Influence of joining direction of AA2024 on the structure and properties of weld joints during friction stir welding

Abstract

This work examines the influence of the rolling direction of plate stocks of the AA2024 aluminium alloy on the structure and properties of weld joints in different modes during friction stir welding (FSW). It has been established that during FSW, when the instrument's load on the material ranges from 1900 to 100 kg, the instrument's rotation rate— from 250 to 450 rpm, and the instrument's travel speed—from 100 to 500 mm/min, it is possible to obtain defect-free samples. It has been determined that during welding of D16 aluminium alloy 5 mm thick, the best results are obtained during FSW in the rolling direction, at that the rolling direction does influence the structure of weld joints. It has been shown that during welding of plate stocks in the transverse direction of rolling, the strength of the weld seam is no more than 88% of the strength of the base metal, whereas weld joints, obtained in the rolling direction, reach 91–92% of the strength of the base metal. Weld joints, obtained in the rolling direction, also have the highest values of the relative elongation (from 2 to 28%) in comparison with those of the samples, obtained in the transverse direction of rolling of AA2024.