铝对45钢交流电场增强中温粉末法硼铝共渗的影响

Influence of Al on alternating current field enhanced pack boron-aluminizing at a medium temperature for 45 carbon steel

以45钢为处理对象进行800℃交流电场增强粉末法硼铝共渗研究。利用光学显微镜、X射线衍射仪和显微硬度计对共渗层组织、厚度、相与显微硬度进行观察和分析。结果表明：随渗剂中铝粉含量由0增至5%,渗层厚度先增加后降低再增加,渗层组织由渗硼特征逐渐过渡到渗铝特征,表层相依Fe2B→Fe B→Fe3Al＋Al N顺序发生变化;呈现渗硼组织特征的共渗层表层硬度约为1200~1800 HV0.05,呈现渗铝层组织特征的共渗层表层硬度约500 HV0.05;在低硼势渗剂中添加1.8%铝粉并施加2 A电流的交流电场,使渗层厚度较相应常规渗硼的增加约2倍,较相应常规硼铝共渗的增加约70%。

Alternating current field enhanced pack boron-aluminizing at 800 ℃ on 45 carbon steel was studied. Microstructure,thickness,phases and microhardness of the treated layer were investigated by means of optical microscope,X-ray diffraction,and microhardness testing.The results show that when the content of aluminum powder in the pack media increases from 0 to 5%,the treated layer thickness increases first,decreases later and then increases again. Microstructure of the treated layer changes gradually from a boriding structure to an aluminizing structure. The surface layer phases change with the sequence of Fe2 B→Fe B→Fe3 Al ＋ Al N. The surface microhardness is around1200-1800 HV0. 05 for the treated layer with boriding structure,and around 500 HV0. 05 for that with aluminizing structure. By adding1. 8% Al powder in the boriding medium with low boron potential and applying an alternating current field with a current of 2 A,the treated layer is two times thicker than that by conventional boriding or 70% thicker than that by conventional boron-aluminizing.