METAL TRANSFER
The continuously fed electrode wire is melted in the arc heat and the droplets thus formed at the wire tip are transferred to the weld pool. The way in which material is transferred from the tip of the consumable electrode into weld pool has a significant influence on the overall performance of the process. The various types of metal transfers have been classified int o groups. The basic modes by which metal is transferred from the electrode to the weld pool are short circuiting transfer (dip) and free flight transfer. In free flight transfer an arc is maintained between the electrode and work piece and t he met al is transferred across the arc in the form of droplets. The common free flight modes are globular and spray. These modes of metal transfers are controlled by the various forces that are acting on the droplet. The electromagnetic pinch force and the surface tension force are considered as the primary forces responsible for the various modes of metal transfer in GMAW process.