TWI

With regard to the development of the stationary shoulder friction stir welding (FSW) technique as a long term loading joining process offering enhanced weld seam mechanical properties, an investigation is presented into coordinated material flow between the shoulder and probe and the use of appropriate process parameters, tool materials and surface coatings. Weld seam surfaces joined by conventional and stationary shoulder FSW tools are compared. Tool materials and restrictions for long term loading are outlined with respect to elevated temperature compressive yield strength, creep resistance, thermal fatigue strength, fracture toughness and thermal expansion coefficient between probe and shoulder materials. Tool wear and fracture behaviour are described. Other issues discussed include an initial minimum shoulder pressure of 110 MPa, excess material removal and probe stabilisation.

12th International Symposium, 26-28 Jun 2018, Session 3A: Techniques I, Paper 02