oil quenching 440C revisited

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Read some old threads. Found some good info from Ed Fowler, but I have a few more questions.

What was everyone using to heat the steel with? I have a heat shrink torch and a pile of fire bricks. I can use either mapp gas or propane. Its just a specialty type head for a plumbing torch bottle though so capabilities are still limited. I can get about 6" of 3/32" O1 up to a dull orange with plain old propane, easily gets 2-3 inches hot enough for bad scaling if your not careful. Do I have enough heat for a 3"-4" blade kitchen knife in 440C? Use MAPP gas?

Also how light of an oil do you quench in? Texaco type A is what I remember in the other threads. I've just been rednecking it with used motor oil on O1 and getting good results (no harsh testing but the knives have all gotten hard enough to skate a file before tempering, and seem to keep a fine grain and everything) Do I need to quit being a cheap SOB an buy some of the real stuff?

Temper 2 hours at 350? Thats what was done before, anyone tried some more and changed things any?

Thanks. I've been knocking out knives fairly regularly in O1 and have given quite a few away to family and friends. All hunting, and folding knives though. The womenfolk in the family have gone beyond admiring to hinting an actin jealous, so I need to work out something for them here sometime :D Think I'm not in trouble with my mom after giving her a little 2" utility knife with a kydex slipsheath for christmas (and putting black micarta on everything in the butcher block), but my sister mentioned how the slice-o-matic ginsu ninja knives they got as a wedding present AREN'T REALLY indestructable(imagine that)after looking over a knife I made.
 
I was also looking thru the older threads on this subject last night.
I'm wondering if an overnight freeze between quenches is the way to go or if one can heat then quench till the blade is just warm to the touch then heat and quench, and do the third quench all in a single day.
This may have been covered and I just missed it, but curiousity is getting me antsy to find out the exact procedure for this operation.
I'm glad you opened this thread Matt. Maybe we can both get an answer.:)


All the best,
Mike U.
 
I have attempted to heat treat two 440c knives at home, so I am by know means an expert. The first knife is still being tested. I quenched it 3 times in vegetable oil that was around 140 degrees. I left the blade in the oil overnight, between quenches, between the 2nd and third quenches, it actually sat for 2 days. After the last quench I let it cool till it was cool enough for me to handle, and I ground off all the scale, until it was shiny, and etched the blade to make sure it looked ok, then I tempered it at 4oo degrees three times for about 2hours a time. The test knife has took a very sharp edge very easily, and has out performed a very similar 440c Entrek knife in every way. It has a thinner edge, so it cuts better, but it has also proven to be a tougher edge. I have no idea how hard my oil quenched knife is, but the Entrek knife was 57-58 Rc if I remember right. The other knife which I heat treat at the same time as the test knife is currently in the hands of fellow Forum member Thomas Clegg a.k.a Possum. I hope to hear how it performs for him soon. It was part of the knife in the hat trade organized on this forum a few months ago.
Kyle Fuglesten
 
I may be out of line but 440C is an air quench steel. Normal hardening temp is 1850 to 1900 degrees and the tempering is done around 300 degrees. Plus there are soak times envolved also for hardening on a normal blade around 10 to 15 minutes and at least one 2 hour soak at the tempering temp. You don't edge quench air hardening steel........Ray
 
I,ve done a few blades of 440C using the triple quench in oil,Heating them up in a forge, I got very little scale The first knife a 9" fillet knife was a performer Other attemps were not as successful It does work and will make a excellent blade .Like all methods there are a lot of of ways to come up with a end result.
 
Thats what I thought too the first I saw anything about this Ray.
Turns out that you can oil quench 440C, and maybe other air hardening steels as well. It doesn't seem to be a common practice, and you have to do multiple quenches to get the right effect. But somehow it works :confused:


Thanks Alan and Kile
Sounds like it worked for both of you even if you haven't worked out a definite method of doing things. I guess I'll give it a try too.
I don't have to do the magic chant and secret dance do? I ;)
 
Absolutely you can oil quench 440C. Some steels allow both methods. I asked this question several months ago (torch/forge heating, with oil quench, heat treat of 440C), and was fortunate to get an Ed Fowler answer. He said the best heat treat results he had ever gotten with 440C was with a triple oil quench.
 
I'm actually hoping Ed Fowler has been able to find his notebook which contains his exact methods for oil quenching this steel.
I'm interested to see if it can be done one HT after another in the same day or do the HT's have to be broken up by an overnight chill in ye old freezer to gain maximum effect.


take care and all the best,
Mike U.
 
I've done two blades this way, but quenched each time immediately after it cooled to air temp. I'll be quite interested to see if I screwed that up. I tempered at 375 twice for one hour, again immediately after cooling to air temp. So far the one blade I have access to is working well.

Dave
 
FWIW I occasionally do multiple quenches right in a row on O1, when it doesn't seem like it took right the first time (file test, skates more in some spots than others) and have always gotten good results. It might get optimum performance, but I don't think it has any ill effects either. My guess is that you have to everything else exactly right for over night freezing to make an appreciable difference. ( a situation I'm not in very often ;) )
 
So I had an old blacksmith teach me a trick I use on 440C and 154CM. I am not super anal about hardening but I do a file test and use the blades so I know I get a decent hardening. I oil quench from the forge. Then when the oil stops boiling I quench in a bath of Aceton and dry ice. I essentially "carbonate" the acetone and bring the temp down to -100ish and do the final quench in there.

I then temper in the oven but I've had pretty good success with this process. Anyone else out there heard of this?
 
So I had an old blacksmith teach me a trick I use on 440C and 154CM. I am not super anal about hardening but I do a file test and use the blades so I know I get a decent hardening. I oil quench from the forge. Then when the oil stops boiling I quench in a bath of Aceton and dry ice. I essentially "carbonate" the acetone and bring the temp down to -100ish and do the final quench in there.

I then temper in the oven but I've had pretty good success with this process. Anyone else out there heard of this?
Start a new thread. All the guys that started this conversation in this thread have moved on long long ago. (2003)
 
So I had an old blacksmith teach me a trick I use on 440C and 154CM. I am not super anal about hardening but I do a file test and use the blades so I know I get a decent hardening. I oil quench from the forge. Then when the oil stops boiling I quench in a bath of Aceton and dry ice. I essentially "carbonate" the acetone and bring the temp down to -100ish and do the final quench in there.

I then temper in the oven but I've had pretty good success with this process. Anyone else out there heard of this?
It’s very bad advice to heat treat stainless out of a forge, with or without an oil quench and subzero quench.

Hoss
 
Holy necro post crypt keeper. This is digging way back. Also do not heat treat air hardening steels in a forge. Just because something gets hard does not mean it’s usable for a knife.

stacy you probably want to lock this bad boy down.
 
Yes, time to put this puppy to bed.

My personal advice is to NOT use a forge and direct quench for stainless steels.
I sure as heck don't recommend quenching any blade warmer than room temp in acetone and dry ice.
 
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