Could be anything. I think Wayne Goddard mentioned some implement parts being 10XX steels. Two simple tests will get you in the ballpark. One, hit it with the grinder and look for fuzzy sparks. If the sparks are fuzzy, it's a good sign. Two, heat some up a bit past nonmagnetic and quench in oil. If it will skate a file, it's a good sign. Don't temper it, but put it in a vise and try to break it. Should snap fairly easily and have fine grain structure if it's any good for knife making. Again, this is just to put you in the ballpark. Hard to hit a home run with found steel. That said, I use found steel pretty often and make some knives that do what I want them to do. Run some tests and make a knife.