Low Carbon Chromium Steel Transformation Plasticity during Tempering

Abstract

The transformation plasticity of low carbon chromium steel was studied experimentally. The studied material was two-phase stainless steel with martensite base containing approximately 1 % of ferrite. The results of transformation plasticity of stainless steel were compared with the results of steel transformation plasticity of similar chemical composition (except chromium content). After quenching bending tests were performed at various temperatures ranging from 420 °C to 650 °C for 1 hour. The specimens of investigated steel were exposed to the bending stress (90 MPa) during heating for tempering. Also, the transformation plasticity of both types of steel after a long-term tempering at 700 °C temperature for 24 h, 48 h and 120 h was investigated. First results show that the transformation plasticity of investigated steel depends on the structural and chemical composition that undergoes changes with varying tempering temperature and tempering duration. Carbon and chromium precipitation from the solid solution and formation of carbides has significant influence on the mechanical behavior of steel during tempering.