Modelling of Wire Melting Behaviour of Coaxial Hybrid Solid Wire in Gas Metal Arc Welding in a Pure Argon Shielding Gas

Abstract

Coaxial multi layer solid wires (coaxial hybrid solid wires) have been developed in order to stabilize welding in pure Ar shielding gas. This coaxial hybrid solid wire has a double structure, the composition of inner part and outer part is different. The wire melting behaviour of coaxial hybrid solid wire is different from that of conventional solid wires because the electric current path and the heat transfer behaviour depend on the characteristics of inner and outer materials. Therefore, in order to obtain stable welding, to combine appropriate materials for inner part and outer part is necessary. To understand the influence of the material properties of the inner part and outer part on the wire melting behaviour, a simulation model for wire melting has been developed. The influences of the melting temperature, the specific heat, and the thermal conductivity on wire melting behaviour were examined. Simulations show that the shape of the solid wire tip is affected by changing melting temperature and specific heat of the inner part. Furthermore, these changes have a large effect on the length of the wire extension. The thermal conductivity effects on wire tip shape and temperature distribution, but has little effect on the wire extension.