Heat treat 15n20 - procedure

R

Rythorne

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Sep 27, 2015
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ive been reading through previous posts and i finally found that Stacy heats 15n20 to 1500 In an oven then holds 10 minutes then quenches in oil then plates. I have a paragon, so my only question is does the blade need to be wrapped or anti scale compounded for those 10 minutes or can i just out the blade in on a rack.
 
It does not need to be protected from scale. It will get a little scale and some decarb but will be fine. How thick is your 15n20? I get amazing results with my thin 15n20 with a 5min soak. That's 5 min once I shut the door. Takes 2-3min to come up to heat and the a few min at temp. Then right into 75° parks 50. 15n20 likes to be kept under 1500°. The closer you keep it to its curi temp the harder it will get. Currently I have tested down to 1450° and at that temp I get 66.5rc. 1500° will get you around 64 if my memory is correct. But that is my oven and the temps could be off a hair. If you have a hardness tester then do your own tests.
 
Great so you use 1450...was thinking of claying the blade then edge heating it and ferric to make a mock Hamon. Using .09 thick stuff
 
Man tried twice with veg oil. Have no parks 50 but I let it soak once for 7 minutes then a full 15 minute like Stacy suggested...really didn’t get as hard as I was hoping. Gosh
 
valknut said:
How did you test the hardness?
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I have a hardness tester but it’s no necessary. Files don’t scate at all and I use other knives both my own 440c knifes that are finished and an Arno Bernard stainless knife they all rip the handle apart. Gonna fire up the forge today and try it old school.
 
I use 1465, but haven’t experimented with 1450 yet. I consistently get Rc66+ out of quench. 5-10min soak.
 
What temp did you use?
Every oven is different and just being off by a handful of degs will mean success or failure. If your going to walk the thin line of performance then you really need to do a handful of coupons at different temps. Then hardness test them and see where your sweet spot is. I know or at least I suspect my oven runs a little hotter then the controller shows. I have thought this for a while and in the end does not matter as long as you do your testing. I just changed out my thermal couple to one that is much longer and bent at a 90deg ang. My first thermal couple was in my opinion way to short. If its to short the heat will travel down the TC and it will be hard for the tip to come up to temp. I witnessed this first hand when the oven says its at X temp and holding. You open it and the Tip of the TC is a shade darker then everything else in the oven. Sorry I am rambling on about something unrelated to your problem. What I am getting at is this, find your sweet spot.

15n20 will get SCREAMING hard. Make you up a handful of test coupons. Mine where like 1"x2" and I had like 5 or 6 I think. I then started at 1500 and dropped 10deg per coupon. If your questioning your quench oil then quench these small coupons in brine. Thy are small enough that thy should survive, at least enough of it will for testing. Also before hardness testing you need to grind the top and bottom. Then take the top up to a med finish so you get an accurate reading.
 
COuld the issue be that it’s 35-40 degrees and when i open the oven and grab the blade by the time it gets to quench it’s been too long?8 mean i do it as fast as possible but I’m sure the heat is ripping out as it’s pretty thin stock.i used my forge and it’s hard now but I’m definitely going to do some testing.i like the idea of having a super hard blade for kitchen slicers
 
JTknives said:
It does not need to be protected from scale. It will get a little scale and some decarb but will be fine. How thick is your 15n20? I get amazing results with my thin 15n20 with a 5min soak. That's 5 min once I shut the door. Takes 2-3min to come up to heat and the a few min at temp. Then right into 75° parks 50. 15n20 likes to be kept under 1500°. The closer you keep it to its curi temp the harder it will get. Currently I have tested down to 1450° and at that temp I get 66.5rc. 1500° will get you around 64 if my memory is correct. But that is my oven and the temps could be off a hair. If you have a hardness tester then do your own tests.
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For those of use using a simple forge what is more important, having some sort of a soak or temperature control. I have been trying to give my blades that have more alloy than 1084 a soak. I am trying this because some of the blades I did with 80CrV2 won't hold much of a edge even though they are hard. With my mini forge there isn't much i can do about the heat other than pumping it in and out. I'm sure there is a big leg in what I can see and how i can respond.
 
Temp control is more important in my opinion. If you can't control temp, how do you know what temp you are soaking at?
Just my point of view...
 
A pipe muffle with sealed ends and and a temperature probe will help that quite a bit, but you may need to build a bigger forge first.
 
skillgannon said:
For those of use using a simple forge what is more important, having some sort of a soak or temperature control. I have been trying to give my blades that have more alloy than 1084 a soak. I am trying this because some of the blades I did with 80CrV2 won't hold much of a edge even though they are hard. With my mini forge there isn't much i can do about the heat other than pumping it in and out. I'm sure there is a big leg in what I can see and how i can respond.
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I have heat treated 80crv2 for a handful of people and thy have come back to me saying thy where not impressed with the edge holding. It might be tough but has the edge retention of 5160 it seams, which really is not that great. Not knocking it but both these steels are known for toughness not retention. And my experance puts 15n20 above these steel in toughness and edge rentention.
 
JTknives said:
I have heat treated 80crv2 for a handful of people and thy have come back to me saying thy where not impressed with the edge holding. It might be tough but has the edge retention of 5160 it seams, which really is not that great. Not knocking it but both these steels are known for toughness not retention. And my experance puts 15n20 above these steel in toughness and edge rentention.
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My experience is the same. 80crv2 for axes and choppers, 15n20 for knives.
 
hugofeynman said:
So, Willie71 Willie71 , if 15n20 has better toughness than 80crv2, shouldn’t 15n20 be a good choice for big choppers and axes (if thicker pieces where available, that is)?
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Yes. 15n20 was designed with toughness and cutting wood in mind. The fact that it seems to outperform it’s chemistry in high hardness applications is the bonus that we love with this steel.
 
Here in Europe we have something even tougher (lower carbon and almost 2% Nickel), 1.2714 (conforms with L6). This should behave more or less like 15n20 but maybe less wear resistance. Only advantage (for me) is availability in thicker stock.
 
valknut said:
What are y'all tempering the 15n20 at?
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Depends on the blade and desired hardness. But normaly from 300°-400° with most of the blades around 300°-350°. 62-63RC is not at all out of the question on a lot of knives the we use 15n20 for.
 
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