The Friction Stir Welding process uses a non-consumable pin tool to create frictional heat between two materials. As the pin tool spins, it “stirs” the two materials together, creating plastic deformation between 70-90 percent of the solidus temperature. Solidus is the highest temperature at which an alloy is completely solid. Plastic deformation changes the shape of the solid body without weakening the material.

Because Friction Stir Welding is a solid-state joining process, the two materials being friction welded never melt, and joining occurs below the solidus of the equilibrium phase for the materials. As a result, the metals better retain their original mechanical properties.

Because Friction Stir Welding creates extremely high-quality, high-strength joints with low distortion, the solid-state joining process is the preferred technology for welding aluminum sheets, extrusions, panels, and other products.

Friction Stir Welding is also commonly used to join dissimilar lightweight metals and hybrid electric vehicle applications.

There are several advantages to using friction stir welding, especially over fusion welding processes. Here’s just a few:

• Virtually Defect-Free Bonding: As a solid-state process, FSW avoids common fusion welding issues like shrinkage, cracking, and porosity.
• Superior Mechanical Characteristics: FSW creates strong, fatigue-resistant welds with minimal distortion.
• Machine-Controlled Process: FSW is highly repeatable and operator-independent, with real-time monitoring and control for consistent weld quality.
• Environmentally Friendly Process: FSW is clean and energy-efficient, requiring no consumables, gases, or heavy protective gear.
• Join Dissimilar Alloys: FSW can weld dissimilar metals without melting, preserving material properties and eliminating the need for fillers.

Rotary Friction Welding is a solid-state process in which one part is rotated at a high speed and is pressed against another part that is held stationary. The resulting friction heats the parts, causing them to forge together. MTI is the only company that offers all three types of RFW technologies - Direct Drive, Inertia, and Hybrid.

There are dozens of applications suitable for Rotary Friction Welding, but here is a list some of the most common examples by industry:

• Aerospace components such as engine rotor components, rotor assemblies, jet engine fan shafts, landing gear
• Automotive applications including drive shafts, bi-metallic valves, turbocharger shafts, pistons
• Construction and Agriculture parts such as hydraulic cylinder rods, piston rods, water pumps, track rollers
• Oil & Gas components including rock drill pipe, drill pipe and directional drill pipe

Rotary Friction Welding is a quicker, stronger and more environmentally friendly alternative to fusion welding processes such as electric arc or gas welding or high-energy processes like electron beam or laser welding. Other key benefits of Rotary Friction Welding include the ability to join bi-metallics or dissimilar metals, faster weld cycles, and minimal joint preparation.

The Low Force process uses an external energy source to raise the interface temperature of the two parts being joined, thereby reducing the process forces required to make a solid-state weld compared to traditional friction welding. The process applies to Rotary Friction Welding.