Friction stir welding (FSW) is a relatively new welding process that was invented at The Welding Institute in Cambridge, UK in 1991. FSW is a solid-state joining process that uses frictional heat combined with accurately directed forging pressure to produce high integrity welded joints for extruded or wrought aluminum. The process can also be used to join copper, titanium, and certain alloys. This automated frictional welding process is more robust than other joining processes and is a good fit for industries that must employ high-volume production, such as the automotive industry.
How Does This Process Work?
The friction stir welding process uses a wear-resistant rotating tool to join two facing surfaces. Heat is created between the tool and the material, resulting in a softened area near the FSW tool. It then mechanically intermixes the two pieces of metal at the site of the joint. Due to the elevated temperature, the softened material can be joined using mechanical pressure as applied by the tool.
What Are Some FSW Applications in the Automotive Industry?
Government-mandated fuel efficiency requirements in the U.S. and Europe required auto manufacturers to use more aluminum in the production of lighter vehicles. Friction stir welding, with its excellent mechanical properties and a low rate of defects, is well-suited for the joining of aluminum in a number of automotive applications. These include tailor welded blanks (semi-finished components for car doors), stabilizer bars, center tunnels, drive shafts, pistons, camshafts, turbochargers, U-joints, bumper shocks, and even car hoods and trunk lids, among numerous others.
How Does Friction Stir Welding Benefit the Automotive Industry?
The friction stir welding process has proven to be highly advantageous for automotive manufacturers. Some of the most important advantages are:
- Cost reduction. Lower set-up and operating costs, less employee training and no need for consumables in this process result cost savings.
- Environmentally-friendly conditions. FSW has a low energy output that involves no gas fumes or radiation.
- Ability to join dissimilar metals. Friction stir welding can be used to join aluminum to certain alloys for some components when all-aluminum construction is not feasible.
- High production capability. The FSW process is ideal for handling variations in high-volume production line typically found in auto manufacturing.
- Consistency. Automation of this process ensures that components are made the same way each time.
- Process reliability. Its dependability makes the FSW process essential in the auto industry’s just-in-time manufacturing model, where components are made on demand.