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.

Reduction in Fretting Fatigue Strength of Austenitic Stainless Steels due to Internal Hydrogen

2014 ◽  
Vol 891-892 ◽  
pp. 891-896 ◽  
Author(s):  
Ryosuke Komoda ◽  
Naoto Yoshigai ◽  
Masanobu Kubota ◽  
Jader Furtado
Keyword(s):  
Plastic Deformation ◽  
Fatigue Strength ◽  
Crack Initiation ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Fretting Fatigue ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Internal Hydrogen ◽  
Major Factors

Fretting fatigue is one of the major factors in the design of hydrogen equipment. The effect of internal hydrogen on the fretting fatigue strength of austenitic stainless steels was studied. The internal hydrogen reduced the fretting fatigue strength. The reduction in the fretting fatigue strength became more significant with an increase in the hydrogen content. The reason for this reduction is that the internal hydrogen assisted the crack initiation. When the fretting fatigue test of the hydrogen-charged material was carried out in hydrogen gas, the fretting fatigue strength was the lowest. Internal hydrogen and gaseous hydrogen synergistically induced the reduction in the fretting fatigue strength of the austenitic stainless steels. In the gaseous hydrogen, fretting creates adhesion between contacting surfaces where severe plastic deformation occurs. The internal hydrogen is activated at the adhered part by the plastic deformation which results in further reduction of the crack initiation limit.

Evaluation of Hydrogen Environment Embrittlement and Fatigue Properties of Stainless Steels in High Pressure Gaseous Hydrogen: Investigation of Materials Properties in High Pressure Gaseous Hydrogen—2

2007 ◽  
Author(s):  
Tomohiko Omura ◽  
Mitsuo Miyahara ◽  
Hiroyuki Semba ◽  
Masaaki Igarashi ◽  
Hiroyuki Hirata
Keyword(s):  
High Pressure ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Fatigue Properties ◽  
Chemical Compositions ◽  
Hydrogen Environment

Hydrogen environment embrittlement (HEE) susceptibility in high pressure gaseous hydrogen was investigated on 300 series austenitic stainless steels and A6061-T6 aluminum alloy. Tensile properties of these materials were evaluated by Slow Strain Rate Testing (SSRT) in gaseous hydrogen pressurized up to 90MPa (13053 psig) in the temperature range from −40 to 85 degrees C (−40 to 185 degrees F). HEE susceptibilities of austenitic stainless steels strongly depended upon the chemical compositions and testing temperatures. A6061-T6 aluminum alloy showed no degradation by hydrogen. Fatigue properties in high pressure gaseous hydrogen were evaluated by the external cyclic pressurization test using tubular specimens. The tubular specimen was filled with high pressure hydrogen gas, and the outside of the specimen was cyclically pressurized with water. Type 304 showed a decrease in the fatigue life in hydrogen gas, while as for type 316L and A6061-T6 the difference of the fatigue life between hydrogen and argon environments was small. HEE susceptibility of investigated materials was discussed based on the stability of an austenitic structure.

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.

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.

scholarly journals Effects of Extreme Hydrogen Environments on the Fracture and Fatigue Behavior of Additively Manufactured Stainless Steels

2019 ◽  
Author(s):  
Thale R. Smith ◽  
Chris San Marchi ◽  
Joshua D. Sugar ◽  
Dorian K. Balch
Keyword(s):  
High Pressure ◽  
Stainless Steels ◽  
Fatigue Behavior ◽  
Austenitic Stainless Steels ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Gaseous Hydrogen ◽  
Tensile Fracture ◽  
Manufacturing Defects ◽  
Service Environments

Abstract Additive manufacturing (AM) offers the potential for increased design flexibility in the low volume production of complex engineering components for hydrogen service. However, the suitability of AM materials for such extreme service environments remains to be evaluated. This work examines the effects of internal and external hydrogen on AM type 304L austenitic stainless steels fabricated via directed-energy deposition (DED) and powder bed fusion (PBF) processes. Under ambient test conditions, AM materials with minimal manufacturing defects exhibit excellent combinations of tensile strength, tensile ductility, and fatigue resistance. To probe the effects of extreme hydrogen environments on the AM materials, tensile and fatigue tests were performed after thermal-precharging in high pressure gaseous hydrogen (internal H) or in high pressure gaseous hydrogen (external H). Hydrogen appears to have a comparable influence on the AM 304L as in wrought materials, although the micromechanisms of tensile fracture and fatigue crack growth appear distinct. Specifically, microstructural characterization implicates the unique solidification microstructure of AM materials in the propagation of cracks under conditions of tensile fracture with hydrogen. These results highlight the need to establish comprehensive microstructure-property relationships for AM materials to ensure their suitability for use in extreme hydrogen environments.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

scholarly journals Hydrogen-Assisted Fracture of Type 316L Tubing and Orbital Welds

2013 ◽  
Author(s):  
C. San Marchi ◽  
L. A. Hughes ◽  
B. P. Somerday ◽  
X. Tang
Keyword(s):  
Stainless Steels ◽  
Base Material ◽  
Austenitic Stainless Steels ◽  
Gaseous Hydrogen ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Testing ◽  
Type 316L ◽  
316L Austenitic Stainless Steel ◽  
Outside Diameter ◽  
Assisted Fracture

Austenitic stainless steels have been extensively tested in hydrogen environments. These studies have identified the relative effects of numerous materials and environmental variables on hydrogen-assisted fracture. While there is concern that welds are more sensitive to environmental effects than the non-welded base material, in general, there have been relatively few studies of the effects of gaseous hydrogen on the fracture and fatigue resistance of welded microstructures. The majority of published studies have considered welds with geometries significantly different from the welds produced in assembling pressure manifolds. In this study, conventional, uniaxial tensile testing was used to characterize tubing of type 316L austenitic stainless steel with an outside diameter of 6.35 mm. Additionally, orbital tube welds were produced and tested to compare to the non-welded tubing. The effects of internal hydrogen were studied after saturating the tubes and orbital welds with hydrogen by exposure to high-pressure gaseous hydrogen at elevated temperature. The effects of hydrogen on the ductility of the tubing and the orbital tube welds were found to be similar to the effects observed in previous studies of type 316L austenitic stainless steels.

A Study of Nozzles in Pressure Vessels under Pressure Fatigue Loading

1967 ◽  
Vol 182 (1) ◽  
pp. 657-684 ◽  
Author(s):  
J. Spence ◽  
W. B. Carlson
Keyword(s):  
Fatigue Life ◽  
Mild Steel ◽  
Pressure Vessel ◽  
Special Interest ◽  
Maximum Stress ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Full Size

Nozzles in cylindrical vessels have been of special interest to designers for some time and have offered a field of activity for many research workers. This paper presents some static and fatigue tests on five designs of full size pressure vessel nozzles manufactured in two materials. Supporting and other published work is reviewed showing that on the basis of the same maximum stress mild steel vessels give the same fatigue life as low alloy vessels. When compared on the basis of current codes it is shown that mild steel vessels may have five to ten times the fatigue life of low alloy vessels unless special precautions are taken.

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