High Productivity Cladding with Non-Consumable Electrode Arc Processes

摘要

Non-consumable electrode arc processes such as tungsten inert gas (TIG) and plasma arc (PA) welding are commonly used to produce high quality welds and claddings for a variety of alloy materials. Unfortunately, their deposition rates are low compared with consumable electrode arc processes such as metal inert gas (MIG) and submerged arc (SA) welding. Therefore, there is a considerable industrial interest in developments to increase their throughputs. In the present paper, two approaches will be presented. First, hot wire TIG and plasma cladding were investigated. In the hot wire process, the filler wire was resistance heated prior to entering the weld pool to increase the melting efficiency. Comparison charts for cold and hot wire processes at various cladding parameters are presented. Results show that a significant increase in the deposition rate and thus productivity can be achieved with the hot wire technique in both the TIG and plasma processes. Secondly, a novel twin-wire TIG cladding technique in which two cold wires are fed simultaneously into the weld pool was evaluated. Results show that a significant increase in the deposition rate can be achieved with this technique. The overlay quality was found to be comparable or even better than that obtained with single wire cladding. In summary, both the hot wire and twin-wire approaches hold good promises for industrial applications where both high quality and high productivity are required.