基于残余应力分布优化的TBM滚刀刀圈激光熔覆涂层制备工艺研究

目的 为改善TBM(全断面隧道掘进机)涂层刀圈残余应力分布，针对刀圈涂层制备过程中的激光扫描路径开展研究，以优化刀圈涂层及涂层/基材界面的残余应力分布。方法 使用MSC. Marc 2016软件建立了刀圈涂层制备的三维完全热机耦合模型，通过试验验证了模型的准确性，并针对激光熔覆过程中扫描顺序、扫描方向和扫描终点夹角等3个工艺变量开展了应力场分析研究。结果 刀圈表面近涂层区周向/径向残余应力数值计算结果分布趋势与试验基本一致，且在涂层与基材结合的界面处，残余应力梯度达到最大，当激光扫描方向为安装孔到刃顶时，涂层刀圈残余应力的不合理分布得到了明显改善且应力最值显著降低，其中基材部分残余应力最高降低35 MPa，而调整扫描顺序和扫描终点夹角未能有效改善刀圈残余应力的分布及应力最值。结论 通过合理设计熔覆过程中的扫描路线，可以有效改善刀圈涂层的残余应力分布并降低残余应力最值，对延长TBM涂层刀圈服役寿命具有重要的指导意义。

Preparation of Laser Cladding Coating for TBM Cutter Ring Based on Optimization of Residual Stress Distribution

Metal-matrix ceramic coating can be prepared on the surface of TBM (Tunnel Boring Machine) cutter ring by laser cladding technology to improve the wear resistance, but the residual stress distribution of cutter ring significantly changes in the preparing process. The unreasonable distribution of residual stress of coating may cause low cycle fatigue fracture of cutter ring in service. In this study, the influence of scanning path on stress distribution and maximum/ minimum value of stress is studied during the process of coating preparation to decrease the failure risk of TBM coated cutter ring, which will provide theoretical guidance for optimizing the residual stress distribution of coated cutter ring.