Dana, I've been off on a canoe trip for a while or I would have helped you right away.
Pardon me for saying something - you said, "This is the hardest steel I have ever seen".
I hope not.
Your steel should be getting a LOT! harder when you harden your blades - right?
This is 5160, a very deep hardening steel, with a long time for martensite creation.
Jeff answered your question right in the third post.
If you bring 5160 up ABOVE! non-magnetic, and let it slow cool, it'll harden.
Not as hard as it might be if you quenched it in the proper oil, but it will air-harden due to all the chromium.
You will want to do this, like Jeff says, at least once after forging, because you always want your first post-forging thermal cycle done at your forging temps.
Maybe twice.
But see where Jeff says, "bring up to below non-magnetic/air cool maybe couple of times".
That's the method - "BELOW" non-mag.
That way, you are not making any austenite by going ABOVE critical.
Martensite won't form while cooling from a temp that is not above critical - you'll get pearlite.
Do it in a dark room and just bring your steel up to a dark red and a magnet still sticks and let cool.
Do a few times.
Sticking it in a bucket of lime for 2 seconds, 2 minutes or two days doesn't accomplish anything after going above non-magentic other than making your steel hard, if it's a deep hardening steel.
We toss this word "anneal" around way too loosely.
There's more than one type of annealing.
Lot's of guys stick their blades in the forge and let them cool in there, and that's just bad news.
Especially if it's a steel with more than .84% Carbon.
A person should NEVER! slow cool a steel that has more carbon than .84% from above non-magnetic.
And it's not a good idea to do it with steel below that much carbon, unless you WANT! martensite - like you'll get in 5160/O1/L6/52100.
Topic: Hard as hell (Read 969 times)
