12C27 stainless heat treat ??

bladegrinder said:
All I've ever used is the 321 and have run it up to 1975 with no problems.
I'll give you a tip though Von, I never had a problem with 440-C but with the CPM154 I was having serious problems with the foil wanting to weld to the blade. I started dusting my knives with baby powder and it never happened again, now I dust every knife before putting it in the foil. if you do this make sure it's the 'talc' powder and not corn starch. the perfume doesn't make any difference, it all burns up.
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Willl installl that tip in the memory banks thanks Steve.
 
Smallshop said:
Yes...I do 20 blades in one wrap...talc them...ad a half sheet of paper towel folded up to burn up the oxygen...You really can't add too much paper...when the air is gone you end up with a nice soft black particle of paper. I would rather have a bit more than none at all...and maybe it matters not at all...some guys doing single blades don't add paper...and get great results.
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That is something I hadn't known about Ted. I had thought the bades were done singularly in individual wraps but from what you say multiple blades can de done in the one wrap by talcing each blade.
Does it matter where and how the half sheet of paper towel is placed within the wrap??
 
The thing that is still puzzling me is how to know when the wrapped blades have reached temp to time the 5 minute soak. With unwrapped carbon blades I can see what is happening but with a wrapped blade that is not possible and in particular if you have multiple blades within one wrap I expect there is a time lag between the outer blade reaching temp compared to the inner blades in the wrap.
Having the thermocouple probe and thermometer I can know when the forge has reached critical tem and can hold it there with air controll but from there can you explain how to know when the blades are done or is it done by time in the heat and then if there are multiple blades how does that effect the time?
 
Von Gruff said:
That is something I hadn't known about Ted. I had thought the bades were done singularly in individual wraps but from what you say multiple blades can de done in the one wrap by talcing each blade.
Does it matter where and how the half sheet of paper towel is placed within the wrap??
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the blades wrapped tight together become a "block" I put them on their backs...blade up and put the p-towel in the handle area. I'm using airhardening and can get all my blades hung in under a minute. Remember as a block they will need soaking longer than a single blade.
 
Smallshop said:
the blades wrapped tight together become a "block" I put them on their backs...blade up and put the p-towel in the handle area. I'm using airhardening and can get all my blades hung in under a minute. Remember as a block they will need soaking longer than a single blade.
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So it takes just a minute to get a single blade to temp once the forge is at the right temp. Do you multiply that time in the forge by the number of blades in the wrap??
 
Von Gruff said:
The thing that is still puzzling me is how to know when the wrapped blades have reached temp to time the 5 minute soak. With unwrapped carbon blades I can see what is happening but with a wrapped blade that is not possible and in particular if you have multiple blades within one wrap I expect there is a time lag between the outer blade reaching temp compared to the inner blades in the wrap.
Having the thermocouple probe and thermometer I can know when the forge has reached critical tem and can hold it there with air controll but from there can you explain how to know when the blades are done or is it done by time in the heat and then if there are multiple blades how does that effect the time?
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multiples will increase time...and will need experimenting. I wonder if you could put a stack of junk steel with one blade steel in the middle for testing(less$$)? I wrap my blades tight because i want them to behave as a block. I hammer the edges of my foil packet till the blades don't jingle. I am twenty minutes longer soaking at temp on A2 than doing a single blade. The stainless will be different of course...all my blades are exactly the same shape.
 
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Von Gruff said:
So it takes just a minute to get a single blade to temp once the forge is at the right temp. Do you multiply that time in the forge by the number of blades in the wrap??
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no...it won't math out that way. It will be some educated guessing as to how to get there. If it was a time x # of blades and you were soaking one blade at 5 minutes after equalizing you would be soaking for 100 minutes!! it will work out much less than that...more towards doubling the soak time or a bit more. I use a furnace so I'm able to see when the temps stop bouncing. Also your equalizing times at different temps will increase a bit. I do a short wait (equalizing)at 1200 another at 1400 the up to 1775 for my final temp on the A2. Which is where I soak at.

Haven't done stainless yet so I don't know how you would be ramping.
 
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My friend here has a furnace as well but will have a yarn with him and see if I can get a bit of an idea on times etc although he uses N690 more than anything else but has been a ful time knife maker for over 20 years so may have started out with a forge and have some tips on timing etc.
 
He should have better insight than me...I'm still pretty new to the HT side of things and most guys don't seem to be air quenching or doing as many multiples as I am trying so it's been more experimenting than I'd hoped to be doing...lol.
 
Here's what I would do, and this is only my opinion because heat treating stainless in a forge is kind of unheard of..as far as I know, I could be wrong.
I don't add paper to the pouch, I had the first and only knife I did that too get some funky stuff embedded in the tang where the paper was.

I would only do one knife at a time, dusted with talc. knowing when the steel is up to temp. will count on your experience with your forge temps and the readings off whatever electronics you have connected to it.
I would let a determined soak time go two extra min. to be on the safe side. plate quench it with aluminum or steel plates to prevent warping.

What I really see as the ultimate endgame issue is your hardness target, I'm getting my 12C27 to finish at 63 rc, but if only checking with files it may show it reached hardness but maybe only 58-60 which is all good but you may not achieve the full hardness this steel has to offer.

I don't know if you have a Rockwell tester or not. the thing with stainless is it's almost a one time shot at heat treating, if it doesn't work the first time there's considerable annealing in the future to try again.

This isn't to say you won't hit it dead on...in fact I'm really waiting to hear how this process works out and I hope your
successful. I'm sure theirs quite a few people here waiting to hear your results.
 
My friend John (ripiknives) only lives an hour and 20 away and has a rockwell tester so I can go up to check how they go. When he tested my O1 and 10 series blades he found them to be in the 61- 62 range. I wil try and catch up with him later in the day and see what he says.
 
I just had a good conversation with John about the forge HT of 12C27. He said to use a muffer pipe and put the thermocouple probe into that and when it is up to and stabilised at the correct heat to put the wrapped blade in and when the pouch and knife are at the same colour as the muffler pipe (should be able to almost see the knife through the pouch) then the 5 minute soak time can be started, quench in heated canola oil. When it is at hand hollding temp to put in the freezer for 20 min.
 
Why in the world would he suggest oil quench when you've got the aluminum quench plates already setup? With 12C27 all you have to do is get the temp below 1100F in less than 2 minutes for full hardness. plate quench really helps prevent warp issues also.
 
KenH said:
Why in the world would he suggest oil quench when you've got the aluminum quench plates already setup? With 12C27 all you have to do is get the temp below 1100F in less than 2 minutes for full hardness. plate quench really helps prevent warp issues also.
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I agree, I wouldn't even think of doing a quench in oil. I mean it might work fine for hardening, but you might cut open that foil pouch and find a 12C27 banana .
 
The other thing you face with quenching in oil is getting it out of the foil first then quenching it....yikes, may as well use plates, then you don't have to remove the foil.
And if you quench it while it's still in the foil, I would think the foil would act as an insulator enough to make that blade
scream....what the heck is going on out there!
 
We discussed that and when I said that there would be a few blades at a time and my quench plates are just 3/8''. With the recomendation I read for oil quench seemed like a solution untill I get a decent set of plates. The other option was to get a few pieces of foam and wet then freeze them to cool the plates between use.
On the other hand I did no know and it was not mentioned that there was a 2 minute "quench time" which puts a different equation into the mix. I am away to the city next week and will see about getting some thicker plates.
 
Was in the city today and picked up decent poiece of box for a muffer as my previous one was not deep enough to take the 3 in bade of the kitchen cleaver and a pair of 3/4 in quech plates and have the SS foil on the way so that should be here in about 2 weeks.
I have the thermocouple and digital thermometer on hand so with the blades profiled I will have to start the grinds
 
Good deal - keep us updated on your progress. I think you'll find the forge to work pretty good for HT'ing SS
 
So a ready to go on the 12C27 stainless steel kitchen blades now as the foil turned up this morning. I will not be able to get to it till next week as there is a hunt organised among a few other obligations that will come first..
This is the set up I have in place now. I got a piece of 4x2 box and modified it by having it cut down to 3 3/4 in height to fit the forge opening, then welded a couple of supports to hold the probe toward the top of the box and clear of touching either the foil wrapped blade or the box itself.
The angle iron is a heat blocker, unbreakable and just as effective as a fire brick.
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You can see the probe supports inside the muffer. The flange to the side and underneath makes sure there is no flame line towards mu hands when putting a blade in or out of the muffler and also protects the rest of the probe covering past the insulators.
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The angle iron also has a probe usability if I need to controll the heat when not using the muffler or without the probe in place it is a good heat blocker
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