等温时间对低硅含铝热轧TRIP钢组织性能的影响

为了实现低硅含铝热轧TRIP钢的工业应用,以低硅含铝热轧TRIP钢为研究对象,采用扫描电子显微镜、透射电子显微镜、拉伸试验和X射线衍射等试验方法,研究了不同等温时间对试验钢显微组织和力学性能的影响。结果表明,试验钢的显微组织主要由多边形铁素体、贝氏体铁素体和残余奥氏体组成,随着等温时间的增加,板条贝氏体的体积分数升高,粒状贝氏体的体积分数降低;当等温时间为20 min时,试验钢的综合力学性能最佳,抗拉强度为732.25 MPa,断后伸长率为36%,强塑积为26.36 GPa·%;残余奥氏体的体积分数和碳含量先升高后降低,等温时间为20 min时试验钢表现出较强的加工硬化行为。

Effect of isothermal time on microstructures and mechanical properties in hot rolled TRIP steels with low Si and more Al

In order to achieve the industrial application of hot rolled TRIP steels with low Si and more Al，hot rolled TRIP steels with low Si and more Al were set as studied object using scanning electron microscopy，transmission electron microscopy，tensile test and X-ray diffraction to study the effect of different isothermal time on microstructures and mechanical properties of experimental steels. The results show that the microstructures of experimental steels consist of polygonal ferrite，bainite ferrite and retained austenite. With isothermal time increasing，the volume percent of laminar bainite increases，while the volume percent of granular bainite decreases. When isothermal time is 20 min，the comprehensive mechanical properties of experimental steels reach the best，and the tensile strength，the total elongation and the strength ductility balance is 732.25 MPa，36% and 26.36 GPa·%，respectively. The volume percent and carbon concentration of retained austenite initially increases and then decreases，and the experimental steels exhibit excellent work hardening behaviour with isothermal time 20 min.