针对激光沉积修复316L不锈钢展开研究, 重点研究了修复界面形状对修复区与基材结合处冶金质量的影响。将316L不锈钢基材预处理为底角为不同角度的倒等腰梯形坡口形貌, 采用YAG脉冲激光器对切除区域进行多道多层激光沉积修复, 观察修复区的沉积层生长特性及界面结合处的冶金质量。结果表明, 当梯形坡口角度为105°时, 启光侧靠近界面处熔覆层间开始产生熔合不良及未熔粉等缺陷; 坡口角度约150°时, 收光侧的沉积层生长出现波动, 且波动性随着坡口角度的减小而显著增加; 当坡口角度减小至90°时, 启光侧修复界面处产生大量缺陷, 收光侧无法形成沉积层生长。基于倾斜角度对激光能量密度的影响以及粉末与熔池的交互作用分析, 揭示了坡口角度对缺陷形成及沉积层稳定性的影响机理。

This study investigates the laser deposition repair of 316L stainless steel, with emphasis on the influence of laser repair groove angles on the metallurgical quality between the repair zone and the substrate. Inverted isosceles trapezoidal groove with different corner angles were made on 316L stainless steel. The YAG pulsed laser was used to repair the excised area by multichannel multilayer laser deposition. The growth characteristics of the sedimentary layer and the metallurgical quality of the interface of the repair zone was observed. The results show that when the trapezoidal groove angle is 105°, the interface at the start of the laser repair process demonstrated defects such as ill bonding and unmelted powders. When the groove angle is 150°, the deposition at the end of the laser repair process demonstrated the fluctuations, and the fluctuation increase significantly with the decrease of the groove angle. When the angle is reduced to 90°, the side in the beginning of laser repair results in a large number of defects, the deposition at the end of laser repair can not form sedimentary layer growth. Based on the influence of inclined angle on laser energy density and the interaction between the powder and molten pool, the paper discuss the influence mechanism of groove angle on the formation of the defects and the stability of sedimentary layer.