400MPa级超细晶粒钢焊接接头的低温韧性

Low-Temperature Toughness for Weld Joint of 400 MPa Ultrafine Grained Steel Strip

利用CO2+Ar气体保护焊,分别采用单道焊接和双道焊接工艺对厚度为8 mm的400 MPa级超细晶粒钢钢板进行了焊接,采用系列冲击试验方法对焊接接头的低温韧性进行了研究。试验结果表明,在焊接接头中,焊逢位置低温韧性较差。由于双道焊较小的热输入,减小了焊缝及热影响区组织粗化,其焊接接头的低温韧性好于单道焊,并使热影响区面积变小。

The 400 MPa ultrafine grained steel strip with thickness of 8 mm was connected by CO2 ＋Ar arc welding under single-pass welding and double-pass welding, and the low-temperature toughness for weld joints was investigated by series impact test. The experimental results show that the low-temperature toughness for weld is worse among the weld joint. The low-temperature toughness for weld joint by double-pass welding is better than that of single-pass welding, and its heat affected zone（HAZ） is decreased because smaller heat input reduces grain growth coarsening,