It's highly likely tht the steel plates are fine. It's also highly likely that you have incorrect clutch plates, especially given WHEN you bought them.
Here's why:
All of the vendors were (accidentally) selling too-thin clutch plates for the 500/550 between 2008 and about 2014 or so, and these paltes are still mixed into the parts supply here and there.
The problem: the OEM clutch plate for the 500/550 is 0.121" thick. The ones being sold are 0.106" thick, and fit more recent superbikes (with 9- and 10-plate clutches). When you install the thin plates into the clutch, you end up at the extreme ends of the clutch cable adjustments, but it [just barely] works after a fashion. It also slips, because the whole stack-up of plates is less than Honda's worn-out spec for those plates, and the spring pressure is too low.
Here's where it gets more confused: some vendors sought to "fix" this by selling stronger clutch springs for the clutch pack. While this slightly improved on the slippage problem, it also squishes all the oil out of the plates, drying out the cork, and making the clutch...'squawk' when released. Sound familiar?
Here is the 'fix':
1. Shop for the correct clutch plates: I have contacted most of the vendors and a few, like PartsNmore, have responded nicely by putting the thickness of the plates on their listing for these bikes.
2. If you cannot get the 0.121" thick plates, get 2 or 3 of the CB750 plates form their 6-plate set: these are 0.140" thick. You can add two or three of these in place of 2 or 3 of the too-thin ones and get a proper stack height. The proper height is: the face of the top plate must be flush with the top edge of the fingers of the clutch basket. Chances are the ones you have are sitting almost a full plate deeper than that now.
Note: if you already installed the stiffer springs, DON'T try to use those with the new full-height clutch pack. It can break the pressure plate (don't ask how I know that, because I won't tell you...).
