Hydrogen Resistance of Steels Alloyed with Nitrogen

We study the resistance of stainless steels with different contents of nitrogen after plasma-arc remelting to hydrogen degradation. The dependence of the mechanical properties of steels on the content of nitrogen is quite complicated, which is explained by changes in the phase composition. In the analyzed collection of steels (Kh18AN9, Kh20AN15, Kh18AG10, and Kh18AG15), Kh18AG15 steel has the best combination of the characteristics of strength and plasticity in hydrogen.     

Distinctive features of hydrogen degradation of heat-resistant alloys based on nickel

We present the comparative data on the resistance to hydrogen degradation of three oodifications of dispersion-hardened heat-resistant KhN60MV alloy (in deformed, as-cast, and powder forms) under the conditions static tension in gaseous hydrogen under a pressure of 35 MPa in the temperature range 293–1093°K. We show that the powder modification is preferable under pressure of 0–35 MPa in the temperature range 293–1093°K. It exhibits a high level of strength, the lowest sensitivity to hydrogen degradation, and the maximum stability of plastic properties. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 33, No. 4, pp. 115–120, July–August, 1997.     

Mechanical properties of chromium-manganese austenite steels in a hydrogen environment

We study the influence of gaseous hydrogen on the mechanical properties of hardened and deformed specimens of 07Kh13G20AN4 and 03Kh13N9G19AM2 steels under a pressure of 35 MPa in the temperature range 293–773 K. We establish that hydrogen causes the strain martensite transformation of nitrogen-containing austenite stable in air. Formation of a polygonal dislocation substructure by means of preliminary mechanical or thermomechanical treatment significantly decreases the tendency of steels toward hydrogen degradation. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 35, No. 5, pp. 75–78, September–October, 1999.     

Methodological Aspects of Determination of Hydrogen Resistance of Steels

We consider main conditions of the adequate estimation of degradation of mechanical properties of chromium–nickel alloys in gaseous hydrogen. We establish that evacuation is a necessary procedure for preparing a working chamber for testing. The low-cycle fatigue and relative contraction are the most sensitive to hydrogen embrittlement. We determine the strain rate and hydrogen pressure that maximally impair mechanical properties.