超高强热轧马氏体钢的开发和组织性能的研究

Development of Ultra-high-strength Hot-rolled Martensite Steel and Research of Microstructure and Properties

设计了一种高Ms相变点的Al-Si-Mn-Cr热轧马氏体钢成分体系,进行该成分体系下1200 MPa级热轧马氏体钢的开发。对其进行力学性能检测及组织形貌观察,探究Mn含量和不同卷取温度对热轧马氏体钢组织及力学性能的影响。结果表明:Al-Si-Mn-Cr热轧马氏体钢在400℃左右的卷取温度下,可以获得全马氏体组织,并且随着卷取温度的升高,试验钢中马氏体组织粗化,有向贝氏体转变倾向,从而使得试验钢的抗拉强度以及屈服强度略微降低,伸长率升高;Mn含量的提高促进淬火马氏体相区的扩大,并通过固溶强化的作用大幅度提高试验钢的强度;1.54%Mn的试验钢在410℃卷取温度下获得最佳的强塑性配合,抗拉强度1210 MPa,屈服强度908 MPa,伸长率10.0%,满足GB/T20887.5-2010的要求。

The Al-Si-Mn-Cr hot-rolled martensite steel composition system with high Msphase change point was designed, and 1200MPa hot-rolled martensite steel under this composition system was developed. The mechanical properties were tested, and the microstructure was observed. The effects of Mn content and different coiling temperatures on the microstructure and mechanical properties of hot rolled martensite steel were investigated. The results show that the Al-Si-Mn-Cr hot-rolled martensitic steel can obtain a full martensite structure at a coiling temperature of about 400 ℃, and with the coiling temperature increasing, the martensite structure in the test steel becomes coarser and tends to bainite transform ation, which makes the tensile strength and yield strength of the test steel slightly decrease, and the elongation increases;the increase of Mn content promotes the expansion of the quenched martensite phase region, and the strength of the test steel is greatly improved through the effect of solid solution strengthening. The best strong plastic fit is obtained at the coiling temperature of 410℃ for 1.54% Mn test steel with tensile strength of 1210 MPa, yield strength of 908 MPa, elongation of10.0%, which meets the requirements of GB/T 20887.5-2010.