Laser welding is capable of welding at high speeds by high-density energy. While arc welding is an effective construction method from the viewpoint of tolerance of the gap and welding position. Laser-arc hybrid welding has both these features. The authors have researched suitable welding parameters and consumables for this hybrid welding process that couples laser beam with MAG arc for lap fillet weld joining of thin steel sheets. As a results, the following welding parameters have been proven to be the most appropriate for better bead shapes and root-gap tolerance, i.e. laser leading (kept at a right angle) and MAG trailing (kept at a push angle), the laser-arc distance was 3 mm and the laser beam focus size was 2 mm. In addition, it was proven that HT490-class welding wire of Si-Mn-Ti type (JIS YGW11) was the most appropriate for better bead shapes and root-gap tolerance. The bead shape was apt to be better in cases of higher surface tension of welding wire. The result of the tensile shear test of the joint by welding with HT490-class welding wire of Si-Mn-Ti type(JIS YGW11) under selected welding condition demonstrated that the value of the tensile strength of parent material was equal to that of lab fillet joints.
