Role of Threaded Tool Pin Profile and Rotational Speed on Generation of Defect Free Friction Stir AA 2014 Aluminium Alloy Welds

  • Suresh D. Meshram Defence Metallurgical Research Laboratory, Hyderabad
  • G. Madhusudhan Reddy Defence Metallurgical Research Laboratory, Hyderabad
  • A. Venugopal Rao Defence Metallurgical Research Laboratory, Hyderabad
Keywords: Frictions stir welding, rotational speed, aluminum alloy, conical tool pin

Abstract

Influence of threads on tool pin and rotational speeds on defect occurrence in friction stir welding (FSW) of aluminum alloy AA 2014 T6 plates has been studied. The effect of FSW forces on the evolution of mechanistic defects, caused in turn through a variation in heat generation during the process has also been examined. In case of conical tool pin, relatively lower rotational speeds resulted in unbounded zones and micro defects while high speeds caused excessive flash, thereby resulting in surface defects and voids inside the weld. The FSW joints were defect-free at moderate speeds, hinting an optimum heat generation and flow. Reaction forces on the tool pin, in the welding direction, were correlated with the defect formation. Tools equipped with a threaded conical pin profile resulted in sound welds, irrespective of the tool rotational speeds in the entire range of 400 rpm - 2400 rpm. The threaded conical pin, with a relatively larger frictional area, may be contributing to higher levels of heat generation compared to a plain conical pin. Further, positive displacement of the hot plasticised material by the threads will carry away excess heat from the advancing-to-the-retracting side and simultaneously downwards, thus confining all heat within the weld zone.

 

Author Biographies

Suresh D. Meshram, Defence Metallurgical Research Laboratory, Hyderabad

Mr Suresh D. Meshram received BE (Mechanical) from NIT, Surat, in 2000 and MTech (Prod. and Ind. System Engg.) from IIT Roorkee, in 2002. Currently pursuing his PhD from IIT Delhi. He is working as Scientist ‘E’ at Defence Metallurgical Research Laboratory (DMRL), Hyderabad. His area of research mainly includes joining of advance similar and dissimilar materials through process like electron beam welding, friction welding and friction stir welding and characterisation of welded joints.

G. Madhusudhan Reddy, Defence Metallurgical Research Laboratory, Hyderabad
Dr G. Madhusudhan Reddy obtained PhD in Metallurgical Engineering from Indian Institute of Technology, Madras in 1999. Presently as a Scientist ‘H’, he is heading the Metal Joining Group of DMRL, Hyderabad. He has more than 300 scientific publications to his credit. He is a Fellow of the Indian Welding Society and Institution of Engineers (India). Government of India recognised his contributions to the metallurgical sciences by the award ‘Metallurgist of the Year’.
A. Venugopal Rao, Defence Metallurgical Research Laboratory, Hyderabad
Dr A Venugopal Rao received PhD. in Mechanical Engineering from the Indian Institute of Technology Madras (IIT Madras). Presently as a Scientist ‘F’, he is heading the Modelling and Simulation Group at DMRL, Hyderabad. His research interests include : Computer aided engineering, fracture mechanics, workability analysis in metalworking, and continuum damage mechanics. He is also the Team Leader for Simulation in the DRDO project on Development of Life Prediction Technologies for Aeroengine Components. He has published over 20 papers in International and National journals.
Published
2016-01-27
How to Cite
Meshram, S., Reddy, G., & Rao, A. (2016). Role of Threaded Tool Pin Profile and Rotational Speed on Generation of Defect Free Friction Stir AA 2014 Aluminium Alloy Welds. Defence Science Journal, 66(1), 57-63. https://doi.org/10.14429/dsj.66.8566
Section
Engineering Science & Technology