scholarly journals Hydrogen Effects on Fatigue Life of Welded Austenitic Stainless Steels Evaluated With Hole-Drilled Tubular Specimens

2020 ◽  
Author(s):  
B. Kagay ◽  
C. San Marchi ◽  
V. Pericoli ◽  
J. Foulk
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Stainless Steels ◽  
Fatigue Crack Initiation ◽  
Austenitic Stainless Steels ◽  
Internal Hydrogen ◽  
Weld Fatigue ◽  
Crack Initiation Life ◽  
Tubular Specimens

Abstract Limited fatigue data exists for small-volume welded austenitic stainless steel components typically employed in hydrogen infrastructure due to the difficulty of testing these components with conventional specimen designs. To assess the fatigue performance of orbital tube welds of austenitic stainless steels, a hole-drilled tubular specimen was designed to produce a stress concentration in the center of the orbital weld. Fatigue life testing was performed on welded and non-welded 316L stainless steel hole-drilled tubular specimens, and the effects of hydrogen were evaluated by testing specimens with no added hydrogen and with internal hydrogen introduced through gaseous precharging. When accounting for the differences in flow stress caused by microstructural variations and the presence of internal hydrogen, the total fatigue life and fatigue crack initiation life of the welded and non-welded tubes were comparable and were reduced by internal hydrogen. In addition, the fatigue life results produced with the hole drilled tubular specimens were consistent with fatigue life data from circumferentially notched stainless steel specimens that have a similar elastic stress concentration factor. To better understand the mechanics of this specimen geometry, mechanics modeling was performed to compare the stress and strain distributions that develop at the stress concentration in the hole-drilled tubular and circumferentially notched specimens during fatigue cycling.

Fatigue Behavior of Circumferentially Notched Round Bars of Austenitic Stainless Steel Under Torsional and Axial Loads

2010 ◽  
Author(s):  
Masao Itatani ◽  
Keisuke Tanaka ◽  
Isao Ohkawa ◽  
Takehisa Yamada ◽  
Toshiyuki Saito
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Static Tension ◽  
Cyclic Torsion ◽  
Cyclic Tension ◽  
Crack Initiation Life

Fatigue tests of smooth and notched round bars of austenitic stainless steels SUS316NG and SUS316L were conducted under cyclic tension and cyclic torsion with and without static tension. Fatigue strength under fully reversed (R=−1) cyclic tension once increased with increasing stress concentration factor up to Kt=1.5, but it decreased from Kt=1.5 to 2.5. Fatigue life increased with increasing stress concentration under pure cyclic torsion, while it decreased with increasing stress concentration under cyclic torsion with static tension. From the measurement of fatigue crack initiation and propagation lives using electric potential drop method, it was found that the crack initiation life decreased with increasing stress concentration and the crack propagation life increased with increasing stress concentration under pure cyclic torsion. Under cyclic torsion with static tension, the crack initiation life also decreased with increasing stress concentration but the crack propagation life decreased or not changed with increasing stress concentration then the total fatigue life of sharper notched specimen decreased. It was also found that the fatigue life of smooth specimen under cyclic torsion with static tension was longer than that under pure cyclic torsion. This behavior could be explained based on the cyclic strain hardening under non-proportional loading and the difference in crack path with and without static tension.

A Proposal of Fatigue Life Correction Factor Fen for Austenitic Stainless Steels in LWR Water Environments

2002 ◽  
Author(s):  
Makoto Higuchi ◽  
Kunihiro Iida ◽  
Akihiko Hirano ◽  
Kazuya Tsutsumi ◽  
Katsumi Sakaguchi
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Reduction Factor ◽  
New Models ◽  
Fatigue Data ◽  
Few Data ◽  
Fatigue Life Reduction ◽  
Remarkable Reduction

The fatigue life of austenitic stainless steel has recently been shown to undergo remarkable reduction with decrease in strain rate and increase in temperature in water. Either of these parameters as a factor of this reduction has been examined quantitatively and methods for predicting the fatigue life reduction factor Fen in any given set of conditions have been proposed. All these methods are based primarily on fatigue data in simulated PWR water owing to the few data available in simulated BWR water. Recent Japanese fatigue data in simulated BWR water clearly indicated the effects of the environment on fatigue degradation to be milder than under actual PWR conditions. A new method for determining Fen in BWR water was developed in the present study and a revised Fen in PWR water is also proposed based on new data. These new models differ from those previously used primarily with regard to the manner in which strain amplitude is considered to affect Fen in the environment.

scholarly journals Comparison of Internal and External Hydrogen on Fatigue-Life of Austenitic Stainless Steels

2016 ◽  
Author(s):  
Paul J. Gibbs ◽  
Chris San Marchi ◽  
Kevin A. Nibur ◽  
Xiaoli Tang
Keyword(s):  
Fatigue Life ◽  
Stainless Steels ◽  
Life Stress ◽  
Maximum Stress ◽  
Austenitic Stainless Steels ◽  
Fatigue Tests ◽  
Gaseous Hydrogen ◽  
Fatigue Performance ◽  
Notched Specimens ◽  
Internal Hydrogen

The degradation of stress-controlled fatigue-life (stress-life) of notched specimens was measured in the presence of internal and in external hydrogen for two strain-hardened austenitic stainless steels: 316L and 21Cr-6Ni-9Mn. To assess the sensitivity of fatigue performance to various hydrogen conditions fatigue tests were performed in four environments: (1) in air with no added hydrogen, (2) in air after hydrogen pre-charging to saturate the steel with internal hydrogen, and in external gaseous hydrogen at pressure of (3)10 MPa (1.45 ksi), or (4) 103 MPa (15 ksi). The fatigue performance of the strain-hardened 316L and 21Cr-6Ni-9Mn steels in air was indistinguishable for the tested conditions. Decreases in the fatigue-life at a given stress level were measured in the presence of hydrogen and depended on the hydrogen environment. Testing in 103 MPa (15 ksi) external gaseous hydrogen always resulted in a clear decrease in the fatigue-life at a given maximum stress. Alloy dependent reductions in the observed life at a given maximum stress were observed in the presence of internal hydrogen or in gaseous hydrogen at a pressure of 10 MPa (1.45 ksi). The measured fatigue-life of hydrogen pre-charged specimens was comparable to the life with no intentional hydrogen additions. Accounting for the increased flow stress resulting from the supersaturation of hydrogen after pre-charging results in consistency between the measured fatigue-life of the pre-charged condition and measurements in 103 MPa (15 ksi) external hydrogen. The current results indicate that internal hydrogen may be an efficient method to infer hydrogen-assisted fatigue degradation of stainless steels in high-pressure gaseous hydrogen.

scholarly journals Effects of LWR Coolant Environments on Fatigue Lives of Austenitic Stainless Steels

1998 ◽  
Vol 120 (2) ◽  
pp. 116-121 ◽  
Author(s):  
O. K. Chopra ◽  
D. J. Gavenda
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Statistical Model ◽  
Stainless Steels ◽  
Type Strain ◽  
Fatigue Cracks ◽  
Austenitic Stainless Steels ◽  
Strain Range ◽  
Fatigue Tests ◽  
Ferritic Steels

Fatigue tests have been conducted on Types 304 and 316NG stainless steels to evaluate the effects of various material and loading variables, e.g., steel type, strain rate, dissolved oxygen (DO) in water, and strain range, on the fatigue lives of these steels. The results confirm significant decreases in fatigue life in water. Unlike the situation with ferritic steels, environmental effects on Types 304 and 316NG stainless steel are more pronounced in low-DO than in high-DO water. Experimental results have been compared with estimates of fatigue life based on a statistical model. The formation and growth of fatigue cracks in air and water environments are discussed.

A Proposal of Fatigue Life Correction Factor Fen for Austenitic Stainless Steels in LWR Water Environments

2003 ◽  
Vol 125 (4) ◽  
pp. 403-410 ◽  
Author(s):  
Makoto Higuchi ◽  
Kazuya Tsutsumi ◽  
Akihiko Hirano ◽  
Katsumi Sakaguchi
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Reduction Factor ◽  
New Models ◽  
Fatigue Data ◽  
Few Data ◽  
Fatigue Life Reduction ◽  
Remarkable Reduction

The fatigue life of austenitic stainless steel has recently been shown to undergo remarkable reduction with decrease in strain rate and increase in temperature in water. Either of these parameters as a factor of this reduction has been examined quantitatively and methods for predicting the fatigue life reduction factor Fen in any given set of conditions have been proposed. All these methods are based primarily on fatigue data in simulated PWR water owing to the few data available in simulated BWR water. Recent Japanese fatigue data in simulated BWR water clearly indicated the effects of the environment on fatigue degradation to be milder than under actual PWR conditions. A new method for determining Fen in BWR water was developed in the present study and a revised Fen in PWR water is also proposed based on new data. These new models differ from those previously used primarily with regard to the manner in which strain amplitude is considered to affect Fen in the environment.

ALZ 316

Alloy Digest ◽  
1999 ◽  
Vol 48 (8) ◽  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Heat Treating

Abstract ALZ 316 is an austenitic stainless steel with good formability, corrosion resistance, toughness, and mechanical properties. It is the basic grade of the stainless steels, containing 2 to 3% molybdenum. After the 304 series, the molybdenum-containing stainless steels are the most widely used austenitic stainless steels. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-756. Producer or source: ALZ nv.

ALLOY 0Cr25Ni6Mo3CuN

Alloy Digest ◽  
1998 ◽  
Vol 47 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Temperature Performance ◽  
Steel Research ◽  
Oil Refinement

Abstract ALLOY 0Cr25Ni6Mo3CuN is one of four grades of duplex stainless steel that were developed and have found wide applications in China since 1980. In oil refinement and the petrochemical processing industries, they have substituted for austenitic stainless steels in many types of equipment, valves, and pump parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming and joining. Filing Code: SS-706. Producer or source: Central Iron & Steel Research Institute.

CARTECH 347

Alloy Digest ◽  
2021 ◽  
Vol 70 (9) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Intergranular Corrosion ◽  
Austenitic Stainless Steels ◽  
Heat Treating ◽  
Intermittent Heating ◽  
Technology Corporation ◽  
Carpenter Technology Corporation

Abstract CarTech 347 is a niobium+tantalum stabilized austenitic stainless steel. Like Type 321 austenitic stainless steel, it has superior intergranular corrosion resistance as compared to typical 18-8 austenitic stainless steels. Since niobium and tantalum have stronger affinity for carbon than chromium, carbides of those elements tend to precipitate randomly within the grains instead of forming continuous patterns at the grain boundaries. CarTech 347 should be considered for applications requiring intermittent heating between 425 and 900 °C (800 and 1650 °F). This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1339. Producer or source: Carpenter Technology Corporation.

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