Effect of Thermomechanical Treatment on the Properties of Steel with a Mixed Martensitic-Bainitic Structure

Abstract

The structure formation features of steel with 0.4 C, 1.5 Cr, 1.5 Ni, 0.5 Mo (wt. %) after high-temperature thermomechanical treatment with martensite-bainite transformation of austenite was investigated. It was found that a mixed structure consisting of alternating elongated areas of tempered martensite and lower bainite was formed by steel treatment. The proposed treatment can significantly increase impact strength and fracture toughness of steel. This technological process is mostly effective for strengthening alloy steels with increased resistance of under-cooled austenite.