1、STP-NU-035EXTEND ALLOWABLE STRESS VALUES FOR ALLOY 800HSTP-NU-035 EXTEND ALLOWABLE STRESS VALUES FOR ALLOY 800H Prepared by: Robert W. Swindeman Cromtech Inc Douglas L. Marriott Stress Engineering Services Inc Jude R. Foulds Clarus Consulting, LLC Date of Issuance: November 20, 2012 This report was
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12、SBN No. 978-0-7918-6859-1 Copyright 2012 by ASME Standards Technology, LLC All Rights Reserved Extend Allowable Stress Values for Alloy 800H STP-NU-035 iii TABLE OF CONTENTS Foreword . vi Abstract vii INTRODUCTION . 1 1THE DATABASES . 2 2The Assembly of the Database for Calculation of the SY1and SUV
13、alues . 2 2.1The Assembly of the Database for Calculation of the Sr, Stand SmtValues 3 2.2ANALYSIS OF TENSILE DATA 6 3Analysis of Yield and Ultimate Tensile Strength Data for Estimating the SY1and SU3.1Values 6 ANALYSIS OF STRESS-RUPTURE DATA . 9 4Analysis Stress-Rupture Data for Minimum Stress-to-R
14、upture, Sr. 9 4.1ANALYSIS OF CREEP DATA 14 5Analysis of Tensile Curves 14 5.1Development of an Alternate Plasticity Model for Alloy 800H 15 5.2Analysis of the Time to Initiate Tertiary Creep . 19 5.3RECOMMENDATIONS OF ALLOWABLE STRESS INTENSITY VALUES . 28 6Values for SY1and SU. 28 6.1Values for Sm.
15、 29 6.2Values for St30 6.3Values for Smt. 33 6.4Values for Sr36 6.5DISCUSSION 39 7SUMMARY AND RECOMMENDATIONS 40 8References 41 Appendix 1 - Estimation of the Time to Tertiary Creep . 44 Appendix 2 - Time-Temperature Parametric Analysis . 48 Appendix 3 - Notes on the Hot Tensile Curve . 51 Acknowled
16、gments 57 LIST OF TABLES Table 1 - Comparison of Chemistries for Variants of Alloy 800 . 2 Table 2 - Typical Minimum Stress-to-Rupture Values in MPa 12 Table 3 - Modulus Values for Alloy 800H . 14 Table 4 - Summary of the Curve-Fitting Results . 19 Table 5 - Fit of Three Time-Temperatures to Alloy 8
17、00H Stress-Rupture Data and Comparison of Predicted Average Rupture Strengths (ksi) for 100,000 h at 1650F (900C) . 49 STP-NU-035 Extend Allowable Stress Values for Alloy 800H iv Table 6 - Fit of Three Time-Temperatures to Alloy 800H Tertiary Creep Data and Comparison of Predicted Average Strengths
18、(ksi) for 100,000 h at 1650F (900C) . 50 Table 7 - Coefficients for the GA Hot Tensile Equation 51 Table 8 - Values for the Cefficients in a New Hot Tensile Model for Alloy 800H and the Calculated Stress for 1% Strain 53 Table 9 - Coefficients for the Ramberg-Osgood Model for the Hot Tensile Curve .
19、 54 LIST OF FIGURES Figure 1 - Definition for the Components of Creep Used in ASME Section III, Subsection NH 3 Figure 2 - Various Shapes for Creep Curves Observed in Alloy 800H 5 Figure 3 - Coefficients and R-squared Values for Polynomial Fit to RYand RTCustomary Units . 6 Figure 4 - Fit of the the
20、 Polynomial to the RY1Values for Alloy 800H 7 Figure 5 - Fit of the Polynomial to the RTValues for Alloy 800H . 7 Figure 6 - Distribution of the Yield Strengths Relative to the SYRYTrend Curve . 8 Figure 7 - Distribution of Ultimate Tensile Strengths Relative to STRT8 Figure 8 - Stress Versus the La
21、rson-Miller Parameter for the Stress-Rupture of 106 Lots of Alloy 800H (Stress in MPa, Parameter Based on Temperature in Kelvin) . 10 Figure 9 - Residuals in Log Time Versus Temperature for Larson-Miller Parameter for the Stress-Rupture of Alloy 800H . 10 Figure 10 - Histogram of Residuals in Log Ti
22、me for the Fit of the Larson-Miller Parameter . 11 Figure 11 - Cumulative Percent of Residuals in Log Time for the Fit of the Larson-Miller Parameter to Stress-Rupture Data for Alloy 800H . 11 Figure 12 - Calculated Rupture Life Versus Observed Rupture Life for the Fit of the Larson- Miller Paramete
23、r to Stress-Rupture Data for Alloy 800H. 12 Figure 13 - Minimum Stress-to-Rupture Versus Time for Alloy 800H 13 Figure 14 - Comparison of Minimum Stress-to-Rupture Values at 100,000 h for the Current ASME III-NH, the German Standard KTA-3221 and the New Analysis Reported Here . 13 Figure 15 - Modulu
24、s Data for Alloy 800H . 15 Figure 16 - Comparison of Hot Tensile Curves for 1400F (760C) 17 Figure 17 - Calculated Hot Tensile Curves for Selected Temperatures (deg F) . 17 Figure 18 - Stress Versus the Larson Miller Parameter for 1% Strain and a Parametric Constant, C, of 21.21. 19 Figure 19 - Leyd
25、a-Rowe Plot for Classical Creep (left) and Tertiary-Type Creep (right) of Alloy 800H 20 Figure 20 - Larson Miller Parameter for Time to Initiate Tertiary Creep for Classical-Type 21 Figure 21 - Larson Miller Parameter for Time to Initiate Tertiary Creep for “Tertiary-Type” Creep . 22 Figure 22 - Lar
26、son Miller Parameter for Time to Initiate Tertiary Creep for all Data 22 Extend Allowable Stress Values for Alloy 800H STP-NU-035 v Figure 23 - Residuals in Log Time Versus Temperature for Larson-Miller Parameter for the Tertiary Creep of Alloy 800H Including Combined Classical and Tertiary-Type Dat
27、a 23 Figure 24 - Histogram of Residuals in Log Time for the Fit of the Larson-Miller Parameter for the Tertiary Creep of Alloy 800H Including Combined Classical and Tertiary-Type Data 24 Figure 25 - Cumulative Percent of Residuals in Log Time for the Fit of the Larson-Miller Parameter to All Tertiar
28、y Creep Data for Alloy 800H . 24 Figure 26 - Calculated Time to Tertiary Creep vs. Observed Time to Tertiary for the Fit of the Larson-Miller Parameter to All Tertiary Creep Data for Alloy 800H 25 Figure 27 - Isothermal Curves for Tertiary Creep Covering 450 to 900C in 50C Increments 25 Figure 28 -
29、Isothermal Curves for Tertiary Creep Covering 850 to 1650F in 100F increments . 26 Figure 29 - Stress Versus Time to Initiate Tertiary Creep at 1650F and 900C . 26 Figure 30 - Stress Versus Time Rupture for Alloy 800H at 1650F and 900C 27 Figure 31 - StVersus Temperature . 30 Figure 32 - SmtVersus T
30、ime . 33 Figure 33 - Minimum Stress-to-Rupture 36 Figure 34 - Typical Plot of Creep Data Supplied by HAI for Alloy 800HT (1.7 ksi at 1800F) . 44 Figure 35 - Examples of the Etimation of the Time to Tertiary Creep, t3, for Tertiary-Type Creep Curves Plotted from the HAI Data for 1500 and 1600F (816 a
31、nd 871C) . 45 Figure 36 - Examples of the Estimation of the Time to Tertiary Creep, t3, for Tertiary-Type Creep Curves Plotted from the Petten Database . 46 Figure 37 - A Creep Curve for 1472F (800C) Extracted from a VAMAS Report Showing Sigmoidal Character . 47 Figure 38 - Examples of the Estimatio
32、n of the Time to Tertiary Creep, t3, for Tertiary-Type Creep Curves Plotted from the NIMS Data for 1650F (900C) 47 Figure 39 - The Effect of Extension Rate Changes on the Flow Stress of Alloy 800H at 1650F (900C) . 55 Figure 40 - The Effect of Extension Rate on the Yield Strength (left) and Ultimate
33、 Tensile Strength (right) at 900C (1650F) . 55 Figure 41 - Estimated Hot Tensile Curves for Alloy 800H Based on the Consideration of the Effect of Slow Extension Rate (0.005/minute) on the Ultimate Tensile Strength 56 STP-NU-035 Extend Allowable Stress Values for Alloy 800H vi FOREWORD This document
34、 is the result of work resulting from Cooperative Agreement DE-NE0000288 between the U.S. Department of Energy (DOE) and ASME Standards Technology, LLC (ASME ST-LLC) for the Generation IV (Gen IV) Reactor Materials Project. The objective of the project is to provide technical information necessary t
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36、rogram Plan. This report is the result of work performed under Task 13 titled “Extend Allowable Stress Values for Alloy 800H.” ASME ST-LLC has introduced the results of the project into the ASME volunteer standards committees developing new code rules for Generation IV nuclear reactors. The project
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44、wable Stress Values for Alloy 800H STP-NU-035 vii ABSTRACT The tensile, creep and stress-rupture databases for alloy 800H (UNS N08810) were assembled and analyzed with the intent of extending the allowable stresses in ASME Section III, Subsection NH for service to 500,000 h at 1400F (760C) and below
45、 and recommending new allowable stresses for limited service times to temperatures as high as 1650F (900C). Values for SY1and SUwere produced for the temperature range of 800 to 1650F (425 to 900C). These include a revision of existing values to 1500F (800C). Values for Smwere produced for the same
46、temperature range. Values for the minimum stress-to-rupture, Sr, were produced for the temperature range of 800 to 1650F (425 to 900C), including a revision of existing values to 1400F (750C). Development of values for Stand Smtrequired the construction of tensile curves to 1% strain, the estimation
47、 of the stresses to produce 1% creep strains to 500,000 h and the estimation of the minimum stress to initiate tertiary creep for times to 500,000 h. Because of the shortage of very long-time data for all categories, extensive use was made of time-temperature parametric models based on Larson-Miller
48、. The observation of “non-classical” creep behavior in many of the creep curves for alloy 800H greatly reduced the confidence in the extrapolations needed to estimate stresses corresponding to the criteria on which the Stand Smtvalues were based. As a result, restrictions on the scope of the Stvalue
49、s were recommended. These restrictions limited values to less than 500,000 h for temperatures of 1550F (or 850C) and above. STP-NU-035 Extend Allowable Stress Values for Alloy 800H viii INTENTIONALLY LEFT BLANK Extend Allowable Stress Values for Alloy 800H STP-NU-035 1 INTRODUCTION 1This work was undertaken in support of the ASME/DOE Generation IV Reactor Materials Program 1. Most of the advanced nuclear reactor concepts being considered in the Generation IV effort will require that the structural materials operate at temperatures where time-depe
