工艺参数对钴基合金等离子熔覆残余应力的影响

目的 探究钴基合金等离子熔覆在不同工艺参数下残余应力的分布规律，选取最优工艺参数组合，以达到降低残余应力的目的。方法 设计正交试验，采用等离子熔覆技术制备9组不同工艺参数下单道钴基等离子熔覆样件，利用盲孔法对每个样件的熔覆起点、中间位置及终点位置的残余应力进行测量，分析工作电流、扫描速度、送粉速度等工艺参数对残余应力的影响规律。结果 工件表面残余应力主要以拉应力为主，其中间位置的残余应力最大。各个位置平行于扫描路径方向的残余应力均大于垂直于扫描路径方向的残余应力。当工作电流为92 A、扫描速度为100 mm/min、送粉速度为12 r/min时，所成形的样件残余应力最小。结论 工作电流对熔覆起点和终点平行于扫描路径方向的残余应力影响最为显著，其余各位置各方向上，影响最显著的因素为扫描速度。工作电流越大，残余应力越大；随着扫描速度的增大，残余应力不断变小；随着送粉速度的增大，残余应力有增大的趋势。选取合适的工艺参数组合能够有效地控制残余应力。

Influence of Process Parameter on the Residual Stress of the Co-based Alloy Plasma Cladding

The work aims to study the distribution of residual stress of plasma cladding of Co-based alloy under different process parameters and select the optimal combination of process parameter to reduce the residual stress. Orthogonal experiment was designed and nine groups of single channel Co-based plasma cladding samples with different process parameters were pre-pared by plasma cladding. Blind-hole method was used to measure the residual stress at the starting location, intermediate location and finish location of each sample, and the influence of working current, scanning speed and powder feeding rate on the residual stress was analyzed. The residual stress on the surface of the samples was mainly tensile stress, and the residual stress at middle location was the maximum. The residual stress parallel to the scanning path was greater than that perpendicular to the scanning path. When the working current was 92 A, the scanning speed was 100 mm/min, and the powder feeding rate was 12 r/min, the residual stress of the formed sample was the minimum. The working current has the most significant impact on the residual stress of the starting location and the finish location parallel to scanning path and other locations in all directions. The most significant factor is the scanning speed. The greater the working current is, the greater the residual stress is. With the increase of the scanning speed, the residual stress becomes smaller. With the increase of the powder feeding rate, the residual stress has an increasing trend. The residual stress can be effectively controlled by selecting the proper combination of process parameters.