Austenitic steel material having excellent hydrogen-embrittlement resistance

Abstract

Disclosed is an austenitic material having excellent hydrogen-embrittlement resistance, comprising, by weight, 0.1-0.5% of C, 5% or less (0% exclusive) of Cu, 1% or less (0% exclusive) of N, a contentof [Mn] satisfying [Mn]>=-10.7C+24.5, 10% or less of Cr, 5% or less of Ni, 5% or less of Mo, 4% or less of Si, 5% or less of Al, and a balance amount of Fe and inevitable impurities, with a T-El2 / T-El1 ratio of 0.5 or higher, wherein T-El1 is an elongation at break according to a tensile test at 25oC under an atmospheric condition of 1 atm and T-El2is an elongation at break according to a tensiletest at 25 DEG C under a hydrogen condition of 70 MPa.

Description

technical field [0001] The present invention relates to an austenitic steel material excellent in hydrogen embrittlement resistance, and more specifically relates to an austenitic steel material excellent in hydrogen embrittlement resistance suitable for high-pressure hydrogen storage tanks, piping and transportation equipment. Background technique [0002] In the prevention of global warming and environmental pollution, many efforts have been made to reduce environmental pollutants and greenhouse gas emissions. Among them, the technology of using hydrogen as an energy source has recently been continuously developed. Hydrogen is the most environmentally friendly energy source. It is different from fossil fuels such as coal and oil. It is attracting attention as a future new energy source with almost no pollutant emissions, especially as a fuel for hydrogen vehicles using fuel cells. [0003] Hydrogen vehicles usually use high-pressure compression of hydrogen to make it high-...

AI Technical Summary

Problems solved by technology

[0005] However, recently, in order to achieve long-distance driving and large-scale storage by filling hydrogen once, the pressure of hydrogen has been increased to tens or hundreds of MPa. Therefore, in the case of ordinary low-strength austenitic stainless steel, in order to To withstand the load under high pressure, it is necessary to increase the thickness of the material, as a result, it is difficult to avoid the increase in weight and size of the container or equipment, thereby limiting its commercial application

[0006] As a technology to solve this problem, Japanese Laid-Open Patent Publication No. 5-98391 and International Laid-Open Patent Publication No. 2014-111285 disclose the technology of improving the strength of austenitic stainless steel through cold rolling, but the cold rolling process The increase in strength will reduce the ductility and toughness, and reduce the stability of austenite, which may cause strain-induced martensite, so it is not suitable as a container for hydrogen storage

In addition, Korean Laid-Open Patent Publication No. 10-2006-0018250 discloses a technique for ensuring the stability of austenite by performing cold working twice in different directions. However, in order to increase the stability of austenite, it is necessary to add a large amount of Expensive alloying elements Cr, Ni, which is an unfavorable disadvantage in terms of cost

[0007] In addition, Korean Laid-Open Patent Publication No. 10-2011-0004491 and Korean Laid-Open Patent Publication No. 10-2013-0045931 disclose that the expensive alloy element Ni contained in the conventional austenitic stainless steel is replaced by an inexpensive alloy element Mn, It is a technology to ensure stable austenite and improve hydrogen embrittlement resistance, but it still contains a large amount of expensive alloying elements, so it becomes a stumbling block hindering commercial application in terms of economy

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