球墨铸铁表面激光堆焊层组织和性能的研究

Study of microstructure and properties on cast iron surface laser overlaying

借助光学显微镜、扫瞄电子显微镜,能谱仪对堆焊层显微组织及热影响区组织进行观察、分析,得知堆焊层显微组织特征是树枝状的V8C7分布在FeNi基体上,热影响区组织为细的莱氏体,堆焊层与基体结合良好。通过显微硬度计测试了堆一层的显微硬度为900～1200,堆两层的HV为700～900,堆焊层数增加,裂纹倾向减少。

A laser overlaying experiment was studied on cast iron surface by using the special alloy wire. Through observing the heated affected zone by optical micro-cope, SEM, XRD, the result shows that the dendritic V_8C_7 distributes on FeNi matrix, and thin ledeburite distributes on the heat-affected zone. The surfacing layer has the better metallurgy bonding with matrix. After microhardness test, the hardness of one surfacing layer is 900～\{1 200\} HV and that two surfacing layers 700～900 HV. The study results show that the trend of crack reduces with layer increasing.