PRODUCTIVITY IMPROVEMENT IN GRADE 91 STEEL WELDING USING ORBITAL HOT WIRE GAS TUNGSTEN ARC WELDING PROCESS

摘要

In a thermal power plant, there is a large requirement for the butt welding of pipes. In position welding, pipes cannot be rotated and has to be welded in the fixed position. The processes which are widely employed are semi-automatic GMAW and GTAW processes. In addition to these processes, the recently developed orbital hot wire GTAW process (OHW-GTAW) can also be applied for the orbital welding of pipes. The fully automatic OHW-GTAW process ensures the quality of weld metal. In addition, since the process is free from human factor, the total time required for the welding process is less. The paper makes a comparison of the techno-economic advantages of the OHW-GTAW process compared to the semiautomatic GMAW and GTAW processes. The results of the study shows that the OHW-GTAW process gives defect free weld with superior weld properties at higher production rate compared to conventional GTAW& GMAW processes.