Investigation of structure and properties of low-carbon low-alloyed Cr-Mo pipe steel intended for operating in sour environment

Abstract

The paper presents the results of the study of microstructure, mechanical and corrosion properties of the promising high-strength economically alloyed Fe-Cr-Mo steel, designed for the production of the oil country tubular goods (OCTG): casing and tubing. The main qualifying standards for this steel are to provide simultaneous increase of strength and resistance to sulfide stress cracking (SSC). It was shown that these requirements could be achieved by a special heat treatment, which results in the formation of a secondary sorbite structure with a lower dislocation density and dispersion-strengthened V, Nb carbides.The paper presents the results of the study of microstructure, mechanical and corrosion properties of the promising high-strength economically alloyed Fe-Cr-Mo steel, designed for the production of the oil country tubular goods (OCTG): casing and tubing. The main qualifying standards for this steel are to provide simultaneous increase of strength and resistance to sulfide stress cracking (SSC). It was shown that these requirements could be achieved by a special heat treatment, which results in the formation of a secondary sorbite structure with a lower dislocation density and dispersion-strengthened V, Nb carbides.