The effects of tool rotation speed and traverse speed on friction stir welding of AISI 304 austenitic stainless steel

In this study, AISI 304 (X5CrNi18-10, material identification number 1.4301) austenitic stainless steels, 3.0 mm thick, were joined by friction stir welding by applying different tool rotation speeds and traverse speeds, compressive forces and tool angles. The strength of the welded joints was improved by selecting suitable welding parameters. The maximum notch impact toughness was achieved on samples produced with 950 rpm rotation speed, 60 mm min(-1) traverse speed, 9 kN compressive force, and 1.5 degrees tool tilt angle. The maximum tensile strength of the weld zone was obtained on samples welded with 47.5 mm min(-1) traverse speed, a rotational speed of 750 rpm, compressive force of 9 kN and tool tilt angle of 1.5 degrees. The traverse speed of 47.5 mm min(-1) was found to optimize the results of tensile strength and impact tests. Fine-grained microstructures occurred in the welded area. The weld joints obtained with friction stir welding have lower tensile strength compared to that of the base material. The experimental results indicate that AISI 304 austenitic stainless steels can be successfully joined considering both the strength of the welded joint and the appearance of the welding bead by selecting proper tool material and welding parameters using friction stir welding.