热处理对65Mn钢表面渗硼层组织和性能的影响

Effects of heat treatment on microstructure and properties of boriding layer on 65Mn steel

研究淬火-中温回火和等温淬火两种热处理工艺对65Mn钢表面渗硼层组织和性能的影响。结果表明:经该工艺热处理后,65Mn钢表面渗硼试样呈现出典型的表硬芯韧组织特征,其表面为高硬抗磨的硼化物,芯部为强韧的回火屈氏体或下贝氏体;同时,渗硼层物相由以FeB相为主转变为以Fe2B相为主,虽硬度、耐磨性有所下降但其脆性降低了1～2个等级;此外,等温淬火处理在降低热处理应力、保持表面硬度及耐磨性和改善芯部强韧性等方面均好于淬火-中温回火处理。

Effects of quenching and tempering at medium temperature and isothermal quenching on microstructure and properties of boriding layer of 65Mn steel boronized were investigated. The results show that the boronized 65Mn steel after the heat treatment is characterized by typical hard-surface and toughening-core mierostrueture,whieh consists of high-hardness and wear resistant boride layer of surface and tempered troostite or lower bainte with good combination of strength and toughness in core. Meanwhile, the main phase of boriding layer is transformed from FeB to Fe2 B after the head treatment, which results in the brittleness decrease by 1-2 grade although the hardness and wear resistance are also ligtly reduced. Moreover, the isothermal quenching exhibits positive effects in decreasing heat treatment stress, keeping surface hardness and wear resistance and improving strength and toughness of the core than that by quenching and tempering at medium temperature.