在 2 0Cr2NiSiW基体上熔覆添加碳化钨的镍基合金 ,对熔覆层的应力状态进行了分析。未预热的熔覆层存在热应力的残余应力峰值 70 0MPa ,和相变应力的残余应力峰值 85 0MPa。熔覆件整体的熔前预热和熔后保温 ,可以改善熔覆层的应力分布。消除部分热应力和相变应力 ,残余应力也有所降低。虽然仍呈现熔覆层受拉应力 ,热影响区受压应力的状态 ,但热应力的峰值降到 5 10MPa ,热应力峰也从表面移到了熔覆层的中部。界面的相变拉应力峰被消除 ,得到了应力分布状态较好的激光熔覆层。在未预热的熔覆层内 ,先共晶的奥氏体枝晶的生长 ,从界面开始逆温度梯度方向定向生长 ,直到熔覆层的表面。而在预热的熔覆层内 ,先共晶的奥氏体的生长方向变为从熔池的四周垂直于熔池的边界生长 ,到熔覆层的中部结束 In 20Cr2NiSiW matrix with tungsten carbide added to the nickel-based alloy, the cladding layer of the stress state was analyzed. The preheated clad layer has a peak value of residual stress of 70 0 MPa for thermal stress and a peak value of residual stress of 85 0 MPa for phase-change stress. Preheating and melting of the cladding as a whole before melting can improve the stress distribution of the cladding. Eliminate part of the thermal stress and phase transformation stress, residual stress is also reduced. Although the cladding layer is under tensile stress and heat affected zone is under compressive stress, the peak value of thermal stress drops to 510 MPa and the thermal stress peak also moves from the surface to the middle of the cladding layer. The phase transition stress of the interface is eliminated, and the laser cladding layer with better stress distribution is obtained. In the non-preheated cladding layer, the growth of the first eutectic austenite dendrite grows in the opposite direction of the temperature gradient from the interface toward the surface of the cladding layer. In the preheated cladding layer, the growth direction of the first eutectic austenite becomes from the periphery of the puddle to grow perpendicular to the boundary of the puddle to the end of the middle of the cladding layer