ML18267A089

1130 Large Scale Fatigue Test in Japan

ML18267A089
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Issue date:	09/24/2018
From:	Robert Tregoning NRC/RES/DE
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0© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.Seiji Asada Yun WangMitsubishi Heavy Industries, Ltd.Hitachi, Ltd. Masahiro TakanashiKentaroHayashiIHI Corporation The Kansai Electric Power Co., Inc.Development of New Design Fatigue Curves in Japan-Discussion of Best Fit Curves based onFatigue Test Data -Environmentally Assisted Fatigue (EAF) Research and Related ASME Activities,NRC Public Meeting, September 25, 2018 1© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.1OutlinesIntroductionFatigue Tests Using Small Specimens [*1]Large-Scale Fatigue Tests Using Carbon and Low-Alloy Steel Plates [*2]Large-Scale Fatigue Tests Using Stainless Steel Piping [*3]Conclusions(Notes)The details of the above fatigue experimental tests are shown in the following 2018 PVP papers.[*1] Wang, Yun, et al., -Discussion of Best-Fit Curves Based on Fatigue Test Data With Small-Scale Test Specimen --84052, ASME, 2018.[*2] Takanashiof New Design Fatigue Curves in Japan -Discussion of Best-Fit Curves Based on Large-Scale Fatigue Tests of Carbon and Low-Alloy Steel Plates --84456, ASME, 2018.[*3] Bodai, M-Discussion of Best-Fit Curves Based on Fatigue Test Data with Large-Scale Piping --84436, ASME, 2018.

2© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.2Introduction The DFC1/DFC2 subcommittee has not only developed a new fatigue evaluation method but also produced beneficial outcomes. To support this study, a Japanese utility project performed not only large scale fatigue tests using carbon & low-alloy steel flat plates and austenitic stainless steel piping but also fatigue tests using small specimens to obtain not only basic data but also fatigue data of mean stress effect.Fatigue life of a small specimen is generally defined as the number of cycles by 25% load drop, and this is considered to correspond to 3mm-deep crack in the test specimen. Hence, the fatigue lives of the large-scale fatigue tests are compared with the best-fit curve developed by the DFC1 subcommittee and the fatigue lives obtained by the small specimen fatigue tests.In this presentation, the fatigue tests using small specimens and large scale fatigue tests using carbon & low-alloy steel flat plates and austenitic stainless steel piping are summarized.

3© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.3Fatigue Tests Using Small Specimens [*1]Materials MaterialCSiMnPSNiCrMoCuFeSUS316LTP0.0120.441.760.0240.00014.4717.382.62Bal.STPT3700.2000.250.820.0140.001Bal.SQV2A0.180.241.430.0050.0020.660.110.5200.001Bal.SCM435H0.370.280.760.0140.0110.080.910.15Bal.Materialu(MPa)0.2(MPa)Elongation(%)Reduction of Area (%)SUS316LTP556 (480)238 (175)53 (35)86STPT370493 (370)272 (215)32 (30)68SQV2A597 (550-690)450 (345)26 (18)77SCM435H1074 (930)991 (785)17 (15)58[Notes]-SUS316LTP (SA312 TP316L)was taken from the large-scale piping.-STPT370 (is a carbon steel piping.-SQV2A (SA533 Gr.BCl.1)was taken from the large-scale Low-Alloy Steel (LAS) plate.-SCM435H is a Cr-Mo steel with high tensile strength.[wt%]

4© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.4Fatigue Tests Using Small Specimens [*1] (continued)Fully Reversed Axial Fatigue Tests SUS316LTPSTPT370BFC of DFC Subcommittee (u= 556 MPa)BFC of DFC Subcommittee (u= 493 MPa)[Best-Fit Curve of DFC Subcommittee]For Stainless Steels[Best-Fit Curve of DFC Subcommittee]For CS&LAS Steels 5© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.5Fatigue Tests Using Small Specimens [*1] (continued)Fully Reversed Axial Fatigue Tests (continued)SQV2ASCM435HBFC of DFC Subcommittee (u= 597 MPa)BFC of DFC Subcommittee (u= 1074 MPa)[Best-Fit Curve of DFC Subcommittee]For CS&LAS Steels 6© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.6Fatigue Tests Using Small Specimens [*1] (continued)Fully Reversed Axial Fatigue Tests (continued)SUS316LTP (ta=0.15%, Nf=1.06x106cycles)STPT370 (ta=0.135%, Nf=5.40x105cycles)SQV2A (ta=0.15%, Nf=1.89x107cycles)SCM435H (ta=0.3%, Nf=1.01x105cycles) 7© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.7Fatigue Tests Using Small Specimens [*1] (continued)Mean Stress CorrectionModified Goodman ApproachGerber ApproachPeterson ApproachSmith-Watson-Topper Approach: Stress Amplitude, : Equivalent Stress Amplitude, : Tensile Strength Mean Stress (MPa)0200400600800100012000200400600800u=1000MPay=0.72uw0=0.45uGerberPetersonS-W-TMod.GoodmanyyFatigue Endurance Limit (MPa) 8© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.8Fatigue Tests Using Small Specimens [*1] (continued)Mean Stress CorrectionSUS316LTPSTPT370SCM435HSQV2AConservative 9© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.9Large-Scale Fatigue Tests Using CS&LAS Plates [*2]Test Specimen and Test Machine Stress Concentration Factor = 1.27 10© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.10Large-Scale Fatigue Tests Using CS&LAS Plates [*2](continued)Test Results IDMat.AimUpper strain (%)Strain amp.(%)Mean strain(%)CS1CSSize effect0.240.240CS2CSMean stress0.30.240.06LAS1LASSize effect0.220.220LAS2LASSize effect0.180.180LAS3LASMean stress0.30.220.08LAS4LASMean stress0.30.180.12[*]Fatigue Life: Crack penetrated the plate width or the load decreased 11© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.11Large-Scale Fatigue Tests Using Stainless Steel Piping[*3]Test Specimen and Test Machine Notched Portion170.3216.3216.3233Point A(Center)Point B(Edge)XLoad [Load Cell]Strain GagesDisplacement, a[Actuator]u1u2u4u5d1d2d4d5d3ThermocoupleLu8u10 u14u9u6u7Stress Concentration Factor = 1.39 12© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.12Large-Scale Fatigue Tests Using SS Piping[*3](continued)Test Specimen and Test Machine Strain AmplitudeMean StrainTP-A?<0.44%NoTP-B?<0.44%NoTP-C?<0.25%NoTP-D?<0.25%+2.25%TP-E?<0.5%+2.0%TP-F?<0.2%+2.3%

13© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.13Large-Scale Fatigue Tests Using SS Piping[*3](continued)The fatigue lives of pipes for 3 mm crack and through-wall crack (TWC) are compared with the fatigue lives of the small specimens and the estimated best fit curve developed by the DFC subcommittee.Number of CyclesStrain, Range at 1/2Nor 1/2N25, (%)SUS316LTP (in air): Pipe [No Mean Stress, 3mm crack]: Pipe [No Mean Stress, TWC]: Pipe [Mean Stress, 3mm crack]: Pipe [Mean Stress, TWC]: Small Specimens (N25)---: Estimated Best Fit Curve (TS=542MPa)TP-A ( , ): 0.98%, 1.00%TP-F of Through Wall Crack( ):[estimated from the average ofratio between 3mm crack andTWC for TP-A to TP-E]

14© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.14Large-Scale Fatigue Tests Using SS Piping[*3](continued)[Fatigue Test] Target strain amplitude = ?<0.44%Observation on Notched Portion by replica printingNumber of Cycles: 10,000Number of Cycles: 11,450Number of Cycles: 8,000Number of Cycles: 9,000Cracks 15© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.15Large-Scale Fatigue Tests Using SS Piping[*3](continued)[Fatigue Test] Target strain amplitude = ?<0.44% (continued)Observation of Fracture Surface (beach marking)1323345678 16© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.16Large-Scale Fatigue Tests Using SS Piping[*3](continued)The data of the tested pipes are plotted for nominal strain amplitude and nominal mean stress calculated from the loads at 3 mm crack depth with mean stress correction.The S-W-T approach is more appropriate than the Modified Goodman approach: TP-A (0%): TP-B (0%): TP-C (0%): TP-D (2.25%): TP-E (2%): TP-F (2.3%)[Note] ( )= Mean Strain: S-W-T: Modified GoodmanNominal Mean StressNominal Stress Amplitude, a(MPa) 17© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.© 2018 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.17ConclusionsTo support the new fatigue evaluation method by DFC1/DFC2 subcommittee, a Japanese utility project performed not only large scale fatigue tests using carbon & low-alloy steel flat plates and austenitic stainless steel piping but also fatigue tests using small specimens to obtain not only basic data but also fatigue data of mean stress effect.ThefatiguelivesofnotonlythesmallspecimensbutalsotheCS&LASplatesandthestainlesssteelpipesareclosetothebest-fitcurvedevelopedbytheDFC1subcommittee,andthesizeeffectcanbeconsideredasnegligible.Themeanstresseffectisremarkableinmaterialswithhighertensilestrength.ThecorrectionofmeanstresseffectwiththeS-W-TapproachshowsgoodagreementwiththeBFCs.

18© 2016 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.