Effect of tool tilt angle on weld joint properties of friction stir welded AISI 316L stainless steel sheets

•FSW of 316L stainless steel was carried out to study the effect of tool tilt angle.•The change in tool tilt angle altered the material flow characteristics of stir zone.•A highest weld joint strength (96% of the base steel) was achieved.•The best tool tilt angle for FSW of 316L stainless steel was found at 1.5o. The effect of tool tilt angle on mechanical and metallographic characteristics of friction stir welded AISI 316L austenitic stainless steel joints was investigated. Three experimental trials were performed between 0° to 3° in steps of 1.5°, while keeping the other primary FSW parameters constant (tool rotational speed of 600 rpm, welding speed of 45 mm/min and axial load of 11 kN). The experimental findings prove that the tool tilt angle has significant effect on dynamic volume of the stir zone, peak temperature and the intensity of the shear band formation in the weld zone. The weld joint made at 1.5° was the best tool tilt axis that exhibited higher strength and superior microstructural features leading to onion ring formation at the weld stir zone. 0° tilt angle resulted in slight shoulder plunge whereas, 3° tilt angle paved the way to the formation of void in the weld zone.