Rotary Friction Welding

Rotary Friction Welding is a solid-state process of joining two materials, generally metals, by rotating them axially against each other under pressure. The rotational energy and pressure create heat at the interface under the material’s melting point, making it a solid-state process. Typically, the process has three phases: Pre-Heating, Heat, and Forging.

Before welding, the Rotary Friction Welding Machine butts the two materials without rotation and essentially measures the components being welded or zeroing a distance measuring counter. If the two components are not within a proper length tolerance, the machine will not weld the part and notify the operator that the parts are out of length tolerance.

1. Pre-Heat Phase

Rotary Friction Welding Process Phase 1

The materials are subjected to light pressure and rotational energy that “pre-heats” the materials. This phase also burns off any oils and oxides at the weld interface and is typically controlled by time.

2. Heat Phase

Rotary Friction Welding Process Phase 2

A higher pressure is applied in this phase while rotating the parts against each other, and the materials become plasticized. The material at the interface begins to squeeze out, which is called “flash.” Any remaining oxides or contaminates at the weld interface are displaced into the flash. This phase is typically controlled by distance. Once a pre-determined distance or material length loss is achieved, the machine goes into the forging phase.

3. Forge Phase

Rotary Friction Welding Process Phase 3

In this phase, rotation is stopped, and a higher pressure is applied to the parts. The parts begin to cool and are forged together while cooling and creating a strong bond.

A Computer-Controlled Process
Variables like pressure, RPM, and length are monitored. The machine will notify the operator to act if any key variable is outside any pre-determined window.

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Advantages of Rotary Friction Welding include:
  1. A full-strength bond with complete penetration through the full cross-section of the weld with no oxides, porosity, or contamination at the weld interface.
  2. A narrow Heat Effective Zone(HAZ), which limits affecting the base material properties.
  3. The ability to weld dissimilar metals such as stainless steel to carbon steel, copper to aluminum, etc.
  4. Quick cycle times and easily automated process.

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Contact American Friction Welding today for more information or to request a quote!