Experimental Study of FSW T-joints of EN-AW 6082-T6 and Their Behaviour Under Static Loads

Abstract

At present, one of the most popular and effective methods for joining metal structures is welding. The process of joining such materials sometimes generates problems. No structural transformations in the solid state along with good heat and electric conductivity cause problems related to welding and resistance welding of aluminium alloys. Some aluminium alloys are even regarded as non-weldable due to a risk of hot cracking occurrence. A solution to such inconveniences is the friction stir welding method (FSW) developed by The Welding Institute (TWI), Cambridge, in the 1990s. The paper deals with an investigation of mechanical properties of T-joints of EN-AW 6082-T6 produced by FSW technique. Different ways of base metal preparation prior to welding (T-joints welded as two-pieces and as three-pieces), as well as two various shapes of steel dies directly forming the shape of tee connections, were used in experiments. The test joints were produced by welding at different rotational and linear speed of FSW tool. It was shown how welding conditions influences structure and static properties of FSW joints. Results shown that for specified tool speeds a significant imperfections, like voids, were formed. The study reveals also metallographic macroscopic and microscopic examination results, indicated typical imperfections arising during FSW process of T-joints, as well as results of hardness measurement of joints cross section.