TWI Industrial Member Report Summary 331/1987
By M H Rodwell
Despite the increased use of more advanced mechanised and automated welding systems, a number of persistent material-related problems exist which, when they occur, can seriously reduce the effectiveness of such systems. The nature of these problems is that different casts (batches) of parent material or filler wire can exhibit significant variations in welding characteristics, even though they conform to the same nominal specification and may even have been produced by the same manufacturer. The phenomenon has been observed for several arc welding processes including the increasingly popular metal inert gas (MIG) welding process. This report describes a study on the influence of the surface condition of the filler wire on arc stability in MIG welding. Three copper-coated, mild steel MIG wires, exhibiting significant differences in arcing behaviour, were tested in the spray metal transfer mode of operation to determine the cause of the observed variations in arc characteristics.