Developing Empirical Relationships to Predict Tensile Strength, Elongation and Hardnesss of Friction Stir Welded Pure Copper Joints

This investigation was undertaken to predict the tensile strength, elongation and hardness of friction stir welded pure copper. Response surface methodology based on a central composite rotatable design with three parameters, five levels and 20 runs, was used to conduct the experiments and develop the mathematical regression model by using of Design-Expert software. The three welding parameters considered were tool rotational speed, welding speed and axial force. Analysis of variance was applied to validate the predicted model. The developed mathematical model can be effectively used to predict the tensile strength, elongation and hardness of FSW joints at 95% confidence level. Also, microstructural characterization was examined using optical microscopy and the effects of the welding parameters on mechanical properties of friction stir welded joints were analyzed in detail.

Keywords:

Copper , Design of experiments , Friction stir welding , Tensile strength , Response surface method