为了减少熔覆开裂，提高熔覆质量，本文采用一定光束间距的并联双光束激光对铸铁表面进行熔覆，建立熔覆过程三维热力耦合模型，分析双光束激光熔覆热/力特征变化。计算结果表明，双光束激光在提高熔覆效率的同时，相邻两熔道彼此进行预热与缓冷，减小了激光熔覆过程中急剧升温与冷却产生的巨大温度梯度，降低熔层和结合区的残余应力水平，进而达到抑制裂纹产生的效果。1 800 W-1 400 W功率组合、光束间距为12.5 mm是较为理想的参数组合。

As for reducing cladding cracks and improving the quality, this paper uses dual-beam laser with specific beam spacing to clad on the gray cast iron surface. Three-dimensional thermo-mechanical coupling model in dual-beam laser cladding process is established. The thermal / mechanical characteristic is analyzed. The simulation shows that dual-beam laser can not only improve the cladding efficiency, but also decline the great temperature gradient in the laser process by pre-heating and cooling slowly between adjacent cladding channels. This could reduce the residual stress of cladding layer and bonding area, and then inhibits the crack initiation. The combination with power combination of 1 800 W-1 400 W and beam spacing of 12.5 mm is the ideal parameter combination.