Heat generation and steel fragment effects on friction stir welding of aluminum alloy with steel

Abstract

ABSTRACTJoining two dissimilar materials, like aluminum and steel, has been a topic of great importance in modern engineering applications. Therefore, this research expounds on joining aluminum alloy (Al5052) with low-carbon mild steel using friction stir welding. A novel approach is employed that quantifies the discontinuities (steel debris and voids) in the weld stir zone using image analysis. Furthermore, a parametric investigation was conducted following a full factorial approach with three tool rotational and traverse speed levels, and a heat input factor (ω2/v) was derived through theoretical modeling of process parameters. The heat input factor was substantiated experimentally with thermal cycle measurements. Results revealed that both the ω2/v factor and the extent of discontinuities determined the soundness and strength of the weld joints. A low rotational speed of 386 revolutions/minute and moderate traverse speed of 140 mm/minute, having minimal discontinuities, rendered maximum joint strength of approximately 212 MPa.