고효율 TIG용접을 위한 용융지 제어 방법에 관한 연구

Abstract

TIG welding is a welding that melts the basic material and filler metal by generating tungsten electrodes and arc among inert gas atmospheres and using arc heat. TIG welding process becomes necessary in various industries such as ship, plant, and nuclear power because it can obtain high quality welding and its demanding is increasing. Therefore, many industries have changed over from manual to automatic TIG welding or are in progress. The application of automation is difficult due to molten pool sag in an overhead position or an inclined up position, penetration is shallow, and deposition rate is late due to low arc efficiency so that the production is low, which becomes a trouble in actual industries. If deep penetration is necessary for automatic TIG welding, this study controled molten pool by controling active flux, shield gas components, electrical characteristics, and arc length for penetration increase in root pass welding. To solve problems caused by welding attitudes in orbital welding and others, this study considered arc force, shied gas force, etc for control of molten pool. In addition, it controlled molten pool by controlling wire resistance heating for low welding heat input and high deposition with wide and shallow penetration in overlay TIG welding. Through an analysis on control methods and application of molten pool for automatic and high efficient TIG welding, the following conclusions are obtained. The application of active flux and mixture gas made deep penetration of molten pool and convex back bead was obtained by using shield gas pressure in orbital welding. The application of a Hot wire method with filler metal resistant heating increased deposition rate largely and reduced welding heat input.