I worked in the Steel Industry for thirty-five years. Steel does in fact contain Carbon, Manganese, Vanadium and so on. It is the PERCENTAGE of these alloying elements that determines exactly what type of steel that you have.
Another factor that has a great deal to do with the final product, is heat treating. Hardening, drawing, annealing and so forth.
Iron and Carbon are the basic ingreients of Steel. The additives determine the outcome. Just as Flour is the basic ingredient of Bread. It also figures prominently in Cake, Gravy and Paste. It's what the Flour is mixed with, and how it is treated after that, that makes it what it is.
Almost all steel is Magnetic...there are some grades of Stainless that aren't. Different grades of Carbon Steel are applicable to different uses. The alloying agents determine the specific use. Chrome-Vanadium Steel is a good Blade Steel. For Many years the W.R. Case Company (Makers of Case XX knives) used it a LOT.
52100 is Ball Bearing Steel and the Marble's Company used to make knives from it, they still might, I'm not sure. That stuff is as hard as Chinese Arithmetic. The 100 (last three digits of the designation) refers to 100 points of Carbon in the makeup of the Steel. That's ONE PERCENT Carbon. That's a lot!
But I digress.
Jeeter