Friction Stir Welding (FSW) is being investigated as a method to fabricate a partial penetration closure weld of the steel vessel of a copper-coated used fuel container. The hemi-head is made of A516 Grade 70 steel and the cylinder body is made of A106 Grade C steel. In this initial feasibility study, the objective is to use FSW to demonstrate the merits of FSW using flat steel plate in concert with a closure weld joint designed specifically for a cylindrical container. To complete this objective, there are two initial feasibility demonstrations. First, demonstrate the capability of FSW to create defect free welds in a corner joint design with specific dimensions (10 mm deep weld nugget). Subsequently, verify the weld quality by ultrasonic inspection and metallography. Further, characterize weld zone properties by establishing mechanical properties and hardness at room temperature, and impact toughness at-5°C. Second, demonstrate the ability to use FSW to repair defects that might occur in the initial friction stir weld. Weld repair was accomplished by intentionally creating tunnel defects by FSW, performing metallography and ultrasonic inspection to characterize the morphology of the defects, performing a second friction stir weld repair over the defects, and verifying the subsequent weld integrity by repeating the metallography and ultrasonic inspections. Results on these initial two phases of this program are presented herein.
Test of a flat steel-plate floor under loads
