大面积激光熔覆的工艺研究

Study on Laser Cladding Process on a Large Area

采用6 kW CO2激光器和同步送粉熔覆技术,从比能量对熔覆层质量的影响入手,引入优化因子,结合搭接质量,对工艺参数进行了优化研究。同时对未后热和后热的熔覆层质量进行了对比研究。结果表明:送粉率为19.7 g/min,比能量选择在1.4～1.6104 J/cm2之间,搭接率为50%～60%,可获得无裂纹、气孔、夹渣等缺陷的大面积涂层,控制稀释率可获得平缓的硬度梯度;后热处理可改善变形和表面应力状态、细化组织、提高硬度。

By using a 6 kW CO2 laser and synchronous powder feeding system, the processing parameters have been investigated combining with the influence of specific energy on the quality of cladding layer, optimal factor and the overlapping quality. The quality of the cladding layer with post treatment was also studied compared with that without post treatment. The experimental results showed that a large area of cladding layer without cracks, pores and inclusions can be obtained in the conditions of powder-feed rate 19.7 g/min, specific energy 1.4~1.6104 J/cm2 and overlapping rate 50%~60%. A mild microhardness distribution can be obtained by controlling the dilution rate of cladding layer. The post treatment can improve deformation and surface stress state, refine microstructure and increase hardness of cladding layer.