The Phase Transformation of Low Carbon Steel using Controlled Cooling Systems

Abstract

Abstract: Automobile manufacturers face mounting pressure to develop new materials that improve their vehicles' fuel economy, pollution emissions, and crash safety. These objectives appear ambiguous when they must be met while reducing the weight of a vehicle. This requires using materials with a high strength-to-weight ratio and high formability. The objectives of the work presented in this paper were to control the cooling of steel with lean chemistry to generate a multi-functional multi/dual-phase steel. The calculations were performed using JMat-Pro and Thermo-Calc. The CCT, TTT, equilibrium diagram, and phase fraction diagram of the steel is under investigation. It was found that inter-critical annealing can be achieved with a variety of strength-ductility combinations in steels with proper cooling pathways. Therefore, by modifying the heat treatment parameters, the examined steel's alloy chemistry enabled the achievement of a wide variety of strengths and ductility combinations.

 Index Terms: dual-phase  (DP) steels, heat treatment, annealing, phase transformation, control cooling