逆转变+Q&P复合工艺对低合金高强钢组织和性能的影响

Effect of austenite reverse transformation and Q&P process on microstructure and mechanical properties of high strength low alloy steel

利用SEM、XRD分析及拉伸试验,研究了逆转变+淬火-配分(ART+Q&P)复合工艺对完全淬火后0.22C-2.0Mn-1.8Si钢组织性能的影响。结果表明:经ART+Q&P工艺处理后,该钢组织为亚温铁素体、贝氏体/马氏体和均匀分布的残留奥氏体。逆转变奥氏体富集Mn、C元素,淬火-配分过程中碳自马氏体配分至残留奥氏体时二次富C,使其稳定化,因此该钢室温下获得残留奥氏体的含量超过15%。在拉伸变形过程中残留奥氏体转变成马氏体的TRIP效应,使得钢材在变形过程中获得稳定的加工硬化能力,实现了良好的强塑性结合,抗拉强度达到1233 MPa,屈服强度为893 MPa,均匀伸长率29.6%,强塑积高达36 GPa·%以上。

Using SEM, XRD analysis and tensile test, influence of austenite reverse transformation＋quenching and partitioning （ ART＋Q＆P） process on microstructure and mechanical properties of a low carbon 0. 22C-2. 0Mn-1. 8Si alloyed steel was studied. The results show that after ART＋Q＆P treatment, the microstructures of the steel is composed of intercritical ferrite （IF）, martensite, bainite and uniform retained austenite （ RA） . The content of RA is higher than 15% due to the enrichment of the carbon and manganese in the reversed austenite during ART step, and enrichment of carbon in retained austenite during the following Q＆P step. During the tensile deformation, TRIP effect occurred in the process of transformation of retained austenite to martensite, which makes the steel obtain a stable working hardening ability and realize the good strength-plastic match, tensile strength 1233 MPa, yield strength 893 MPa, total elongation 29. 6% and product of strength and elongation over 36 GPa＆#183;%.