EFFECT OF FLUX RATIO IN FLUX-CORED WIRE ON WIRE MELTING BEHAVIOUR AND FUME EMISSION RATE

In GMAW, the welding wire melts itself due to the arc discharges from the electrode. Both the Joule heating and the arc heating of the electrode contribute to the melting of the wire. In general, it is said that flux-cored wire (FCW) melts faster than solid wire as the welding current flows mainly through the sheath of the FCW. FCW structure differs from solid wire and these differences affect not only the wire melting behaviour, but also the fume emission rate (FER). However, at present, no report exists which defines these effects in detail. Therefore, it is very important to clarify the effect of these differences in wire structure on the wire melting behaviour and FER in order to understand how to reduce the latter. In this study, we found that FER increased with the flux ratio of FCW. It is assumed that these results can be attributed to the state of the stability of the flux column in the arc and the heat content of the droplets.