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In an industrial application, what are the relative advantages of using inertia or continuous drive friction welding processes?


Frequently Asked Questions

The advantages of using one of the main friction welding processes (inertia or continuous drive rotary) over the other depends to a large extent on the components to be joined, i.e. size, materials and geometric considerations.


In order to understand the process advantages it is essential to first understand the process mechanism. Continuous drive rotary friction welding, which is used mainly in Europe, the former USSR and Japan, involves rotating one round component against a stationary component under an axially applied force. The rubbing action removes surface contamination from the joint interface and the resultant friction heating softens material in the weld zone. Once sufficient material softening has been achieved, the rotation is stopped and the axial force is either maintained or increased to consolidate the solid phase weld.



Inertia welding, which is predominately used in North America, also involves rotating one component against another but the rotating component is clamped to a flywheel. This flywheel is rotated to a set speed, disengaged from the drive motor and the components brought into contact under an axially applied force. Rotation reduces as the energy from the flywheel is dissipated into the weld interface as friction heating, then completing the weld.

Inertia welding has some advantages over continuous drive rotary welding as follows: -



  • Fewer variables, thus simpler to operate
  • Shorter weld times
  • Narrower heat affected zones
  • Potentially lower cost machines for larger components

In comparison the advantages of using continuous drive friction welding are: -

  • More control of parameters and potentially greater flexibility
  • Less severe initial contact phase, if required
  • The welded component length can be accurately controlled
  • Angular orientation to better than ± 1° can be achieved
  • There are no flywheels that need to be changed when welding various components

Productivity rates, operator skill levels and mechanical properties are thought to be broadly similar for most applications.

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