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Austenitic stainless steel 1.4435, a candidate material for high-pressure tubing for hydrogen applications, was investigated in two different stages of cold deformation (0 and 27 %) regarding its hydrogen embrittlement tendency. The determination of effective diffusion coefficients revealed slightly increased diffusion kinetics at 60°C for the cold-reduced material (8.0 · 10−15 m²/s) compared to the solution annealed one (5.0 · 10−15 m²/s). High-pressure gaseous hydrogen charging shows no differences regarding the degree of cold deformation with a maximum hydrogen concentration of 112 wt.-ppm. Furthermore, a significant ductility loss expressed by the ratio of the reduction of area was observed. • Cold drawn material shows enhanced diffusion kinetics than solution annealed state. • Hydrogen contents of up to 112 wt.-ppm are present after gaseous charging. • No failure occurred in constant load tests at 90 % of the yield strength. • SSRTs show no significant decrease in fracture elongation due to hydrogen charging. • 1.4435 is applicable for hydrogen tank systems within the tested conditions. [ABSTRACT FROM AUTHOR]

• SSRT with Hollow Probe Specimens show a decrease in K55′s mechanical properties. • Charging with 200 bar H 2 leads to a loss of 63 % of fracture elongation. • The embrittlement tendency increases with increasing charging pressure. • Beneficial influence of pearlite inhibiting the crack propagation. The susceptibility of ferritic pearlitic steel K55 to hydrogen embrittlement in high pressure gas atmospheres was investigated using slow strain rate tests with hollow probe specimens. Therefore, the specimens were charged with an internal hydrogen pressure of up to 20 MPa according to planned conditions for underground gas storages. The results show a significant decrease in ductility caused by hydrogen embrittlement yielding a loss in fracture strain of 46 % at 10 MPa and 63 % at 20 MPa hydrogen partial pressure compared to a specimen tested in nitrogen atmosphere. Furthermore, observations on the cross-sections of the tested specimens reveal that pearlite acts as obstacle for hydrogen enhanced crack growth. [ABSTRACT FROM AUTHOR]

Hydrogen uptake and embrittlement characteristics of a cold-drawn austenitic stainless steel wire were investigated. Slow strain rate testing and fracture surface analysis were applied to determine the hydrogen embrittlement resistance, providing an apparent decrease in resistance to hydrogen embrittlement for a 50% degree of cold deformation. The hydrogen content was assessed by thermal desorption and laser-induced breakdown spectroscopy establishing a correlation between the total absorbed hydrogen and the intensity of near-surface hydrogen. The sub-surface hydrogen content of the hot-rolled specimen was determined to be 791 wt.ppm. • TDS combined with LIBS was applied to quantify H-diffusion profiles. • Critical hydrogen concentrations for brittle fracture were obtained. • The degree of cold-drawing was correlated to hydrogen-induced damage. [ABSTRACT FROM AUTHOR]