STEEL FOR HYDROGEN GAS ENVIRONMENT, STRUCTURAL HARDWARE MEMBER AND METHOD FOR PRODUCING SAME

摘要

Disclosed is a steel which does not suffer from hydrogen embrittlement even when the steel is used in a hydrogen gas environment. Also disclosed are a method for producing such a steel and a container for high-pressure hydrogen gas or other hardware made of such a steel. A steel containing 0.3-30% of Cr is used as the base material, and a oxide film having a thickness of 100 nm or more is formed on the surface of the base material. The oxide film contains at least two elements selected among Fe, Cr and Al in the form of oxides, respectively in an amount of 5 atom% or more. The oxide film is formed through single-step or two-step heating wherein the steel is heated in the atmosphere at 600-900°C for not less than 3 minutes but not more than 2 hours if necessary, and then heated in a hydrogen atmosphere at 700-1200°C for not less than 3 minutes but not more than 2 hours while controlling the water vapor partial pressure within the range from 10-8 to 10-1 MPa.