球墨铸铁表面激光熔覆钴基合金涂层的研究

The research of laser cladding Co-base alloy coating on ductile cast iron

为了研究在球墨铸铁QT600-3基体上熔覆钴基合金,采用6kW CO2激光器进行激光熔覆,用扫描电镜对激光熔覆层进行形貌观察,分析裂纹及气孔的形成原因,取得在球墨铸铁基体上熔覆钴基合金的最佳工艺参数。结果表明,球墨铸铁基体与熔覆层能形成良好的冶金结合,但熔覆功率过高使得熔覆层开裂倾向增大,过渡区及热影响区的球状石墨由原来的“牛眼状”变为单独的石墨球,石墨球外围的环状铁素体出现消溶。

A 6kW CO2 laser is used to investigate how to clad the Co-base alloy on QT600-3 ductile cast iron matrix, the mierostmeture of laser cladding layer is observed with sweep electronic microscope and the formation reason of cracks and voids is analyzed. So the optimal process parameters of laser cladding Co-base alloy on ductile iron are obtained. The conclusion is that laser cladding coating and ductile east iron could form metallurgical bonding, but with the increase of laser power density, the tearing tendency of laser clad coating increase. The graphite nodule in the transition region and heat-affected zone might change into isolated nodule from the original bull＇s eye patternand the ferrite tings surrounded graphite nodules might be dissolved.