GMAW 수평자세 고효율용접에서 비드처짐 극복을 위한 적층설계 연구

Abstract

Large pipe fittings are being widely used in plant industry and shipbuilding industry. When high rate welding is performed in horizontal position for high productivity, there are problems such as undercut and overlap. In addition for plant industry, FCAW process is limited in many cases. When ceramic material is used to prevent bead sagging, cost and time are required for installation. Accordingly, the purpose of this paper is to develop a welding process that can increase productivity in horizontal butt welding. One-pulse one-drop condition was established in butt pulse GMAW horizontal welding. Also using the problem of molten pool sagging by gravity, deposition cross sectional area of pass 3 was designed with large size on the lowest plate. For layered design with large bottom and small top generating bottom bead, standards for stable pass 3 were settled based on experiments with teaching height, deposition area, and working angle of pass 3. 6pass deposition welding was made possible at 45-degree L-groove and 5pass deposition welding was made possible at 25-degree L-groove through overall layer welding experiment according to groove angle of horizontal L-groove. Stable bead without defect was obtained.