Performance of high strength steel CO₂ laser-MAG hybrid weld

Performance of 590 MPa grade high strength steel weld made by CO₂ laser welding and CO₂ laser-MAG hybrid welding was investigated. For CO₂ laser-MAG hybrid welds, the weld metal in the arc zone mainly consisted of bainite and pearlite, while that in the laser zone was mainly composed of martensite. The distribution of Mn and Mo elements was inhomogeneous in laser-MAG hybrid weld metal. The tensile test of laser welded joint and laser-MAG hybrid welded joints meet the requirements, and the strength of the weld was higher than that of base metal. The hybrid weld metal showed higher toughness than the laser weld metal at test temperature range of -60℃ to +15℃. The hardness of hybrid weld metal was between 250 HV and 400 HV, higher than that of the base metal.