Microstructure and mechanical properties of weld metal in laser and gas metal arc hybrid welding of 440-MPa-grade high-strength steel

• 作者: Fu-xing Yin Xu-chen Li Cui-xin Chen Lin Zhao Yun Peng Zhi-ling Tian
• 来源期刊: 钢铁研究学报（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: ORIGINAL PAPERS
• 页码范围: 853-861
• 页数: 9页
• 语种: 英文

摘要

Fiber laser and gas metal arc hybrid welding of 440-MPa-grade high-strength marine steel was carried out at different welding speeds.The influence of welding speed on the micro structure and mechanical properties of weld metal was investigated.The weld-metal microstructure mainly consisted of pre-eutectoid ferrite,side-plate ferrite,acicular ferrite and lath bainite at a low welding speed.With the increase in welding speed,acicular ferrite and lath bainite were the dominant weld-metal microstructures.All samples failed at the base metal during tensile tests,which indicates that there is no soft zone in the hybrid welds.The welding speed had a significant effect on the impact toughness of the weld metal.The impact absorbed energy of the weld metal increased from 35 to 105 J with the increase in welding speed from 0.8 to 2.0 m/min.Large amounts of acicular ferrite and lath bainite were formed in the weld metal at a high welding speed,which resulted in an excellent impact toughness.