Ductility and Fatigue Strength Loss of a Hydrogen-Charged 316L Austenitic Stainless Steel

2019 ◽  
Author(s):  
Un Bong Baek ◽  
Thanh Tuan Nguyen ◽  
Seung Hoon Nahm ◽  
Kwon Sang Ryu
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Strength Loss ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Fracture Elongation ◽  
Life Measurement ◽  
316L Austenitic Stainless Steel ◽  
Fatigue Life Test

Abstract The susceptibility of 316L-type austenite stainless steel to hydrogen was quantified by means of SSRT results and low-cycle fatigue life measurement. Both tests were conducted in the air condition after being charged with high-pressure hydrogen gas of 10 MPa and a temperature of 300°C for 120 hours. In addition, SSRT tests in gaseous hydrogen at a pressure of 10 MPa were also performed and compared to the tests conducted in hydrogen pre-charged and as-received conditions. The 0.2% yield strength and tensile strength did not show there to be a considerable difference between hydrogen pre-charging and the as-received conditions, whereas the gaseous hydrogen condition revealed a remarkable degradation in tensile properties, especially in terms of fracture elongation. In the case of fatigue life test, a considerable influence of hydrogen pre-charging in fatigue life properties was observed in the high strain amplitude regime whereas the measured values in the low strain deformation region are consistently comparable to that in the as-received condition. Fatigue limit was not affected by hydrogen pre-charging.

Effect of High Pressure Gaseous Hydrogen on Fatigue Properties of SUS304 and SUS316 Austenitic Stainless Steel

2018 ◽  
Author(s):  
Takashi Iijima ◽  
Hirotoshi Enoki ◽  
Junichiro Yamabe ◽  
Bai An
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Room Temperature ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Life Test ◽  
Air Atmosphere ◽  
Fatigue Life Test

A high pressure material testing system (max. pressure: 140 MPa, temperature range: −80 ∼ 90 °C) was developed to investigate the testing method of material compatibility for high pressure gaseous hydrogen. In this study, SSRT and fatigue life test of JIS SUS304 and SUS316 austenitic stainless steel were performed in high pressure gaseous hydrogen at room temperature, −45, and −80 °C. These testing results were compared with those in laboratory air atmosphere at the same test temperature range. The SSRT tests were performed at a strain rate of 5 × 10−5 s−1 in 105 MPa hydrogen gas, and nominal stress-strain curves were obtained. The 0.2% offset yield strength (Ys) did not show remarkable difference between in hydrogen gas and in laboratory air atmosphere for SUS304 and SUS316. Total elongation after fracture (El) in hydrogen gas at −45 and −80 °C were approximately 15 % for SUS304 and 20% for SUS316. In the case of fatigue life tests, a smooth surface round bar test specimen with a diameter of 7 mm was used at a frequency of 1, 0.1, and 0.01 Hz under stress rate of R = −1 (tension-compression) in 100 MPa hydrogen gas. It can be seen that the fatigue life test results of SUS304 and SUS316 showed same tendency. The fatigue limit at room temperature in 100 MPa hydrogen gas was comparable with that in laboratory air. The room temperature fatigue life in high pressure hydrogen gas appeared to be the more severe condition compared to the fatigue life at low temperature. The normalized stress amplitude (σa / Ts) at the fatigue limit was 0.37 to 0.39 for SUS304 and SUS316 austenitic stainless steels, respectively.

Low Cycle Fatigue Life of Type 316 Stainless Steel Notched Specimen Under Proportional and Non-Proportional Multiaxial Loadings

2010 ◽  
Author(s):  
Takamoto Itoh
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Strain Path ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Notched Specimen ◽  
Life Estimation ◽  
316 Stainless Steel ◽  
Strain Parameter ◽  
Strain Paths

This study discusses multiaxial low cycle fatigue life of notched specimen under proportional and non-proportional loadings at room temperature. Strain controlled multiaxial low cycle fatigue tests were carried out using smooth and circumferentially notched round-bar specimens of type 316 stainless steel. Four kinds of notched specimens were employed of which elastic stress concentration factors, Kt, are 1.5, 2.5, 4.2 and 6.0. The strain paths include proportional and non-proportional loadings. The former employed a push-pull straining or a reversed torsion straining. The latter was achieved by strain path where axial and shear strains has 90 degree phase difference but their amplitudes is the same based on von Mises’ criterion. The notch dependency of multiaxial low cycle fatigue life and the life estimation are discussed. The lives depend on both Kt and strain path. The strain parameter for the life estimation is also discussed with the non-proportional strain parameter proposed by the author with introducing Kt. The proposed parameter gives a satisfactory correlation with multiaxial low cycle fatigue life of notched specimen of type 316 stainless steel under proportional and non-proportional loadings.

Effect of Surface Finish and Loading Conditions on the Low Cycle Fatigue Life of Stainless Steel Welded Piping in PWR Environment

2013 ◽  
Author(s):  
Yuichi Fukuta ◽  
Yuichiro Nomura ◽  
Seiji Asada
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Surface Finish ◽  
Loading Condition ◽  
Low Cycle Fatigue ◽  
Complex Loading ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Effect Of Surface

NUREG/CR-6909 of USA and JSME of Japan proposed new rules for evaluating environmental effects in fatigue analyses of reactors components. These rules were established from a lot of fatigue data with polished specimens under simple loading condition. The effects of surface finish or complex loading condition were reported in some papers, but these data were obtained with the simple shaped specimens. In order to evaluate the effects of surface finish and loading condition and to confirm the applicability of the proposed rules to actual components, Low Cycle Fatigue tests are performed in PWR environment with the specimens cut from 316 austenitic stainless steel welded piping. The pipes are machined to have three levels of surface finish condition and the load pattern simulating the thermal stress is applied to specimens. In this study, the effect of surface finish on fatigue life is included to be small for 316 austenitic stainless steel welded piping. Considering the insensitive region in the current evaluation rule, predicted accuracy is increased and possibility of improving the current rule is indicated.

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