My long time favorite supplier for washers, shim, stampings, etc is Bokers in Minneapolis Mn. When I enteres 32x45x1 into their search engine I got:
bokers washers.jpg
It's approx 0.008" oversize OD, and 0.010" undersize ID- available in the right thickness range. I wouldn't worry about the small OD difference, and clamping a few of them together into a sandwich and running a reamer through them would size the ID. I'll be doing this myself over the winter- I'll probably order them a little fat and take them to a friend with a surface grinder to get the thickness I need. If you can wait I'll make you some, but it won't be until at least January or so.
I'm not sure if just a mild steel is the right material- they will make washers from a high carbon tool steel that can be hardened, but, with a hard washer something else will wear first, so I don't know if hard is good or not.
Rick