A relatively young technique in the field of welding, friction stir welding was invented then scientifically proven as a viable method in December of 1991. By definition it is a ‘solid-state joining process,’ meaning that the material being used for welding is not melted. This process employs the use of a third body tool to join together the two facing surfaces.
The process starts with heat being generated between the friction stir welding tool and material, which leads to a softened region. The tool then mechanically mixes the metals between the two pieces at the place of the joint. The softened metal can then be joined by pressure, supplied by the welding tool. This process is described as being much like joining pieces of clay or dough. Friction stir welding is excellent for items requiring superior hold strength without the need of a post-weld heat treatment.
There are several advantages that friction stir welding has been observed to have over traditional fusion welding. Some of these include;
- Free range operation positions (horizontal, vertical, etc.) because there is no weld pool.
- No consumables.
- Easily automated on simple milling machines due to lower set up costs and less training.
- Improved safety due to the absence of toxic fumes or the spatter of molten welding materials.
- Reduced impact on the environment.
As with the advantages, a few disadvantages also go along with the friction stir welding process. A few examples of the disadvantages are;
- An exit hole is left in the metal when the tool is withdrawn.
- Less flexibility than whats found in manual and arch welding processes.
- Often slower than fusion welding techniques, however this can be offset if a smaller number of welding passes are required.
Despite being a relatively new process, friction stir welding has already made a place for itself in several industries. These include automotive, offshore and ship building, aerospace, railways, personal computers, and various electronics. The future for this process is promising, paving a way for itself to maybe one day surpass traditional welding methods as the go to technique. If you would like to know more about friction stir welding, or other fabrication processes such as hydroforming, feel free to contact us at our website.