Non-Heat-Treated Steel for Manufacturing Automotive Part

The non-heat-treated steel for a cold forging does not require post-heat-treatment to meet mechanical requirements of product. This steel is very cost-effective due to the elimination of quenching-tempering heat treatment. In this study, the developed non-heat-treated-steel which is a Fe-Mn-Si-C-based multi-phase steel was used to manufacture the automotive part, pillow ball. Non-heat-treated steel was prepared and subjected to a two-step heat treatment process. The microstructure, phase composition, and mechanical properties of the non-heat-treated steel were investigated before and after the two-step continuous heat treatment. Subsequently, a pillow ball was manufactured using the developed non-heat-treated steel through a multi-stage cold forging process. The hardness analysis of the forged part was conducted and compared with that of a forged part made of conventional steel subjected to quenching-tempering heat treatment. Result showed that developed non-heat-treated steel meets the mechanical requirements of pillow ball without post-heat-treatment.