以铝替硅的Q-P-T钢的工艺设计与力学性能

Process Design and Mechanical Properties of Q-P-T Steel Containing Al Instead of Si

基于奥氏体晶粒长大规律研究和约束条件下碳准平衡热力学(CCE)模型的模拟计算结果,优化设计了以铝(1.79%,质量分数,下同)替硅的Q-P-T(Quenching-Partitioning-Tempering)试验钢的热处理工艺,测试了钢的力学性能。采用OM、SEM、TEM和XRD对试验钢组织进行了观察和分析。结果表明:试验钢具有良好的强塑性匹配,当抗拉强度为1 260MPa时,总伸长率可达到18%,同时发现,试验钢初始淬火板条马氏体的回火转变是影响试验钢力学性能及随碳分配-回火时间变化的主导因素,从而使其具有回火马氏体性能变化的特征。

The heat treatment process parameters of a Q-P-T steel containing 1.79%Al instead of Si were designed based on the research of the austenite grain growth feature and the CCE model.Mechanical properties of experimental steel were tested and the steel microstructures were studied by using OM,SEM,TEM and XRD.The results show that the experimental steel has good strength and ductility.When the tensile strength is 1 260 MPa,it′s total elongation reaches 18%.Meanwhile,it is also found that the changes during partitioning-tempering of the initial lath martensite are decisive factors for the mechanical properties and the way of mechanical property change with partitioning-tempering time is of the same characteristics of the property change of martensite with tempering time.