激光熔覆工艺参数对Fe W B熔覆层质量的影响

采用激光熔覆技术在65Mn钢表面熔覆FeW B三元硼化物熔覆层。通过单道熔覆与单层多道熔覆实验,探究激光功率、扫描速度、送粉速率、搭接率对熔覆层质量的影响,获得优化激光工艺参数组合。并通过光学显微镜、X射线衍射仪和维氏硬度计对熔覆层进行分析。结果表明:工艺参数对熔池高度与熔池宽度的影响程度由小到大排列为:送粉速率、扫描速度、激光功率,对维氏硬度的影响程度由小到大排列为:扫描速度、送粉速率、激光功率。获得的最优工艺参数组合为:激光功率800W,扫描速度3mm/s,送粉速率4 g/min,搭接率50。此时熔覆层的维氏硬度均值为7579 HV,是基材的35倍。熔覆层与基材冶金结合良好,其微观组织由枝状晶、胞状晶和柱状晶组成。

Influence of laser cladding process parameters on the quality of Fe W B cladding layer

The laser cladding technology is used to clad Fe W B ternary boride cladding layer on 65Mn steel surface.Through the experiments of single pass cladding and single layer multi channel cladding,the effects of laser power,scanning speed,powder feeding rate and lap rate on the quality of cladding layer are explored to obtain the optimal combination of laser process parameters.The cladding layer is analyzed by optical microscope,X ray diffractometer and Vickers hardness tester.The results show that the influence of process parameters on the height of the molten pool and the width of the molten pool are in descending order:powder feeding rate,scanning speed and laser power,and the influence on Vickers hardness is in descending order:scanning speed,powder feeding rate and laser power.The optimal combination of process parameters is obtained as follows:laser power of 800 W,scanning speed of 3mm/s,powder feeding rate of 4 g/min,lap rate of 50%.The average Vickers hardness of the cladding layer is 757.9 HV,which is 3.5 times that of the substrate.The cladding layer is well combined with the metallurgy of the substrate,and its microstructure consists of dendritic crystals,cytocrystals and columnar crystals.