Have I got this right???

Chris Railey

Chris Railey

Well-Known Member
I was reading up on heat treating 15N20 for my upcoming fillet knife project and it recommends a plate quench. My definition of a "plate quench" is quench to black heat quickly in oil then slap it between two metal plates so it cools the rest of the way straight. Because I am using .060" I am tempted to do this anyway. Is that what is meant by plate quench or am I missing something?
 
I used P50 but did after put it between 2 steel plates to help keep it straight. It turned out well. Good luck!
 
Chris Railey said:
I was reading up on heat treating 15N20 for my upcoming fillet knife project and it recommends a plate quench. My definition of a "plate quench" is quench to black heat quickly in oil then slap it between two metal plates so it cools the rest of the way straight. Because I am using .060" I am tempted to do this anyway. Is that what is meant by plate quench or am I missing something?
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Take the blade out of the oven and stick it directly between the plates and clamp. I’d have to check the graph but I think it has about a minute to get below 600. Someone please correct me if I’m wrong.

Air hardening steels don’t need a “quench” in the typical sense of an immediate dunk. They can be hung up in still air and will cool quickly enough to harden. The plates are supposed to prevent warp. In my experience, they help some. But a blade that wants to warp will still take a tiny warp and need a bit of straightening.
 
I have plate quenched 15n20 between two aluminum plates direct from heat treat oven. Cooling rapidly is what you are after.
 
I have only used 15n20 very little but I oil quenched it and treated it like 1084.

......Kevin....Keeeevin can you help us out?
 
My understanding is its basically 1075 with some Nickel tossed in so I am gonna oil quench like normal because that is what I trust. I was just curious about the plate quench. I really only have trouble with .060” stock when I clay the blade for a hamon. It always warps on me no matter what I do. Normalize or don't normalize, heck I have even annealed it before the clay and quench but 99% of the time it still warps. That being said the fillet blade will not be clayed so it should be fine.
 
Kevin Zito said:
Ok... to get it right, you have to double-clutch quench ONLY in old bacon grease. Oh, wait, you meant Cashen, yeah he can probably help too. Try that double-clutch, though, it might work.
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So, you are AWOL for a very long time , then you show up with an answer that is just plain wrong...everyone knows you have to use NEW bacon grease.!
I'm pretty sure that John Wilson will back me up on this completely bogus claim, won't you John? John? Where did he go now?

!
 
It's not what you cool with/in..... it's the speed at which a given steel is cooled. Since 15N20 is usually gona be less than .100" thick..... it will fully harden when plate quenched. The primary reason for the plate quench is straightness...... if you get a warp in thin 15N20 when oil quenching, you might as well toss it and start over...... it's that much of a pain in the rear to try to straighten. ;)
 
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EdCaffreyMS said:
It's not what you cool with/in..... it's the speed at which a given steel is cooled. Since 15N20 is usually gona be less than .100" thick..... it will fully harden when place quenched. The primary reason for the plate quench is straightness...... if you get a warp in thin 15N20 when oil quenching, you might as well toss it and start over...... it's that much of a pain in the rear to try to straighten. ;)
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OK so its a go on the plate quench. I have some 1/4 inch steel plates that are long enough will those work?
 
Chris...thicker aluminum plates will work much better...aluminum draws the heat MUCH quicker...an inch thick is about what you want.
 
Bjmac said:
So, you are AWOL for a very long time , then you show up with an answer that is just plain wrong...everyone knows you have to use NEW bacon grease.!
I'm pretty sure that John Wilson will back me up on this completely bogus claim, won't you John? John? Where did he go now?

!
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Lol. You got me ... I’m totally embarrassed. I was thinking about hamoning elmax lol
 
I only use fresh bacon grease for hand sanding because instead of wasting paper towels I just lick my fingers between grits. I went to air hardening steel to save bacon grease instead of quenching with it. Although that does make the shop smell wonderful.
 
John Wilson said:
I only use fresh bacon grease for hand sanding because instead of wasting paper towels I just lick my fingers between grits. I went to air hardening steel to save bacon grease instead of quenching with it. Although that does make the shop smell wonderful.
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You bring up a good point about air hardening steels. I always use air hardening steels, because by the time I finish with the angle grinder, I’m rockwelling low 70’s easy.
 
Smallshop said:
Chris...thicker aluminum plates will work much better...aluminum draws the heat MUCH quicker...an inch thick is about what you want.
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Definitely agree

I picked up two 1 1/2" plates off Ebay cheap

They don't need to be 1 1/2" but I stumbled onto this deal and that's the thickness they happened to be
 
I agree with the others.....aluminum plates. Dissipates (sucks) the heat out much quicker than steel. If I had my druthers......I'd personally prefer 1" thick copper plates, but these days I'd have to mortgage off the house in order to buy them! :)

Ed did you change your profile pic recently? I've heard of "a boy and his dog" but never a "dog and his bowie" lol.
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I did change the image/pic.... Most of you know I'm a big Lab guy.....just love em..... and the pic is of Blade...when he had just turned a year old. I thought it was appropriate for a forum called "KnifeDogs" :)


AND...all you guys talking about bacon grease....you missed the most important part! The grease has to come from jowl bacon, from a Tennessee Durock hog! :p
 
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