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Can non-round parts be rotary friction welded?


Frequently asked questions

Circular-section parts can be rotary friction welded to non-circular cross-sections. This is usually referred to as friction stud welding where the round part is rotated and the non-round part, which has the larger cross-sectional area, is held stationary.

If, however, the cross-sectional area of the round part is greater than that of the non-round part, weld quality is adversely affected. This is because the outer region of the joint is in contact with the atmosphere during heating and becomes contaminated.

When attempting to rotary friction weld square-section bars, for example, two problems are encountered. First, the weld becomes contaminated because the corners of the bars are exposed to the atmosphere during welding. Second, orientation of the bars is unlikely to be as required when the weld is terminated - unless a machine equipped to ensure angular alignment is used (for which accuracies of ± 1 / 2 ° have been claimed).

Fortunately, there are alternative friction welding processes for non-round parts and these use completely different motions to generate frictional heat: orbital friction welding, linear friction welding and angular and arcuate friction welding.

Linear friction welding
Linear friction welding
Orbital friction welding
Orbital friction welding

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