研究激光束焊接工艺参数如激光功率、焊接速度和焦点位置对AZ31B镁合金力学性能和显微组织的影响。采用不同的激光功率、焊接速度和焦点位置焊接了9种接头。焊接接头的拉伸性能与焊接区的微观组织和硬度有关。结果表明,采用激光功率2500W,焊接速度5m/min,焦点位置-1.5mm时,所得的接头具有优良的拉伸性能。焊接区细晶粒的形成、较高的融化区硬度、均匀分布的细小析出物是得到优良拉伸性能的主要原因。 The effects of laser beam welding process parameters such as laser power, welding speed and focal position on the mechanical properties and microstructure of AZ31B magnesium alloy were studied. Nine joints were welded using different laser powers, welding speeds and focus positions. Tensile properties of welded joints and weld zone microstructure and hardness. The results show that the obtained joint has excellent tensile properties when the laser power is 2500W, the welding speed is 5m / min and the focus position is -1.5mm. Fine grain formation in the weld zone, higher melt zone hardness, and uniform distribution of fine precipitates are the main reasons for achieving good tensile properties.