45钢渗硼层的相结构研究

Phase Structure of Boronization Layer in Steel 45

用硼砂石墨型粒状渗硼剂对45钢进行了高温长时间深层渗硼。用光学显微镜、透射电镜及电子探针研究了渗硼层的组织结构与成分分布。结果表明,渗硼层表层为FeB向里为Fe_2B,Fe_2B针间和前沿存在有比Fe_2B针色深的夹缝组织,其显微硬度值为300～500HV_(0.1)。夹缝组织由于Fe_3Si、Fe_5Si_3、FeSi、FeSi_2及FeCSi相组成。渗硼层中碳与硅的分布是不均匀的其富集区大多在Fe_2B齿间和前沿。

Deep boronization of 45 steel was conducted at high temperature for a long time using granular boronizing agent containing borax and graphite. The structure and distribution of elements in boronization layer were studied by TEM, metallurgical microscope and electron probe. It was found that the surface layer was FeB and the inner was Fe2B. There was an abnormal structure with microbardness of about 300~500HV0.1 existing in the boundary seam between boride needles. The abnomal structure consisted of Fe3Si、FeSi3、FeSi、FeSi2 and FeCSi. The distribution of silicon and carbon was not uniform ,and most silicon-rich or carbon - rich zones existed in the regions between tooth-like Fe2B and in front of Fe2B.