Friction Stir Spot Welding (FSSW) is a solid state welding technique which depends upon frictional and deformational heat input developed during the process [1]. Both these mechanisms of heat input are considered to be caused by the interfacial conditions between the welding tool and the work-piece [2]. These conditions are generally studied using theoretical investigations based upon solid mechanics or fluid dynamics [2, 3].

In this presentation, a solid mechanics approach is presented to formulate a physical based definition for fictional co-efficient. Since this co-efficient plays the key role in Coulombic description of frictional heat input therefore a physical approach to define this co-efficient may be expected to improve the mechanism understanding of this relatively new welding technique.

REFERENCES

[1] R. NANDAN, G.G. ROY, T.J. LIENERT, T. DEBROY; “Three-dimensional Heat and Material Flow during Friction Stir Welding of Mild Steel”, Acta Materialia 55 (2007)

[2] H. B. SCHMIDT, J. H. HATTEL; “Thermal Modeling of Friction Stir Welding”, Scripta Materialia 58 (2008) 332-337

[3] RS Mishra, ZY Ma; Friction Stir Welding and Processing; Materials Science and Engineering R 50 (2005) 1-78