Recommendation? Messed up my O1 tool steel heat treatment

A

Andersoncustomknives

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Nov 21, 2016
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I'm a newer knife maker and have been having good success using O1 tool steel. Tonight I had an unfortunate mishap... I placed 3 blades in my Evenheat kiln and set my usual specs for the heat treatment cycle. I then went to work on finishing up some of my other projects and forgot about the blades I had in my kiln. By the time I got to them they had already started to cool down. Not knowing what to do I quenched them. Normally I'm pulling 57hrc - 60hrc from quench. These blades came out at 48hrc - 53hrc. If I had the time I'd do a little more research into the subject but my main question right now is,

Is it possible to redo the heat treatment on these blades or are they garbage now? Would a normalization be an option before redoing the heat treat?
 
DevinT said:
It depends on the HT cycle you ran.

Hoss
Click to expand...
My current recipe for O1 is as follows:

Ramp 600 degrees/hour to 1250
Soak 15 mins
Full ramp to 1450
Soak 25 mins
As soon as soak is complete I quench in ATF preheated to 130-140 degrees

That last step is what I missed this time and I'm not sure exactly how long it sat completed.
 
I wouldn’t bother with your preheat - for the cross sections we work with, it’s not necessary and is likely causing more problems than it’s helping.

Preheat your kiln for an hour (yes, that long, or even longer) BEFORE you put the blade in. You want the mass inside that kiln to be radiating your set temp so that it rebounds quickly after you put the blade in, and shuts those coils off quickly - remember, they have to radiate FAR more heat than your setting to bring the inside of the kiln to temp.

If you want to start using your austemp of 1450°, you can, but I’d consider 1475° or even 1500° for O1. You’ll need to test these variables yourself, to make sure they’re working for you, but that would be the first place to start.

Soak for 15-20 minutes, full quench in oil.

Temper immediately.

I suggest using some form of anti-scale compound such as ATP-641, as the atmosphere in a kiln without inert gas injection will causing scaling and decarburization.
 
don't use ATF, made for transmissions not quench. If nothing else, use canola oil from supermarket heated to 110-120F. as said, preheat furnace to 1475-1500F(800C). take notes. for 1/32 or 3/64, soak about 7min. 1/16 and 3/32 get 10 minutes. if using thinner stock(1/16" or less), I have had good results quenching in canola oil till black then aluminum quench plates till room temperature. if you don't have tempering oven ready, as soon as blades are room temperature, I put mine in ice water. Temper at 300F should give Rc64-65. temper at 350-375F will give you Rc62-63 where O1 has its best hardness/toughness. for 5/32" or less, one hour temper, cold water quench, scrub clean, second one hour temper.
 
Matthew Gregory said:
I wouldn’t bother with your preheat - for the cross sections we work with, it’s not necessary and is likely causing more problems than it’s helping.

Preheat your kiln for an hour (yes, that long, or even longer) BEFORE you put the blade in. You want the mass inside that kiln to be radiating your set temp so that it rebounds quickly after you put the blade in, and shuts those coils off quickly - remember, they have to radiate FAR more heat than your setting to bring the inside of the kiln to temp.

If you want to start using your austemp of 1450°, you can, but I’d consider 1475° or even 1500° for O1. You’ll need to test these variables yourself, to make sure they’re working for you, but that would be the first place to start.

Soak for 15-20 minutes, full quench in oil.

Temper immediately.

I suggest using some form of anti-scale compound such as ATP-641, as the atmosphere in a kiln without inert gas injection will causing scaling and decarburization.
Click to expand...
Thanks for the information! I'll try putting that recipe to the test. Would this work for fixing the blades that I messed up yesterday?
 
Last edited:
If you were on the down side of 1450 and you only hit 48 this step should be just like another normalizing. I will sometimes do this if I'm in a hurry, quench a blade when running normalizing cycles. I run a lot of 01 9/32 x 1/2 and do use the 1215 pre heat for stress relief but my product has been bent and carries a lot of stress.
There are many products that can be used to prevent pitting and scaling on knife blades, when they come from the quench; try a few of them out until you find one that you like. Nothing more depressing than a pitted blade that we've spent so much time making.
Enjoy the craft, Fred
 
I'm just starting to use O1 and getting very good results using the recommended recipe. Preheat my forge at 1475-1500 for and hour soak blade for 18 mins and quench in 120*-125* canola oil. Tempering at 400* for an hour 2 times. Getting 61HRC. I have a PID and thermocouple and can maintain those temps manually very well, it only fluctuates a few degrees.
 
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