45钢低温双辉等离子渗铬硬化的研究

Double Glow Ptasma Chrominm Permeation Hardening of 45 Steel at Lowered Temperature

常规双辉等离子渗铬温度较高(800℃以上),能耗较大。为此,采用双辉等离子渗金属技术,在560℃下对45钢进行了表面渗铬硬化,制备出了性能良好的表面合金改性层。采用X射线衍射仪及其附带的能谱仪测定了渗层物相及成分,采用金相显微镜考察了渗层组织形貌,并采用显微硬度计检测了渗层硬度。结果表明:渗层组织由沉积层及扩散层组成;渗层表层为2～3μm的沉积层,含铬量达到48%以上,沉积层致密并与扩散层结合紧密;内有20～25μm的扩散层,其含铬量呈梯度分布;表面物相由Fe-Cr、Cr7C3、Cr23C6等组成;渗层表面显微硬度达600～700HV,硬度向内呈梯度分布。

Double glow plasma chromium permeation hardening of AISI-1045 steel was carried out at a low-ered temperatures of 560 ℃.The phase composition of the resul-ting surface-modifying layer was analysed by means of X-ray dif-fraction and energy dispersive spectrometry.The morphology of the surface-modifying layer was observed using a scanning electron mi-croscope,and the hardness of the permeated layer was measured as well.Results indicated that the permeated layer consists of deposi-tion layer with a thickness of about ～3 μm and diffusion layer with a thickness of about 20～25 μm.When the content of Cr reached 48% and above,the deposition layer was compact and well adhered to the diffusion layer.Moreover,the chromium in the diffusion layer was dominated by gradient distribution.The perme-ated surface layer was composed of Fe-Cr,Cr7C3,and Cr23C6 and had a hardness of above 700 HV,which was characterized by gradient distribution as well towards the substrate.