Has anyone used a bearing race for knife blade? My best guess as to the composition of the steel is 52100. I'm wondering if there would be any problems with the alloy in the steel. Would it be hard to forge? The added alloy I believe is chromium. Any thought out there? 

Try it and see what you can learn.

I make blades out of beaing races, I forge mine alittle above non magnetic, You well have to be able to control your fire and watch your heat over cook the steel it well crubble to cold and you just bounceing your hammer or the steel it a frustrating steel to learn on . The race might be 52100, 8620, or  case harded steel. Cut a piece of draw it out like bar a of steel about thick as a knife, quench in warm oil , let cool then brake it and see what the grain look likes. make sure with wear all the safety gear.

If it's good steel, yes.  I made one for a guy who sells bearings from one.  After I got it straitened out I realized I could have done it with the "Timken" stamp on the spine.  That would have been awsome.  Made a good knife, would have been cooler with the stamp.

The larger races are usually case hardened something like 8620 IIRC; One of the members here used to be a metallurgist for Timkin and can chime in where they made the crossover from 52100 to a case hardened lower carbon alloy.

I can tell you with certanty, it wasn't case hardened.  It was a pain to straiten even with the 4lb hammer though it was only about 10" once straitened.  It hardened and took a good temper.  The only question was that it did anneal better than I expected 52100 to.  These were for heavy industrial service.  Since that excursion I've purchased some 52100 stock and found it worked similarly.  I do have one more race I started on and got tired of whacking on it.  I think I ended up destroying the stamp around the edge. 

Usually I get these worn out already.  It's pretty easy to spot a case harded bearing due to the "chipping" that occurs.

I've never tried to forge 8620, it would seem to me that it would be pretty apparent that it wasn't knife steel.  Am I wrong?  Does the Nickle toughen it up under the hammer?   

Thanks for the feedback. I'm not sure what you mean larger races? I have some that are 6" O.D. or so. I have never heard of case hardened bearing races. I'm going to try one and see what I can learn.