1、Standard Test Method for Determining Stress Intensification Factors (i-Factors) for Metallic Piping ComponentsASME Code for Pressure Piping, B31AN AMERICAN NATIONAL STANDARDASME B31J-2008Intentionally left blank ASME B31J-2008Standard Test Methodfor Determining StressIntensification Factors(i-Factor
2、s) for MetallicPiping ComponentsASME Code for Pressure Piping, B31AN AMERICAN NATIONAL STANDARDDate of Issuance: May 30, 2008This Standard will be revised when the Society approves the issuance of a new edition. There willbe no addenda issued to this edition.ASME issues written replies to inquiries
3、concerning interpretations of technical aspects of thisStandard. Interpretations are published on the ASME Web site under the Committee Pages athttp:/cstools.asme.org as they are issued and will also be published within the next edition of thisStandard.ASME is the registered trademark of The America
4、n Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American NationalStandards. The Standards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and concerned interests have had
5、an opportunity to participate. The proposed code or standard was madeavailable for public review and comment that provides an opportunity for additional public input from industry, academia,regulatory agencies, and the public-at-large.ASME does not “approve,” “rate,” or “endorse” any item, construct
6、ion, proprietary device, or activity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with anyitems mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability forinfringement of any applicable let
7、ters patent, nor assume any such liability. Users of a code or standard are expresslyadvised that determination of the validity of any such patent rights, and the risk of infringement of such rights, isentirely their own responsibility.Participation by federal agency representative(s) or person(s) a
8、ffiliated with industry is not to be interpreted asgovernment or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the establishedASME procedures and policies, which precludes the issuance of interpreta
9、tions by individuals.No part of this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue, New York, NY 10016-5990Copyright 2008 byTHE AMERICAN SOCIETY
10、 OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword ivCommittee Roster . vCorrespondence With the B31 Committee viIntroduction . vii1 General. 12 Definitions 13 Test Procedure 14 Stress Intensification Factor 35 Variations in Materials and Geometry. 46 Test Report . 4Figures
11、3.1 Representative Test Arrangement . 23.3 Displacement, D, and Force, F, Recorded During Loading and Unloading of a TestSpecimen, in Both Positive and Negative Directions, With LinearDisplacement 2Table4.4 Stress Intensification Increase Factor 3Nonmandatory AppendixA Commentary on B31J 5iiiFOREWOR
12、DIn 1990, the B31 Code for Pressure Piping, Technical Committee on Mechanical Design (MDC),determined that there was a need to develop a standard test method to determine stress intensifica-tion factors (SIFs or i-factors) for piping components and joints. At the time, the B31 Code booksprovided SIF
13、s for various standard piping components and joints, but did not provide guidanceon how to establish SIFs for nonstandard piping components or joints.This Standard is intended to provide a uniform approach to the development of SIFs forstandard, nonstandard, and proprietary piping components and joi
14、nts of all types. In its develop-ment, this Standard has been reviewed by individuals and committees of the Boiler and PressureVessel Code, B31, and B16. Comments resulting from the review have been considered andresponded to, with revisions made to the Standard as appropriate.Under direction of ASM
15、E Codes and Standards, both U.S. Customary and SI units are provided.This Standard was approved by the American National Standards Institute on April 18, 2008.ivASME B31 COMMITTEECode for Pressure Piping(The following is the roster of the Committee at the time of approval of this Standard.)COMMITTEE
16、 OFFICERSM. L. Nayyar, ChairK. C. Bodenhamer, Vice ChairN. Lobo, SecretaryCOMMITTEE PERSONNELH. A. Ainsworth, ConsultantR. J. T. Appleby, ExxonMobil Upstream Research Co.C. Becht IV, Becht Engineering Co.A. E. Beyer, Fluor DanielK. C. Bodenhamer, Enterprise Products Co.J. S. Chin, TransCanada Pipeli
17、ne USD. L. Coym, Worley ParsonsJ. A. Drake, Spectra Energy TransmissionD. M. Fox, Atmos EnergyJ. W. Frey, Stress Engineering Service, Inc.D. R. Frikken, Becht Engineering Co.R. A. Grichuk, Fluor Corp.L. E. Hayden, Jr., ConsultantG. A. Jolly, Vogt Valves Flowserve Corp.W. J. Koves, UOP LLCN. Lobo, Th
18、e American Society of Mechanical EngineersB31 MECHANICAL DESIGN TECHNICAL COMMITTEEW. J. Koves, Chair, UOP LLCG. A. Antaki, Vice Chair, Becht Nuclear ServicesT. Lazar, Secretary, The American Society of Mechanical EngineersC. Becht IV, Becht Engineering Co.J. P. Breen, Becht Engineering Co.J. P. Ell
19、enberger, ConsultantD. J. Fetzner, BP Exploration Alaska, Inc.J. A. Graziano, Tennessee Valley AuthorityJ. D. Hart, SSD, Inc.R. W. Haupt, Pressure Piping Engineering Associates, Inc.B. P. Holbrook, Babcock Power, Inc.vR. P. Merrill, Evapco, Inc.J. E. Meyer, Louis Perry however, they shouldnot contai
20、n proprietary names or information.Requests that are not in this format will be rewritten in this format by the Committee priorto being answered, which may inadvertently change the intent of the original request.ASME procedures provide for reconsideration of any interpretation when or if additionali
21、nformation that might affect an interpretation is available. Further, persons aggrieved by aninterpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not“approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity.Attending Committee
22、Meetings. The B31 Standards Committee regularly holds meetings, whichare open to the public. Persons wishing to attend any meeting should contact the Secretary ofthe B31 Standards Committee.viINTRODUCTIONThe ASME B31 Code for Pressure Piping consists of a number of individually published Sectionsand
23、 Standards, each an American National Standard, under the direction of the ASME CommitteeB31, Code for Pressure Piping.Rules for each Standard provide standardized guidance for a specific task found in one ormore B31 Section publications, as follows:(a) B31G, Remaining Strength of Corroded Pipelines
24、 provides a simplified procedure to deter-mine the effect of wall loss due to corrosion or corrosion-like defects on pressure integrity inpipeline systems.(b) B31J, Standard Test Method for Determining Stress Intensification Factors (i-Factors) forMetallic Piping Components, provides a standardized
25、 method to develop the stress intensificationfactors used in B31 piping analysis.This is B31J, Standard Test Method for Determining Stress Intensification Factors (i-Factors)for Metallic Piping Components. Hereafter, in this Introduction and in the text of this B31 Standard,where the word “Standard”
26、 is used without specific identification, it means this B31 Standard.It is expected that this Standard will be incorporated by reference into the appropriate Sectionsof B31.This Standard sets forth an engineering procedure deemed appropriate for the safe determina-tion of the fatigue capacity of a p
27、iping component or joint in most services, relative to a standardbutt-welded joint. However, the procedure cannot possibly foresee all geometries and servicespossible, and the use of competent engineering judgment may be necessary to extend the procedureto cover unusual geometries and service condit
28、ions or to ensure a safe testing environment.viiIntentionally left blank ASME B31J-2008STANDARD TEST METHOD FOR DETERMINING STRESSINTENSIFICATION FACTORS (i-FACTORS) FOR METALLIC PIPINGCOMPONENTS1 GENERALThe ASME B31 Code for Pressure Piping and theASME Boiler and Pressure Vessel Code, Section III,N
29、uclear Components, Subsections NC and ND pipingrules require the use of stress intensification factors(i-factors or SIFs) when checking the adequacy of com-ponents and joints (welded and nonwelded) in pipingsubject to loadings, including those cyclic loadings thatmay produce fatigue failures. As use
30、d herein, where theword “Code” is used without specific identification, itmeans the Code or Standard which incorporates or refer-ences this Standard. The piping Codes provide stressintensification factors for the most common piping com-ponents and joints. This Standard presents an experi-mental meth
31、od to determine SIFs.2 DEFINITIONSpiping components: mechanical elements suitable for join-ing or assembly into pressure-tight, fluid-containingpiping systems. Components include pipe, tubing, fit-tings, flanges, gaskets, bolting, valves, and devices suchas expansion joints, flexible joints, pressur
32、e hoses, traps,strainers, in-line portions of instruments, and separators.stress intensification factor: a fatigue strength reductionfactor that is the ratio of the elastically predicted stressproducing fatigue failure in a given number of cyclesin a butt weld on a straight pipe to that producing fa
33、tiguefailure in the same number of cycles in the componentor joint under consideration.3 TEST PROCEDURE3.1 Test EquipmentA schematic of a test arrangement is given in Fig. 3.1.(a) The machine framework must be sufficiently stiffto prevent significant rotation at the fixed end of theassembly. A signi
34、ficant rotation is one readily visible tothe observer.(b) The pipe component shall be mounted close to thefixed end of the test assembly, but no closer than twopipe diameters.(c) The test rig shall be capable of applying a fullyreversed displacement at the free end without binding1in the two orthogo
35、nal directions. That is, the free endshall not bind the assembly in a direction out of theplane of testing.(d) The test equipment shall be calibrated to read dis-placements with an accuracy of 1% of the imposed dis-placement amplitude.(e) The piping attached directly to the tested compo-nent should
36、be a similar schedule to the tested com-ponent.3.2 Test SpecimenThe test specimen may be lower strength carbon steel,such as ASTM A 106 Grade B pipe or ASTM A 234Grade WPB fittings, and equivalent plates and forgings,corresponding to the “UTS 80 ksi” curve in Fig. 5-110.1of Appendix 5 of Section VII
37、I, Division 2 of the ASMEBoiler and Pressure Vessel Code. For other materials,the material constant, C, shall be modified as describedin para. 5.1.The fabrication, welding, and examinations of thetested components shall be the same as will be followedin fabrication of the component and installation
38、for ser-vice. Weld contours should be representative of thoseintended to be used in fabrication and installation.3.3 Applied Displacement Calibration(a) The test specimen shall be placed in the test assem-bly and displacements shall be applied in positive stepsto obtain a load-displacement plot anal
39、ogous to thatshown in Fig. 3.3. At least five points shall be recordedin the linear region of the plot.(b) The initial loading sequence shall be stoppedwhen it is clear from the load-displacement plot that therecorded load displacement is no longer linear, i.e., theloading sequence will require one
40、or two steps into thenonlinear range.(c) The specimen must then be unloaded, followingthe same recording sequence as during loading.(d) Steps (a) through (c) are repeated in the negativedirection to approximately the same negative displace-ment as the loading sequence reached in (b).(e) The linear r
41、egion of the load-displacement curveand its straight-line extension will be used in determin-ing the force, Fe, in para. 4.1.ASME B31J-2008Fig. 3.1 Representative Test ArrangementLength, L, to leak pointLeakpointTestedcomponentApplied in-planedisplacement, H9004Fixed endGENERAL NOTES:(a) The force,
42、Fe, is determined from the best-fit straight line (Fig. 3.3) based on H9004.(b) The moment, Me, at the leak point is equal to FeL.Fig. 3.3 Displacement, D, and Force, F, Recorded During Loading and Unloading of a Test Specimen, in BothPositive and Negative Directions, With Linear DisplacementH110026
43、0H1100240H11002200204060H110020.006 H110020.004 H110020.002 0.002 0.004DF0 0.006GENERAL NOTE: The slope of the best-fit straight line is used in the subsequent tests to determine the stress intensification factor.2ASME B31J-20083.4 Cycles to Leakage(a) The test specimen shall be placed in the test c
44、onfig-uration and pressurized with water. The pressure shouldbe sufficient to detect leakage. A head pressure of 12 in.(300 mm) of water at the expected failure location (leakpoint) is usually sufficient. Equivalent methods ofthrough-wall crack detection are permissible.(b) The specimen shall be sub
45、jected to displacementlimited fully reversed cyclic displacements until athrough-wall crack is detected in the component or itsweld to the pipe.(c) The fully reversed displacement shall be appliedat a frequency not to exceed 120 cycles per minute.Higher frequencies are permitted, provided it is show
46、nthat there are no deleterious effects on temperature.(d) The number of cycles, N, at which the through-wall crack occurs shall be recorded. The cyclic displace-ments shall be selected such that failure occurs in aminimum of Np 500 cycles of reversed displacements.The full range of nominal bending s
47、tress at the leakpoint see para. 4.1 and eq. (2) may exceed twice theactual material yield stress.(e) If the displacement level is changed during thetest, the number of equivalent cycles shall be determinedas described in para. 4.6.4 STRESS INTENSIFICATION FACTOR4.1 Calculated StressThe applied mome
48、nt at the leak point, Me,isMep FeL (1)whereFep force corresponding to the applied displacementamplitude, read on the straight line of Fig. 3.3,lb (N)L p distance between the point of applied displace-ment and the leak point, in the direction perpen-dicular to the imposed displacement, in. (mm)Mep ap
49、plied elastic moment amplitude at the timeleakage occurs, in.-lb (Nmm)The elastically calculated stress amplitude corres-ponding to the elastic moment at the leak point isS pMeZ(2)whereS p stress amplitude at leak point, psi (MPa)Z p section modulus as defined in para. 4.2, in.3(mm3)4.2 Section ModulusThe value of the section modulus, Z, used in calculat-ing the stress amplitude at the leak point in para. 4.13Table 4.4 Stress Intensification Increase FactorNumber of Test Specimens Testing Factor, Ri1 1.22 1.13 1.054 1.0shall be that of the pipe intended to be used with thecomponent. If
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