中文摘要：

目前灰铸铁表面缺陷的激光热修复成为铸件装备循环再制造的重要途径，针对该修复过程建立可靠的数值模型，在热源表达和边界条件等方面对模型进行细化，经实验验证达到了较高的求解精度。计算结果表明，二次修复是在预热状态下进行的，与单层修复相比，多层修复能够更好地控制温度循环曲线；随着基体表面材料的熔凝循环，长、宽方向先压缩后拉伸，修复阶段以压应力为主，厚度方向则承受交变的拉一压应力循环并以受拉为主，u槽底部应力较侧面更为集中。

英文摘要：

At present laser thermo-repairing for the defects on gray cast iron surface is becoming an important way of casting equipment cycle remanufacturing. A reliable numerical model for the repair process is established, where the heat source expression and boundary conditions are refined. Then the model is verified by experimental results to achieve higher precision. The calculation results show that the secondary repair is processed in a warm-up state. Compared to single repair, multilayer repair can provide more methods to control temperature cycle curve. In the material fused circulation on matrix surface, the materials are compressed at first and stretched then in length and width direction. Compression stress is given priority in the repair stage, and when materials in thickness direction are under alternating tensile-pressure stress cycle, tension is given priority. Stress becomes more focused in the U trough bottom than its sides.