Regression Modelling of Joining Aluminium Studs to Steel with AA 1100 Interlayer

Recently, there is a steep increase in the requirement for aluminium-steel joints in several automotive and structural applications. But joining of dissimilar metals possesses unique challenges. To overcome these issues, AA 1100 interlayer has been proposed in the friction stud welding of AISI 1030/AA 1050 joints. In the present work, it is found that the use of interlayer not only enhances the joint strength but also inhibits the formation of flash and thereby reduces the consumption of base metals. Applying full factorial design, experiments were conducted to study the influence of interlayer thickness along with other parameters such as rotational speed, friction time and friction pressure on the strength of joint. SEM evaluation on the fractured surface of the specimens was carried out. Ductile mode fracture with dimples observed with 0.95 mm interlayer. Microvoids absorb a lot of energy, and the toughness is high. Hence, the dissimilar joint made using 0.95 mm interlayer have high joint strength. Microhardness measurement across the interfacial region shows increased value near the weld line due to increased plastic deformation. Finally, regression analysis is carried out and an empirical relation has been developed to predict impact strength and axial shortening length in terms of other parameters.