Material Flow Modification in a FSW Through Introduction of Flats
Abstract
Friction stir welding (FSW) is a solid-state process in which a non-consumable weld tool is used to stir metal together to obtain a fully consolidated weld seam. There is controversy regarding the contributions of various attributes of the pin design, especially with regards to flats and flutes. In this study, similar FSWs made with threaded cylindrical pin-tools having 0, 1, 2, 3, 4, and 5 flats were compared. Slight increases in torque were noted with increasing flats. Significant changes in the FSW structure with varying numbers of flats were observed, but without significant changes in tensile strength. Changes in the textural banding shape, the addition of sub-bands, and a new set of bands from coalescence of band kinks constitute the structural changes observed. Explanations of these structural changes in terms of tool interactions with the FSW metal are offered.
- Publication:
-
Metallurgical and Materials Transactions B
- Pub Date:
- February 2016
- DOI:
- 10.1007/s11663-015-0523-7
- Bibcode:
- 2016MMTB...47..720S