Influence Of Novel Q-P-T Process And Traditional Q&t Process On Residual Stress And Structure And Properties

We should develop low-cost advanced high strength steels (AHSS) tomeet the requirements of the resource and energy savings and theenvironmental protection. Therefore, T. Y. Hsu (Xu Zuyao) proposed thenovel quenching-partitioning-tempering (Q-P-T) process. Compared withthe traditional quenching-tempering(Q&T) process, elongation of Q-P-Tsteels increases remarkably while strength decreases slightly. Influence onthe residual stress and structure and properties of novel Q-P-T process andtraditional Q&T process is studied in this work, which establishes the basisfor the potential industrial application of the proposed Q-P-T heattreatment process. Now the main experiments and achievements areexpressed briefly below.1. Compared with Q&T steels, surface residual stress of Q-P-T steelsdecreases35%along X direction and30%along Y direction. Therefore, Q-P-T process can effectively eliminate stress concentration, thus reducingmicroscopic cracks in steels. So this is one important reason why Q-P-Tsteels have high ductility.2. Compared with Q-P-T steels, surface residual stress of M(2)-Q-P-Tand M(3)-Q-P-T steels decreases60%and72%respectively along Xdirection, and19%and45%respectively along Y direction. Even moreimportant is that the interior residual stress also decline sharply, and inM(3)-Q-P-T steels, from the surface to interior, there is no apparent stressgradient.