通过能量平衡原理研究了厚钢板激光深熔焊接的热源模型，得出了激光功率与光斑大小、焊接速度等的关系，并讨论了激光光束质量．实验采用非稳腔输出的６～８ｋＷ高功率高质量的激光焊接４，６，８ｍｍ厚的Ａ３钢板，其焊接速度分别为３．２，２．２，０．９ｍ／ｍｉｎ，焊接深宽比均超过２１，其中６ｍｍ钢板深宽比达到４１．着重研究了激光焊接工艺，并对焊接试样进行了拉伸强度测试和过轧机实验 The heat source model of laser deep penetration welding of thick steel plate was studied by energy balance principle. The relationship between laser power and spot size, welding speed and so on was obtained. The laser beam quality was also discussed. Experimental use of unstable cavity output 6 ~ 8kW high-power high-quality laser welding 4,6,8 mm thick A3 steel, the welding speed was 3.2,2.2,0.9 m / min, the welding aspect ratio More than 21, of which 6mm steel aspect ratio reached 41. Focusing on the laser welding process, and the welded specimens were tested for tensile strength and rolling mill experiments