Development of Fatigue Design Curves for Pressure Vessel Alloys Using a Modified Langer Equation

1979 ◽  
Vol 101 (4) ◽  
pp. 292-297 ◽  
Author(s):  
D. R. Diercks
Keyword(s):  
Pressure Vessel ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Austenitic Stainless Steels ◽  
Cyclic Stress ◽  
Allowable Stress ◽  
Fitting Procedure ◽  
Fatigue Design ◽  
Alloy 800 ◽  
Best Fit

The Jaske and O’Donnell [1] curve-fitting procedure for analyzing fatigue data generated between room temperature and 427° C (800° F) for several pressure vessel alloys is reexamined in the present paper. Substantial improvements over their best-fit curves to the data are found to result from two proposed modifications to their procedure, namely 1) the use of a variable exponent in the Langer equation, and 2) minimization of the sum of the squares of the errors in the logarithms of the cyclic-stress amplitudes rather than in the stress amplitudes directly. Likewise, important differences are observed for the resultant allowable stress-amplitude values for design purposes. In particular, the present analysis permits higher allowable stress amplitudes in the critical low-cycle fatigue-life region for the austenitic stainless steels, alloy 800, and alloy 600. Two best-fit curves and the associated sets of allowable stress amplitudes, corresponding to the inclusion or deletion of load-controlled data, are obtained for alloy 718.

Derivation of Design Fatigue Curves for Austenitic Stainless Steel Grades 1.4541 and 1.4550 Within the German Nuclear Safety Standard KTA 3201.2

2013 ◽  
Author(s):  
Xaver Schuler ◽  
Karl-Heinz Herter ◽  
Jürgen Rudolph
Keyword(s):  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Austenitic Stainless Steels ◽  
Nuclear Safety ◽  
Safety Standard ◽  
Fatigue Design ◽  
Steel Grades ◽  
Best Fit

Titanium and niobium stabilized austenitic stainless steels X6CrNiTi18-10S (material number 1.4541, correspondent to Alloy 321) respectively X6CrNiNb18-10S (material number 1.4550, correspondent to Alloy 347) are widely applied materials in German nuclear power plant components. Related requirements are defined in Nuclear Safety Standard KTA 3201.1. Fatigue design analysis is based on Nuclear Safety Standard KTA 3201.2. The fatigue design curve for austenitic stainless steels in the current valid edition of KTA 3201.2 is essentially identical with the design curve included in ASME-BPVC III, App I (ed. 2007, add. July 2008 respectively back editions). In the current code revision activities of KTA 3201.2 the compatibility of latest in air fatigue data for austenitic stainless steels with the above mentioned grades were examined in detail. The examinations were based on statistical evaluations of 149 strain controlled test data at room temperature and 129 data at elevated temperatures to derive best-fit mean data curves. Results of two additional load controlled test series (at room temperature and 288°C) in the high cycle regime were used to determine a technical endurance limit at 107 cycles. The related strain amplitudes were determined by consideration of the cyclic stress strain curve. The available fatigue data for the two austenitic materials at room temperature and elevated temperatures showed a clear temperature dependence in the high cycle regime demanding for two different best-fit curves. The correlation of the technical endurance limit(s) at room temperature and elevated temperatures with the ultimate strength of the materials is discussed. Design fatigue curves were derived by application of the well known factors to the best-fit curves. A factor of SN = 12 was applied to load cycles correspondent to the NUREG/CR-6909 approach covering influences of data scatter, surface roughness, size and sequence. In terms of strain respectively stress amplitudes in the high cycle regime, for elevated temperatures (>80°C) a factor of Sσ = 1.79 was applied considering and combining in detail the partial influences of data scatter surface roughness, size and mean stress. For room temperature a factor of Sσ = 1.88 shall be applied. As a result, new design fatigue curves for austenitic stainless steel grades 1.4541 and 1.4550 will be available within the German Nuclear Safety Standard KTA 3201.2. The fatigue design rules for all other austenitic stainless steel grades will be based on the new ASME-BPVC III, App I (ed. 2010) design curve.

Fatigue Design Criteria for Pressure Vessel Alloys

1977 ◽  
Vol 99 (4) ◽  
pp. 584-592 ◽  
Author(s):  
C. E. Jaske ◽  
W. J. O’Donnell
Keyword(s):  
Pressure Vessel ◽  
Room Temperature ◽  
High Cycle Fatigue ◽  
Austenitic Steels ◽  
Design Criteria ◽  
Fatigue Design ◽  
Alloy 800 ◽  
Pressure Vessel Steels ◽  
Fatigue Data ◽  
Mean Stresses

Fatigue design criteria for pressure vessel steels are developed herein based on analysis of available material data between room temperature and 427 C (800 F). Strain-controlled low-cycle and high-cycle fatigue data for austenitic steels, alloy 800, alloy 600, and alloy 718 were evaluated. The effects of mean stresses were considered and design curves were proposed for use in Sections III and VIII of the ASME Boiler and Pressure Vessel Code.

Development of a Fatigue Design Curve for Austenitic Stainless Steels in LWR Environments: A Review

2002 ◽  
Author(s):  
Omesh K. Chopra
Keyword(s):  
Stainless Steels ◽  
Pressure Vessel ◽  
Type Strain ◽  
Nuclear Power ◽  
Austenitic Stainless Steels ◽  
Environmental Parameters ◽  
Light Water Reactor ◽  
Code Design ◽  
Fatigue Design ◽  
Asme Code

The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components and specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain–vs.–life (ε–N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This paper reviews the existing fatigue ε–N data for austenitic stainless steels in LWR coolant environments. The effects of key material, loading, and environmental parameters, such as steel type, strain amplitude, strain rate, temperature, dissolved oxygen level in water, and flow rate, on the fatigue lives of these steels are summarized. Statistical models are presented for estimating the fatigue ε–N curves for austenitic stainless steels as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are presented. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue design curves.

Effect of Mean Stress and of Mean Strain in Low-Cycle Fatigue of A-517 and A-201 Steels

1970 ◽  
Vol 92 (1) ◽  
pp. 35-51 ◽  
Author(s):  
J. Dubuc ◽  
J. R. Vanasse ◽  
A. Biron ◽  
A. Bazergui
Keyword(s):  
Plastic Strain ◽  
Pressure Vessel ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
The Mean ◽  
Mean Strain

A number of low-cycle fatigue tests has been carried out at room temperature on two materials commonly used in pressure vessel fabrication. For strain-controlled tests, the influence of different mean strains is studied; similarly, the effect of varying the mean stress is analyzed for stress-controlled tests. Relations involving elastic and plastic strain ranges, and the variations of strains or stresses during the fatigue tests are discussed.

A Study of the Low Cycle Fatigue Characteristics of Annealed AISI 347 Stainless Steel And Overaged 6951-T6 Aluminum Push-Pull Specimens

1977 ◽  
Vol 99 (3) ◽  
pp. 391-398
Author(s):  
J. A. Friedericy ◽  
R. F. Graves
Keyword(s):  
Stainless Steel ◽  
Stress Field ◽  
Room Temperature ◽  
Elastic Limit ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Cyclic Stress ◽  
Test Machine ◽  
Cycle Fatigue ◽  
Temperature Levels

In a cyclic application the Neuber theory becomes the Wetzel-Morrow approach. The Neuber theory for stresses and strains in a notch is extended to apply to specimens for which the nominal stresses and strains in the material in the field adjacent to the notch may exceed the elastic limit. Also, when the cyclic nominal stresses and strains exceed the elastic or proportional limit of the materials, this extension can be applied if a mechanism external to the nominal stress field is applied to cause the stress field to change in a predetermined manner for each successive cycle. In the case of a notched push-pull specimen, the external mechanism would be a tensile test machine and the field adjacent to the notch would be that of the nominally induced stresses and strains by means of the machine. The state of stress and strain in the notch is the result of the shape and size of the notch as well as the nominal stresses and strains adjacent to the notch. A supporting test program is discussed which dealt with the low cycle fatigue testing of two metals, AISI 347 stainless steel and 6951-T6 aluminum. A push-pull specimen was used which was designed to handle fully reversed cyclic loads from 100 cycles on up. Both fatigue and cyclic stress-strain tests were performed. The strain ranges predicted by the extended theory were inserted in the Universal Slopes equation and the cyclic lives of the specimens at various applied stress levels were determined, including those exceeding the elastic limit of the material. Good correlation was obtained between theory and experiment at the temperature levels tested. The steel specimens were tested at room temperature and 1000°F (537°C) and the aluminum specimens at room temperature and 300°F (149°C).

Low-Cycle Fatigue Behavior of TP347H Austenitic Stainless Steels at Room Temperature

2013 ◽  
Vol 815 ◽  
pp. 875-879 ◽  
Author(s):  
Hong Wei Zhou ◽  
Yi Zhu He ◽  
Yu Wan Cen ◽  
Jian Qing Jiang
Keyword(s):  
Fatigue Life ◽  
Stainless Steels ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Austenitic Stainless Steels ◽  
Fracture Morphology ◽  
Cycle Fatigue ◽  
Response Curves

Low-cycle fatigue (LCF) tests were performed with different strain amplitudes from 0.4% to 1.2% at room temperature (RT) to investigate fatigue life and fracture morphology of TP347H austenitic stainless steels. The results show that there is initial cyclic hardening for a few cycles, followed by continuous softening until fatigue failure at all strain amplitudes in stress response curves. The fatigue life of the steels follows the strain-life Coffin-Manson law. Fracture morphology shows that fatigue cracks initiate from the specimen free surface instead of the interior of the specimen, and ductile fracture appears during LCF loading. More sites of crack initiation and quicker propagation rate of fatigue crack at high strain amplitudes than those at low strain amplitudes are responsible for reduced fatigue life with the increasing of strain amplitude.

Investigation on Fatigue Properties of Cold Stretched Austenitic Stainless Steel

2011 ◽  
Author(s):  
Cunjian Miao ◽  
Jinyang Zheng ◽  
Li Ma ◽  
Duyi Ye
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Design Method ◽  
Low Cycle Fatigue ◽  
Rolling Direction ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Fatigue Properties ◽  
Fatigue Design

Cold stretched pressure vessels from austenitic stainless steel (ASS), which are sometimes subjected to alternative loads during operation, have been widely used for storage and transportation of liquefied gases. Understanding how the fatigue properties respond to cold stretching is the basis for establishing fatigue design method of such vessels. This paper involves in the fatigue properties of ASS with 9% plastic deformation by pre-stretching parallel to the rolling direction at room temperature. For this purpose, low-cycle fatigue tests at total strain amplitudes ranging from ±0.4 to 0.8% of cold stretched ASS EN 1.4301 (equivalents include UNS S30400, AISI 304) are performed, while the martensite contents are measured during the fatigue cycles. A comparison study of cyclic stress-strain behavior and fatigue lives is carried out for both cold stretched and solution annealed specimens. Based on the testing results, a S-N curve of cold stretched ASS is obtained, which is compared with the design curves given by the standards such as ASME BPVC VIII-2. These works may help to establish a favorable foundation for the development of fatigue design in cold stretched pressure vessel.

Material and Temperature Effects in Low and High Cycle EAF of Austenitic Stainless Steels

2021 ◽  
Author(s):  
Tommi Seppänen ◽  
Jouni Alhainen ◽  
Esko Arilahti ◽  
Jussi Solin
Keyword(s):  
Nuclear Power ◽  
Austenitic Stainless Steels ◽  
Reference Curve ◽  
Fatigue Design ◽  
Equivalent Number ◽  
Specific Strain ◽  
Simple Change ◽  
The Mean ◽  
Number Of Cycles ◽  
Best Fit

Abstract Fatigue design of nuclear power plant pressure boundary components necessitates the use of design curves, where the allowable number of cycles is a function of the applied stress intensity. Design curves are derived from best-fit curves to small-specimen data, which comprises a range of materials, heats, temperatures and test techniques. This paper continues the series of papers most recently published in PVP2020-21136. At VTT, heat specific strain-life data has been obtained. In this paper, using our data and literature data we demonstrate the significance these heat and temperature specific best-fit curves can have on the predicted number of cycles, when also considering the detrimental effect of environment through Fen factors. Example calculations show that in most cases, a simple change of the reference curve from the Code best-fit curve to a more realistic one adds considerably to the number of predicted cycles, or alternatively, reduces the cumulative usage at equivalent number of cycles. Mainly for high cycle fatigue at high temperature, best-fit heat-specific curves may lie below the reference, taken as the mean curve in NUREG/CR-6909. However, refinement of calculation criteria and/or the Fen methodology is considered to provide additional relief to these cases so that the cumulative usage factor calculation can still be kept below unity.

An Experimental Study for Low-Cycle Fatigue Crack Propagation of Glidcop Al-15

2017 ◽  
Vol 896 ◽  
pp. 128-133
Author(s):  
Yan Yin ◽  
Hai Bo Chen ◽  
Wei Ling Xiao
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Room Temperature ◽  
Stress Amplitude ◽  
Low Cycle Fatigue ◽  
Oxide Dispersion Strengthened ◽  
Cyclic Stress ◽  
Surface Cracks ◽  
Cycle Fatigue

Experiments have been conducted on an oxide dispersion strengthened (ODS) copper Glidcop Al-15 under a range of cyclic stress-amplitudes at room temperature. Special specimens containing an artificial small hole of various diameters, i.e. 150, 200 and 300 μm, were used. Propagation process of surface cracks in the various holed specimens was recorded to investigate the fatigue crack growth rate. Scanning electron microscope (SEM) was used for the observation of the fracture surface after failure specimens. The well-known Coffin-Manson low-cycle fatigue relationship was substantially shown through the results. An equation between the growth rate of the surface crack and the stress amplitude for Gidcop Al-15 was carried out. The experiment proved that prior fatigue history makes little influence on the subsequent crack propagation property under low-cycle condition.

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