1、 STP-NU-013 IMPROVEMENT OF ASME NH FOR GRADE 91 NEGLIGIBLE CREEP AND CREEP FATIGUE Prepared by: Bernard Riou Areva NP Inc. Date of Issuance: September 3, 2008 This report was prepared as an account of work sponsored by US Department on Energy (DoE) and the ASME Standards Technology, LLC (ASME ST-LLC
2、). Neither ASME, ASME ST-LLC, nor others involved in the preparation or review of this report, nor any of their respective employees, members, or persons acting on their behalf, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, o
3、r usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe upon privately owned rights. Reference in this report to any specific commercial product, process or service by trade name, trademark, manufacturer, or otherwise does not necessar
4、ily constitute or imply its endorsement, recommendation or favoring by ASME ST-LLC or others involved in the preparation or review of this report, or any agency thereof. The views and opinions of the authors, contributors and reviewers of the report expressed in this report do not necessarily reflec
5、t those of ASME ST-LLC or others involved in the preparation or review of this report, or any agency thereof. ASME ST-LLC does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure an
6、yone utilizing a publication against liability for infringement of any applicable Letters Patent, nor assumes any such liability. Users of a publication are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their
7、own responsibility. Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted as government or industry endorsement of this publication. ASME is the registered trademark of The American Society of Mechanical Engineers. No part of this document m
8、ay be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. ASME Standards Technology, LLC Three Park Avenue, New York, NY 10016-5990 ISBN No. 978-0-7918-3165-6 Copyright 2008 by ASME Standards Technology, LLC All Rights Reserv
9、ed Improvement of ASME NH for Negligible Creep And Creep-Fatigue STP-NU-013 iii TABLE OF CONTENTS Foreword x Abstract . xi PART 1 IMPROVEMENT OF ASME NH FOR GRADE 91 (NEGLIGIBLE CREEP) . 1 1 INTRODUCTION . 2 2 NEGLIGIBLE CREEP CRITERIA. 3 2.1 ASME 3 2.2 RCC-MR . 4 2.3 Japanese Development of Structu
10、ral Design Standard 5 3 APPLICATION TO MOD. 9CR-1MO STEEL. 6 3.1 Reference Stress for Negligible Creep Curve Using a Criterion Based on Stress to Rupture 6 3.2 Negligible Creep Curve Based on RCC-MR Creep Strain Criterion 8 3.2.1 RCC-MR Creep Strain Law . 8 3.2.2 ORNL Creep Strain Law 8 3.2.3 Japane
11、se Creep Strain Law of Reference 6 . 9 3.2.4 Applicability of Negligible Creep Curve Based on RCC-MR Creep Strain Criterion. 9 3.3 Negligible Creep Curve Based on RCC-MR Stress Relaxation Criteria. 10 3.4 Negligible Creep Curve Based on ASME 0.2 % Creep Strain Criterion 10 3.5 Negligible Creep Curve
12、 Based on Japanese Creep Strain Criterion 11 4 TENTATIVE IMPROVEMENT IN THE CORRELATION FOR MOD. 9CR-1MO AT MODERATE TEMPERATURES . 14 4.1 Minimum Creep Rate 14 4.1.1 Correlation of Minimum Creep Rate and Time to Rupture 14 4.1.2 Minimum Creep Rate Against Stress . 14 4.2 Creep Strain Equations 20 4
13、.2.1 Creep Strain Law in RCC-MR . 20 4.2.2 Comparison with other Creep Strain Laws 20 4.2.3 New Fit Using RCC-MR Creep Strain Law. 21 4.3 Creep Stress to Rupture. 44 4.3.1 RCC-MR Stress to Rupture Data for Modified 9Cr-1Mo 44 4.3.2 Average Stress to Rupture of Modified 9Cr-1Mo Steel Using ORNL Data
14、44 4.3.3 Average Stress to Rupture of Modified 9Cr-1Mo Steel Using Japanese Data. 44 4.3.4 Average Stress to Rupture of Modified 9Cr-1Mo Steel Using Minimum Commitment Method . 44 4.3.5 Average Stress to Rupture of Modified 9Cr-1Mo Steel at Moderate Temperatures 45 4.3.6 Application of Stress to Rup
15、ture at Moderate Temperatures to Negligible Creep. 46 5 DISCUSSION 54 6 CONCLUSIONS . 57 References 58 PART 2 IMPROVEMENT OF ASME NH FOR GRADE 91 (CREEP-FATIGUE) 59 STP-NU-013 Improvement of ASME NH for Negligible Creep And Creep-Fatigue iv 1 INTRODUCTION60 2 MOD 9CR-1MO STEEL61 3 CREEP-FATIGUE PROC
16、EDURES IN THE NUCLEAR CODES 62 3.1 ASME Procedure .65 3.2 RCC-MR Procedure.66 3.3 DDS Procedure 67 3.4 Comparison Between ASME and RCC-MR Design Data for Creep Fatigue68 3.4.1 Fatigue Design Curves68 3.4.2 Stress to Rupture Data 68 3.4.3 Creep and Relaxation Behavior 70 3.5 Comparison between ASME a
17、nd RCC-MR Procedures70 4 PRESENTATION OF THE CREEP-FATIGUE TESTS AVAILABLE ON MOD 9CR-1 MO .72 5 DISTINCTIVE FEATURES OF CREEP FATIGUE OF MOD 9Cr-1 MO 80 5.1 Effect of Mean Stress.80 5.2 Effect of Air Environment .80 5.3 Creep Fatigue Tests in Vacuum.81 5.4 Cyclic Softening of Mod 9Cr-1Mo81 5.5 Effe
18、cts of Prior Aging83 5.6 Effect of Cyclic Softening on Creep Damage in Creep Fatigue Tests.83 5.7 Results of Cyclic Creep Tests 84 6 EVALUATION OF EXISTING PROCEDURES85 6.1 Evaluation of ASME Procedure.85 6.2 Evaluation of RCC-MR Procedure 89 6.3 Comparison of Calculated Stresses at the Beginning of
19、 Hold Time98 6.4 Comparison of Relaxation Procedures.100 6.5 Comparison of Safety Factors101 6.6 Creep-Fatigue Damage Envelope 102 6.7 Example of Application of Proposed Modifications103 6.8 Combination of Primary and Secondary Stresses 105 7 CONCLUSIONS 108 References.109 PART 3 PROPOSED TEST PROGR
20、AM TO ASSESS NEGLIGIBLE CREEP CONDITIONS OF MODIFIED 9CR-1MO .111 1 INTRODUCTION112 2 MATERIAL .113 3 CREEP TESTS.114 3.1 Improvement of Creep Strain Database.114 3.2 Creep Stain Rate 114 3.3 Stress to Rupture at Moderate Temperature 114 3.4 Test Specimens and Number of Tests114 Improvement of ASME
21、NH for Negligible Creep And Creep-Fatigue STP-NU-013 v 4 CREEP FATIGUE TESTS 117 5 CONCLUSIONS . 118 References 119 PART 4 PROPOSED TEST PROGRAM TO VALIDATE CREEP-FATIGUE PROCEDURES FOR MODIFIED 9CR-1MO . 120 1 INTRODUCTION . 121 2 MATERIAL. 122 3 SUMMARY OF CREEP-FATIGUE TESTS RESULTS 123 3.1 Creep
22、-Fatigue Tests in Air 123 3.2 Preliminary Results of Recent Creep-Fatigue Tests in Vacuum . 123 4 PURPOSE OF FUTURE TEST PROGRAM 124 4.1 Knowledge of Stress-Strain Behavior . 124 4.2 Extension of the Relation of Number of Cycles to Failure versus Visco-Plastic Strain . 124 4.3 Characterization of So
23、ftened Material. 124 4.4 Review of Creep-Fatigue Interaction Diagram . 124 4.5 Evaluation of Environmental Effect 125 5 PROPOSED TEST PROGRAM 126 5.1 Tests in Air at 500C or 525C 126 5.2 Long Term Tests in Air at 550C 126 5.3 Tests on Softened Material 127 5.4 Tests on Aged Material . 127 5.5 Tests
24、in Reactor Environment . 127 5.6 Tests on Post Weld Heat Treated Material 127 5.7 Creep Fatigue of Welded Joints 127 6 CONCLUSIONS . 128 References 129 Acknowledgements 130 Abbreviations And Acronyms 131 LIST OF FIGURES Figure 1 - Cyclic Stress Strain Behavior of Mod. 9Cr-1Mo at 500C 6 Figure 2 - Ne
25、gligible Creep Curve from Ref. 3. 13 Figure 3 - Minimum Strain Rate and Time to Rupture Relationship . 16 Figure 4 - Minimum Strain Rate versus Stress at 550C 17 Figure 5 - Minimum Strain Rate versus Stress at 500C 18 Figure 6 - Minimum Strain Rate versus Stress at 450C 19 Figure 7 - Stress for 0.1%
26、 Creep Strain at 550C. 24 Figure 8 - Stress for 0.2% Creep Strain at 550C. 25 STP-NU-013 Improvement of ASME NH for Negligible Creep And Creep-Fatigue vi Figure 9 - Stress for 0.5% Creep Strain at 550C .26 Figure 10 - Stress for- 1% Creep Strain at 550C .27 Figure 11 - Stress for 0.1% Creep Strain a
27、t 500C .28 Figure 12 - Stress for 0.2% Creep Strain at 500C .29 Figure 13 - Stress for 0.5% Creep Strain at 500C .30 Figure 14 - Stress for 1% Creep Strain at 500C 31 Figure 15 - Stress for 0.1% Creep Strain at 482C .32 Figure 16 - Stress for 0.2% Creep Strain at 482C .33 Figure 17 - Stress for 0.5%
28、 Creep Strain at 482C .34 Figure 18 - Stress for 1% Creep Strain at 482C 35 Figure 19 - Stress for 0.1% Creep Strain at 475C .36 Figure 20 - Stress for 0.2% Creep Strain at 475C .37 Figure 21 - Stress for 0.5% Creep Strain at 475C .38 Figure 22 - Stress for 1% Creep Strain at 475C 39 Figure 23 - Str
29、ess for 0.1% Creep Strain at 450C .40 Figure 24 - Stress for 0.2% Creep Strain at 450C .41 Figure 25 - Stress for 0.5% Creep Strain at 450C .42 Figure 26 - Stress for 1% Creep Strain at 450C 43 Figure 27 - Average Stress to Rupture and Experimental Data at 550C .51 Figure 28 - Average Stress to Rupt
30、ure and Experimental Data at 500C .52 Figure 29 - Average Stress to Rupture and Experimental Data at 450C .53 Figure 30 - Negligible Creep Curve for Modified 9Cr-1Mo 55 Figure 31 - Interaction between Negligible Creep and Creep-Fatigue .56 Figure 32 - ASME Fatigue Curves at 540C.66 Figure 33 - Compa
31、rison of ASME and RCC-MR Fatigue Design Curves .68 Figure 34 - Comparison of RCC-MR Average and ORNL Stress to Rupture69 Figure 35 - Comparison of ASME and RCC-MR Stress to Rupture 70 Figure 36 - Comparison of ASME and RCC-MR Creep Fatigue Damage Envelopes .71 Figure 37 - JAPC-USDOE Joint Study Fati
32、gue and Creep Fatigue Test Results72 Figure 38 - JNC Study Fatigue and Creep Fatigue Test Results74 Figure 39 - CEA Studies Fatigue and Creep Fatigue Test Results 74 Figure 40 - EPRI/CRIEPI Joint Studies Fatigue and Creep Fatigue Test Results .78 Figure 41 - IGCAR Fatigue and Creep Fatigue Test Resu
33、lts.78 Figure 42 - Cyclic Softening at 550C and 600C 82 Figure 43 - Tests in Tension-Unaged-Creep-Fatigue Damage-Best Fit Approach.91 Improvement of ASME NH for Negligible Creep And Creep-Fatigue STP-NU-013 vii Figure 44 - Comparison of Stresses at the Beginning of Hold Time at 550C. 98 Figure 45 -
34、Ratio between the Initial Stresses Calculated with ASME and RCC-MR. 99 Figure 46 - Relaxation at 550C . 100 Figure 47 - Comparison of EPRI/CRIEPI and RCC-MR Relaxation Curves 101 Figure 48 - Example of ASME Evaluation using Proposed Modifications Creep-Fatigue Damage Tests in Tension. 104 Figure 49
35、- Extrapolation of Design ASME Creep Stress to Rupture For T=1hr 105 Figure 50 - Comparison of Combination of Primary and Secondary Stresses . 106 LIST OF TABLES Table 1 - Negligible Creep Criteria 3 Table 2 - Temperature Limits in ASME Code . 3 Table 3 - Tensile Properties of Modified 9Cr-1Mo 7 Tab
36、le 4 - Negligible Creep at 450C for Modified 9Cr-1Mo Steel Based on ASME Time Fraction Criterion 7 Table 5 - Negligible Creep for Mod. 9Cr-1Mo Steel Based on ASME Time Fraction Criterion 8 Table 6 - Negligible Creep for Modified 9Cr-1Mo Steel Based on RCC-MR Creep Strain Criterion 10 Table 7 - Negli
37、gible Creep for Modified 9Cr-1Mo Steel Based on RCC-MR Stress Relaxation Criteria 10 Table 8 - Negligible Creep for Modified 9Cr-1Mo Steel Based on ASME Creep Strain Criterion. 11 Table 9 - Negligible Creep for Modified. 9Cr-1Mo Steel Based on Japanese Creep Strain Criterion 12 Table 10 - Set of Par
38、ameters of the New Fit Creep Strain Law . 22 Table 11 - Application of Revised Material Data to Negligible Creep of Table 6. 22 Table 12 - Application of Revised Material Data to Negligible Creep of Table 8. 23 Table 13 - Application of Revised Material Data to Negligible Creep of Table 9. 23 Table
39、14 - Application of Revised Material Data to Negligible Creep of Table 7. 23 Table 15 - RCC-MR Average Stress to Rupture for Times from 10,000 hours to 300,000 h 47 Table 16 - Average Stress to Rupture for Times from 10,000 hours to 300,000 hours Derived from 5. 47 Table 17 - Average Stress to Ruptu
40、re for Times from 10,000 hours to 300,000 hours Derived from 6. 47 Table 18 - Comparison of Average Stress to Rupture for Times from 10,000 hours to 300,000 hours . 48 Table 19 - Minimum Stress to Rupture for Times from 10,000 hours to 300,000 hours . 49 Table 20 - Parameters of the Revised Creep St
41、ress to Rupture 50 STP-NU-013 Improvement of ASME NH for Negligible Creep And Creep-Fatigue viii Table 21 - Application of Revised Material Data to Negligible Creep of Table 5 .50 Table 22 - Negligible Creep Times for Modified 9Cr-1Mo .55 Table 23 - Creep-Fatigue Calculation of Equivalent Strain Ran
42、ge62 Table 24 - Creep-Fatigue Damage64 Table 25 - ORNL- JAPC- USDOE Joint Study - Creep-Fatigue Tests of Modified 9Cr-1 Mo Steel 73 Table 26 - ORNL- JAPC- USDOE Joint Study - Creep-Fatigue Tests of Modified 9Cr-1 Mo Steel Heat 3039473 Table 27 - JNC Testing Result Data of Creep Fatigue Test (Mod 9Cr
43、-1Mo)75 Table 28 - CEA Results of Creep Fatigue Tests at 550C .76 Table 29 - CEA - Results of Stress Controlled Creep-Fatigue Tests at 550C .76 Table 30 - EPRI/CRIEPI Joint Studies Results of Axial Creep Fatigue Tests 77 Table 31 - IGCAR Results of Creep Fatigue Tests79 Table 32 - University of Conn
44、ecticut Results of Cyclic Creep Tests 79 Table 33 - Stress Amplitudes at Mid Fatigue Life at 550C.82 Table 34 - ASME Creep Fatigue Evaluation 85 Table 35 - ORNL-JAPC-USDOE Joint Study ASME Evaluation.86 Table 36 - JNC ASME Evaluation.87 Table 37 - CEA Creep Fatigue Tests ASME Evaluation.88 Table 38
45、- Stress Controlled Creep-Fatigue Tests ASME Evaluation.88 Table 39 EPRI/ CRIEPI Joint Studies ASME Evaluation 89 Table 40 IGCAR Study ASME Evaluation 89 Table 41 - RCC-MR Creep-Fatigue Evaluation .90 Table 42 - ORNL- JAPC- USDOE Joint Study RCC-MR Evaluation 92 Table 43 - JNC RCC-MR Evaluation 93 T
46、able 44 - CEA Creep Fatigue Tests - RCC-MR Evaluation 94 Table 45 - CEA - Stress Controlled Creep Fatigue Tests - RCC-MR Evaluation 95 Table 46 - EPRI / CRIEPI Joint Studies RCC-MR Evaluation .96 Table 47 - IGCAR Creep Fatigue Tests Results RCC-MR Evaluation .97 Table 48 - T-1433-199 Table 49 - Calc
47、ulated Allowable Life for the Eddystone Pipes (With K=0.9)102 Table 50 - Proposal for K Factor .102 Table 51 - Example of ASME Evaluation using Proposed Modifications .104 Table 52 - Comparison of Combination of Primary and Secondary Stresses.107 Table 53 - Proposal of Creep Tests on Mod 9Cr-1 Mo fo
48、r Assessment of Negligible Creep Conditions.115 Improvement of ASME NH for Negligible Creep And Creep-Fatigue STP-NU-013 ix Table 54 - Proposal of Creep Tests on Modified 9Cr 1 Mo for Extension of the Database. 116 Table 55 - Fatigue-Relaxation Tests. 126 Table 56 - Creep-Fatigue Tests 126 Table 57
49、- Fatigue-Relaxation Tests at 550C 126 Table 58 - Creep-Fatigue Tests at 550C . 127 STP-NU-013 Improvement of ASME NH for Negligible Creep And Creep-Fatigue x FOREWORD This document is the result of work resulting from Cooperative Agreement DE-FC07-05ID14712 between the US Department of Energy (DOE) and ASME Standards Technology, LLC (ASME ST-LLC) for the Generation IV (Gen IV) Reactor Materials Project. The objective
