparametric approach will allow statistical limits to be determined without the need to assee a particular distribution f unc-tion. (3) Determine the two-sided tolerance limits for the bolt population that provides a 905 probability that measurements will f all between these limits with 95% confidence (see Reference 1 for the definition of a two-sided tolerance Ilmit and the basis for the statistical criter-Ion). (4) Crmpare the two-sided hardness limits with the appropriate specifica-tion requirements (see Appendix il for a listing of hardness limits by specification). If the computed limits satisfy the requirements for which the material was purchased, then compilance with the intent of the original purchase specification is achieved and no additional evaluation would be required. (5) If additional analysis is required beyond Step 4, compute the one-sided tolerance limits for minimum and maximum hardness level (or strength level) with the same 90-955 criteria (see Reference 1 for the def inition of a one-sided tolerance limit).

7 The above procedure can be repeated for each material group or stratum that was identified as requiring evaluation. The computed one-sided tolerance limits for minimum and maximum hardness will be used in Part 2 of the procedure. 2.3.3 Part 2 - Estimation of Material Properties The procedures outlined below are the steps that will define conservative estimates of yield and ultimate strength, SCC threshold, and fracture toughness based on the one-sided minimum and maximum tolerance limits from Part 1: / b (1) Define the specified minimum yield strength, F, and the speelfied b minimum ultimate tensile strength, F, for the governing material u spectfIcation. (2) Convert the minimum hardness (or tensile strength) limit from Step 5 of Part I to material yield strength, oymin, with the curve provided in Figure 2 (1). ?;' /L( / (3) Convert the minimum hardness limit from Stop 5 of Part I to equivalent / tensile strength units with the tables in ASTM A370 (2). This defines y Yl

umin' (4)

Define the minimum yield strength value at room temperature, o from Step 2 above or the specified minimum yleb as either o ymin strength for the material at room temperature, F, whichever is l Y l lower. (5) Define the minimum tensile strength value at room temperature, o um as either a from Step 3 above or the specified minimum tensile strength for the material at room temperature, F, whichever is u lower.

a e ..E _=_ =_4_ _.:. _:

_0_

g, t _. _;G;C2-_J*- _ _. _ _._ 4- ~~C- - r;

2.4 2-,,_: ;r -,- _ _ _ _ _.__._L_.'_" ::=-t-

._r-.. ~ '. :=. _c _. _ __::= : :... _. -. =

=

_. -- r=_..:.1 _f _.. --v_

.: = -

r.- - - = _.a "= _4 _ _ _. __..a n:- ._ -. g ; = - - =:- :

- __._- Sg-ru=;

--r- .9_ i. _.e.-. _, - _ - g,_ =_ .y_-.' r- .i_ __m _.. i a _. _, _._m. _ _. y-L_ _~.- _m__._ _=.;.__. ._=__g _ _r. A -_ra ._._.y E'3. _=_= - * - - 4 - +-- - _:;.:=_ -= =.. *=g ._a__ e =:- _:- ___ - - " __.:-1.._.__ _.a_ ~ =:.__ - - ^ - =. r --- : : =_, _.: = .. _..g..... ._-s__ 1.._ g.:.= g._ m __ %.a i._ _.t . =.... L__ -m _ -4. _ 4:

2 _= _- - - -

- - ' - - = -A=_ _ - - - - -- N ---- g._

p.. =._

4-- 4, ;= --e +: __;.f__;

y.;

__J - _ 2.__q = =_ c. t-- RJ ._fm,r:..... e._ - y 1_ _a a ; a-gg -- - - - --- 42 :.= __g. __..

1.;~ -f --

_) - :=_ -.g _. -;D c-i. = f-_ --a g-.I:.; p : _,. _ __y_. + m ]___ .1_ Q-A _A. LS :. -.__=_= 's_ =._^~._N-m ~2= _ ~ _ _. _ _ _.._ -r =_- EM_ __.-P"_1..._. . _ _ _ _n:. n' - ~. - ~ ._,_g _,gy .._g ..._7_ _g _a . _ _ _. _.._.Q .j._. _ 3 __ .. __.4 .__f_ e _. g_ m w _g _ g, =___,.:_... 4=- LD ._ g _ -- 1 _.M. .2 _. 7; , 2.; _ - t . _. -. _.-__s - - - = _.g-- =- _a d..__ A.= ,2 uto _n 9. .,n nc,. -,. _._ _ r-P-*; _ __..__ _ _ ". = _ _ L . _.c. ,,, g __. ::= _ - -. -. = - = _.

==m

4. _ =

2.___.___;._,._._=. __g.__ g , 7 _==

.=

_._4- .=._. . m- ~. =g uJ __ .= :.- - _. _ _ __=- = ^__

. O_.

r c 1 _ _- u., .:-- = ---: :.n...

_ _ _. _. _ _. _ _.. =

_ _:==:.;. = in. z:: = 2:

-2 7.r=

.a__

r.. =

-4

a: =

_._ a _.=g t n _=: =_

=_ __

-. :.c:r s _,q....._..._ ..w

:n:.-

.. _...rt: :1=_- -==:; .._.4_ __.: -r: : =_r _ \\ ___.:*_ -- _._..c==_. .-m .c ..J jm,,1 -- -. -M nc... c: =_:.. _m. = .:=*. :r 1:22.u. x.q -- - - r_ a =rd :=--"-A = =:- 2---= r =

=

= - - ^ :=: _;n--- -z

_ = = = x:s z :z r.=1 .==._ ... = =.=._ L_=; -.-=-..=: _

==

--*= I.. _ _

_ =

-.V = . _. _. = =- - M w :. ;-f m J,.M -- = =:ER-g_g =-].==~E _g-j@j:-E_- - 'G _:E -E: Ek= g L=_:~.5 -i.- N _ a:2=T.;r-- ,, _j,...., _ - - 1 ____w...__ _s _..,g 3 7.__ _.___i = =r---- ~

s.

=r._ ' --e 1 c :.1 m3

=4

'T 1- --. _ _[_]a_ _ --: _-. _~ - E y. ] 3.g'.. :-Q pgu .h gg:= =r=2. a _.___a... ____g___.. _ _. _ "I .:~3... 1-n-- 3*

=.'l-;.m C7

_. _ _= - --t=_= - - -- :: - =.=::--___ .:d=:=- = r-- ._.r=,: _ w _..2_____. \\.. ._..:_r._=__ N a..-___-:__i_: E p....=__ ._.-_=_o_-. r._____. = _ _ _....:r =

_.. _. =.. _. = _

J__

f

r. t. _ _.....

r._-E....,____.. _ =... .........m E, -- _.n. _..... =. _ _ _ =.

=

=7 7. :-

. _.i... .:_.2=... _. =.__= .r--.. 2_ r n _.; =_.

M.

L_:=_ - - -.. _ .2 N _,_.p._... _. _ _ _. g .... _: ::. __.. _.T_..r.._...... _=_J r_ y '..: . _ _:=_ ';.r. =......1.=._= .-:=._.. .._-*; r.. { : S.,.y,,... - 2 r.0.:. r

n. 7

'-i'=; r.

.=.: j :1:n
: .a :

n..: _

n;:.

.r;= '... _

m .2 W:

=

-_. rb:=:. H

' -' Q-

.."2 PP= '._C_ C

* @--l
- * =. "O.

f['* J n;-- 'O : y, ;; 2...

- u-2 '

. _,.u ' -=.a.. - ;;a;; m . _.. _:.-i =_._=. E.. _. _.

g,;.'

.:=

... = * - ~:__.._ :.u _. ;..= ..a :_; a" , ::_=- g

g= rr-:-

- - - - m 5: .2:

=

==. _2 r _. =

_ =.. _ _. .... =rn- .. _ _ _n.7 r --". _...

- -=

_2..-

_ _=: : 2: 2..r.:. ;..

- - = = sc .:=--* 2==.; =x=:= - : s vi 43 .:: :.. _. _ =r,r_

r..

4*--' ' - * - " - - " C*:..C.__ 4...- TJC-

...: - : Z -'-' -H

-~ . ~7_* :.'" M' .J. !=. - .- h. C' =-* I /"" 12. '= * - = ."2*= --"-2 ::.__"_:.;-*'~-

21

,n g - =_ ur. -naa... 1: C-- h=- -.u= 2 ....... :_ u -==--- - -. "-. 1 L:

"r*

n--.-- =- =h- .:..-*.-"--* 2% -* 'g _ 2:20.C- ',". _. u_: :- 1 J :=g*-"-. _= 3 :-_ ' = =. n ___.a_._ ..ns. _ 2M-- . = u-u !'I' z - ~'~. ' '*; q' s.,., :2;.. '2 J ~~ ' : - ---:Z t '--?~

-t- -. *: :.

1. -- ^ ~ ** - i:' :*".U - *'

_r _ _ 4 g_, _ _..m .,, _:1 -- **: -"7 2 = __ 7 ;_..; _. - " - * * = :.._. --* = -. *. - - ~ ' _. -.' 5 ___q __.a___ . :2 --- .g_...."2-" r!- . ': 2....

J

: .. J.

.44 :C ! *G....L ::... 'J J 1.. _.

_

- - ' * ~ . i. :. N

4-

.2 ~~--- ~ s._j _r.. .1= - ufr .. r = _.a " r---- --1 ."2 ~ ! :5 . "'j.i

EiE ':ii'}-

"T.T.'

- dT.:

id.;. 5 '5h Os ~[ -d - - - - - * ~ - .i :42.:. . C - M - .4 T -2 . c - - ~.j..; -::j H r :1 "-- . 1 ~~ u;j t ;1 = 7-- T H _- ~ v-* e- .. :J-q r.-- i ]: jO C .I C O .C

f#

O O O O O,w ~ED -j W -~ 1r - . l :- --w"-'S --- CD. ' a.gr. - w .d.*._ .,N 'r 1D ~ ~ 9Er ni

4..s w

' E9 3 N r.N N -}. ] ~r;U..._- ' "-T ~T ' { "[:? 'ri _{-p()Q__.o 3:.o' ', S a.gs_p1au...n.. ;

3 FF].iii"
T'. IiZ

- I::if

4. _.. q r..

..J... g. .r.._ .i. i. ' 9-22.. 'k 1 23 " I'- -N..;h- ' - b: - ' $.d '. 1=:=i'

F$,;

!:-T" ij jTjg --i - q- ]7 l

9 (6) Define a conservative bounding value for K called K isec is e from Figure 3 (1) for the value of maximum hardness from top 5 of Part 1. (7) Define a conservative bounding value for K called K from Figure 4 (1) for the value of maximum herdness f rom Stop 5 of Part 1. It should be noted that since both K and K reach a conservative "threshg" value with r et to increasing material yloid strength of 8 ksi In and 34 ks! In , respectively, the Part 1 evaluation could be deleted by conservatively assuming the conservative bound threshold levels for materials with trends that appear on the hard side. Provided one is assured that there is no dif ficulty in meeting the specified minimum strength requirements, the analysis would be simplif ted significantly 4 if Part I can be eliminated. However, if the maximum hardness limit is greater than 48 R, then the of fact of residual stress due to quenching may l need to be considered in the analysis for allowable bolt stress. l \\ I 2.3.4 Part 3 - Determination of K The following is the procedure to determine the applied stress Intensity factors for a unit appIled stress. The tables in Appendix lil for K are based upon calculations which assume a reference flaw at the root of a thread with depth of 0.02 inches and a flaw aspect ratio (a#) equal to 1/4. (1) Define the gecnetry of the fastener in terms of the foilowing para-meters: (a) Nominal diameter, D (b) Thread pitch p = 1/n where n Is the number of threads per inch (c) Shank or nominal cross-sectional area, A

e '.55 b._ 5 .?.b.5. 25.5 ]*kN55 - q-..

.=..C' _ *;!._.;.: ;;.

..; ';,,,/ _ 4 ---p_. 20; - ~ _ ~' a. 1 , ; 1. ~ =. ~ JJ -"

i. &....

..-4 r _._,4_... ' = - - - _ =: i 22 '- *-' ' = _. '.--.* ;:~ ---1-~". =. " " "---

=; ' -

'---7.-

$ ='. 3.=_

- ' * - -._.f-*-__.4._.- +--- d--: '.; ":.--3---

=

~ ~ ' - ' ' ' - " - - 7" w.-' ,_.,2: -'.' i - - ~.

__E._''.-~--...,_-.n..-

_g*_.-. .2 2.~.J - - * - ".="q-=' _r._. .__g _..- +.- O --

,,--'=

- - ~ - x_ ~ w- --= -.m .m _ 1-i__ .3=a r1_ D O.

_1 g_

__-r._._._ _ ..-._'-:-=. _ _ = .= _... _ _ _.,_ -Ob*~.. - _ "*l'*-*- +. _.. ~ _ -. _ ---I. M _ _._.2_ .. _.. _ __ _ ?- .a 'C.** - - - ~ ~ ' "~.-:---". . M -- ^ ^ ._ _-],-..

{.... - * - -

7]' * ' -__4_ --T-I:,,7. 9 _=_.. =_=.a--- 2: -;=r . - - - * - - + .; = =._1 _ - ;r--_ ;=__ __ a . ;= a 1 .4___ g---, g!"7- _4_... _. + _ _. _+ D *-- .:: =- ._=r___

==---_s. =t .__e =. " ~. 7-*--- ~1. / - N2 __.. _.. Z . _ ;.g'3 =t -- .=- _.. = m_

_.3-

.,y- _u.-.__ 9 =_-q _. _ - - = ._ =_. ~

_-v: --

2--- ~-- ~ ~ ~'" '~ - ~~~,' ' ~ - ' ' _ ~ O 2'# ~. - _ - ' - - .._;.= _,.: _ _ :. .w = M. a --r - - - + - g) , g., q ;, -,- i A q*, I r__*N..-- > L*- -- - n.;_ -. - = M .. - !J a *r*"-- &{ _.2 __ Q __ -i ", # L Z. = O. J. ".L.. j y

~'--'

_p __:.r=- --r --1 :- - _ _ _. _ _ _. _=_ ---"+ - -"=_ __.;_.= 1.. _. --d p; 5 _-_ _ d g .-.-9T I .N 2 , _ _. _ _a-j q.._. a j __._ 7 ** L.j - _ - ..._ g.; ..y =- ~1 = -1 J__.._.-

== _,. _ ----7;,,y,_._=.-.

= t--

= = -

=.-

-'-*- _rC2 ---- -_

_J n-3 -_ -..S

--" l ey f'"!

. _ _r -* --cog

_ ' _. - _

-*9. _- T_ =. _

-*"4' '

I C *'.. _. _ _ _._. =.__ _.. _ = _.= ... _. =. -. .._.=._2=_= __.-- * --- 0

=_

-Q .. +. _.. D an,,, =::M.. D_. lE.# ~= ~~[] 5=:-: Z,3:j ;"

C' _7.=~~22- :12 -,_]

'- C-' 2.j {[_$ 'h i y _y.5 ~ ~ a

== =... -. :---]: - y : - " :L {.,17--* J.r.:- " =T_ - - " - ~ * = M ...4 C 3 =- _7_' "'_ m-'*-C'_-- 3

- =----

I ~ n ;c_ .g: .:.__q.. t- ]* =.n = =;- / -: =_ . = - - - '- - -- - " _. -- = _._ _=.. I2N

-;. 4...; __; n_

-r-n-:--- 4.a r-; -N

:;-= -. =

W C4- :-E 4W 5"":i:E i "~~ }EEiG::- ? * '= W=.W [Elliii *"I = o P ui y ' i=~

u. =

. __.. /: s..4. _.. ;= =_. r., g =..l. u.4.._.

= =

z..

=

u, a _;. = _ =,... _= _=== - - - - - - -= _-- _---t== u-e= a4-:-- ; .: e _2 O. !- "' T.i

.-' - " / 1.=.-

-._ ' ---*.;=

-o_.___. = - r.f,,;s. -: %.. ;;j 3 ... = c.= - -. =- - - --. - - - = _ = _ ---=4--= %r1-= -ra _ __-

_----Y..._

M": N N - =;- n/.2 =1: J= r.ar*E.;.= -=.;20-: 4.__

r.__r,an:

n-

=.- J _.;___~~ 2_ - _

_ _ _ _ -_=*:

.1 $'d*- ":. L.1:7 !_ L.: J 2. ;;-- ..... _. - - - * = [. :.

..*C;. ---

2* e

=.=.: u ---, = = = =. :- --

-4 =:_ - 1<

==.=:--- -- a :_.= .2== . o::: : .:=.s=== = = =-O .:.=== : =- === = = = - - - - _ - * - - / ___ .c y

- :.-=-= =__~n :

__r=3 4 -. ___.1.__... y._.,..... 1.._...._._7._......_;_.,._ g. . g.. __;_. E,, -l.....__.. _ _ . _g;;.;.__ o :-10 -;.--'- ' = O.;.j ' ;.J %.l' ".J. ..-7:.;r;.r

CJ ;--'- =;.' - _:;.-~.;~.: :-----

~ J.. :' '.j ~.'- '~~;--'". - -

_ - '

J-* ;* ...... "...*-"-j****. ?.* O **Z _I f.-**4*"- _... ~..~: L- -*~

...n.-- i* 2: __

_7. r. -' a,,, : k~. "2 = I. - -..... ".1.=....... _._:".=... .f.......... C...I_...:r_...... ;.7 2...-.".l...,._.__,..._-...2.:... ; 1 4

1. r_:.;.-

1- .2:r 2 N 3 _ L.4I 1 h4 M

L.;.; ;

.U.-": = N.;- .-.. '. =.7C.=:._ : n.=

3..: 2g.-;

.... 7J b "._1 i 8 =. --2 = ze=-. _e - =_ = _--- = -: -- 2 3.- . o _u. p

q _

r w

1 J 1:__:

N _ x u 1:= =". =

=.

1.= u.' s: m= '.;; :.: fll, u= u_.n: .n._, . _;n =

7,,

-,. :: =_

c -

=

cs y 7 :... :=_

. : - _ r a- - _. :._ _

x:? :' ".. =

n : -

uu ~ -;._..

a.: "-..nr._ r

_. r

. _. j c _. m ._ :22 _=== =.. =..ug. - - - =2.. :.

2...

-..= ..:. = _ =. _ _ 13 n.; - _u._. h. _:.;._.. _. .__ :.c-. ....L..=.... .2._= :.

2.. =_..:._::.=.. =_.. =_.:_.2 :J. =. 3... =..

. ;=..

:n.

4._.=.--. m5 .C. u_;.=...:.._..:_,;d. =. _ _ . =...... g= __ F ~ ~

. r --- :: -

--1--- .- : n.; 2.:77;. -t =

"--"~ n n:_ - :

N ";

r. '.4 7. 2

...J ff') ;.- "r'-' 1 .?.; .;I' =U r- - _7* C - 2:".

C*

I- - -

d."!- ' - *. *. - - - -*4:r

"] P.-- . i. - 7 n2: ~ O_ W - j-W- 7-: - ..3'_. ..4'. - - " ~ 1 -'". : 1....

]:-- - - - - 2.=

_:- =

t:= u _-- t= ...:! %.= ".--.

n. :==

cur a '; T 1. 'F... .** r%. L: =na . ;.= 22: = -- _F =.. ... _22.:= g E 22.n _, =.. -

== ' -..t j arn:

=.

._n ' -] r

.= =: x=y : :=:a =- :.;6 -r ;_ '

12 - = !D :.= - :=... _v...

.a=

r

== = :

n--

.; t. .c n. ~~:

. 2 _

3.1-3 _ --. .- - _a::: _.: 7 .., " = _ -::_- -

=

-'.L n

2;=

7.:: = ~= u :; _: : ' r.: n.' n= :-- - --- r : 22: = 7= .==.:- _r - --- m.- - +.= ..r = - : -:

"j;r

=! !ix :: -ify y= mj Ei .j j;_is :i. W 9:j;.:-...:;f: :j r

hi !=J;3i;:

-2. .p D, m _._m ___,_b =- o e om .c 6.+. b.-o __8.!-b . _..o o -c __ e ___m r m = _2_ i 1 l i,

.=_=:

.M, f ugsg ' 3351,

1 ~ i y .'= -= ... _ 3_... p ei 4 s.u.a} uj s.s. an s.p toys. aa. y1__. ___.. M 3 I. i i us. - .. _..). ' ; 7.. ' - - ~ - - u n =- - r ' us. c x,.: n ..t= .a., T..

-1 r _: -

.._, a n . 1: 2:.:--.. n x;. .y. _: 1 = ;r r-.

F 7.!.. -

i =5*.'f -i C: K .p'_j C~ ? C". 1 f~j if Tfi d--E 2~$1; b.' -i:i,.i 2 -i".y. Eh. :. _f._".2 g: '= d::'..#_1_-ii.rp..:s -t M _;.j @

1

..r!$ "' ;-Mi !L 2-

Wi l

.r .:j : ? ar =i -.2.. 2 -.r ...l... '1 .:.: 2-ar t

e e _ ' *. -10 '--- _C*-~~_ ; ~ ; -~ .**.T -~

C.~ :.. = - - - 'L

--J '._47=.;.~.- _ _ f ;=_ ' _. _ - =1M l -.. - =:=__.i-_ ---1= --.;- - =t.__ - _ =. - -

= ;;--

._._- r:-.: -= _ .= .:.r. - r ~ r-m_.w

- -== _. _ _ - = _

.... = . :_ ;. _. =. __3. __-- - _ = - _- - --- L _ -== It= 4-- ,n 2 ..e. n t- -- m.a i._.- __.1 b _.4_. ~.b _ =, d._._. . _. _,. _. _*~=_=_i_ _i---- i __. M_. _= _w_ g_._;.

;.y -_,

--q - ___-_4 g._ . u ..4_ w. . _g,__ - _ - _ - _'.;._,,,,!,1. _., d) ;; m, - .g.- --A- _ = :,__& __- = = _ n-

_- - - J. =_ _ -

.s._. _~ ^ _. ~.. _ _. n__ m_ ~~- 3 . _,?_= __ _ _ _ ~ ~ _ ' . _ j _ _~EZI --+- C ~#~E_.,I... i

d,2

a_ .!.-~ ' " * ~ ~ =: -- 'r; ~_. ='- =. _d ~

_7.".

._I I _ "j_" 25.~_'. __q._,q__ =.-+-__ 4' ._7 .-4._ -- =.:m _.__ a_ = _7 M-'--' ---..g)*-*---~ _.=_._._ - _a _2-

==__ --s.-- ._.=;._ - - ~ , = + _,,4*_

^_

- nay. 4 1--

==3 - C' y. { ~@.._- ..as a ._.q_,,,_.-w _.a._.- 4__ 1 2_ ._P-- - - * - - _ g "-

**[---"

- -~~7~~~-

~ ~ ~ ~ ' - - ~ ~.=.=; = _ g =~. _ J - ~ - - - - - ' ' ~ ~ ~ " ' ~ ~ * - ' ' O ~-

:~=

_,_ g.A.. =. _ _ _.. g ._ r -f

=. :.

em 3,= ._(._..___ _..,.;_;; g., v _*:--~~- -.If= T.~'

-'~.:

,*-".:C. .2=d 7-' .-f. gg - ._..e___. __s__ y _. _y--- -]__--. K_ a i .,_p_...- ... = =. n u.__ 2.- -a - - _;= _- : _- :_=-_;_;..__.._-. w:._.. --"r_. _.,

.4

== -=2.

==/ - -- _ = _ = - -~ ur. _ __ :s. :.2.-

.= _

. _ _=: = ,2..-

=d =._.a _- :-

. -= _2-s.... .o._._._..

--L ___.. _... _.._.:..._

... _ ___. 2. _ =f-._-._ - =.. w

:=

= =.-- _.._g--/_. ~ - U-.==C. T O.g ... =. - .:- ~ f - ~- 0 ;;_;:-- :.:.: = ;; - -_. = - --.=1 ': _. _ :" =1 0--

]_. = :

=_w --w-__-- =a__- _ _. =. __:. __ _ _ _.. _... _ __ 4 _ _. ..,i: = = _ _ _. _ ____ _ - = _ _ _, _ =. _ _ _ _ = _ _ .._,s___

== =- 2.

=

- ::=

p. =_;

ur, _..__4,,, __2__ __a. _%.. 4' 4 m'. _._'c-9_.. _. 2.--.. 9._9__ :.Fm_i. ~_=.:.~.. ~. _..3d=. _2 -&. _*~... _EE. _.__..E_.+.'_2 /_=_1 i. E_.__ -. _ _. "._=_.'.r-. 2 E_ F_3.;=. _=_ o c_

z=;:= =.

_;u _ _ 42 ..;.4..:- 23.... ../.. :: : _;.-.=_..:. =_. :- ~ ap ~ = r=- _o : n

==n=$,_ : =.=:: =__ _:t =- - ----_= : :.:. =

c==

_;.:- J : f.__-.==.-- =2

==_ -- =- - = = *. - - =; ., _g -. _. : m _-.:._-.= 3 =_._:__=_h'._ . ---- p- *.f.d.=__..._.. J....._=_- _=_t_=__. * = _ 6 ___3_.._. _.4 3 _ =.s,2 t_ =_ : _ -- - - - m : = =- : -w

=_

=.=f -_ _ __ =

==. : 2:2= = = _ -

.= U 8*

-4

== ,u:_=.=..- _.= = n = =-

= -

::

_ = ;- - - - - = -=.--- - - - - -: - +---.- -~ - -. - - - - =- - - - -. =. - - -:--_._. -.=

- - = = -

1_ -

7_ - - - _ - _=L_= = = = _. _ _ _ _. _.. _ _ _ _

. _ -..:.:..=. _ _:__..=._- u --__ -$_=..:= y _... _'E..E._=__=_=___=__ m q . =.1 __.. _ i,. -- -- e,e _ : yI - - - - -u t. _ -. _:-_.. = =-f -t .;=:.:.. p =-1_=- .-H_= :. = r===- . - - = c --- = ....== _ _ _..= n n _. 3.. :. _ P

m. =..-. _ u_.

. =. _y.. __.;... _ :=.=.... r_..-_,_ =. _ =.. _ _ _..5_. :. _. r2.._.r.;n..m;.=... -.. _: r.. ;.u.a. :_._: j . j _7 v-

=n. :_:

. -j._. J e- ._s ...... _. _ _ _:= : = _-. :.-. _r._u.. : -_ _.. _. _

n.. N. _ _ _..

.. _...:,..... _ _.. :.,_.,;g_ _- _ _.. _ ___ : r=.:. : _.r_: J , g

== r _ w: .:= -i,=..- =.::=_ ~ - - - - - ' :=:.=. d =.=: _-:=..._:= =.

::

2..

,r _ = ;; _ .a.= .. i x.-

r- - -

. T.. ., -. := .e x q al. 4_, _. N

7. e...

.. : =_;- - :.:

:=: = :2 : u===:.

--= = 2 = = = :.- 2,.4_

..., =.

_2_.=

2.. = 2_; =.

u= =: =:4--

=.:

2= .2= . =. c_.:::. =.

=1

.L y . u- ~ m -- m ._.= =_-..j ::. _.:...=:= .1 - en - - . n: :

=

m

=. :r_=_= ; = _.. :: =_

xm .: u ;. a= _ : :....:=

_3=

a 2... ?-- 1_:.. ..=- "J --r----

-:-r :_- ===

.'ln-

==: .- : :=..a nn : st._- -k

==

=-

.. = - - m.2. _.- -: = = :-a - ..i: = c:.::= .23.== :=== ;_._a-

--e.: =

..;. = n - --,1 --,:--

== .a

- = = - - -

_- : _- : =

g = = T =s:.: :

2- :

J = 2 :.r- - n 2=: - :::=== = = = = =_=2;. =

x=1 - -- ---:=. na.---- - - - -

-n._ m-j. ~ .x--

.:..r -

~=_: :: : a u-- v

_ =

i -- .I = :. =, - - - --- 2,:=

_T. :

r d =,2:= -. --: - nn-- - .: :__:..::= _r 2= 2 -e = -:2 -- = = = 2=-r-m x= . _.... _. _ _ = _

g.. _.. _. ~.x.. _s=...

m 4 .. -.._.. =.. - _ _ _ _ =.._ -..--__ _.....-- =._

m-

=... = _. = _ _ ...u.._= .:..:.=..-. an.n. = :n.... _ =.. __::_= 15

i-i ~:
nct in, yirs -i@ 2iij.,i.;-.%is i-5 ": !iEE jii@-

9; anj.M g C !D -Mei no _:.:@ i "O o"i:-cd [. i w ---M iM . : - - C - N o Ei n o, " O ~: m --v ---f S --t a - - e. C' C e .M..j P' .. W. J...y.j.;, ...y ., _ h<. j;;10 -d.._a . -4 N ---e ,0..'. ~...L l --W .j ..j. a_. 1

.:.: - a. :. :.

- -.r-- M5'] . -j j -. r -{Uj TS% J *$SUO@ n01 W h M Jj #G{0 fJ 1 .3.: N. J. - l'i ' .l~ l l ~ ' -:r -i. n .J. lu. _ .i - i;i.n..: u..i..i. -.di i..._- _31. _E:Eri ;i.: :.:i$...E.23.. = =... i.;t..

.-] --i.--d - h.

I

"l Ti =

EL 5@ -i~i E: :-5-4 a :. ^N ^5bi - Nr ci:Er ~:_N.9 2-di-% / i .:3:.rl - - n; ;:: __.=p.--. a n_. : r. -- ut; - i - .y - u i .s. - t l 1 L

12 (d) Not tensile or stress area, A s (2) For the threaded f asteners including studs ena bolts, the value of E, is determined by the following procedures (a) For the given f astener geometry (i.e., diameter, D, and tnread pitch, p) use tables in Appendix fil to define the stress Inten-sity factor for a unit applied stress, K. I (b) If the exact bolt diameter or thread pitch is not listed in the tables, then use linear Interpolation to determine the value of E. 1 (3) For solid pins that are subjected to pure sheer loading,,the value of stress intensity for uniform shear stress (Soction 3.5.3) is determinea from 0.232t (2-1) K = yy Hence, the unit applied stress Intensity factor E for shear pins is E = 0.232 for use later in Parts 4 and 5. Il 2.3.5 Part 4 - Calculation of Allowable Bolt Load Based on SCC The allowable bolt load for prevention against SCC for long-term loading under normal operating condition is determined by the following procedure: l i (1) For threaded f asteners, calculate the allowable stress baseo on cons-sideration for SCC f rom the expression scc (gjg}) g ~ o scc

13 where K is the conservative bound for K estab-Iscc Isec lished under Step 6 of Part 2, and K is the stress Intensity factor i for the postulated reference flaw and unit applied stress from Step 2 of Part 3. The allowable bolt load based on SCC can be computed f rom s scc A (2-3) p cc , y a a s whore A is the not tensile or stress area for the bolt. s (2) For shear pins, the allowable shear stress based on consideration for SCC is calculated from

I kscc (1/Kyy)K{sec

~ T = a where K is the conservative bound for K estab-Isec Isec lished under Step 6 of Part 2, and K = 0.232 from Step 3 of Part 3. The allowable shear load based on SCC is scc sec (2-5) , 7 A y a a where A is the cross-sectional area of the pin. It should be noted that fracture toughness is not considered in the determination of allowable bolt stress for long-term load since K will be less than K and, theref ore, limiting. 4 . ~,. . - -, -.. _ _. -.. ~, _ -, _ _

14 2.3.6 Part 5 - Calculation of Allowable Bolt Loads Based on Fracture The allowable bolt load based on fracture for short-term or accident loacing conditions is determined according to the foiloving procedures (1) For threaded f asteners, compute the allowable stress for preventing fracture from (1/K)Kjc ~ = o, y whsre K is deterinined f rom Step 2 of Part 3, and K is the ~ le I conservative bound for fracture toughness from Step 7 of Part 2. The allowable bolt load based on fracture can be computed from f f ( 2-7 ) . o A p a a s where A is the not tensile or stress area for the bolt. s s (2) For shear pins, the allowable shear stress based on fracture is calcu-lated from: l T, (1/Kyy)Kjg 4.31Kjc (2-8) = = I where K Is given in Step 3 of Part 3, and K is the Ic ii U conservative bound for fracture toughness from Step 7 of Part 2. The l allowable shear load based on fracture is I I

T A (2-9)

Va a l l-

15 where A is the cross-sectional area of the pin. This completes the details of evaluation. At the or d of the Parts 4 and 5, the allowable bolt stress (or loads) for SCC and f recture considerations have been quantified. Some guidelines are presented next as to how to use these results to establish allowable bolt loads that would be the limiting case for the specific bolting application. 2.4 GUIDELINES FOR DETERMINING MATERI AL AC%PTAN2 The criteria for acceptance is based on a fitness-for-purpose philosophy such that if the applied stress is less tha,n the allowable stress, then the material is suitable for service. Hence, the criterla are established as ,st st (2-10) 4 y a tt it (2-11) a , y st it where o and o are the calculated short-form and lonc-tenn stress st Zt conditions, respectively, for the design, and o and o are a a respective allowable stresses. A similar set of criterla can be established for shear carrying members, such as shear pins. The allowable stress is the minimum value of the allowable stresses determined from consideration of fracture, SCC, and tensile-ductile f ailure modes. Therefore, f 5 (2-12) o,st, g or c s whichever is minimura and where o is the allowable stress based on as strength. The allowable stress, o, is calculated in accordance with a 1

16 applicable conventional desim procedures and based on o and o determined in Part 2. $1stlarly for long-term stresses S o, olCC = or O (2-13) whichever is minimum. In order to test for ecceptance, the allowable stress based on strength must be established given the anticipated design mnditions and safety factors. Provided It is accepted tha' the design is sufficient when the specifled minimum strength requirements are achieved, then o' need not be quantified, and the long-and short-term allowables based on sec f o and a need only be compared with the applied stress. Again, a a this is true without question as to the type of design or design criteria when I ymin y F (2-14) o y and g umin 3 F I2' o u Knowledge of the design criteria and Inherent design safety factors will be required if the design basis is not satisfied by the appropriate equations above. If both Eq. (2-14) and Eq. (2-15) are true as determined during the ev,aluation, then the only required check for acceptance is that Eq. (2-10) and Eq. (2-11) are satisf led as written below: of st (2-16) o

17 0 < c (2 17} if Eq. (2-14) or Eq. (2-15) is not satisified, then a review of the design calculations and allowables may be required to insure that o is not a limiting. If this becomes the case, then those parameters that ef fect strength must be considered. If the material is subjected to alevated temperatures during service, then a reduced strength should be used. A yleid strength reduction f acter, C, was developed for cxznmon bolting materials from (4). These f actors are given in Section 3.4 for a range of temperatures between 100*F to 600*F and apply to yleid strength only. In this temperature range, no reduction in the ultimate tensile strength is assisned.

~ 18 Section 3 j ANALYSIS ASSUNFil0NS AND RESTRICTIONS

3.1 INTRODUCTION

in order for this report to be self supporting, this section has been prepared to provide the technical basis for the evaluation procedures. Reference will be made to the RCP-SAS report as required to justify assumptions and information Implemented herein from (1). In the areas that are expansions of the RCP-SAS analysis, background Information is also provided herein. The final objective of this section Is to identify tha key assumptions in order to define the applications where the evaluation procedures are valid. 3.2 FAILURE MODES in the evaluation procedure contained herein, the acceptability requirements for service have been estabilshed based on assuring against service failure from three potential failure modes. These modes of failure are (1) Ductile rupture by plastic Instability (limit load f ailure) (2) Crack propegation in a subcritical manner by Intergranular stress corrosion cracking (3) Brittle or fast fracture due to crack Instability under monotont-cally increasing load In many respects, each failure condition is unique so that assuring f allure prevention for one mode does not guarantee safe conditions for the others. ~

19 When applying the evaluation method, the f ailure mode or modes to be prevented must be described by one of the above failure models; otherwise, Irrelevant conclusions will be achieved. Specific f ailure modes that are not covered by the procedure but are relevant to bolts in general, include general corrosion failure or wastage, fatigue, and correston-assisted f atigue. The procedures would require revision In order to expand the method to cover other modes of failure. 3.3 MATERIALS 3.3.1 Chemistry and Heat Treatment The material properties curves for SCC susceptibility and fracture toughness behavior were derived from a data base of laboratory tests for steels that can be classified as low alloy quenched and tempered. For consistency with the Consumers Power Company commitment to review safety related LAQT steels, we have adopted herein the same definition as was set forth in (3). Specifically, a steel will be considered a low-alloy steel "when the maximum range specified for the content of alloying elements exceeds one or more of the following !!alts: manganese 1.65%; silicon 0.605; copper 0.605; or in which a definite range or a definite minimum quantity is specified or required within the recognized commercial field of alloy steels; aluminium, boron, and chromium up to 3.995, cobalt, columbium, molybdenum, nickel, titanium, tungsten, vanadium, zircontum, or any other alloying element added to obtain a desired alloying effect". In addition, the total content of alloying elements when sunmed shalI not exceed 5% with the exclusion of carbon and commonly ~ encountered amounts of manganese (up to 0.655), silicon (up to 0.15%), and copper (up to 0.105). This definition, although not very precise, was suf ficient to identify those items purchased to specifications which require consideration in the CPCo LAQT review program. A low alloy steel will be considered quenched and tempered if it has experienced a heat troafment that can result in heating to a temperature of 1500'F or greater, followed by rapid cooling, usually in a fluid medium, and .e--.---,,... -~,n e.. ~. -a c,.. _ ,an_..,

20 - subsequent heating to a temperature in the range of 650-1250*F for a period of 1 to 3 hours (or for thick sections, approximately 1 hour per inch of thickness), ~ fof loved by cooling to room temperature. Materials that satisfy the above conditions for chemistry and heat treatment ) can be evaluated by the methods described in this report. A listing of the ASTM and ASE material designations mapiled from Midland fleid purchase records that could have LAQT steels supplied is given in Q). t 3.3.2 Ratio of Yield to Ultimate Strength Correlation j a The yield to ultimate strength correlation was developed in the RCP-SAS report based on specific data for it e supplied materials and reported " typical" bohrvlor for LAQT steels. The study covered a range of material hardness from 21 R to 52 R.. This correlation is given graphically in c c Figure 2 and is based on Eq. (4-1) in (.1). In anticipation of very sof t material behavior, this correlation was expanded to 90 R (~10R ). The b c expansion of the original curve was accompilshed by using, as guidance, the expected value and typical scatter for o and a for quenched and tempered stools reported in Q). Below 21 R, the curve given in Figure 2 was c Aveloped graphically staying within the limits of the reported data band (5). The curve was drawn to approach a constant ratio between o and o equal to 2/3 at 90 R. For hardness limits below 90 R, it is a stned $ hat the b b equation, o = (2/3) o,'Is a reasonable approximation for yield strength. y u -3.4 ENVIRONENT 3.4.1 Stress Corrosion Cracking The SCC susceptibility of LAQT steels is very sensitive to the environmental conditions: spect fleally, the corrosive medium and service temperature. The SCC threshold curve shown in Figure 3 was derived f rom K data measured in the laboratory with either moist air, distilled water, aqueous Nacl solutions or seawater environments. Although not Indicated in all cases, the L

21 testing temperature was typically at roon tomt.orature levels. However, a rowlow of K data given in Appendix IV as a function of test temperature Isec Indicated K is temperature invariant for aqueous solutions. Based on Iscc this background Information, the following restriction for the SCC evaluation for computing the allowable stress level c Is appIIed: a (1) Service environments are restricted to moist air or aqueous Nacl envirornents, or enviroments that are viewed as being less aggros-sive than those from which the test data were developed. (2) Highest service temperature for the bolting appilcation in con-sideration of SCC limits should be Ilmited to 250'F when no atten-tion is given to the use of thread lubricating compounds, etc. (see below).- Caution should be exercised when extending the scope of the K evaluation to other environments or elevated temperatures. Application to temperatures greater than 250*F are allowed, since the aqueous environment will not be present provided that the creation of more aggressive environments such as those caused by the breakdown of thread lubricants or coatings is prevented. 3.4.2 Fracture Toughness For structural appIIcations, the of fact of environment on fracture toughness behavior can be neglected in that there will be no toughness degradation due to service exposure. The ef fect of temperature on toughness will tend to increase fracture resistance as temperature is elevated. Since the data base that validate ( the lower bound K curve in Figure 4 is based on room Ic temperature behavior, any appIIcations above this temperature will be conservatively treated by the evaluation procedure.

22 3.4.3 Yle!d and Ultimate Strength i If the expected service ' temperature is low (i.e., ambient conditions), then the ef fect of temperature on strength can be neglected. Guide!Ines for quantifying the reduction in strength are given in Section 2.4 and Table 1. The yield strength based on room temperature conditons is not significantly affected until tec.peratures in excess of 200 *F are reached. This is observed in Table 1 The strength reduction f actors in Table I were developed f rom Section lli of the ASE Code (1). The yield strength reduction f actors were determined from the yield strength values, S, given in Table I-13.3 for botting materials under Class 1, 2, 3, and Mb components classif Ication. I Although only four material specifications are listed in the Code (and Table 1), reduction f actors for other LAQT materials can be estimated by comparing material chemistry and mechanical strength properties with those of the materials listed in Table 1. With regard to ultimate tensile strength, S for Code design limit for LAQT u matarlais is generally Insensitive to temperature, in most cases, the tensile strength is constant up to temperatures of 600'F or within 98% of their level at rom temperature. It is therefore reasonable to assume rom temperature values for S up to 600'F. u 3.5 BOLT GE0ETRY 3.5.1 Thread-Root Region The bolt gemetry and thrs d-root characteristics are consistent with the Unified Inch Screw Thread Standards of ANSI Bl.1 (4). The stress concentration of fact of the threads and the stress attenuation with distance across the bolt diameter were approximated by literature solutions that describe the stress distribution in single-grooved bars under unlaxlal tension. The capabilities of the evaluation method to handle dif ferent bolt gemetries has been expanded since the first evaluation performed on the RCP snubber anchor studs. This was accompiIshed through the work performed under RP 1757-2 and RP 2055-5 for the Electric Power Research Institute (EPRI) (2)

i l l l l i Table 1 REDUCTION IN YIELD STRENGTH DUE TO TEMPERATURE Minimum Yield Strength Reduction Factor, Cr Temperature (O ) Not to Exceed F ASTM Strength Specification Grade Class Thickness (ksi) 100 200 300 400 500 600 105 1.000 0.933 0.8% 0.871 0.843 0.812 A193 B7 95 1.000 0.931 0.896 0.866 0.843 0.812 75 1.000 0.932 0.896 0.872 0.843 0.812 l 105 1.000 0.971 0.949 0.929 0.909 0.881 B16 95 1.000 0.969 0.947 0.928 0.909 0.881 85 1.000 0.971 0.949 0.928 0.907 0.882 105 1.000 0.933 0.896 0.871 0.843 0.812 m A320 L7 105 1.000 0.943 0.911 0.874 0.843 0.803 L43 525" 105 1.000 0.933 0.896 0.871 L7A 525" 109 1.000 0.936 0.904 0.877 0.851 0.814 A354 BC >2 " < 4" 99 1.000 0.934 0.903 0.t.18 0.852 0.813 BC sih" 125 1.000 0.935 0.903 0.878 0.852 0.814 BD 150 1.000 0.956 0.924 0.896 0.868 0.828 t A540. B21-B24 1 140 1.000 0.956 0.924 0.896 0.868 0.829 821-824 2 130 1.000 0.955 0.927 0.895 0.868 0.829 821-824 3 120 1.000 0.955 0.923 0.898 0.868 0.828 821-824 4 105 1.000 0.954 0.926 0.894 0.866 0.829 B21-B24 5 100 1.000 0.954 0.927 0.894 0.867 0.828 B21-B24 5 NOTE: Developed from (4_). Linear interpolation is permitted. 1 4 r

24 and other plant spectfIc work performed for the Tennessee Valley huthorIty (TVA) (A). The areas of applicability are summarized below: (1) The method is directly applicable to the thread-root region over the span of unengaged threads for studs and bolts. (2) The procedure will be reasonable for evaluating the thread-root region of engaged threads within nuts or Internally threaded con-nectors. s 8 Engineering judgement was used to establish item 2 above; that judgement is based on a comparison between engaged and unengaged regions as to the nature of the stress distributions and the magnitude of the stress concentration. Although it is recognized that the stress concentration factor would tend to be higher for load carrying threads, the loading will be shared over several threads. Results from photoelastic tests on threaded models loaded through nuts (9) Indicate that most of the load is carrled by the first three engaged threads and that the nominal stress at the first thread is approximately 80% of the total not stress. Hence the nominal stress would be approximately 20% less at the highest stress engaged thread than at an unengaged thread plane due to load sharing. Furthermore, the assumption that the stress concentration f actor (K ) for a single groove bar represents a t multiple grooved bar such as a threaded stud Is conservative. A single notch represents a higher degree of stress concentration than a series of closely spaced notches of similar geometry as the single notch. Results from photoelastic tests on multiple grooved plates reported in (10) Indicate about 25% reduction in K for multiple notches typical of a threaded f astener when t compared to the K of a single notch. These ef fects of load sharing and t K reduction could accommodate a 50% decrease in local stress along an t engaged thread plane. These findings have been judged to be suf ficient-to allow the method to also be applicable to engaged thread regions as well. For

-25 these reasons, the procedure is deemed general In oppi! cation to standard ANSI threads in both engaged and unengaged thread regions. 3.5.2 Head-to-Shank Region For headed bolts, another region of high local stress exists at the head-to-shank transition region. Although there is a potential for SCC to initiate at th's location es well, for most situations, It has been judged that the thread root region will be the limiting region from the standpoint of local stress and crack driving force. This judgement is partially based on reported experience with bolting problems (11). Bolt f ailures have been associated more with the thread-root region as compared with the head-to-shank region in common bolt uses. Specifically, 65% of bolt problems are thread-related, whereas,15% are related to the head-to-shank transition region with the remainder of the problems not associated with either the head-to-shank or thread-root regions. An analysis of a socket head bolt with 12UNF threads resulted in a higher stress Intensity factor for the head-to-shank transition region than for the thread-root G). Review of other work Involving stress determinations at the bolt head transition suggest that stress ccncentration of fact at the head may be comparable or less than that for the thread. Hence, the use of the thread-root region as the area of concern seems reasonable. Finally, sinco it is also believed that the assumptions on flaw size and material proper ties are conservative, in the final analysis, satisfying the evaluation procedure will be suf ficient to assure overall bolt Integrity even though only the thread root was examined. \\ 3.5.3 Shear Pins For components that carry pure shear load, such as shear pins in clevis-trunnion attachments, the RCP-SAS procedure was expanded to include an SCC and f racture assessment. Although the contribution of shear stress to either Mode I or Mode ll stress intensity f actors will be small as discussed

26 In (1), a conservative treatment of shear stress on K is included for shear pins in order to provide assurance against SCC and fracture for these specialized components. The stress Intensity factor for uniform shear loading in a semi-Infinite body (.12) is: K =.1.122T/na/,2 (3.j) yy where T is the uniform applied shear stress across the section and e is the elliptical integral. A reasonable approximation for e is given in (.11) as 2 4.593 (a/1)1.65 (3-2) 1 + 4 = For a 0.02 inch reference flaw depth and 1-to-4 aspect ratio, the Mode 1i stress Intensity factor is 0.232T H K = gy In the procedure, K is to be compared with K and K in i l Isec ic order to detarmine the allowable shear stresses. It is reported in (.11) that K is app oximately equal to K for LAQT steels so that the use of Mode I pro F + es is a reasonable approach. 3.6 LOADINGS It is assumed in the evaluation methodology that the predominant loading mode Is untaxial tension. The source of the untaxial stress can be preload, actively applied mechanical loads, or thermally-induced loading due to expansion. For the situation where shear loads are to be carried by the bolts, it was judged in the RCP-SAS report that for SCC and fracture, shear stresses other than torsion, will not significantly contribute to the crack driving force of the postulated reference flaw as described in (1). i Bending stresses have been neglected in the procedure, so any applications where bolts will experience cross-sectional bending loads cannot be handled 1 4 = -- - -,.,s ,-m-,-,y -w-w-r-7 ,y. m-,. ,,,,..,--,,.---,---,-,,,m. ,,.,+,_,-.-.,,.--,--r,.--,--.y .,-w,, .- - +, -,-mw.,----w.-,--

27 directly by the method in its present form. A conservative method to account for any bending f oods is to add the bending stress magnitude to tha tension stress, or + o, b o = where o is the membrane or tensile component and o is the bending a b stress. l l l l l

28 Section 4 LIMITATIONS OF DIE PRESENT E1HODOLOGY 4.1 GENERAL OVERYlEW .The primary objective of Section 3 was to outline the major asseptions of the RCP-SAS report and to provide background information. The purpose of this section is to address the important limitations of the procedures, and to discuss the assumptions that are the most restrictive to the general application of the method. Clearly, the method can be improved in many ways. The important limitations of the method can be categorized into two areas; those asseptions that resulted in the restricted application of the method due to limited data, Information, or details, and those asseptions that caused the analysis method itself to be conservative. The limitations to the general appiIcation of the procedure include: (1) The focusing of the method to bolts, studs, threaded bars, and shear pins only i (2) The quellflod restriction of the procedure to service temperatures beIow 250*F (see Section 3.4) (3) The limitation to the bolt geanetries described Sane of the more restrictive analysis asseptions include: (1) The conservative use of linear elastic analysis when local yleiding will cause lower stresses than those computed under linear condl-l. tions. (2) The definition of a reference flaw that may be much larger than that expected for bolts that have not been subjected to SCC. -+-==v- .-..m..,.m _,..,,,,,_._.m

29 (3) Defining conservative threshold curves rather than statistically based criteria for K and K Ic Iscc (4) The conservative treatment of the SCC and f racture analysis for i shear pins. Two items listed above that have the greatest impact to the general application of the method are (1) the limitation of the present method to focus only on bolting, and (2) the restriction on service temperature. The remaining subsections discuss these two topics and provids guidance and recommendations for evaluating cases that would be otherwise limited by these two restrictions. 4.2 APPLICATION FOR OTHER COMPONEWT SUPPORTS . in its most general application, the methodology must be capable of evaluating all types of component supports and threaded f asteners that are f abricated from LAQT steels and are utilized in a safety related f unction. There are essentially two categories of component supports: linear type supports in which threaded f asteners are members, and plate and shell type supports. Linear type supports are defined as those support elements that are acting essentially under a sir.gle component of direct stress or shear stress. i Besides threaded f asteners, other linear supports would include shear pins, f clevises, eye bolts and other types of clamping devices. The evaluation of shear pins has been included in the method and with slight additions or modifications, the present method can be revised to handle other types of l linear supports. It is recommended that specific procedures for other linear support elements be added on a case-by-case basis. 7 Plate and shell type component supports are supports that are f abricated f rom plata and shell elements and are normally subjected to blaxlal stress field. To evaluate these types of supports, two major complications to the method formulation would have to be resolved. First, the stress intensity factor curves would have to be revised f or the different type of geometries and i l

l 30 siress states that would be encountered. This is actually not a dif ficult probl em, in that a Code procedure already exists to do this; Appendix A of j Section XI to the ASE Code W) contains procedures to calculate K for the 1 i type of stress states that occur in plate and shell structures. One area that must be addressed is the des?gn factors and rules used to design the component supports in order to develop a consistent set of criteria for ~ acceptances to design rules. In general, they are more compIIcated thar. for linear supports and it will be dif ficult to state in simple terms the relationship that provides the allowable stress consistent with all the rulus i of the design. This does not preclude a procedure where the impact of a soit material is assessed by simply returning to the original design calculations in a review mode. Clearly, the only time a concern on the design parameters would occur is when the minimum hardness limits give a value of a or o vm um that is less than the specified minimum values: F or F respectively. y u Recent of forts have been expended to document the technical basis and background to these analytical procedures W), as well as the development of a computational tool to perform the Appendix A procedure G). i l i ..n..

31 ) i Section 5

SUMMARY

General evaluation procedures were developed around the Reactor Coolant Pump (RCP) Snubber Anchor Stud (SAS) assessment report. These procedures can be applied to other botting applications to assess material acceptance in situations where material variab!!Ity In hardness suggests a concern may exist in material resistance to SCC, fracture or tensile-ductile f ailure. The evaluation procedure may also be applied to evaluate materials that f all to meet purchase specification requirements in hardness. A calculational form for documenting and recording the evaluation results is provided. The report dedicates considerable discussion to the assumptions and limitations of the method. The major restrictions of the original method presented in the RCP-SAS report were eliminated; specifically the Il t tation .t on maximum service temperature and restricted gecznetries. Guidance is provided on how other shortcomings in the method can be overcome, and recommendations are made on methodology improvements.

32 REFERENES 1. Cipoila, R.C., R.L. CargilI and J.M. Bersin, " Assessment of Stud Inte-grity for the Reactor Coolant Punp Snubber Anchor Bolting *, AFTEGI Report No. AES-81-08-79 (May 1982). -2. ASTM Annual Standards, Part 4, A370, " Mechanical Testing of Steel Pro-ducts" (1979). 3. Hayes, D.J. and R.C. Cipol f a, " Proposed Screening Procedure For Review of Low Alloy Quenched and Tempered Steel in Midland Plant Units 1 and 2,* APTEm Report No. AES-81-05-68 (October 1981). 4. ASE Boller and Pressure Vessel Code, Section lit, " Rules for Construc-tion of Nuclear Power Plant Components, Division 1 - Appendices," 1977 Edition. 5. ASM Metals Handbook, Volume 1, Pronertf as And Selection:.ir.QD And Staal m, 9th Edition (1979). 6. American National Standards,' Unified Inch Screw Threads (UN and UNR Thread Form)," ANSI B1.1-1974, American Society of Mechanical Engineers (1974). 7. Ci pol l a, R. C., et al., "Rev i ew of Req u i reme nts and G ui de l i ne s f or Evaluation of Cornponent Supports and Bolting Under Unresolved Safety Issue A-12," EPRI RP 1757-2, APTEm Draf t Final Report AES-8008203 (September 1982). 8. Cipolla, R.C. and W.P. McNaughton, " Calculation of Stress Intensity Factor for Elliptically-Shaped Cracks in Bolts," AFTEm Report AES FR8202313 (Rev. 1) (July 1983). 9. Chalupnik, J.D., " Stress Concentrations in Bolt-Thread Roots," runartmantal Machanics, SESA, p. 398-404 (September 1968). 10. Peterson, R.E., streme Conenntration Fac+ ors, J. Wiley & Sons (1974). 11. Bickford, J.H., An Introdue+f on to fha Damien and Bahav for d Bof +ad Joln+m, Marcel Dekker Inc. (1981). 12.

Tada, H., P.C. Paris, and G.R. Irwin,.The Stream Analvsts d Cracks Handbook (June 1973).

13. Marston, T.U. (ed.), " Flaw Evaluation Procedures - Background and Appil-cation of ASE Section, XI Appendix A," EPRI Special Report NP-719-SR (August 1976). (N (/k. ii l 0

33 14. Snalder, R.P., J.M. Hodge, H. A. Levin, and J.J. Zudens, " Potential for Low Fracture Toughness and Lamellar Tearing on PWR Steam Generator and Reactor Coolant Pep Supports - Resolution of Generic Technical Activity A-12, NUREG-0577 (for comment) (October 1979). i 15. ASE Boller and Pressure Vessel Code, Section XI, " Rules for the Inser-vice Inspection of Nuclear Power Plant Components - Division 1," Appendix A,1977 Edition. 16. Cipolla, R.C., " Computational Method to Perform the Flaw Evaluation Procedure as Speelfled in the ASE Code, Section XI, Appendix A - Part 1: General Description and Background, EPRI RP 700-1 Key Phase Report NP-1181 (September 1979). O l

34 Appendix 1 BOLTING EVALUATION FORM A calculational form has been developed to assist in completing the evaluation procedures. The form is provided for guidance and modifications or improvements to the form to suit Individual organizations are encouraged. All important input data are recorded on the form, as well as the results of the analysis. Space is provided on each form for the stratum number, originator of the calculations, the verifier, and general remarks. The remainder of the form follows the procedural outline given in Section 2. It is recommended that the form be used while following the Individual steps of the procedure. One form should be prepared for each stratum where at least the bolt diameter, thread pitch and support category are the same for alI bolts. Substratum categories may be required to assure commmon input parameters for the evaluation. .I k ,-.~,, ,__..r_,

LAGT$ EVALUATION FCfg4 CCNTINUED 36 1 ORIGINATCWt STTtATW 10. DATE VERIFIER I DATE CONTIPAJED ) 4. ESTIMATICN4 OF MATERI AL TOUCD4 NESS PROPERTIES (PART 2 A. M940LD STTtESS INTENSITY FACTOR, K (USE FIGURE 3 AfC b FROM 2C) MX S. FRACTURE TOUGetESS. K-(USE FIGURE 4 APC FRCN 2C) a 5. ST7tESS I NTTNS I TY F ACTOR. K (PART 3) A. THREADED FASTENERS (TENSION) Kg = ( FROM APPEt@IX l I I ) 3. SEAR PINS (SHEAR ONLY) k" 0.232 gg 6. ALLOWABLE STRESSES FOR SCC AND FRACTURE (PARTS 4 AFC 5 ) A. ALLOWAB!.E STRESS (SCC) (1/K )K' = X e O A I ISCC (t/KIl)K' SCC = 4.38 X = T I A scc, sec pscc, gscc,S A

X

= yy A A A A f 3. ALLOWABLE STRESS (FRACTURE) I (1/KE) K' X = O

EC l

A ~ 8 4.38 X (l/kIl) K T

IC A

i P n O A CR V =7 A 8 X a 7. REMARKS l l l l APTECH ENGINEERING SERVICES, INC. )

9 35 LAQTS EVALUATION FORM S17tATW PC. ORIGINATM DATE VERIFIER DATE 3. GENQ AL INFORMATIQN A. MATUt I AL 3. CC54PorErff TYPE BOLT STUD SN AR PIN OTER C. DIAETER, D D. TMtEADS/ INCH, N E. TENSILE AREA, Ag F. NOMINAL AREA, A 1. HARDPESS LIMITS (PART I) A. SPECIFICATION (APP II) 5. TW-SIDED (90-95%) C. OPE SIDED (90-95%) h = MIN h = max D. TWO. SIDED LIMITS FALL WITNIN SPECIFICATION 7 YES NO (lF YES, EVALUATlCN IS COMPLETE) 3. ESTIMATION OF MATERI AL STREPGTH PROPERTIES [PART 21 ~ A. SPECIFIED MINIMLN YIELD STRENGTH, F y -s. S.v CIFIED MINIMUM TENSILE STRENG1N, F g C. ESTIMATE YlELD STRENGTH, C (USE FIGURE 2 APO hlN F ) D. ESTIMATE TENSILE STRENGTH, O MIN (USE ASTM A370 TABLE 3A APO IN FROM 3C) E. MINIMUM YlELD STRENGTH, O Y (LOWER OF 3A AND 3C) F. MINIMUM TENSILE STRENGTH, 0, (LOWER OF 33 AND 3D) APTECH ENGINEERING SERVICES, INC.

37 Appendix ll RECX) MENDED HARDNESS LIMITS FOR SATISFYING ASTM /ASE SPECIFICATIONS 11-1

SUMMARY

Hardness limits were established for candidate LAQT materials supplied to the Midland Site. These Ilmits are provided in Table 11-1 and give the ulnimum end maximum hardnesses In Rockwell-scale and Leeb-scale units. The technical basis for the limits Is doctsnented in (.LL.L through.LL-1). Specifically, the limits were established under the following conditions: (1) When a nerdness limit (either minimura or maximum) is given as a requirement in the material specifications, then this limit is given in Table 11-1. If the hardness limit is given in units other than those listed in Table 11-1, then the hardness limit was converted to equivalent Rockwell-scale units according to ASTM A370 (.LL-1). (2) When a hardness limit (either minimum or maximum) is not specified, then engineering judgement was used to establish a ilmit based upon consideration of specified material yleid strength, tensile strength, and product thickness. The limits that were established by engineering judgement are identif!sd in Table 11-1 by an asterisk (*). 1 ,,-.n

38 Il-2 REFERENES 11-1 Letter to J. A. Pastor (CPCo) from R.C. Cipolla (APTE01) entitled, " Hardness Limits for Receipt inspection Program," (January 14, 1982). 11-2 Letter to J.A. Pastor (CPCo) from R.C. Cipolla (APTEdi) entitled, " Revised Hardness Limits for CPCo Receipt inspection Program," (September 17, 1982). 11-3 Letter to J.A. Postor (CPCo) from R.C. Cipolla (APTECH) entitled, " Response to Questions on LAQT Determinations and Hardness Limits," (October 28, 1982). Il-4 ASTM Annual Standards, Part 4, A370, " Mechanical Testing of Steel Products," (1979). l l

l Table 11-1 REC 0t99ENDATIONS ON HARDNESS LIMITS FOR LAQT Materials III HARDNESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS THICKNESS MIN. MAX. MIN. MAX. A7-66 (see Note 1) A36-77a (see Note 1) A125-73 (see N6te 2) 38HRC* 50HRC 634L* 731L SA155-75 CMSH-80 (3) 21" thick 86HRB* 22HRC* 434L* 514L* w (s4HRC) = Over 2)" to 4" 83HRB* 22HRC* 421L* 514L* (41HRC) A182-78/SA182-78 F1 78HRB 91HRB 400L 462L (%10HRC) F2 78HRB 91HRB 400L 462L 1 ) (%10HRC) i Fil 78HRB 94HRB 400L 479L (%14HRC) F12 7811RB 94HRB 400L 479L (%14HRC) i F21 82llRB 94HRB 418L 479L (s14HRC) l l l

(TABLE 11 Continued) III HARDNESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS THICKNESS MIN.

MAX, MIN.

MAX. = i 1 A182-78/SA182-78 F22 82HRB 94HRB 418L 479L (Continued) (s14HRC) i F22a 69HRB* 86HRB 372L* 435L (s4HRC) A193-78a/ SA193/78a B7 (21" Dia. 26HRC* 36HRC* 544L* 618t* Over 21" to 4" 22HRC* 33HRC* 514L* 596L* Over 4" to 7" 95HRB* 28HRC* 485L* 558L* (s16HRC) B7M (21" Dia. 94HRB 22HRC 473L 514L j (s14HRC) B16 (21" Dia. 26HRC* 36HRC* 544L* 618L* Over 21" to 4" 20HRC* 31HRC* 500L* 581L* Over 4" to 7" 95HRB* 28HRC* 485L* 558L* (s16HRC) 1 A194-80a/ SA194-80a 4 All 24HRC 38HRC 529L 634L 7 All 24HRC 38HRC 529L 634L 7M All 83HRB 22HRC 421L 514L l (s1HRC) l A234-80/ SA234-78 WP1 All 65HRB* 92HRB 361L* 468L 4. (s12HRC) WP12 All 69HRB* 92HRB 372L* 468L (s12HRC) WP11 All 69HRB* 92HRB 372L* 468L (s12HRC)

(TABLE 11 Continued) III HARDNESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS THICKNESS MIN. MAX. MIN. MAX. A234-80/ WP22 All 69HRB* 92HRB 372L* 468L SA234-78 (s12HRC) I (continued) WPR All 72HRB* %HRB 382L* 490L (s17HRC) l A304-79 (see Note 4) i A320-80b/(5) L1 <1" Dia. 26HRC* 36HRC* 544L* 618L* SA320-78 L7, L7A, L7B, L7C 521" Dia. 26HRC* 36HRC* 544L* 618L* L7M <21"Dia. 94HRB 22HRC 473L 514L I (s14HRC) L43 c4" Dia. 26HRC* 37HRC* 544L* 626L* ~ j A322-80 (see Note 4) I A325-78a/ SA325-78a 2, 3 1" to 1" Dia. 24HRC 35HRC 529L 611L j (see Note 6) 1 1/8" to 11" Dia. 19HRC 31HRC 497L 581! l A331-74 (see Note 4) A333-79 8 95HRB* 28HRC* 485L* 558t* (s16HRC) A354-78a/ j SA354-78a BC 1" to 21" Dia. 26HRC 36HRC 544L 618L l Over 21" Dia. 22HRC 33HRC 514L 596L BD '4 " to 2'3" Dia. 33HRC 38HRC 596L 634L Over 2'3" Dia. 31HRC 38HRC 581L 634L

I7) (TABLE 11 C ntinued) HARDNESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS THICKNESS MIN. MAX. MIN. MAX. SA420-78 WPL3 Plate 74HRB* 95HRB* 389L* 490L* (54 inches) (-17HRC) Forgings 79HRB* 25HRC* 405L* 536L* (All sizes) WPL9 Forgings 72HRB* 22HRB* 382L* 514L* (All sizes) A434-76 BB 11" Dia. and less 20HRC* 31HRC* 500L* 581L* 4 Over 11" to 21" 97HRB* 28HRC* 496L* 558L* (%19HRC) Over 21" to 4" 95HRB* 28HRC* 485L* 558L* (%16HRC) Over 4" to 7" 93HRB* 25HRC* 471L* 536L* O (%13HRC) Over 7" to 91" 91HRB* 22HRC* 460L* 514L* (%10HRC) BC 11" Dia. and less 28HRC* 38HRC* 558L* 634L* 4 Over 11" to 21" 26HRC* 36HRC* 544L= 518L* Over 21" to 4" 22HRC* 33HRC* 514L* 596L* Over 4" to 7" 20HRC* 32HRC* 500L* 588t* Over 7" to 91" 97HRB* 30HRC* 496L* 573t* (s19HRC) BD 11" Dia. and less 34HRC* 40HRC* 603L* 649t* Over 11" to 21" 33HRC* 38HRC* 596L* 634L* Over 21" to 4" 31HRC* 38HRC* 581L* 634L* Over 4" to 7" 29HR(,* 38HRC* 566L* 634L*

(TABLE 11 Continued) HARDNEb 1.lMITS(7) ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS THICKNESS MIN. MAX. MIN. HAX. l A434-76 (Continued) BD Over 7" to 94" 28HRC* 37HRC* 558L* 626L* A487-80 1Q.2Q 91HRB* 22HRC* 460L* 514L* (%10HRC) 97HRB* 34HRC* 496l* 603L* 40,110,120,130 i (%19HRC) 1 40A 22HRC* 33HRC* 514L* 5%L* 24HRC* 34HRC* 529L* 603L 6Q 7Q 21" thick 22HRC* 33HRC* 514L* 596L* 8Q,9Q 95HRB* 29HRC* 485t* 566L* (%16HRC) l 10Q 25HRC* 34HRC* 536L* 603L* 24HRC* 38HRC* 529t* 634L* 14Q A490-80a All Grades I" to 1)" Dia. 33HRC 38HRC 596L 634L A514-77 All Grades to 3/4" thick 22HRC 31HRC 514L 581L over 3/4" to 21" 22HRC* 32HRC* 514L* 588L* over 21" to 6" 95HRB* 33HRC* 485L* 596L* (%16HRC) A519-80 (see Note 4) A521-76 CG 44" Solid Dia. or Thick 90HRB* 22HRC 456t* 514L* or (2" Bored Wall Thick (%10HRC) >4" to 7" (Solid) 88HRB* 96HRB* 440L* 490L* or >2" to 3)" (Bored) (%7HRC) (%17HRC) >7" to 10" (Solid) 88HRB* 96HRB* 440L* ~490L* or >3)" to 5" (Bored) (%7HRC) (%17HRC)

O (TABLE II Continued) III HARDNESS LIMITS ~ ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION __0R CLASS _ THICKNESS MIN. MAX. MIN. MAX. A521-76 CG >5" to 10" (Bored) 88HRB* 96HRB* 440L* 490L* (Contd.) (%7HRC) (%17HRC) AD s7" Solid Dia. or Thick 92HRB* 25HRC* 468L* 536L* or (31" Bored Wall Thick (%12HRC) >7" to 10" (Solid) 90HRB* 22HRC* 456L* 514L* or >31" to 10" (Wall) (%10HRC) AE 47" Solid Dia. or Thick 95HRB* 29HRC* 485L* 566L* or (31" Bored Wall Thick (%16HRC) >7" to 10" (Solid) 94HRB* 29HRC* 479L* 566t* or >3)" to 5" (Bored) (%14HRC) g >10" to 20" (Solid) 92HRB* 25HRC* 468L* 536L* or >5" to 8" (Bored) (%12HRC) AF s4" Solid Dia. or Thick 25HRC* 34HRC* 536L* 603L* or 52" Bored Wall Thick >4" to 7" (Solid) 22HRC* 32HRC* 514L* 588L* or >2" to 31" (Bored) >7" to 10" (Solid) 97HRB* 31HRC* 497L* 581L* or >31" to 5" (Bored) (%19HRC) AG <4" Solid Dia. or Thick 31HRC* 38HRC* 581L* 634L* or 52" Bored Wall Thick >4" to 7" (Solid) 30HRC* 37HRC* 573L* 626t* or >2" to 31" (Bored) >7" to 10" (Solid) 28HRC* 36HRC* 558L* 618L* or >31" to 5" (Bored) l

(TABLE 11 Continued) III ~ HARDNESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS THICKNESS MIN. MAX. MIN. MAX. A521-76 AH 44" Solid Dia. or Thick 36HRC* 43HRC* 618L* 673L* (Contd.) or (2" Bored Wall Thick- 'I >4" to 7" (Solid) 36HRC* 43HRC* 61Bl* 673L6 or >2" to 3)" (Bored) >7" to 10" (Solid) 34HRC* 42HRC* 603L* 665L* l or >3)" to 5" (Bored SA537-78 2 421" thick 86HRB* 22HRC* 434L* 514L* (s4HRC) over 21" to 4" 83HRB* 22HRC* 421L* 514L* (slHRC) A540-77a/ OI SAS40-77a B21, CL5 <2)" thick 23HRC 30HRC 522L 573L over 2" to 6" 24HRC 32HRC 529L 588L over 6" to 8" 25HRC 33HRC 536L 596L 821, CL4 <3" thick 28HRC 36HRC 558L 618L over 3" to 6" 29HRC 38HRC 5571 634L B21, Cl3 c3" thick 31HRC 38HRC 581L 634L over 3" to 6" 32HRC 40HRC 588L 649L B21, CL2 54" thick 33HRC 43HRC 596L 673L I B21, CLI c4" thick 34HRC 46HRC 603L 698L B22, CL5 (2" thick 24HRC 31HRC 529L 581L

(TABLE 11 Centinued) III HARONESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS _ THICKNESS MIN. MAX. MIN. MAX. A540-77a/SA540-77a B22, CLS Over 2" to.4" 25HRC 32HRC 536L 588L (continued) B22, Cl4 <1" thick 28HRC 37HRC 558L 626L Over 1" to 4" 29HRC 39HRC 566L 642L. B22, Cl3 (2" thick 31HRC 39HRC 581L 642L Over 2" to 4" 32HRC 40HRC 588L 649L B22,Cl2 43" thick 33HRC 43HRC 596L 673L B22,CL1 41)" thick 34HRC 43HRC 603L 673L B23,CL5 (6" thick 24HRC 33HRC 529L 596L Over 6" to 8" 25HRC 34HRC 536L 603L Over 8" to 9)" 27HRC 34HRC 551L 603L B23, Cl4 (3" thick 28HRC 37HRC 558L 626L Over 3" to 6" 29HRC 38HRC 566L 634L Over 6" to 9)" 30HRC 39HRC 573L 642L

B23, Cl3 43" thick 31HRC 39HRC 581L 642L Over 3" to 6" 32HRC 40HRC 588L 649L Over 6" to 91" 33HRC 42HRC 596L 665L B23, CL2 (3" thick 33HRC 42HRC 596L 665L Over 3" to 6" 33HRC 43HRC 596L 673L Over 6" to 9!"

34HRC 45HRC 603L 689L i

(TABLE 11-1 -- Csntinued) I7) HARDNESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS' TH!CKHESS MIN. MAX. MIN. MAX. AS40-77a/SAS40-77a 823; CL1 43" thick 34HRC 45HRC 603L 689L (continued) Over 3" to 6" 36HRC 46HRC 618L 698L Over 6" to 8" 37HRC 47HRC 626L 707L 4 " thick 24HRC 33HRC 529L 596L 6 824, CL5 Over 6" to 8" 25HRC 34HRC 536L 603L Over 8" to 9)" 27HRC 34HRC 551L 603L B24, Cl4 43" thick 28HRC 37HRC 558L 626L Over 3" to 6" 29HRC 38HRC 5661. 634L i Over 6" to 8" 30HRC 39HRC 573L 642L 0 B24, CL3 43" thick 31HRC 39HRC 581L 642L Over 3" to 8" 32HRC 42HRC 588L 665L Over 8" to 91" 33HRC 42HRC 596L 665L B24, Cl2 47" thick 33HRC 43HRC 596 673L 1 Over 7" to 91" 34HRC 45HRC 603L 689L B24, CL1 (6" thick 34HRC 45HRC 603L 689L Over 6" to 8" 36HRC 46HRC 618L 698L 4 " thick 31HRC 39HRC 581L 642L 4 B24V, Cl3 Over 4" to 8" 32HRC 40HRC 588L 649L Over 8" to 11" 33HRC 42HRC 596L 665L l

III HARONESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEEB-SCALE (L) SPECIFICATION OR CLASS THICKNESS MIN. MAX. MIN. MAX. A540-77a/SA540-77a B24V. CL2 44" thick 33HRC 42HRC 596L 665L (continued) 0.ger 4" to 8" 33HRC 43HRC 5%L. 673L, 4 Over 8" to 11" 34HRC 45HRC 603L 689L B24V, CLI (4" thick 34HRC 45HRC 603L 689L Over 4" to 8" 36HRC 46HRC 618L 698L Over 8" to 11" 36HRC A7HRC 618L 707L 4)" Dia. 39HRC 45HRC 642L 689L A574-80 (5/8" Dia. 37HRC 45HRC 626L 689L ao A563-78a DH3 1" to 4" size 24HRC 38HRC 529L 634L C3 1" to 4" size 78HRB 38HRC 400L 634L A668-79a F, FH <4" thick 90HRB 22HRC 456L 514L (%10HRC) Over 4" to 7" 88HRB 96HRB 440L 490L (%7HRC) (%17HRC) Over 7" to 10" 88HRB 96HRB 440L 490L (%7HRC) (%17HRC) Over 10" to 20" 88HRB 96HRB 440L 490L (%7HRC) (%17HRC) J, JH c7" thick 92HRB 25HRC 468L 536L (%12HRC) Over 7" to 10" 90HRB 22HRC 456L 514L (%10HRC) K. KH 47" thick 95HRB 28HRC 485L 558L (%I6HRC)

i. .(TABLE 11 Continued) I HARDMESS LIMITS ASTM /ASME GRADE AND/ DIAMETER OR ROCKWELL-SCALE LEE 8-SCALE (L) SPECIFICATION ,0R, CLASS THICKNESS MIN. MAX. MIN. MAX. A668-79a K, KH Over 7" to 10" ?4HR8 28HRC 479L 558L (Contd.) (%14HRC) L, LH 44" thick 25HRC 34HRC 536L 603L Over 4" to 7" 22HRC 32HRC 514L 588L

4 Over 7" to 10"

. 97HR8 31HRC 497L 581L (s19HRC) M, MH 44" thick 31HRC 38HRC 581L 634L Over 4" to 7" 30HRC 37HRC 573L 626L i Over 7" to 10" 28HRC 36HRC 558L 618L N, NH (4" thick 36HRC 43HRC 618L 673L i g I Over 4" to 7" 36HRC 43HRC 618L 673L Over 7" to 10" 34HRC 42HRC 603L 665L 26HRC* 34HRC* 543L* 603L* A687-79 All Grades A739-76 79HRB* 25HRC* 405L* 536L* 5A739-76 B11 l 822 82HR8* 25HRC* 417L* 536L* 23HRC 34HRC 522L 603L F568-79 8.8 23HRC 34HRC 522L 603L i 8.8.3 9.8 27HRC 36HRC 551L 618L 33HRC 39HRC 5%L 642L 10.9 3 10.9.3 33HRC 39HRC 596L 642L t l 12.9 38HRC 44HRC 634L 6R71

(TABLE 11 Continued) NOTES 8 Bolts or nuts when included with material purchases can be supplied to A325. 2The specified or indicated minimum hardness must be sufficient to develop the required strength to withstand the solid stresses of the spring design. 'Same material grade as A537 Class 2. " Maximum surface Brinell hardness, if specified by purchaser as a supplementary requirement, shall be agreed upon between the manufacturer and the purchaser. Mechanical strengths are not specified. sSA320-78 is identical to A320-76 except for the deletion of Grade L1.

Bolts shall not exceed maximum hardness specified. Bolts less than three diameters in length shall have a hard-ness value not less than the minimum nor more than the maximum in hardness limits, as hardness is the only l

requirement. ' Hardness values supp1,ied are in HRC and L-scale numbers unless otherwise noted. Mechanical strengths are not specified.

These limits are not ASTM or ASME specified limits but based upon a review of yield and tensile strength require-ments and a comparison with other ASTM materials with specified hardness requirements.

51 Appendix ill TABULATION OF STRESS INTENSITY FACTORS (K ) I

52 Table III-I BASIC DIMENSIONS AND KI FOR EXTERNAL FOUR-THREAD SERIES (4-UN/4-UNR) Primary. Basic Major Minor Tensile Stress Stress Intensity Size Diameter, D Diameter, d Area, Aj Factor K (Inches) (Inches) (Inches) (Inchest) (InchesI/ 2-1/2 2.5000 2.1933 4.00 0.5701 2-3/4 2.7500 2.4433 4.93 0.5817 3 3.0000 2.6931 5.97 0.5903 3-1/4 3.2500 2.9433 7.10 0.6002 3-1/2 3.5000 3.1933 8.33 0.6076 3-3/4 3.7500 3.4433 9.66 0.6142 4 4.0000 3.6933 11.08 0.6200 4-1/4 4.2500 3.9433 12.61 0.6252 4-1/2 4.5000 4.1933 14.23 0.6299 4-3/4 4.7500 4.4433 15.90 0.6341 5 5.0000 4.6933 17.80 0.6379 5-1/4 5.2500 4.9433 19.70 0.6414 5-1/2 5.5000 5.1933 21.70 0.6446 5-3/4 5.7500 5.4433 23.80 0.6475 6 6.000 5.6933 26.00 0.6502 l t

7 53 Table III-2 BASIC DIMENSIONS AND E] FOR EXTERNAL SIX-THREA0 SERIES (6-UN/6-UNR) Primary Basic Major Minor Tensile Stress Stress Intensity Size Diameter, D Diameter, d Area, A Factor (Inches) (Inches) (Inches) (Inchesh (InchesIg) 1-3/8 1.3750 1.1705 1.155 0.4895 1-1/2 1.5000 1.2955 1.405 0.5003 1-5/8 1.6250 1.4205 1.680 0.5098 1-3/4 1.7500 1.5455 1.980 0.5181 1-7/8 1.8750 1.6705 2.300 0.5254 2 2.0000 1.7955 2.650 0.5319 2-1/4 2.2500 2.0455 3.420 0.5431 2-1/2 2.5000 2.2955 4.290 0.5522 2-3/4 2.7500 2.5455 5.260 0.5598 3 3.0000 2.7955 6.330 0.5663 3-1/4 3.2500 3.0455 7.490 0.5718 3-1/2 3.5000 3.2955 8.750 0.5766 3-3/4 3.7500 3.5455 10.110 0.5808 4 4.0000 3.7955 11.570 0.5845 4-1/4 4.2500 4.0455 13.120 0.5878 4-1/2 4.5000 4.2955 14.780 0.5907 4-3/4 4.7500 4.5455 16.500 0.5934 5 5.0000 4.7955 18.400 0.5958 l 5-1/4 5.2500 5.0455 20.300 0.5979 5-1/2 5.5000 5.2955 22.400 0.5999 5-3/4 5.7500 5.5455 24.500 0.6017' 6 6.0000 5.7955 26.800 0.6034

1 54 Table III-3 BASIC DIMENSIONS AND E" FOR EXTERNAL EIGHT-THREADSERIES[8-UN/8-UNR) Primary Basic Major Minor Tensile Stress Stress Intensity Size Diameter, D Diameter, d Area. As Factor K' (Inches) (Inches) (Inches) (Inches 2) (Inchesl/2b 1 1.0000 0.8466 0.606 0.4253 1-1/8 1.1250 0.9716 0.790 0.4405 1-1/4 1.2500 1.0966 1.000 0.4504 1-3/8 1.3750 1.2216 1.233 0.4603 1-1/2 1.5000 1.3466 1.492 0.4691 1-5/8 1.6250 1.4716 1.780 0.4741 1-3/4 1.7500 1.5966 2.080 0.4775 1-7/8 1.8750 1.7216 2.410 0.4830 2 2.0000 1.8466 2.770 0.4879 2-1/4 2.2500 2.0966 3.560 0.4941 2-1/2 2.5000 2.3456 4.440 0.5004 2-3/4 2.7500 2.5966 5.430 0.5075 3 3.0000 2.8466 6.510 0.5129 3-1/4 3.2500 3.0966 7.690 0.5190 3-1/2 3.5000 3.3466 8.960 0.5254 3-3/4 3.7500 3.5966 10.340 0.5280 4 4.0000 3.8466 11.810 0.5317 4-1/4 4.2500 4.0966 13.380 0.5345 4-1/2 4.5000 4.3466 15.100 0.5379 4-3/4 4.7500 4.5966 16.800 0.5400 5 5.0000 4.8466 18.700 0.5417 5-1/4 5.2500 5.0966 20.700 0.5445 5-1/2 5.5000 5.3466 22.700 0.5466 5-3/4 5.7500 5.5966 24.900 0.5485 6 6.0000 5.8466 27.100 0.5504 )

55 Table III-4 BASIC DIMENSIONS AND R FOR EXTERNAL _1 12-THREAD SERIES (12-UN/12-UNR) Primary Basic Major Minor Tensile Stress Stress Inte0sity Size Diameter, D Diameter, d Area, A Factor' K (Inches) (Inches) (Inches) (Inchesdh (Inchesl/ ) 7/8 0.8750 0.7728 0.495 0.4148 1 1.0000 0.8978 0.663 0.4258 1-1/8 1.1250 1.0228 0.856 0.4346 g 1-1/4 1.2500 1.1478 1.073 0.4419 1-3/8 1.3750 1.2728 1.315 0.4479 1-1/2 1.5000 1.3978 1.580 0.4531 1-5/8 1.6250 1.5223 1.870 0.4574 1-3/4 1.7500 1.6478 2.190 0.4613 1-7/8 1.8750 1.7728 2.530 0.4646 2 2.0000 1.8978 2.890 0.4675 2-1/4 2.2500 2.1478 3.690 0.4725 2-1/2 2.5000 2.3978 4.600 0.4765 2-3/4 2.7500 2.6478 5.590 0.4798 3 3.0000 2.8978 6.690 0.4826 3-1/4 3.2500 3.1478 7.890 0.4849 3-1/2 3.5000 3.3978 9.180 0.4870 '3-3/4 3.7500 3.6478 10.570 0.4887 4 4.0000 3.8978 12.060 0.4533 4-1/4 4.2500 4.1478 13.650 0.4916 4-1/2 4.5000 4.3978 15.300 0.4929 4-3/4 4.7500 4.6478 17.100 0.4940 'S 5.0000 4.8978 19.000 0.4949 5-1/4 5.2500 5.1478 21.000 0.4959 5-1/2 5.5000 5.3978 23.100 0.4967 5-3/4 5.7500 5.6478 25.200 0.4974 6 6.0000 5.8978 27.500 0.49G1

Sizes less than 7/8 inch are not listed.

Table III-5 BASIC DIMENSIONS AND RI FOR EXTERNAL C0 ARSE THREADS (UNC/UNRC) WITH 4-1/2, 5, 7, AND 9 THREADS PER INCH Threads Basic Major Minor Tensile Stress Stress Intensity I Size Per Diameter. D Diameter, d Area, A Factor,RJ (Inches) Inch (Inches) (Inches) (Inches (Inchesl/2) l I 7/8 9 0.8750 0.7387 0.419 0.4272 1-1/8 7 1.1250 0.9497 0.693 0.4612 l 1-1/4 7 1.2500 1.0747 0.890 0.4740 l j 1-3/4 5 1.7500 1.5046 1.740 0.5219 2 4-1/2 2.0000 1.7274 2.500 0.5405 2-1/4 4-1/2 2.2500 1.9774 3.250 0.5553

57 Appendix IV EFFECT OF TEMPERATURE ON THE THRESHOLD STRESS CORROSION CRACKING.5%ESS INTENSITY VALUES OF LOW ALLOY QUENCHED AND TEMPERED STEELS IV-1 INTRODUCTION The potential deleterious ef fect of temprature on SCC susceptibility has been observed in high strength materials In the form of Increased cracking velocities. For AISI 4320 and H11 steel crack growth rates in aqueous solutions increase sharply with. temperature (.lY:1,.LY:2). Similar of facts have been observed in enviroments saturated with water vapor, but in the absence of complete saturation, crack velocity has been observed to decrease with Increasing temperature (.11:2). More relevant are the observations in the data derived f rom tests of procracked specimens that show that the threshold stress Intensity factor is insensitive to temperature in high strength stools. It is reported In IV-2 that K Is remarkably constant. In aqueous solutions containing 150 and 3000 ppm of H S, K has been known to increase with temperature, i 2 Isce approximately doubling the val m of K of a 132 ksi yleid strength steel. i Iscc Such trends suggest that the loan temperature behavior for the test data can be used as a conservative estimate for behavior under elevated temperature conditions. A possible upper limit for the K could be established at Isce the point where the aqueous solution enviroment would be losi, that is a temperature In excess of 200'F. The purpose of this appendix is to confirm the trends for K reporfed in Isec the above mentioned review papers. The original cited references were obtained and reviewed and a samary of the review is presented next. 1 j

58 l i IV-2 H S ENV1RONENT 2 in 1952, Fraser and Treseder (IV-3) found an " increasing tendency to cracking" with a decrease in temperature from experiments on unnotched high strength steels strained In 3 point bending and placed in 0.5% Qt 000H/H S 3 2 (ocetic acid and hydrogen sutilde) solutions. Thlt temperature ef fect was substantiated by Warren and Beclean (.ly-4) in their study of sulfide corrosion cracking of high strength botting material. In 1971, Townsend (ly-1) observed that the time to f ailure of free corroding, bent, high strength carbon steel wires immersed in H S solutions was a minimin at room temperature - increasing f allure periods being observed both above and below roan temperature. If stress corrosion crack growth rates are measured as a function of opening modo stress Intensity factor values, then three distinct cracking velocity regimes (da/dt) may be observed. Region I crack growth is the first stage of growth where the applied K level Is low and where there is a significant stress dependence on crack velocity. Region ll follows Region I where there is a change In slope on de/dt so that the crack growth is nearly independent of stress. Finally, Region lli represents a final slope change In da/dt versus K where the slope rapidly increases. At a very slow crack growth rate, an apparent threshold value of stress Intensity is reached, below which crack growth rates become luneasurably small. The value of stress Intensity where this occurs is ref erred to as the critical stress corrosion cracking threshold stress Intensity value, K In the experiments mentioned previously, it is not clear whether the of facts observed were actually depicting changes in versus temperature, or changes In the combined crack growth rates KIscc experienced in Regions I, il and Ill. However, In a study of H S stress 2 corrosion cracking of steels by Dvoracek (IV-6), measured values of K iscc were observed to increase with increasing temperature. IV-3 WATER AND OTHER ENVIRONENTS in 1965, Johnson and Wilner (IV-7) measured threshold stress Intensity values on H11 steel in water at various temperatures and found the threshold stress /

59 to be constant over a temperature range from 30'F to Intensity value, K These resubs a,re shown in Figure IV-1. 150*F. More recently,- In a study by Nelson and Willions (11-B) with 4130 steel, it was shown that K was Indeed Invariant throughout the temperature range of 33'F to 190*F when placed in a distilled H 0 environment. These test 2 data are shown in Figure IV-2. During this study, measurements of K in Isce molecular hydrogen enviroments as a function of temperature were also made. The results are shown In Figure IV-3 for 4130 steel with two dif ferent yield strengths. These data also depict an increase In threshold stress Intensity values with increases in temperature. Furthermore, the reversibility of this temperature offact was shown In an experiment in which lowering the temperature of a specimen which was previously experiencing slow crack growth -7 (1 x 10 m/sec), resulted in an Immediate Increase in crack growth rate. 1 IV-4

SUMMARY

OF FINDINGS The data relevant to the determination of K are plotted in Figure IV-4. Based on the data obtained during this review, the following conclusions are established: (1) K of high strength steels in distilled water is invariant with Isce temperature over the temperature range of 30'F to 190'F. (2) K of high strength steels In molecular hydrogen increases with Iscc Increased temperatures over the temperature range of -45'F to 260'F. (3) K of HSLA steel in H S enviroments increases with Isec 2 I increased temperatures within the temperature range 75'F to 300*F. l (4) Based on these findings, the of fact of temperature on Kisec derived from roan temperature tests seems not Important for structural /

60 bolt applications where aqueous envirorments are Involved. This obser-vation seems valid up to temperatures of 190*F and possibly higher. IV-5 REFERENCES s IV-1 Fujita, T. and Y. Yamada, " Physical Metallurgy and SCC in High Strength Steels," Firmlny Conf erence, NACE-5 (1973). IV-2 Carter, C.S. end M.V. Hyatt, " Review of Stress Corrosion Cracking in Low Alloy Steels with Yleid Strengths Below 150 ksi," Firminy Con-forence, NAE-5 (1973). IV-3 Frayer, J.T. and R.S. Treseder, " Cracking of High Strength Steels In Hydrogen Sulfide Solution," Corrosion, Volume 8, p. 342 (1952). IV-4 Warren, D. and G.W. Beckman, " Sulfide Corrosion Cracking of High Strength Bolting Material," Corrosion, Volume 13, p. 631t (1957). IV-5 Townsend, H.E., " Hydrogen Sulfide Stress Corrosion Cracking of High Strength Steel Wire," Corrosion, Volume 28, p. 39 (1972). IV-6 Dvoracek, L.M., " Sulfide Stress Corrosion Cracking of Steels," Corrosion, Vol ume 26, p.177 (1970). IV-7 Johnson, H.H. and A.M. Wilner, " Moisture and Stable Crack Growth in a High Strength Steel," Appl. Matl. Res., Vol ume 4, p. 33 (1965). IV-8 Nelson, H.G. and D.P. Williams, " Quantitative Observations of Hydrogen-induced Slow Crack Growth in a Low Alloy Steel," Firminy Conf erence, NACE-5 (1973). /

i 61 g 50-G.e a1, t 3,0 h9 = 3 = 0 40 60 40 20 12 0 14 0 wee,i. w e,. - m: a Prco.cteo Figure IV Influence of Water Temperature Upon Threshold Stress, Intensity Values (After Johnson and Willner, Reference (IV-7)). 10*3 oI o 12 o 24 o 39 a 53 h 62 10** - o 72 j so-s D. o* 8 o SiG f lo"* p o l l 1o-7 io-. i i__2__ O 10 20 30 to SO GO

x. uwm-3'2 l

Figure IV The Stress Intensity KI, Dependence af Crack Growth Mate, da/dt at Various Temperatures in Distilled Water For 4130 Steel With a Yield Strength of 1330 MN/m2 (After Nelson and Williams, Reference (IV-8)). I /

I 3d 10"3 - T. 4 7, g e -43

-85 o

h - 11 0 -73 c, o 24 0 -63 a 53 A-M 4 o 75 D -43 10 o 87 o 24 0 10 2 10-8 o 53 6 830 6 e4 /, Ir5 a l 7o a P l T i 3 10-7 o f' %lG 4 [ l n 8 Els irs , o a i. 4 0 N 3 6 \\[ 10-8.- j 10-7 o k " i 30-9 L.. _1 I . l.__. J ..J 10-8 -20 30 40 50 so o 10 20 30 40 50 so o 10 M. nasm-3'8 x, enem-3/2 Dependence of Crack Growth Rate, da/dt, at Various Figure IV The Stress Intensity, Kr,2 Hydrogen For 4130 Steel With the Two Listed Yield Temperatures In 77.3 kN/m Strengths (After Nelson and Williams, Reference (IV-8)).

f"' '9 ...t... .g g .e .t.. _...._7s.

s....

2 .. 2... ..t.... 4.. ..2..... .,,1. se....... : ..M...

e........

i.. @o.. .t. 1400. _ -....a.... . 1. _... i _.....4_.. ..p. ,.,... 3.s...__4 .. _.... q....l_. .. L...._. _..,... _.l..._j __.. _...._.4. _. L....l........ j.. . - + - - -. = 1190 ",M 2 4130 steel in 77.3kN/m H(g);o --:p.r E

n. a, :. =

2 y . _u... =._=. :: =. -...n D 4130 steel in 77.3kN/m H (g); o = 1330 MN 2 . 3 2 y 2 m 1 N,N 4 O H-11 steel in distilled H 0(1); o = 1580 2 y 7 l m I e 4130 steel in distilled H 0(1); o = 1330 MN 2 y 2 m .2 ~ Q&T steel in H S(t) (2880 ppm), pH3; o = 908 MN y . -j. 2." A 2 g

3...

.t . :.._.. _..- -,.......j........j i i . = = _ : :rn :=== . :- n. a =- .........i .._L...... :. ...]_... 1,,._ t............ . m. ..w s . r..._..e p.. j .i. m, .g 3 I. .u. ....s .t.. ,.. o ) m .surw _ t._.... .,.....o....... i 4 3 . a...:. = : :..:. _i.._.._ ......._j ..... m.. . =.. 2 .....t ... n. ... s.... _. _. .i ..1 ....j.....,-

n...,

7.. o,..._ 9, .... :o. i .. _.......,s, .. n.... t a f i. m a... t.... ~~). ..,i i i. ....l.g w ..s .i... .i i ....3 ( l .....4.. ......i.. . 2 _... ...__.4...;

a..

. u. .. n...... u._=L;._.. =u =: =. :... =;=. - us u..=== .=1==..==t==u=:= u.:--....... ..... 1.. ... = _... ...t. y ._ _1 _ _.... _ _ _.1 ._.4... i. .. 2...._.. 4.. ..a .....2..... ...... _ ___.2...____. ....i..... ...,. _.... e.. .............. _.n .g .go. .......,..._... gqq._.. _...... ...... y. o. _ J......... sppo..... .l.. . i.... %..... w >a}l d nrl ,. [. ........... -.....n" . 3. ... :3..= x .; =_ = z. .. t..... , i.. j,..., -.,..... .t . i... l . - :. a = Figure IV Dependence of the Threshold Stress Corrosion l Q Cracking Stress Intensity Value, KIscc, with ._..q Temperature For Various Steels and Environments. ~ l }.. _.:... 2 _.:..[- l i t i .}}

ML20082P711

Contents

Text

References:

Subject:

SUBJECT:

Attachment:

SUBJECT:

Title:

SUMMARY

.=

=

= - - ^ :=: _;n--- -z

_ =

s.

= =

=.

d,2

=

::

::

:=: = :2 : u===:.

_3=

3.1 INTRODUCTION

SUMMARY

SUMMARY

SUMMARY

Navigation menu

ML20082P711

Text

References:

Subject:

SUBJECT:

Attachment:

SUBJECT:

Title:

SUMMARY

.=

=

= - - ^ :=: _;n--- -z

_ =

s.

= =

=.

d,2

=

::

::

:=: = :2 : u===:.

_3=

3.1 INTRODUCTION

SUMMARY

SUMMARY

SUMMARY

Navigation menu

Search