一种微合金化超高强韧弹簧钢的热处理工艺与组织性能

Heat treatment process,microstructure and properties of a microalloyed ultra-high strength and toughness spring steel

超高强韧弹簧钢在汽车轻量化和节能减排方面发挥着重要的作用.本文中以一种新设计的中碳中硅弹簧钢为实验材料,利用金相显微镜、扫描电镜及力学性能测试等手段,研究了热处理工艺对试验钢微观组织和力学性能的影响.结果表明:在880℃保温60 min后油淬及350℃回火保温120 min后水冷的工艺下,试验钢的微观组织为回火板条马氏体;在相变强化、析出强化和固溶强化等多种强化机制的共同作用下,试验钢可以获得较佳的综合力学性能,具有超高的强韧性,抗拉强度和屈服强度分别达到1955和1742 MPa,伸长率和断面收缩率分别为12.4%和45.5%,室温冲击功为30.8 J.

Ultra-high strength and toughness spring steel plays an important role in automobile lightweight,energy saving and emission reduction.In this article,we used a newly designed medium carbon and medium silicon spring steel as experimental material,the effects of heat treatment process on the microstructure and mechanical properties of this steel were studied by means of metallographic microscope,scanning electron microscope and mechanical properties test.The results show that the microstructure of the experimental steel is tempered lath martensite after oil quenching at 880℃for 60 min and water cooling at 350℃for 120 min.Under the various strengthening mechanisms such as transformation strengthening,precipitation strengthening and solid solution strengthening,better comprehensive mechanical properties and ultra-high strength and toughness can be obtained.The tensile strength and yield strength reach 1955 and 1742 MPa,respectively,while the elongation and reduction of area are 12.4%and 45.5%,respectively.The impact energy at room temperature is 30.8 J.