Adopting coaxial and side blown protective gas to control plasma, many experiments of C02 laser welding of zinc coated high strength steel to vehicle body are finished to welding joints Joint microstructure and stress-strain curve of specimen are investigated. Technology parameters of C02 laser welding of zinc coated high strength steel affect joints' mechanical properties such as tensile strength, yield strength and extensibility, the experimental result shows that hardness value in weld zone becomes low with increasing of energy input,at the same time the cracked zone of tensile specimen、the nick dimple of cross-section in welding seam and the distribution are also different, and tensile crack of welding seam extends to the base metal, which indicates deep penetration laser welding can effectively avoid softening of welding joints during laser welding of high-strength galvanized steel.%采用同轴和侧吹保护气体控制等离子的方法,对车身专用高强度镀锌钢板的CO2激光焊接接头的性能进行了大量的焊接试验研究,并对焊缝进行显微组织分析和相关的机械性能检测.研究激光焊接高强度镀锌钢板的工艺参数对焊接接头的抗拉强度、屈服强度和延伸率等机械性能指标的影响规律,优化了激光焊接的工艺参数.试验表明随着激光焊接过程中输入线能量的增加,焊缝区的硬度值逐渐下降,拉伸试件断裂的区域、断口韧窝大小及分布情况各不同,且焊缝的拉伸裂纹均向母材扩展,说明激光深熔焊接可以有效地避免高强度镀锌钢板焊接接头的软化.
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