The results show that welding and without heat treatment, the microstructure of CGSW is bainite, a little ferrite and pearlite, there is new type bainitic microstructure in heat-affected zone.

• 结果表明：二氧化碳保护焊焊后不热处理接头焊缝组织为贝氏体、少量铁素体和珠光体，热影响区为新型贝氏体组织；