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采用５ｋＷ光束加热设备对珠光体合金灰铸铁进行了表面相变硬化处理。研究了相变层的组织和硬度特征，以及光束能量参数对相变层组织和硬度的影响规律。实验结果表明，合金铸铁光束表面相变硬化层由与基材相邻的不完全相变区及表面完全相变区组成。完全相变区的组织是马氏体，随能量密度提高马氏体针片尺寸增加，硬度降低。不完全相变区是残余珠光体与托氏体型珠光体的混合组织，其硬度较完全相变区显著下降。采用光束相变硬化处理可在灰铸铁表面获得深度 ０．２ｍｍ以上，硬度近 ９００ｋｇ／ｍｍ２的强化层。
5kW beam heating equipment was used to pearlite alloy gray cast iron surface hardening treatment. The microstructure and hardness characteristics of phase change layer and the influence law of beam energy parameters on microstructure and hardness of phase change layer were studied. The experimental results show that the phase change hardened layer on the surface of the alloy cast iron beam consists of the incomplete transformation zone adjacent to the substrate and the complete transformation zone of the surface. Complete phase transition zone organization is martensite, martensite with the energy density increased needle size, hardness decreased. Incomplete phase transition zone is the mixed structure of residual pearlite and periclase pearlite, the hardness of which is significantly lower than the complete phase transition zone. The use of beam transformation hardening process can be obtained in the gray cast iron surface depth of 0.2mm or more, the hardness of nearly 900kg / mm2 strengthening layer.