激光熔覆热损伤磁记忆检测试验研究

对Q235基体材料激光熔覆Ni基合金试件进行磁记忆信号检测,探讨金属磁记忆技术检测激光熔覆热损伤的可行性,研究不同激光熔覆参数造成的热损伤对磁记忆信号的影响规律以及激光熔覆参数对热损伤程度的影响规律。结果表明金属磁记忆技术可有效检测激光熔覆热损伤,利用磁记忆信号均值梯度曲线的突变位置可以标明热损伤位置,采用熔覆区域均值梯度突变峰值和所有检测点均值梯度平均值的比值对热损伤程度进行定量评估。热损伤程度定量评估结果表明激光功率增加、光斑直径减小、扫描速度降低,都会使激光熔覆热损伤程度增加。

Experimental study on thermal damage of laser cladding by magnetic memory methods

Magnetic memory signals of laser cladding Ni-based alloy on Q235 substrate are detected,and the thermal damage of laser cladding is detected by metal magnetic memory technology.The thermal damage caused by different laser cladding parameters are investigated through the magnetic memory signals.Results show that the metal magnetic memory technology can detect the thermal damage of laser cladding effectively.The thermal damage location can be predicted according to the mutational characters of average gradient curve.Quantitative assessment is made for the degree of the thermal damage based on the ratio(R) of the average gradient mutational peak of cladding region and the average gradient on all testing points.Assessment result shows that the specimen has severe thermal damage if the absolute value of the R is greater than 1,and the thermal damage degree of laser cladding will increase with the increasing of laser power,the decreasing of spot diameter,and the reducing of scanning speed.