Next question about ss

JAWilliams

KNIFEMAKER
OK I have picked my ss to try first. But now for the next couple of questions.

ATS-34 Stainless is what I am going to try. OK do you oil quench it, and how do you heat treat it? Is there more that I am missing? I will be honest I do like carbon steels but I have noticed that people will look at carbon and say will if it was stainless I would buy it. So I thought about doing knives in both. I have never worked with it and know nothing about it. If there is a site or if someone can give me the run down. Thanks, James
 
You really need an Heat Treating oven/furnace for Stainless, but for that steel I heat to 1900*F and hold it for 15-20 minutes depending on the size. I Plate quench Between two pieces of aluminum plate 1" thick 8"wide and 10" long. These steels are Air Quenching, After they are down to room temp I put them in Liquid Nitrogen over night. Then to temper it I heat the Blades to around 375*F or so. for 2 hours 2 times.
 
Lets see if I under stand, there is no oil quench. It is a heat quench, then you pull it out and put it between two pieces of aluminum till it cools down, then put it in cryo over night and then you put then in an oven for its cycles. Am I understanding right? But do you weight the aluminum plates down or just let them cover them?
 
Lets see if I under stand, there is no oil quench. It is a heat quench, then you pull it out and put it between two pieces of aluminum till it cools down, then put it in cryo over night and then you put then in an oven for its cycles. Am I understanding right? But do you weight the aluminum plates down or just let them cover them?

I use a hand ratcheting clamp from sears, you know the slide bar ones, to put a little bit of pressure on the plates doesn't take much I guess you could use weight for that. and yes it is an Air Quenching steel.
 
Cryo will help reduce retained austentite by continuing the conversion process in complex alloys past what occurs up until room temperature. That will typically give you a couple of points of hardness and maybe even a bit more toughness.

For general use, you may or may not notice the difference, honestly. I do LN cryo's on my CPM154 and other complex alloys just to reduce RA and make the best product I can.

James, as others mentioned, ATS34 need a bit of a soak at a very high and well controlled temperature (thus the need for a heat treating oven). I also plate quench between 1" aluminum and clamp the plates. This just ensures a solid contact between the plates and the steel and may decrease warps a bit. The aluminum acts as a large heat sink and pulls out the heat form the blade steel, cooling it faster than in air.

Keep in mind because of the high temperature and longer soak, you will need some sort of scale protection. Most (me included) use a high temp SS foil pack and plate quench with the foil pack still in place.

--nathan
 
Cryo will help reduce retained austentite by continuing the conversion process in complex alloys past what occurs up until room temperature. That will typically give you a couple of points of hardness and maybe even a bit more toughness.

For general use, you may or may not notice the difference, honestly. I do LN cryo's on my CPM154 and other complex alloys just to reduce RA and make the best product I can.

James, as others mentioned, ATS34 need a bit of a soak at a very high and well controlled temperature (thus the need for a heat treating oven). I also plate quench between 1" aluminum and clamp the plates. This just ensures a solid contact between the plates and the steel and may decrease warps a bit. The aluminum acts as a large heat sink and pulls out the heat form the blade steel, cooling it faster than in air.

Keep in mind because of the high temperature and longer soak, you will need some sort of scale protection.
Most (me included) use a high temp SS foil pack and plate quench with the foil pack still in place.
--nathan

Why cant the scale just be sanded off?
 
With certain stainless steels, the holds can approach 45 minutes in length. That amount of time in an oxygen rich enironment without protection (argon environmnet, PCB coating, SS foil) will cause significant scale and pitting. When you have a ground knife with an edge that can be at or often thinner than 1/32", you will have decarb at the edge that can approach the full thickness of the edge. Decarb occurs as carbon from the steel is robbed into the atmosphere at high heat. So your edge will have very little carbon content and thus not harden. Also, pits can form that can be a bear to grind off as they can be quite deep.

So unless you want to do all your grinding after heat treat (which many makers do...and even then they almost without fail use some sort of protection), why not just protect the blade? And even if you grind after heat treat, an unprotected blade blank is going to have a LOT of decarb going on, effecting your final thickness after you've ground it all away.

--nathan
 
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With certain stainless steels, the holds can approach 45 minutes in length. That amount of time in an oxygen rich enironment without protection (argon environmnet, PCB coating, SS foil) will cause significant scale and pitting. When you have a ground knife with an edge that can be at or often thinner than 1/32", you will have decarb at the edge that can approach the full thickness of the edge. Decarb occurs as carbon from the steel is robbed into the atmosphere at high heat. So your edge will have very little carbon content and thus not harden. Also, pits can form that can be a bear to grind off as they can be quite deep.

So unless you want to do all your grinding after heat treat (which many makers do...and even then they almost without fail use some sort of protection), why not just protect the blade? And even if you grind after heat treat, an unprotected blade blank is going to have a LOT of decarb going on, effecting your final thickness after you've ground it all away.

--nathan

Thanks!
 
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