This is a really deep subject, IMHO. You can learn a lot about this subject
right on the internet.
Just google "hardening steel" to get started.
But a lot depends on how deeply you want to go into it and what the
ramifications are for being wrong with your heat treatment or in guessing
what steel you actually have.
I know all too many guys who use the same hardening and tempering process on
whatever steel they are working with.
I know I'll get a lot of comments for saying this, but the least
scientific approach to identifying steels is spark testing, again IMHO. If
you want to get anywhere with that process, you need to get close to someone
who can show you, hands-on how they do it.
I see a couple of reasons why someone would want to Identify steels, other
than knowing for sure because you labeled it when you bought it , like I do:
1. You want to use junkyard steel just because----
2. You have already have some steel that you need identify because the tag
fell off or because you thought you'd never forget what it was and now you
did forget or you found unmarked stock at a sale or auction.
For reason number one, google "junkyard steel" and read on. One of the
first hits takes you to anvilfire. Looks like a pretty good article to me.
It also points you to a list of "junkyard steels". This list may be a good
starting point, but the article posses some valid concerns about using it
For reason number two, I have heard that shops that do use spark testing
usually use it to determine which one out of 2 or 3 possibilities a certain
bar is. They have marked and stored samples of each steel in a safe place.
They spark test the unknown bar and then compare the sparks to the control
samples. And they probably do this a LOT to get good at it.
I think spark testing is useful to separate steels of widely varying
analyses, but do you think you can tell the difference between 1060 and
1084? ----And bet you life on it in a critical application?
Even with a metalurgical lab to do the analysis, things can go wrong. We
once destroyed a 300 pound coil of 1/4" diameter molybdenum wire and part of
a vacuum furnace by using the wrong annealing process because "the lab" told
us it was tungsten.