Mon, 21 February, 2022
TWI Ltd and Coventry University have conducted a joint study on residual stresses in wire arc additively manufactured aluminium alloy samples. This study was part of the PhD work of Karan Derekar, who was a student at the time and is now a project leader at TWI.
A research paper on the same topic has been published in the Journal of Manufacturing Science and Engineering, which is an ASME publication. The paper ‘Effects of process variants on residual stresses in wire arc additive manufacturing of aluminium alloy 5183’ discusses the effects of processing conditions on residual stress formation and distribution. The paper highlights that the base plate thickness and deposit height play a vital part in residual stress distribution, whilst the temperature of deposit (interlayer temperature) has an effect on the magnitude of residual stresses. Residual stresses were found to be lower with higher interlayer temperature.
Samples for the study were manufactured at TWI using the pulsed metal inert gas (MIG) processes applied robotically and the residual stress measurement using the contour method and computational approach were conducted at Coventry University by Bilal Ahmad. Lei Xu, Geoff Melton and Adrian Addison from TWI; Bilal Ahmad, Xiang Zhang and Jonathan Lawrence (now with Arden University) from Coventry University and Sameehan Joshi from University of North Texas were involved in the study.
This study was funded by Lloyd’s Register Foundation (LRF) and the Kraken project (Horizon 2020 project of European Commission). Kraken set out to develop an automated robotic system capable of wire arc additive manufacturing of aluminium parts up to 20m long with an accuracy of 0.1mm, with control over residual stresses and deformation.
Karan Derekar is continuing to work on wire arc additive manufacturing and robotic arc welding. He is currently involved in TWI Core Research projects on automated process parameter optimisation systems development for welding and additive manufacturing and study on residual stresses and fracture behaviour in additively manufactured objects. He is also involved in UK and European funded collaborative projects and a number of different industrial member projects on wire arc additive manufacturing and robotic welding of different alloys such as aluminium, Ti-6Al-4V and different grades of steels.