深冲钢冷轧薄板压平缝焊接头的组织及力学行为

Microstructural Distribution and Tensile behavior of Mash Seam Welded Joints of Deep-drawable Steel Sheet

对两种不同级别的深冲钢冷轧薄板进行了高速压平缝焊焊接试验。试验考察了不同焊接工艺参数、热处理状态下接头的组织性能及高、中温力学行为。结果表明，接头焊态组织可分母材纤维组织区、部分再结晶区、细晶区、粗晶区及熔核中的非平衡组织区；连续退火后显微组织可分为细晶区、粗晶区及非平衡组织区；接头焊态强度主要受内部飞溅及熔合不足等焊接缺陷的影响；焊态强度较高的接头，在高、中温状态及退火状态下其强度亦较高；当不含焊接缺陷时，再结晶态接头的强度高于母材，断口处于母材，属韧性断裂；而未再结晶态的接头强度低于母材，断口处于焊趾处，属脆性断裂。

The high speed mash seam welding experiments were conducted on two kinds of deep-drawable cold rolled steel sheets with thickness ranges of 0.5 to 1.5mm.The influence of welding parameters and annealing treatment on microstructural distribution and tensile strength of the joints was investigated. The elevated temperature tensile behavior was also investigated using a Gleeble 1500 machine. The results shown there were fiber zone, partially recrystallized zone, fine grain zone, coarse grain zone and unequilibrium microstructure zone in the as-welded joint. There were fine grain zone, coarse grain zone and unequilibrium microstructure zone in the annealed joint. The tensile strength of the as-welded joint was greatly reduced when there was crack, resulted from splash or incomplete fusion , in the weld. A joint with higher strength at as-welded state had higher strength at annealed state or at elevated temperature. Joint strength was higher than that of base metal in recrystallized state, and lower than that of base metal in non-recrystallized state.