一种新型热处理工艺对中碳钢组织性能影响

Effect of a novel heat treatment process on microstructure and mechanical properties of medium carbon steel

为提高钢的强塑性,基于传统淬火-碳分配-回火(quenching-partitioning-tempering,Q-P-T)工艺,结合热变形技术,提出变形-淬火-碳分配-回火(deforming-quenching-partitioning-tempering,D-Q-P-T)的设计思想,通过扫描电镜、透射电镜、X射线衍射和拉伸试验,研究变形作用对试验钢的微观组织结构和力学性能影响,讨论了变形-淬火-碳分配-回火工艺提高钢的强塑性机理,采用变形-淬火-碳分配-回火工艺最终获得了具有高位错密度的板条状马氏体和残余奥氏体组织,实现了钢的多相组织的设计思想,在870℃变形量为60%,变形速率为1s-1条件下,D-Q-P-T工艺可使钢的抗拉强度比传统淬火-碳分配-回火工艺提高58 MPa,伸长率增大5%,对于实现汽车轻量化,拓宽高强钢的应用领域具有重要意义。

To improve the strength and plasticity of high strength steel,based on the traditional quenching-partitioning-tempering(Q-P-T)process a novel deforming-quenching-partitioning-tempering(D-Q-P-T)process was proposed by a medium carbon steel.The microstructure evolution and mechanical property were investigated based on the SEM,TEM,X-ray diffraction characteristic techniques and mechanical properties tests.The mechanism of quenching-partitioning-tempering process to improve the strength plasticity of steel were discussed.The deformingquenching-partitioning-tempering process was used to obtain the lath like martensite and retained austenite with high dislocation density,which realizes the design idea of multiphase structure of steel.Compared with the traditional quenching-partitioning-tempering process,the deforming-quenching-partitioning-tempering process can increase the tensile strength by 58 MPa and the elongation by 5%.The research is of great significance for realizing automobile lightweight and widening the application field of high strength steel.