Could, you please explain the damage over the interference fitting process?
I made an industrial interference study and found good correlation using Forge software. But, understanding the damage criteria seems difficult.
For simple understanding, shaft with case hardening property with hole profile part is through hardened steel at the end of fitting process chip was evolved.
What can we interpret from process perspective? Can, we consider the part is failed or else the part can be validated through structural test?
There is two types of interference fit:
1. Press fit where the shaft is being pressed into the hole. In this case if the interference is excessive sometimes galling (cold welding and seizure) takes place. This seems to be your case. If you do not plan to disassemble these parts anymore they could be used as is and most likely will retain strong connection. The only risk is that galling that usually takes place on one side of the shaft might introduce some eccentricity between shaft and bushing. If you plan to remove your shaft it will most likely get damaged even worst and both parts will be useless.
2.Shrink fit where bushing is being preheated to the point where thermal expansion eliminates interference and parts can be assembled with very little or no axial force. After cooling down you will have very strong and very concentric permanent connection. In case you use excessive interference sometimes stress can cause bushing to crack from inside.
Follow standard ISO press fit interference tolerances to avoid future problems.
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