High strength martensitic stainless steel excellent in resistance to corrosion by gas carbon dioxide and resistance to stress corrosion fracture by sulfide

摘要

"High strength martensitic stainless steel excellent in resistance to corrosion by gas carbon dioxide and resistance to stress corrosion fracture by sulfide. The present invention relates to a martensitic stainless steel in which the elements specified in a steel composition are limited.The martensitic stainless steel can have high strength of 0.2% proof stress of 860 MPa or more and excellent resistance to corrosion by carbon dioxide and a tensile stress corrosion sulfide by the limitation of the steel composition of the elements specified and the definition of the Mo content in the steel for the relations with the The s values of IM and the conformation of the microstructure of the steel with mainly martensita seasoned.Carbide precipitated during tempering and intermetallic compounds such as stage wash phase sym and similar.As a result, martensitic stainless steels of this invention can be applied to practical steels, which can be widely used in pipes for oil wells and the like in environments including gas, carbon dioxide, hydrogen sulfide, chlorine ions or two or Most of them, in large fields.