Texture Inheritance in the Ferrito-Martensite Structure of Low-Alloy Steel after Thermomechanical Controlled Processing

Abstract

The electron back-scatter diffraction (EBSD) method was used to study the structural and textural states of low-carbon low-alloy steel after thermomechanical controlled processing (TMCP) and subsequent heat treatment (HT) including austenitization, holding at the temperature of the decomposition of the γ phase by the diffusion mechanism for different times, and quenching. As a result of the HT, structures were obtained consisting of polygonal ferrite and martensite in various ratios. The crystallographic textures of both martensite and ferrite after HT reproduced the texture of bainite formed as a result of the TMCP. The orientations that form this texture are related to the main orientations of deformed austenite grains upon the TMCP via the orientation relationships (ORs) intermediate between the Kurdjumov–Sachs and Nishiyama–Wassermann ORs. In the case of both ferrite and martensite, the orientational connection between the components of the texture components is explained by the onset of the realization of the phase transformation on crystallographically stipulated (including special) boundaries.