对激光成形修复2Cr13不锈钢热影响区分别进行了单道单层、多道单层、单道多层和多道多层4种形式的修复实验.通过金相观察和硬度测试确定了激光成形修复区域的组织特征, 结合热影响区温度场模拟分析了组织形成机理.结果表明: 热影响区内微观组织从基材到修复区底部呈现连续性变化, 其中, 主要相结构经历了α铁素体→α铁素体+少量马氏体→马氏体+少量α铁素体→马氏体的转变,马氏体的出现导致硬度快速上升; 同时, 原M₂₃C₆型碳化物逐渐溶解, 直至消失, 且晶内碳化物先于晶界碳化物发生溶解;伴随碳化物的溶解逐渐出现δ铁素体;随着趋近修复区底部, δ铁素体逐渐增多、长大并连成骨架; 当沉积层数增加后, 硬度峰值随之下降, 在热影响区中部的部分区域会出现晶粒细化, 且热影响区顶部的晶界逐渐开始析出碳化物, 同时, δ铁素体骨架逐步被晶界打断.

2Cr13 martensitic stainless steel is widely used in the manufacturing of heavy load components,which are easy to be damaged due to their severe service environment. If these damaged components can be repaired rapidly, considerable savings in materials, processing and time costs can be achieved. Four kinds of laser forming repairing for 2Cr13 stainless steel sample, single-track single-layer, multi-track single-layer, single-track multi-layer and multi-track multi-layer, was conducted to investigate their microstructure characteristic and evolution of heat-affected zone (HAZ). The formation mechanism of microstructure was analyzed based on the temperature field simulation. It is found that microstructure varies continuously from substrate zone (SZ) to the bottom of laser repaired zone (RZ), in which the main phases varied asα ferrite→α ferrite+ martensite →martensite+α ferrite→martensite, and the appearance of the martensite led to a rapid increase in hardness. Meanwhile, the primary M₂₃C₆ dissolved gradually and disappeared eventually. It is interesting to note that the dissolving of intragranular carbides occurred prior to the intergranular carbides. With the carbides dissolving, δ ferrite particles appeared, coarsened and connected into skeleton patterns eventually when closing to the bottom of RZ. As the deposited layers increased, the hardness peak decreased, and the grains were refined in the partial region of the middle of HAZ. The carbides precipitated again in the grain boundary at the top of HAZ, meanwhile, δ skeleton is gradually interrupted by the grain boundary.