Experimental and numerical analysis of the effect of preheating in friction stir welding

Abstract

Friction stir welding has been frequently used for fabrication of low melting point materials. Nevertheless, it is capable to join thin sheet of high melting point materials such as stainless steel, titanium etc. but tool wear rate is high. A Heat-assisted backing plate (HABP) was developed to preheating the welded specimen. In this paper, a modified 3D FE model was established to simulate the heat-assisted backing plate of friction stir welding by using ANSYS APDL to study of the temperature distribution of workpiece. Numerical simulation was defined by six different load steps for preheating, plunge, dwell, traverse, pull out of tool and cooling stage. Observations of preheated friction stir welding were compared with traditional friction stir welding results. It was found that the preheated friction stir welding increased 7.39 % and 7.55 % of peak temperature as compared to traditional friction stir welding in FEA and experimental respectively. In addition, preheating improve the uniform temperature distribution along the thickness of welded joint.