抄録
Recently a new type of MIG welding torch, so-called a spool-on-gun torch has been developed in Japan. This study has been made to put this torch to practical use for welding thinner aluminum alloy sheets which cannot be welded by the conventional MIG welding torch. First the welding parameter guides in all positions for making butt and fillet joints of the thicknesses from 1 to 3 mm were chosen. Because of its smooth feeding of fine wires this type of torch facilitates the welding of thinner materials to which an ordinary push type manual torch has not been applicable. The useful minimum sheet thicknesses by this torch are seemed to be 0.8mm in a butt joint and 1.6mm in a tee joint respectively. This process is also applicable to all position welding at nearly the same welding condition as in the flat position. Welding speed by this process being faster than by TIG process, this process may be an effective joining method for aluminum to minimize welding distortion and to prevent the loss of mechanical properties caused by welding heat. The hardness survey for welds showed that the heat affected zones in MIG welds usually narrower than in TIG welds and consequently the joint effeciencies of undressed MIG welds were superior to those of TIG welds but without reinforcement they behaved adversely possibly due to a lot of fine porosities in weld metal made by this process.
