12C27 stainless heat treat ??

Von Gruff

Well-Known Member
#1
Is anyone heat treating 12C27 stainless in thier gas forge without a thermocoupe and digital readout. . I have a lazer heat guage so reading the blade at 1080C - 1976F shouldn't be a problem but is there anything ese I need to look out for with this steel.
 

bladegrinder

Well-Known Member
#2
I use quite a bit of 12C27 Von, I use it in .100 thickness for filet - boning knives and small skinners.
being that thin I always heat treat prior to grinding. it still wants to warp coming out of the oven but I use aluminum quench plates and they finish perfectly straight. I use an evenheat oven so the heat treat is pretty straight forward with a short soak time for the thickness I'm using.

I actually find this steel to be kind of strange compared to the CPM154 I usually use, it's almost like aluminum in the annealed state but it hardens great, I keep mine at around 62 C scale and it takes an absolute wicked edge.

To better answer your question, if you feel you can keep the soak on your steel at 1975 you shouldn't have any problems, but running stainless in a forge for heat treating is always going to be a hit or miss to some extent.
 

KenH

Well-Known Member
#3
Since 12C27 doesn't require any long soak, if you can hold it fairly close to 1950 to 1975 (can even use lower temp) for 5 minutes or so, you should be pretty good. I'd use a muffler pipe to shield blade from direct flames.

What's this lazer heat gauge you mention? That's not one of those IR thingys is it? Got a link to the item?
 

Von Gruff

Well-Known Member
#4
Yes I called it wrong as a lazer when it is a 3000F IR themometer.
I have a muffler pipe so and a set of AL plates in a vertical vise so that is two points covered. The steel will be 1/8 thick so shoulld be good for grinding before heat treat as I normally do for my carbon steels.
So you dont see any difficulty in HT in my forge as described??
 

KenH

Well-Known Member
#5
Have you confirmed the accuracy of that IR thermometer? Normally they don't work that well - and for sure the one I have doesn't work good at all in a forge. Some guy on a forum had a technical explanation why, but forget what it was.
 

KenH

Well-Known Member
#7
That will certainly do the trick - It will be interesting to see how the IR works when compared to the new system you've got coming.
 

Von Gruff

Well-Known Member
#8
It will give me consistency I think Ken. There have been a few instances where I know I have overheated a blade at times with the IR as I have been using it to check blade temperature where with the probe and thermoeter I can regulate the forge temperature via the air flow.
 

bladegrinder

Well-Known Member
#9
You may have a problem with decarb and possibly pitting if it's not wrapped in foil.
I don't know about just putting it in a forge and getting up to temp. real fast, but I've seen what happens to stainless when it's put in a oven and brought up to temp. slowly with a pinhole or small tear in the foil, and it ain't pretty.
 

Von Gruff

Well-Known Member
#10
You may have a problem with decarb and possibly pitting if it's not wrapped in foil.
I don't know about just putting it in a forge and getting up to temp. real fast, but I've seen what happens to stainless when it's put in a oven and brought up to temp. slowly with a pinhole or small tear in the foil, and it ain't pretty.
I have a length of 3x1 box steel with the end closed that I would put the blade in that should keep the decarb at bay if the 3x1 box is up to temp when the knife goes into it.
 

KenH

Well-Known Member
#11
While it would be better (MUCH better) if you'd wrap in SS foil, if you'll coat with some of that high temp stuff, and perhaps once the forge/box gets up to temp, stick a bit of paper bag in box to burn up some of the oxygen, just as you're putting the blade in. My mind is blade right now (on first cup of coffee) there is a high temp coating that's rated almost 2,000F that would be good. I've never used it, it's not as good as SS foil, but might help.

Good luck and let us know how it goes.
 

Von Gruff

Well-Known Member
#12
Where do you get your SS foil as here the only lot I can find is well over $200 for a 75M roll to get it from Australia to me here in NZ.
 

KenH

Well-Known Member
#16
I have used the 321 rated at 1900F or 2,000F depending on who was rating it and it works "ok". I'd be careful about with the muffler pipe and forge. My last batch was 309 rated at 2200F and works just fine also. Read the instructions that say this still is razor sharp and WILL cut you like a razor. IT WILL!!! ask me how I know {g}

Be sure the seams are sealed (hammered tight).
 
#17
Thanks Ken and Ted for the links. I see some is rated at 2000F and others at 2400F.
http://usaknifemaker.com/knife-maki...il-tool-wrap-321-002-x24-x10-up-to-1900f.html
This looks to be the best price @ $45 for 10' for 2000F foil as a start for the very few SS knives I will be doing so will see if my friend will get some ordered asap for me.
also, the widths of the various foils vary. some are 10" all the way to 24"...sure you noticed just giving a double check...
 

Von Gruff

Well-Known Member
#18
I have a knifemaker friend who told me about the sharpness when he was HT a blade I ground from a piece of N690 he gave me so hopefully I will avoid that particular trap but having said that I know that knives are sharp and that hasn't stopped me from getting bitten from time to time.
Ted, I did see the different widths when I was checking through all the offerings in the link at USA knifemaker. I have been getting all my belts and a few other things from them or at least my friend is getting my needs from there for me so it is good that we can have a supply outlet that has all the bits and pieces I need in the one place. I get my steel though a NZ outet of an Australian supply house so the two outlets cover it all.
 

bladegrinder

Well-Known Member
#19
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.
 
#20
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.
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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