Recent developments in steel friction stir welding: Project HILDA

Athanasios Toumpis, Alexander Galloway, Duncan Camilleri, Larbi Arbaoui

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

1 Citation (Scopus)
77 Downloads (Pure)


Friction stir welding of steel presents an array of advantages across many industrial sectors compared to conventional fusion welding techniques. Preliminary studies have identified many positive effects on the properties of welded steel components. However, the fundamental knowledge of the process in relation to structural steel remains relatively limited, hence industrial uptake has been essentially non-existent to this date. The European-funded project HILDA, the first of its kind in terms of breadth and depth, is concerned with enhancing the understanding of the process on low alloy steel, establishing its limits in terms of the two more significant parameters which can be directly controlled, tool traverse and rotational speed, thus improving its techno-economic competitiveness to fusion welding.

A detailed study investigated the effect of process parameters on the evolved microstructure. In parallel, a full programme of mechanical testing was undertaken to generate data on hardness, impact toughness and fatigue. From this, it has been established that friction stir welding of steel produces high integrity joints that exhibit excellent fatigue properties.
From a simulation perspective, a local microstructural numerical model has been developed to predict the microstructural evolution within the weld zone during friction stir welding of low alloy steel. This model concentrates on predicting grain size evolution due to dynamic recrystallization with respect to tool traverse and rotational speed. Furthermore, a computational efficient local-global numerical model capable of predicting the thermal transients, stir and heat affected zone, residual stresses and distortion produced by friction stir welding of DH36 plates is presented.
Original languageEnglish
Title of host publicationASME 2015 International Mechanical Engineering Congress and Exposition
Subtitle of host publicationAdvanced Manufacturing
Number of pages11
Publication statusPublished - 30 Nov 2015
EventASME International Mechanical Engineering Congress & Exposition, IMECE 2015 - Texas, Houston, United States
Duration: 13 Nov 201519 Nov 2015


ConferenceASME International Mechanical Engineering Congress & Exposition, IMECE 2015
Country/TerritoryUnited States


  • friction stir welding (FSW)
  • low alloy steel
  • optimisation
  • microstructure
  • mechanical testing
  • numerical models
  • dynamics recrystallisation
  • residual stresses
  • out-of-plane distortion


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