Questions about forging and HT'ing 440-C

hillbillychuck

hillbillychuck

Joined
Jan 24, 2001
Messages
137
Hey Y'all,

Today I was messing around and I've been wanting to do some stainless blades for guys that I know who hunt a lot. I decided to see if I could forge a blade out of it and was successfully able to do so without it cracking anywhere.

Then I started looking at all the old posts dealing with HT'ing 440-C and decided it was worth experimenting with a torch hardening and edge quench in mineral oil just like I do for my carbon steel knives. I torch HT'ed the blade until it was fairly hot cause I read that the hardening temp is fairly high for 440 (I also read somewhere that the magnet test does not work for 440) then I edge quenched it in mineral oil that was 150F. The blade got super hard but also seemed to harden further up the blade than I'm used to cause the back of the blade seems fairly hard too , though not quite as hard as the edge, but it was a rather small blade (1/8 x 1/2 x 3 inches). I had the oil about half way up the blade on the quench. Also I'm using a gas forge if that makes a difference.

Now for the questions:

1. Is this a viable way to HT 440-C or am I doing something fundamentally wrong here that I just don't know about?

2.Does the magnet test work with this steel or not?

3.Did I just have beginners luck with eyeballing the hardening temp? I didn't use any soak times or anything like that, did it just like my carbon steel blades except for the magnet.

4. If I get a good hard edge and a softer back on another blade does anyone know if it will show any sort of faint temper line? Should I use a slower or faster quench? I don't imagine that you can etch stainless too well, but if you can let me know that too.

5. does a multiple quench or repeated thermal cycles refine grain structure or help the alloying elements make better carbides like 5160 or 52100 in 440-C?

6. Should I start at the low end of the tempering cycle (350F) or does someone have a better place to start for a knife blade temper? Do multiple tempers benifit this steel?

Thanks for any help and advice anyone can give me on this subject, I really appreciate it.

HillbillyChuck aka Chuck Fogarty
 
440C is a deep hardening steel. It will air harden. That is why your spine is hard. Try to hold it at non-magnetic for several minutes. I austenitize 440C at about 1850 F and soak there for about 25 minutes. It is probably difficult to do with a forge but seems like you did something right.

Oh, you should probably temper at 400 F. I cryo and do a snap temper at about 300 F before cryo and then temper at 400 F, then at 375 F (2 hr per). About 58 - 58.5 HRc.

RL
 
Chuck, One of the best 440c blades i ever had was done in the forge, and also the only one i had really good sucess with,if i remember i heated above non magnetic to a point where the shadows disappeared,i tripled quenched in 140 degree oil and double tempered at 400 degree.It passed all testing i could conceive.. Again i could not repeat the results but it definately can be done.Worth expermenting with.
 
Thanks for the info guys. So both y'all went with the non-magnetic threshold for the hardening, interesting..... guess what I read about that not applying was wrong.

Oh, also forgot to ask above if the tempering colors are the same or do you have to do more testing with this steel.

Thanks again for the help,

Chuck
 
I've never tested it but I would guess 1850 F is well above non-magnetic. If you soak it at 1850 for the recommended time expect deep decarburation unless you can foil wrap it and still do it in the forge. Best to leave her fat enough to grind 5 or more thousanths off.

RL
 
Dang Chuck , what the heck are you doing messing with that icky stuff Brother? :)

I cant lie. I've played with it myself. But never tried to heat treat it. I know Matt Shade has had successes oil quenching it. Look up his posts and there should be some referance to his techniques. Hope to see you this Fall.
 
Hey Mark,

You gonna be at trackrock this fall? Can't wait to see ya brother!!!

Heh, I've started messing with stainless cause I have a couple of seriously redneck cousins that I use to torture test all my knives and they have come back with some pretty inventive ways of tearing them up and they rarely take care of them like they should. So I say to myself OK no more high carbon steel or scagel styled handles for you guys, y'all just tear them up. So I got a couple of bars of 440-C to play with. Then I started looking at how much it was gonna cost to send them off to be heat treated, and the turn around time, and the fact that I hate having to let someone else mess with my knives that I don't even know. I just thought to myself that if I could HT these puppys by my lonesome and make them come out good I would be way ahead of the game. Plus you know how damn slow I am, it takes me so long to make a knife that my profit margin is very low and if I pay someone to HT it is even lower.

Hope to see ya soon,

Chuck
 
Hey y'all,

Just did a search on Matt Shade's posts and that brought back some good results for me. Found out I wasn't using quite the right search terms. Actually quite a bit of good stuff here on doing 440-C. Also found some previous posts by Rlinger that helped a lot too.

Chuck
 
Good Lord willing and the creek dont rise, I'll be there Chuck. looking forward to it. Is Pat going to bring his collection this time?
 
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