Abstract: The 400 MPa ultrafine grained steel strip with thickness of 8 mm was connected by CO2+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.

Key words: Ultrafine grained steel , Welding , Grain growth , Ductile-brittle transition temperature

摘要： 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8mm 的400MPa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。

关键词: 超细晶粒钢 , 焊接 , 晶粒长大 , 韧脆转变温度