Laser-arc Hybrid Welding Performances Of High Strength Steel

WEL-TEN590high strength steel was widely used in ship, automobile and otherindustries. In order to further improve the quality and efficiency of welding, this paperstudied the performance of laser-arc hybrid welding.In this paper, YLS-2000laser system, TPS-5000of FRONIUS MAG welding machine,robot of KUKA-KR60HA, hybrid welding head and other equipment were used to laser-archybrid welding590MPa high strength steel of6mm in laser-arc hybrid welding system. Themode of metal transfer and plasma of the different heat source lead produce were observedby high-speed video system. The results show that the effect of number of spatter laser-archybrid welding produced on weld shape and optimal laser-arc distance(DLA). A phenomenathe beam attract arc were observed, because laser beam owned micro plasma properties.Metal transfer was short circuiting transfer and the transfer frequency was increase than purearc welding in laser-arc hybrid welding.The effect of laser-arc distance, defocusing distance, MAG current and welding speed onweld shape of laser arc hybrid welding through the weld appearance inspection andcross-sectional observation when laser lead or arc lead. The results show that deeperpenetration can be available and less plasma can be produced by arc leading. DLAhad affectednot only the weld bead, but also the frequency of metal transfer, the optimum DLAwas0mm.The penetration was maximum which was4mm when defocusing distance was-2mm. Theeffect of MAG current on weld shape, with the increase of MAG power, the penetrationincreased in the experimental range from100A to200A. The optimum speed was0.6m/min.The distribution of alloying elements of Mn and Mo in laser-MAG hybrid weld wasmeasured by EMPA, it can be found that the concentration of Mo and Mn was homogeneous,while the concentration of Mn and Mo was not homogeneous in weld metal, and theircontent over base metal;. In order to analyze the microstructure of weld metal, weld wasdivided into two zones, they were laser zone(PL) and arc zone(PM). PMthe organization wasmainly composed of bainite and martensite, also contains a small amount of ferrite; PLorganization is mainly composed of martensite and bainite, also contains a small amount offerrite. Depending on the hardness test, the hardest area appeared in the HAZ area. The peak of hardness distribution of welded joint appeared in overheated zone of HAZ, its maximumwas382HV. Mechanical properties experimental results show that the maximum tensilestrength and elongation range of weld joint were680.78~687.98MPa and18.72~20.83%,the fracture location on base metal; The range of impact toughness value were15.89~81.29J when impact test temperature for-60~15℃.