目的 改善S136D模具钢的表面粗糙度。方法 提出一种双激光抛光方式，采用两种不同的激光光束对S136D模具钢表面进行抛光实验。先采用较高能量的连续激光对材料表面进行抛光处理，使其表面粗糙度大幅度降低，再使用脉冲激光对S136D模具钢表面进行第二次抛光处理，进一步降低表面粗糙度。结果 采用连续激光抛光，可将表面粗糙度由7.973 μm降低至0.872 μm，摩擦系数由初始表面的0.650降低至0.609。采用双激光抛光，粗糙度进一步降低至0.67 μm，总降低率达91.6%，摩擦系数为0.590，耐摩擦性能进一步提高。在激光作用下，重熔区域、热影响区域以及退火区域的总厚度为175 μm左右，重熔区域、热影响区域的硬度和杨氏模量均高于基体，退火区域的硬度和杨氏模量略低于基体。结论 通过优化连续激光(P=190 W，v=30 mm/s，D=0.05 mm)和脉冲激光(P=30 W，v=20 mm/s，D=0.04 mm)的各类参数，双激光抛光技术可以显著降低材料的表面粗糙度，而且能有效地提高表面硬度和杨氏模量，并降低材料表面的摩擦系数和磨损量，提高材料表面的耐摩擦性能。

To ameliorate the S136D die steel surface, the dual-beam laser polishing was proposed. Two different laser beams were used to polish the surface of S136D die steel. Firstly, the continuous laser with high energy was used to polish the material surface and decrease the roughness. Secondly, the surface was polished again by using the pulsed laser to further decrease the roughness. The result shows that the surface roughness can be reduced from 7.973 μm to 0.872 μm and the friction coefficient can be reduced from 0.650 to 0.609 by continuous laser polishing. By using dual-beam laser polishing, the roughness was further reduced to 0.67 μm, the total reduction rate was 91.6%, the friction coefficient was 0.590, and the friction resistance was further improved. Under laser irradiation, the total thickness of remelting zone, heat-affected zone and annealing zone is about 175 μm. The hardness and Young’s modulus of remelting zone and heat-affected zone are higher than those of substrate, while hardness and Young‘s modulus of annealed zone are slightly lower than those of substrate. The experimental results show that by optimizing the laser power, scanning speed, scanning distance and other parameters of continuous laser (P=190 W, v=30 mm/s, D=0.05 mm) and pulse laser (P=30 W, v=20 mm/s, D=0.04 mm), the dual laser polishing technology can significantly reduce the surface roughness of the material, effectively improve the surface hardness and Young‘s modulus, reduce the friction coefficient and wear amount of the material surface, and improve the friction resistance of the material surface.