Advanced Welding Processes: Technologies and Process Control

Metal cored Rutile
Basic Self-shielded
Gas metal arc welding 109
7.11 Schematic representation of transfer types observed with fluxcored
wires.
slag layer on the surface of the droplet, a small amount decomposes to form
shielding gases whilst some un-melted flux is transferred to the weld pool
where it melts and produces a protective slag blanket. The un-melted flux
projects from the tip of the wire as shown in Fig. 7.11.
Basic flux-cored wires
The basic flux formulation gives irregular dip transfer at low currents and
non-axial globular transfer at higher currents. The un-melted flux forms a
pronounced finger which projects from the wire into the arc. The effect of
the flux formulation on the droplet size for gas-shielded flux-cored wires is
shown in Fig. 7.12.
Self-shielded flux-cored wires
Dip and globular repelled transfer are commonly found with this type of
consumable and very large levitated globular ‘boots’ may form at the wire
tip. The globular tendency may be reduced by flux formulation and there is
evidence of secondary transfer occurring from the base of the globule as well
as explosive droplet transfer.