酸洗-冷轧联合机组闪光焊接头断带原因分析

Strip Breakage Analysis on Flash Welding Joints of Pickling Line-tandem Cold Rolling Mill

采用宏观分析、力学性能测试、金相检验和断口分析等手段对某酸洗-冷轧机组闪光焊低碳Stb35L钢薄板接头在冷轧过程中频繁出现断带的原因进行了分析。结果表明:闪光焊接头发生开裂和断带的主要原因是其热轧原料钢板的头尾板形较差,而闪光焊前又未对其进行校平或剪切,从而导致接头局部出现焊缝搭接错边现象;在冷轧过程中,焊缝搭接处产生折叠和缺口裂纹,裂纹不断扩展最终导致断带;另焊缝中存在未挤压干净的链状氧化物是导致接头开裂和断带的另一个原因。

Frequent strip breakage reasons for soft Stb35L thin steel strip flash welding joints of pickling line-tandem cold rolling mill was investigated by macro analysis,mechanical properties test,metallographic examination and fracture analysis.The results show that the head and end sheet shape of the hot rolling material strip was bad,and it wasn＇t leveled or cut before welding,which caused lap weld at part zone of the flash welding joints.Then in the cold rolling process,folds and cracks formed at the lap weld position,and the strip breakage happened with the constant extension of the folds and cracks.The other reason for the strip cracking and breakage was that there were chains oxide in the flash weld.