A Study on Productivity Improvement in Narrow Gap TIG Welding
Abstract Adoption of narrow gap welding shall be increased for the butt joint of thick plate, because the deformation and welding cost is reduced by decrease of cross sectional area. However, sometimes narrow gap causes defects such as lack of fusion since it has small groove angle and narrow groove width. Therefore, GMAW, GTAW and SAWprocess shall be adopted to narrow gap welding with small bead hight and low deposition rate. In this study, Super TIG welding using C type strip was applied to semi narrow gap butt joint in order toincrease the welding productivity. High deposition rate 10kg/hr was obtained by high current 600A without undercut, humping bead and other welding defects. Measuring the mean and standard deviation of the meltingdepth to evaluate the developed processes, the fusion line type was determined by measuring the difference betweenmaximum and minium melting depth. Furthermore, a model on arch fusion line and linear fusion line was suggested in order to prevent LF on groove wall in narrow gap butt welding. Key Words Narrow gap, Butt welding, TIG welding, Super TIG welding, Deposition rate, Melting depth, Fusion lineISSN 1225 6153Online ISSN 2287 8955