TWI

A procedure has been developed for repairing welds made by friction stir welding (FSW) in cases where the tool breaks during welding. It involves the following stages: excavating the broken FSW tool, milling out a slot across the hole, machining an insert to fill the slot, softening the insert and hammering it into the slot, running first and second friction stir repair welds over the insert, and NDT. The double-pass welding technique was characterised by offsetting in turn the welding runs to each side of the original weld line, making the welding passes in opposing directions, and each repair weld sweeping the insert interface towards the centreline of the weld. The repair process was simulated using two 30 mm thick 7010 aluminium plates. The use of a single-pass repair technique would require a pin diameter 8 mm larger than the failed FSW tool pin.

3rd International Symposium, 27-28 Sep 2001, Session 3: Process Development 3, Paper 01