等离子堆焊参数对合金层热冲击性能的影响研究

Study on the Influence of Plasma Surfacing Parameters on Thermal Shock Properties of Alloy Layers

高温镍基合金具有良好的耐高温腐蚀、耐高温磨损和高温强度,被用作柴油机气阀密封面堆焊材料。但是,密封面合金层堆焊质量不能有效通过热冲击检测,热冲击后合金会开裂,影响着产品的应用和推广。基于此,文章研究堆焊线速度对合金热冲击通过性的影响,采用等离子堆焊技术,在45Cr9Si3材质的气阀上以不同的焊接线速度,制备3组Colmonoy56 SPL粉末合金堆焊层,然后通过金相组织观察、硬度测试等手段分析合金层的微观组织、洛氏硬度。试验结果表明:镍基高温合金堆焊参数区间窄,线速度是影响合金层抗裂性的主要变量;针对试验气阀,70 mm·min^(-1)的堆焊线速度可以有效解决热冲击后合金开裂这一应用难题,使产品满足热冲击检测的要求。

High temperature nickel base alloy has good resistance to high temperature corrosion,high temperature wear and high temperature strength,and is used as surfacing material for diesel engine gas valve sealing surface.However,the surfacing quality of the sealing surface alloy layer cannot pass the thermal shock detection effectively,and the alloy will crack after thermal shock,which affects the application and promotion of the product.Based on this,this paper studies the effect of surfacing wire speed on thermal shock permeability of alloy.Plasma surfacing technology is used to prepare three groups of Colmonoy56 SPL powder alloy surfacing layers on 45Cr9Si3 gas valves at different welding wire speeds.Then the microstructure and Rockwell hardness of the alloy layer were analyzed by means of metallographic observation and hardness test.The experimental results show that the parameters of nickel-based superalloy surfacing welding are narrow,and the linear velocity is the main variable affecting the crack resistance of the alloy layer.For the test valve,the surfacing speed of 70 mm·min^(-1)can effectively solve the application problem of alloy cracking after thermal shock,so that the product can meet the requirements of thermal shock detection.