METAL TRANSFER IN CO2 WELDING
In CO2 welding, two distinct types of metal transfers are identified viz. short circuiting transfer and free flight globular transfer.
Short Circuit Transfer: When the welding voltage and the current are low, the mode of metal transfer would be of short circuiting type. In short circuiting mode, metal transfer occurs from tip of the wire electrode to the job whenever the wire tip touches the weld pool. The arc is extinguished during the short circuit period and is re-ignited after the short circuit is cleared. Short circuiting transfer is used for joining thin sheets, welding out of position and root pass welding of tubes and pipes.
Free Flight Transfer: When the arc voltage and current are high, the metal droplets are transferred non axially as large globules and this is called non axial free flight transfer. The non axial free flight transfer produces deep penetration. Hence, this mode of transfer is used for welding thick sections in down hand and horizontal positions.