An investigation of dynamical metal transfer in GMAW—Effects of argon shielding gas

• We make use of our developed measuring method to determine the unbalance radial electromagnetic force.
• The effect of this electromagnetic force on the formation of spray transfer mode was investigated.
• Lower unbalance radial electromagnetic force is essential to avoid droplet stuck on the welding wire which lowers down the transfer rate of droplet.
• This finding is contrary to literature because higher electromagnetic force was reported to be essential for faster transfer rate of droplet.

The unbalance radial electromagnetic force was firstly obtained by measuring the real-time input electrical impedance of GMAW. This force acts as an attaching force because it pushes the droplet aside of the welding wire and sticks on the tip of welding wire as result of surface tension force. In spray transfer mode, lower unbalance radial electromagnetic force was observed when argon shielding gas was used. The finding presented in this paper is contrary to the literature which reported that higher electromagnetic force is desirable for faster transfer rate of droplets in spray transfer mode.