So, what was talked about in Atlanta?
It was a good presentation with a good turn out. I counted about 45 people. If any of you were there, I was the guy (with exceptional self restraint) sitting behind the fellow with the cell phone who actually placed another call after answering one (if you are present in this forum, please know that I say with all due respect that you are a douche). * Apparently the presentation was 90 min, which was enough time to touch the high spots, but I think 180 would have been better, but the room was only available for 90.
He went over the fundamentals of metallurgy as it pertains to hardening with pictures of different structures such as martensite and pearlite and austenite.
He had a chart of the different steels in common usage with simple to heat treat steels on the left, and difficult complex steels on the right. As expected the simple 10X stuff was on the left and 52100 was on the right. What I found surprising was O1 was right beside 52100. Turns out that, while it may be easy to forge out, grind and get hard, it is not easy to heat treat well due to its alloy content and carbides. Get it too hot and it will get away from you in such a manner that it won't be easy to repair, don't soak it long enough and it will appear hard, but perform poorly because too much carbon is locked up in carbide, reducing the quality of the martensite. Also interesting (but common knowledge to folks that have been here long) is you just about can't over soak O1. He showed micrographs of a short soak (looked pretty bad) a recommended soak (looked pretty good) and a 5 hour soak (also looked pretty good). The 5 hour soaked stuff looked good and had fine grain. Accurate temperature and sufficient time is everything. To sum up this paragraph, 1084 is a great steel to start with (and a great steel in general) but O1 and 52100 require time and temperature control you're not going to achieve in a forge and are not for the beginner. You'll need an oven or saltpots to do them well.
We touched on what the alloying elements are and what they do. We talked about how to achieve fine grain and a nice carbide structure. The best way uses salt pots or ramping ovens, but another good way is a few subcritical anneals (still magnetic) of quenched martensite with a good soak and slow cool down at successively lower temperatures to achieve a nice spheroidized carbide structure (did I get that right?).
Bainite does not turn him on.
In a discussion I had with him at his table (did ya'll see that quillion dagger, damn!) we discussed cryogenics. His problem with this subject is all the hype around it by folks who have an ulterior motive. For example, a PhD metallurgist, who is in a position of seemingly authoritative knowledge, hyping the stuff because he has a monetary stake in a cryo business, so tells folks some pretty outrageous unsubstantiated claims not backed by science. I believe panacea was the word Kevin used. Kevin doesn't like the disingenuous hype, but does say that on a precision cutter in a steel such as D2 or stainless he would use it if he felt the blade would benefit from the additional martensite. We also discussed snap tempering before cryo. I'd been under the impression that any halt or reversal of the quench could cause austenite to stabilize, but I didn't (and still don't) really understand the mechanism of austenite stabilization, and he feels a snap temper won't cause a problem.
Lets see, what else did I miss. Ah yes, bladesmithing invented metallurgy, which went on to better civilization. But in the late 1700's, firearms displaced blades, and the science of bladesmithing broke off from industrial metallurgy and failed to keep pace with modern advancements, so modern day bladesmiths are often working with techniques that have missed some opportunities for improvement. And the modern steels (O1, 52100 etc) aren’t really as optimal for forging as steels similar to the old bloomery irons.
I'm putting a lot of words into Kevin's mouth here, so I hope he'll forgive me if I got some of it wrong, I'm going by (imperfect) memory.
. Perhaps free circus peanuts! As a joke I put them out on my table at the last show I did and they all vansihed
, I was shocked at how many people actually like those nasty, nauseating, little, orange, stale marshmallow, toxic treats!
