56NiCrMoV7钢激光熔覆Ni60合金涂层的质量预测与性能分析

Quality prediction and performance analysis of laser cladding Ni60 alloy coating on 56NiCrMoV7 steel

基于响应面法开展56NiCrMoV7钢表面激光熔覆Ni60合金粉末的理论及实验研究。以激光功率、扫描速度、送粉速率和搭接率为影响因素,以涂层表面平整度、稀释率及显微硬度为响应目标建立多元回归预测模型,进行工艺参数优化和涂层质量预测。结果表明:送粉速率和扫描速度的交互作用对表面平整度影响最大;激光功率、送粉速率及搭接率对稀释率均有显著影响;送粉速率对显微硬度影响最大,激光功率次之。优化的工艺参数为激光功率1647 W,送粉速率0.5 rad/min,扫描速度5 mm/s,搭接率0.4,所制备Ni60合金涂层的表面平整度、稀释率和显微硬度预测值与实验值一致性较好。Ni60合金涂层与56NiCrMoV7基体之间为冶金结合,涂层的硬度和耐磨性均优于基体,表面强化效果明显。

Theoretical and experimental studies on laser cladding of Ni60 alloy powders on 56NiCrMoV7 steel surface were carried out based on response surface method.The laser power,scanning speed,powder feed rate,and overlap rate were taken as the influencing factors,and the multiple regression prediction model was established using the coating surface smoothness,dilution rate,and microhardness as the response targets to optimize the process parameters and predict the coating quality.The results show that the interaction of powder feed rate and scanning speed has the greatest influence on the surface smoothness;the laser power,powder feed rate,and overlap rate have a significant influence on the dilution rate;the powder feed rate has the greatest impact on the microhardness,followed by the laser power.The optimized process parameters are laser power of 1647 W,powder feed rate of 0.5 rad/min,scanning speed of 5 mm/s,and overlap rate of 0.4,and the predicted values of surface flatness,dilution rate,and microhardness of Ni60 alloy coatings are in good agreement with the experimental values.The metallurgical bonding of Ni60 alloy coating and 56NiCrMoV7 substrate is good,and the hardness and abrasion resistance of the coating are superior to those of substrate,the surface strengthening effect is obvious.