In reply to jimtitt: I was about to jump in and point this out as well...
I'm a chemist, not a metallurgist, but I did do a couple of years of materials science as part of my undergrad, and one of the things that stuck in my mind was the (probably simplified) steel phase diagram that we had to learn and the amazing number of things that you can do with it. It was regularly hammered (excuse the pun) into use that the processing was far more important than the original composition, which was a confusing thought for a chemist!
To a certain degree, if the OP is asking because he wants to make his own, then presumably using "standard" processes of forging, quenching & tempering that will give some strength, just not equal to using the commercially-optimised conditions...