激光熔覆原位合成WC增强镍基熔覆层的组织与性能

Microstructure and properties of in-situ synthesized WC reinforced nickel-based cladding layer by laser cladding

采用响应面法的中心复合设计建立了激光功率、扫描速度、气流量和碳钨粉末配比对熔覆层硬度和面积影响的数学模型,并通过方差分析和试验验证检测了数学模型的准确性。结果表明:熔覆层的硬度与激光功率和碳钨粉末配比成正比,与扫描速度成反比;熔覆层面积与激光功率成正比,与扫描速度成反比,碳元素盈余量对熔覆面积的影响不显著。以熔覆层的硬度和面积最大为优化目标进行验证试验,并基于数学模型对工艺参数进行优化与预测,得到最佳工艺参数为激光功率1700 W、扫描速度5 mm·s^(-1)、气流量13 L/min、碳钨粉末配比1.05∶1。采用最佳工艺参数所得的熔覆层硬度和熔覆面积的预测值和实际值的误差分别为0.56%、1.45%,验证了所建立模型的准确性。

A mathematical model of the influence of laser power,scanning speed,gas flow rate and carbon tungsten powder ratio on the hardness and area of the cladding layer was established by using the central composite design of response surface methodology(RSM).The accuracy of the mathematical model was verified by variance analysis and experiments.The results show that the hardness of the cladding layer is proportional to the laser power and the carbon tungsten powder ratio,and inversely proportional to the scanning speed.The area of the cladding layer is proportional to the laser power and inversely proportional to the scanning speed.The influence of carbon element surplus on the cladding area is not significant.The verification test is carried out with the maximum hardness and area of the cladding layer as the optimization objective,and the process parameters are optimized and predicted based on the mathematical model.The optimal process parameters are obtained as follows:laser power of 1700 W,scanning speed of 5 mm·s^(-1),gas flow rate of 13 L/min,and carbon tungsten powder ratio of 1.05∶1.The errors between the predicted values and the actual values of the cladding layer hardness and cladding area obtained by using the optimal process parameters are 0.56%and 1.45%,respectively,which verify the accuracy of the established model.