TWI

With regard to the development of ausformed H13 tool steel for high strength friction stir welding (FSW) tools, an investigation was undertaken to explore methods to improve equal channel angle extrusion (ECAE) as the deformation step. Studies involved scaling up to a larger ECAE die, characterisation of room temperature and elevated temperature (482 deg.C) mechanical properties for smooth and notched bars, and determination of notched bar rotating-bending fatigue life at 482 deg.C. Issues discussed include the failure to scale up to a larger die owing to strain localisation probably associated with strain hardening and the formation of martensite on the H13 tool steel bar surfaces.

12th International Symposium, 26-28 Jun 2018, Session 4A: FSW Tools, Paper 04