Friction stir spot welding (FSSW) of dissimilar S45C steel and 6061-T6 aluminum alloy in a butt configuration is experimentally investigated. Butt spot welding is performed using a convex scrolled shoulder tool at different tool rotational speeds. FSSW butt joints are successfully fabricated by offsetting the tool to the steel side. https://poolsproductscanadas.shop/product-category/pool-accessibility/