It's not that easy. You ought to be able to find it annealed. 4140 is not like carbon steel, it needs to soak (be held at temp) for specific times (possibly hours) for each operation, and case hardening needs the same temps as any other hardening. I bought some 4140 flame cut drops, they were diamond hard (so to speak) I couldn't hack saw them. I built a charcoal fire in my grill, put the two pieces (3/4 by 3/4 by 12 ") in and let it burn out. cooled overnight. I could then cut it with high speed steel but it wore the cutter pretty quickly. Once it's annealed (Half Hard) its still RC 30 or so.If i cant find annealed i can anneal it myself then case harden it correct?