Issue 37

C. Patil et alii, Frattura ed Integrità Strutturale, 37 (2016) 325-332; DOI: 10.3221/IGF-ESIS.37.43 325 Experimental investigation of hardness of FSW and TIG joints of Aluminium alloys of AA7075 and AA6061 Chetan Patil Mechanical Department, PSE, Saki-Palsana, Gujarat (India) Hemant Patil Mechanical Department, D. N. Patel C.O.E., Shahada, Maharashtra, (India) hspatil28@gmail.com Hiralal Patil Mechanical Department, GDEC, Abrama, Gujarat (India) A BSTRACT . This paper reports hardness testing conducted on welded butt joints by FSW and TIG welding process on similar and dissimilar aluminium alloys. FSW joints were produced for similar alloys of AA7075T 651 and dissimilar alloys of AA7075T 651 - AA6061T 6 . The Friction stir welds of AA7075 & AA6061 aluminium alloy were produced at different tool rotational speeds of 650,700, 800, 900, 1000 and transverse speed of 30, 35, 40 mm/min. TIG welding was conducted along the rolling direction of similar and dissimilar aluminium plates. The Brinell hardness testing techniques were employed to conduct the tests; these tests were conducted on the welds to ascertain the joint integrity before characterization to have an idea of the quality of the welds K EYWORDS . FSW; Rotation Speed; Transverse Speed; Hardness. I NTRODUCTION riction Stir Welding (FSW), a solid state joining process was developed and patented by the Welding Institute (TWI) in 1991 [1]. FSW is considered to be the potentially useful solid state welding technique in which welding is done below the melting point of the work piece material [2-3]. Because of low heat input and absence of complete melting, FSW offers several benefits over the conventional fusion welding process. Metallurgical benefits includes good dimensional stability, repeatability, no loss of alloying elements, excellent mechanical properties in the joint area due to re crystallized micro structure in the stir zone. Environmentally the process is a green one because it eliminates grinding wastages, no harmful emissions, required minimum surface cleaning [4]. FSW has various application in the fields of marine like hulls, superstructures, storage vessels for the shipbuilding, in aerospace like airframes, fuselages, wings, fuel tanks; in railway like high speed trains, railway wagon; in automotive like chassis, truck bodies [5]. A cylindrical shouldered tool with different pin probe is rotated and slowly plunged into the joint line between plate materials, until the shoulder of the tool forcibly contacts the upper surface of the material and the pin is a short distance from the back plate. The pieces are rigidly clamped onto a backing plate in a manner that prevents the abutting joint faces from being forced apart. The fixturing prevents the plates from spreading apart or lifting during welding. Frictional heat is generated between the tool F