Impact of Tool Plunge Depth, Tool Tilt Angle, and Tool Offset on Microstructure, Mechanical Properties, and Fracture Morphology of Friction Stir Welded Pure Copper Butt Joints
摘要
This experimental examination aims to explore the effect of tool plunge depth (TPD), tool tilt angle (TTA) and tool offset (TO) on pure copper butted weld joint by friction stir welding (FSW) method where other parameters such as tool rotating speed (750 rev min−1) and traverse speed (24 mm min−1) were fixed. The different tool plunge depths of 0.1, 0.2 and 0.3 mm, tool tilt angles of 1°, 2° and 3° and tool offsets of 1 and 2 mm are considered as welding parameters. Microstructural feature, mechanical (tensile and hardness) attribute, fracture morphology were conducted experimentally. The experimental results showed that the advancing side had a greater welding temperature in comparison to the retreating side in all the welding situations. The peak temperature of 433 °C on the advancing side was achieved at a 3° tilt angle and the lowest temperature on the retreating side was 286 °C at 2 mm tool offset. The results also confirmed that peak temperature was dominant in controlling grain size and mechanical attributes. Fine grains were attained at lower tool plunge depth and tool tilt angle. The tensile properties exhibited a relative correspondence to the hardness variation in the weld region in all the weld joints. The maximum tensile strength of 201 MPa (approximately 87.39% of base metal) was showed by the joint made at a 2° tilt angle. The obtained results were correlated with the microstructural features and fractural morphology. From this present work it was noted that the tool plunge depth and tool tilt angle had significant impact on copper-copper similar friction stir welded joint. However, tool offset was demerit for copper-copper similar friction stir welded joint.