Influences of alloying elements on warm deformation behavior of high-Mn TRIP steel with martensitic structure

Abstract

Warm deformation behaviors of high-Mn TRIP steels with martensitic structure were investigated using a Gleeble 1500 hot simulator within the temperature range of 550–650°C and the strain rate range of 0.001–0.1s−1. The influences of common alloying elements, i.e. C, Mn, Si and Al, on the flow stress and the microstructural evolution during warm deformation were analyzed. The results showed that the flow stress was increased with the increase in C content, Mn content, Si content or Al content at the same condition, and the deformation activation energy Q was increased with the increase in Mn content and decreased by the increase in C content. The increase in Si content or Al content showed slight influence on the deformation activation energy Q. During warm deformation the decomposition of martensite into ferrite and carbides occurred firstly, and then dynamic recrystallization (DRX) of ferrite and the reverse transformation of austenite took place. DRX of ferrite was retarded by the increase in Mn content or Si content and accelerated by the increase in C content. Meanwhile, the reverse transformation of austenite was promoted by the increase in Mn content and retarded by the increase in C content, Si content or Al content.