Sometimes described as more of a forging process than actual welding – Friction Stir Welding is a solid state joining technique used to join metals that can’t be easily fused with traditional welding.
The result? A stronger, tougher bond that can be virtually defect free. Friction Stir Welding, or FSW, allows aluminum, copper and even tough steel alloys to be permanently joined without arc welding. This operation can be done on equipment that resembles standard milling machines.
These FSW machines use a cylindrical tool with a profiled threaded probe, called a pin tool, which is rotated at constant speed and then plunged into the joint between two pieces of metal. Friction heat created between the welding tool shoulder, pin and metals being joined causes the metals to soften to a point just below their melting point. Essentially, the metals soften to a plastic-like state but do not melt. In this plasticized state, the two metals are literally stirred together – creating a solid-state bond of the now mixed material. The entire process allows for minimal distortion of joined parts, and an extremely high weld strength.
The problems that typically occur from the cooling of the liquid phase during fusion arc welding are not present in friction stir welding. Problems such as solidification cracking, porosity, and solute redistribution are not an issue when friction stir welding is used.
Ideal for metals such as aluminum, copper and other metal alloys that are difficult to join with traditional welding techniques, FSW is commonly used in the Aerospace, Railway, Automobile, Ship Building and Marine industries. It is also a process that can be easily automated which makes it perfect for industrial use.
Advantages & Benefits of Friction Stir Welding include:
- Provides opportunities for new solutions to old joining problems
Friction Stir Welding is a leading-edge technology. Bond Technologies is continually identifying new applications for the process and, therefore, new solutions for its customers.
- Virtually defect-free welding
Easily controlled process parameters – such as pin tool geometry, pin tool force, rotational speed and traversing speed – are easy to monitor and control, allowing for avoidance of errors.
- Versatile applications including complex contours
FSW can weld complex contoured parts, including seam welding of cylinders. Many joint geometries are possible with the FSW process include butt, T-butt, lap, butt laminate, butt both sides, T-butt dual pass, lap laminate, L-outside, flange, multi-thickness, T-single weld, and L-inside (which requires special joint preparation).
- Large panel length and width
The process flexibility of FSW accommodates the welding of large parts. Aluminum extrusions used for ship decks, rail cars and truck beds are ideal applications of FSW.
- Superior mechanical characteristics
This joining technology offers a weld with high weld strength and toughness. The weld has a fine grain structure that resists fatigue stress. Due to the low heat input and small heat-affected zone, there is minimal distortion of the joined parts, reducing the costs associated with preparing the part for subsequent use.
- Join dissimilar alloys
FSW may be used to weld dissimilar alloys, even combinations that are not compatible with other welding processes.
- “Green” process
Low energy input and lack of fumes, gases, etc., resulting from the process, makes FSW friendly to our environment.
Unsure of whether FSW will work for your application? Contact Bond Technologies, and we can help you come up with a solution.