process for the manufacture of workpieces of alloy steel with good mechanical behavior in the presence of hydrogen and then received workpieces

摘要

An alloy steel for use in the presence of pressurised H2 or during H2 prodn. has the wt. compsn. 0.05-0.35% C, 0.1-10% Si, 0.3-1% Mn, 0.5-4% Cr, 0.2-1.5% Mo, 0.5-4% Ni, 0-0.2% V and the remainder is iron and impurities. The steel is subjected to a heat treatment in two stages; (a) an austenizing stage at temp. 800-1,000 degrees C followed by rapid cooling; and (b) (depending on the thickness and the mechanical props.) is a tempering stage at 625-750 degrees C and produces a tempered bainite. If the steel is to be welded to itself a supplementary heat-treatment at 600-700 degrees C is required. The steel does not become brittle 200 degrees C or permit methane formation 220 degrees C in the pressure of hydrogen.