Effect of friction stir welding parameters on mechanical and dry sand abrasion characteristics of different thermoplastic joints

This paper discusses the mechanical and dry sand abrasive wear characteristics of thermoplastics joints by friction stir welding (FSW). The thermoplastics selected for this study include polycarbonate (PC), high-density polyethylene (HDPE), polypropylene (PP), and polyamide (PA), all in 10 mm-thick plates. A triangular pin profile tool made of mild steel is used for FSW of thermoplastic plates. The control parameters of the FSW, including tool feed rate (28, 56 mm/min) and tool rotational speed (710, 1000 rpm), have been selected to weld the thermoplastic plates. The HDPE, PC, PP, and PA plates were not successfully welded using a control parameter combination of 28 and 56 mm/min tool feed rate with 1000 rpm tool rotation speed. Whereas, HDPE, PC, PP, and PA plates were successfully welded using the control parameter sets: 56 mm/min tool feed rate with 710 rpm tool rotation speed, and 28 mm/min tool feed rate with 710 rpm tool rotation speed. The dry sand abrasive wear and mechanical characteristics, i.e., tensile strength and impact strength, were examined for the successfully welded thermoplastics according to ASTM standards. The experimental results reveal that all mechanical characteristics of the PA thermoplastic weld are highest at both 28 and 56 mm/min tool feed rates, with a 710 rpm tool rotation speed, compared to the HDPE, PE, and PC thermoplastic welds. Moreover, the dry sand abrasion resistance constructed the order of PA > PC > PP > HDPE, which makes PA-based FSW joints suitable to be used in abrasive conditions.