Effect of rotation and traverse speeds on the microstructure and mechanical properties of friction stir processed 2205 duplex stainless steel

Abstract

The effects of rotational speed in range of 800–1600 rpm and traverse speed in range of 12–40 mm/min on the mechanical and microstructural properties of 2205 duplex stainless steel were studied. The temperature and strain were crucial to the microstructural evolutions in the stir and thermomechanical affected zones. The major microstructural evolution is the breaking of austenite islands and morphological change into spherical volumes named as “dynamic globularization”. The hardness was maximum in the stir zone and decreased by passing through the thermomechanical and heat affected zones. A linear equation was developed between hardness and the ratio of ω/S. The highest hardness was obtained at 1000 RPM and 12 mm/Min. The results of tensile test showed that the ultimate tensile strength (UTS) and fracture strain are improved by FSP. UTS and fracture strain increased with increase in the rotation speed and decrease in the traverse speed.