High-deposition-rate position welding of Al 5083 alloy for spherical-type liquefied natural gas tank

Abstract

High-deposition-rate welding is used in the fabrication of liquefied natural gas tanks from thick aluminium plates because the weld defect generally increases and the productivity decreases with increasing number of passes. In this study, high-deposition-rate gas metal arc welding was implemented in vertical-up and horizontal positions. High deposition was achieved in the vertical-up position by pulse welding using 2.4-mm single wire and 1.6-mm twin wires and in the horizontal position by electromagnetic lifting of the weld pool. The arc stabilities for the applied processes were examined and welding procedures for thick plates were developed. A total of 14 welding passes were required for the vertical-up welding of a 70-mm thick plate by using the conventional 1.6-mm single-wire process, and the fully penetrated welds could be achieved with 8 welding passes by using twin-wire welding. Also, 10 welding passes were required for the horizontal welding of a 35-mm-thick plate by the conventional approach, and 6-pass full-penetration welding was successfully implemented by applying an external electromagnetic field.