Sunken weld is one of the common defects of tailor welded blanks, which seriously affects the strength of weld,and gap is the main reason for sunken weld.The effects of gap on weld quality and reasons for gap were studied, and the relationship between gap and process parameters was discussed based on theoretical analyses and experiments.The results show that gap relates to offset, blank thickness, weld width and the minimum melting width of thinner blanks. The minimum melting width of thinner

blanks was related to the materials of blanks.Positive offset can compensate the harmful effects of gap.The models for the maximum gap and offset tolerance were proposed,and a compensation method was also given, thus the adaptability of the gap was enhanced. The results can provide theoretical guidance for the optimization of process parameters.

焊缝凹陷是激光拼焊板的常见缺陷之一，严重影响焊缝强度，间隙是产生焊缝凹陷的主要原因。基于理论分析和工艺试验，研究了间隙的产生原因和对焊缝质量的影响，分析了间隙与工艺参数等因素的关系。研究结果表明:在不等厚板激光拼焊中，允许间隙的大小主要与偏移量、板厚组合、焊缝宽度以及薄板最小熔宽有关,薄板最小熔宽主要与钢板的材料有关。可以采用正偏移量对间隙进行补偿。该研究通过建立最大允许间隙和偏移量的计算公式，给出了间隙的偏移量补偿方法，从而提高了激光拼焊对间隙的适应能力。该结果可为优化工艺参数提供理论指导。

激光拼焊, 间隙, 偏移量, 不等厚板