(Session 2A)Development of simultaneous double side corner FSW process using Ad-Stir technique for LNG tank construction

摘要

In this study, a double sided corner friction stir welding technique for LNG tank construction was developed. To simplify the welding operation and to obtain high productivity, simultaneous double side SSFSW process was developed. Partial penetration corner SSFSW was selected to avoid potential collision of the tool probes.To prevent defects in stir zone, the material feeding system was optimized. Defect-free weld can be obtained under a wide range of rotational speed. The tensile strength of the double-side partially penetrated weld satisfied the strength limit of the base metal. To improve process stability for long welding length, the friction between workpieces and shoulder was optimized. Tool life for long welding length was also examined. Finally, the process stability was evaluated by long length welding test.