Understanding the dissimilar friction stir welding through force and temperature evolution

Friction stir welding (FSW) is a promising technology to join aerospace grade aluminium alloys that are difficult to be welded by conventional fusion welding processes. Force and temperature measurement during FSW process plays a vital role in understanding the process, tool degradation analysis, predicting the tool life, mechanical properties and microstructure of the welded joints. In the present research work, an attempt has been made to investigate the effect of traverse speed on longitudinal force and temperature distribution during FSW of dissimilar aluminium alloys. Traverse speed, on which heat input depends, was varied from 160 mm/min to 250 mm/min keeping the other FSW parameters constant. It was observed that increase in the traverse speed resulted in the higher longitudinal force. Results revealed that highest longitudinal force of 971 N was observed at maximum traverse speed of 250 mm/min attributed to higher flow stresses resulting from low heat input and higher weld consolidation rate. Conversely, lower longitudinal force was observed at lower traverse speed as slow traversing of the tool resulted in high heat input leading to sufficient softening of the material being welded. HAZ peak temperature of 218 degrees C and 193 degrees C was detected at retreating side and advancing side respectively. (C) 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Advances in Materials & Processing: Challenges & Opportunities (AMPCO-2017).