I know that a professional Eleiko bar is rated around 2000kg. However I also know that bouncing and dropping that bar whilst it's loaded, would eventually render it garbage bin property due to either a noticeable or unnoticeable bend within it, or because it would simply snap in half once old enough.
Take home message: no matter how good the bar is, get rid of it once your sense register a change in it...., alternatively, just use it for squatting and other less critical movements that warrants fine precision.
Sorry I can not comment on bench press's effect on lifting bars, since this movement does not fall within my specialty.