Q&P工艺对中碳Ti-Mo高强钢机械性能的改善研究

Improvement of mechanical properties of medium-carbon Ti-Mo high-strength steel by Q&P process

为改善中碳Ti-Mo高强马氏体钢的机械性能,分别采用传统淬火-回火(QT)、一步和两步Q&P工艺对Ti-Mo钢进行热处理,结合SEM、XRD、TEM、EDS和力学性能测试等手段,对比研究了不同工艺处理后Ti-Mo钢的微观组织和力学性能。结果表明,QT工艺处理后,Ti-Mo钢组织为回火马氏体,经Q&P工艺处理后,钢的显微组织均由一次马氏体、二次马氏体、碳化物和少量贝氏体组成。与传统QT工艺相比,经Q&P工艺处理后,Ti-Mo钢的抗拉强度略有降低,但其延伸率及低温冲击韧性均显著提高,其中两步Q&P工艺处理后钢的综合力学性能最佳,其抗拉强度、延伸率和低温冲击韧性分别达到1442 MPa、13.61%和76.3 J。

In order to improve the mechanical properties of medium carbon Ti-Mo high-strength martensitic steel,traditional quenching-tempering(QT),one-step and two-step Q&P approaches were used to heat-treat the Ti-Mo steel,and with SEM,XRD,TEM,EDS and mechanical property tests,the microstructure and mechanical properties of Ti-Mo steel treated by different processes were investigated comparatively.The results show that the microstructure of Ti-Mo steel treated by QT process is tempered martensite,and the microstructure of steel treated by Q&P methods is composed of primary martensite,secondary martensite,carbide and a small amount of bainite.Compared with the traditional QT process,the tensile strength of the Ti-Mo steel treated by one-step and two-step Q&P approaches is slightly reduced,but the elongation rate and low temperature impact toughness are significantly improved,and the comprehensive mechanical properties of the steel treated by two-step Q&P process are the best,with its tensile strength,elongation rate and low temperature impact toughness reaching 1442 MPa,13.61%and 76.3 J,respectively.