K418高温合金多层多道激光熔覆工艺研究

为修复某型涡轮导向器损伤叶片，在K418高温合金基底上自配粉末进行了多层多道激光熔覆试验，优化了工艺参数，分析了熔覆层的显微组织，测试了熔覆层的硬度，研究了激光熔覆修复某型涡轮导向器损伤叶片工艺的可行性。结果表明，当激光功率为730W，保护气流1．5L／min，扫描速度为8mm／s，搭接系数为50％时，可获得宏观和微观上均没有缺陷的熔覆层；熔覆层区组织由柱状枝晶与等轴晶组成，工艺参数影响晶粒大小；激光熔覆层平均显微硬度值为415HV；通过优化工艺参数可达到修复和强化叶片的目的。

Research on Laser Cladding Superalloy K418 by Multipass and Multi-layer Method

In order to repair one certain type of damaged turbine blade, experiment on the superalloy K418 with manualmixed power by multi path and multi-layer laser cladding method. In this paper, the technological parameters were optimized, the microstructure of the laser cladding was analyzed, and the hardness was tested. The feasibility on the strengthening and repairing of superalloy turbine blades by laser cladding was discussed, the experimental results show that good quality cladding layer could be obtained when the laser power is 730 W, the flux of protect gas is 1.5 L/min, the scan speed is 8 mm/s and the amount of lap is 50% ; the cladding layer is composed by columnar crystals and equiaxed crystals whose dimension is affected by the technological parameters. The average hardness of cladding layer is 415HV; the goal of repairing and strengthening turbine can reached by optimized technological parameters.