Frequently Asked Questions
Friction stir welding of aluminium alloys has been cited by many users as a cost-saving process. This is in part due to the elimination of consumable costs, but is also due to the ability to make most welds in one or two passes, even in thick material. It is also a very efficient process in terms of energy consumption, which can also lead to significant cost savings. The avoidance of multiple passes eliminates the need for inter-run cleaning, back gouging, etc., and the avoidance of spatter means that post weld dressing is reduced or not required. The fully automated nature of the process also reduces labour costs.
Many companies have reported significant savings due to the considerable reduction in repair and re-work, low distortion, and general equipment flexibility.
On the down-side, bespoke FSW equipment can be expensive, but overall the costs/metre of weld are significantly lower than for fusion processes.
The following comments on cost savings were published by users of the FSW process and speak for themselves:
- The Boeing Company reported that 'the FSW specific design of Delta IV and Delta II achieved 60% cost saving, reduced the manufacturing time from 23 to 6 days.'
- For 'Slipper', the US Army's cargo interface pallet, 'FSW processing reduced the sandwich assembly cost, including raw materials, extruding, and welding, from 61% to only 19% of the total fabrication cost. The Air Force estimates the total cost savings attributed to FSW (for a projected buy of 140,000 slippers) at $315 million.'
- Hydro Marine Aluminium reported that at shipyards using prefabricated FSW panels the "improvement in the aluminium fabrication has resulted in 15% reduction in the man-hour per ton rate."
- Fjellstrand claimed 'a total fabrication cost saving of approximately 10% based on improved ship design, streamlined fabrication at the shipyard and by supply of prefabricated FSW panels and structures based on extruded profiles.' They said that using prefabricated FSW panels 'has enabled the shipyard to reduce the production period for a 60m long aluminium catamaran hull from 10 to 6 months, which means a 40% increase in production capacity and turnover at the yard.'
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