TWI Industrial Member Report Summary 30/1976
By A W Carter
The suitability of the switched arc twin MIG process is examined with respect to joint preparation angle, root gap and material thickness for welding mild steel with 1.2mm diameter wires, in A/2%O2 shielding gas for currents up to 400A. Some comparison tests were also made in A/5%CO2.
In joint filling and capping in the flat position, the system appears to have a wide tolerance in current and gives an excellent degree of sidewall fusion with a smooth top bead and an unusually low contact angle.
This process is also suitable for overlaying, and in the vertical down position gives a uniquely thin deposit. These layers are approximately 1 to 2mm thick and with a build-up of three layers (4mm thick deposit) the dilution can be brought down to less than 3%.