温度场是影响激光焊接焊缝成形质量的关键因素。针对非熔透型激光搭接焊接头焊缝成“钉头”状的特点，通过分析焊接时材料吸收激光能量的分布情况，提出了高斯面热源加线性递增式柱热源的复合体热源模型。模型考虑板间接触热阻的影响，并将计算结果和试验结果进行了对比，发现模拟出的焊缝形状和试验吻合较好；此外基于本模型对焊缝各处的热循环与焊缝组织形貌及显微硬度的关系进行了分析。结果表明，焊缝组织形貌及显微硬度除与加热和冷却速率有关外，峰值温度对其也有重要影响；在热循环基本一致的情况下焊缝的性能相似。该模型较准确地模拟了薄板激光深熔焊接熔池温度场，对研究激光深熔焊接温度场问题和激光工艺参数的优化选择具有参考价值。

Temperature field is the key factor affecting manufacturing quality in laser welding. For a nail head shape of weld cross-section in the partial penetration laser lap welding, a hybrid heat source model combined with a circular disk source with a Gaussian distribution on the top surface and a linear increasing column source along the depth of weld is proposed, by analyzing the absorption mechanism of the welding material. The effect of the contact thermal resistance between the upper sheet and bottom sheet is considered in the model. The comparison of experimental and simulated results shows that the geometry of weld cross sections is in good agreement. In addition, the relationship is investigated between the thermal cycles and microstructure as well as the micro-hardness. Besides the heating and cooling rate, the peak temperature also has an important influence on mechanical properties of the weld. The performance of the weld is similar when thermal cycles are consistent. The numerical model can help to study the temperature field of the laser deep penetration welding and choose appropriate laser parameters.