A. Heidarzadeh - Young Researchers Club, Ahar Branch, Islamic Azad University, P.O. Box ۵۴۵۱۶, Ahar, Iran.
H. Khodaverdizadeh - Young Researchers Club, Ahar Branch, Islamic Azad University, P.O. Box ۵۴۵۱۶, Ahar, Iran.
E. Nazari - Young Researchers Club, Ahar Branch, Islamic Azad University, P.O. Box ۵۴۵۱۶, Ahar, Iran.
A. Mahmoudi - Young Researchers Club, Ahar Branch, Islamic Azad University, P.O. Box ۵۴۵۱۶, Ahar, Iran.

Friction stir welding is a mechanical, solid-state joining process that is used to joining structural aluminium alloys. Compared with the fusion welding processes, in friction stir welding the metal in solid state welding does not reach its melting temperatures so there are fewer defects in welded joints. Mechanical properties of welded joints are influenced by the welding parameters. Therefore, an attempt was made to establish a mathematical model for predicting the mechanical properties of AA6061-T4 aluminium alloys by incorporating friction stir welding process parameters. Three factors (rotational speed, welding speed and tool profile), five levels central composite design were used to optimize the experimental conditions. Response surface method was applied to establish the mathematical model. Design-Expert software was used to evaluate the coefficients for different responses. Also, effect of welding parameters on mechanical and microstructural properties was studied in detail.

Aluminium alloys; Design of experiments; Friction stir welding; Mechanical properties; Response surface method