(Plate Quenching) I've decided to cross over

Jeff,
I use a pair if 1" x 12" x 12" 6061 alu plates. At one time I was using a 6x18 magnetic chuck and it worked ok for steels other than CPM. When I started using 3V and S30V, the Crucible guys recommended the aluminim for a much faster quench.
I grind after heat treat so no knowledge how some of the wierd grinds would work. Tapered tangs and long distal tapers with a flat grind might present a problem.
I pull em out, throw em on the bottom plate, drop the top plate on top, put a 25 pound piece of steel on it and then use 4 quick squeeze wood working clamps.
An engineer friend of mine told me the formula for figuring up how large the plates should be in relation to blade size. It was something like Pi are round, cornbread are square iirc. :)
 
Kit Carson said:
Jeff,
I use a pair if 1" x 12" x 12" 6061 alu plates. At one time I was using a 6x18 magnetic chuck and it worked ok for steels other than CPM. When I started using 3V and S30V, the Crucible guys recommended the aluminim for a much faster quench.
I grind after heat treat so no knowledge how some of the wierd grinds would work. Tapered tangs and long distal tapers with a flat grind might present a problem.
I pull em out, throw em on the bottom plate, drop the top plate on top, put a 25 pound piece of steel on it and then use 4 quick squeeze wood working clamps.
An engineer friend of mine told me the formula for figuring up how large the plates should be in relation to blade size. It was something like Pi are round, cornbread are square iirc. :)
Click to expand...

Thanks, Kit. That gives me all I need. I think I would do this for anything I would be comfortable grinding after hardening. Now let's talk about the pie. When I was living in Del Rio, I lived next to this old Mexican feller. I don't recall him speaking a whole lot of English, but that was okay. My high school Spanish got me along just fine. Thing is, that old guy made the best damn pecan pies. He had a whole grove of them trees out back, and since he lived alone, he'd shower us with more damn pies and pecans than you could shake a stick at. Good food.

Cornbread, too. My Momma always made the best cornbread and beans. Real good! :D
 
Jeff,

Kit uses it before grinding and he's the man.

But don't forget lots of folks use this process after grinding. Including me. It still works just fine, even if the entire blade surface isn't in contact. If you can harden a blade (as many do) taking the time to remove from a packet and place in front of a fan. Flopping that baby directly from the oven on to a sheet of aluminum and sucking the heat out of it will do just fine. I'll bet my blade edge is below the 'nose' in that aluminum sandwhich, before I could can get a packet open.

Steve
 
Press quenching is the only way to go. You can clamp if you want, but, I'm standing on my plates (on a concrete floor) before you've tightened your first clamp and at 220 LB, plus the "jumping" thing I do, I'm putting over 300LB on my blades and have never been able to detect any variation in my blades that would indicate that I wasn't getting optimum contact everywhere. Neither could Crucible when they analyzed my HT'd microstructure!

And flat? Yes, every time, every blade, every day.

Give it a try, it's the best.
 
I forgot to mention that heat treating in my shop is a 2 man operation. I can't remember many times in the last 4.5 years that MikeO wasn't here. We just pick a day when we both have blades to do. Four hands make it happen pretty quick, even with a batch of folder blades.

Am I the only guy crazy enough to grind after heat treat?
 
Kit Carson said:
Am I the only guy crazy enough to grind after heat treat?
Click to expand...

Johnny Stout does it. I do it. Well, I do it mostly when doing folders now. Most of the time now I like a hamon or diff-quench on fixed blades.
 
What I'd like to cobble together is a treadle of some sort to support the plates - lay the blade in, press on the treadle (no hands) and bring the top plate down. Seems to me to be preferable to playing with clamps to get the plates into contact.

2 things I've missed in all of this - if you've foil wrapped the blade, do you bother stripping the foil off before quenching like this? Also, is there much benefit to doing this with the non-stainless steels (other than D2, I guess)?

Peter
 
Forgive my dragging this thread up and reminding you of all that shocking imagery. We're discussing the topic on BritishBlades and this thread was linked to.

mete said:
Thermal conductivity - Iron -.18, Aluminum - .53 . Interesting that you are quenching from a temperature well above the melting point of aluminum [~1000F]!!! The quench rate is definitely faster with aluminum.
Click to expand...

If so, then it's definately a priority to sink the heat away from the contact surface ~ pronto!

mete said:
This will work for any air hardening steel.[like uniform -no warp]
Click to expand...

What about other oil hardening steels like O1, L6, 5160, 52100 and 1090? So you just clamp the hot blade between two large blocks of metal?

mete said:
The quench rate is definitely faster with aluminum. This will work for any air hardening steel. 1" should be enough. Definitely leave the foil on.It saves lots of fumbling and oxide forming while air gets to the hot steel. Clamping is done to insure no insulating gaps between plate/foil/blade. [like uniform -no warp]
Click to expand...

According to a website, there are several materials more conductive than even aluminium, (I'm English, BTW).

Material: Thermal conductivity (W·m-1·K-1)
Diamond: 1000-2600
Silver: 406
Copper: 385
Gold: 320
Aluminium: 205
Brass: 109
Platinum: 70
Steel: 50.2
Lead: 34.7
Mercury: 8.3
Ice 1.6
Water 0.6

For practical reasons, we can obviously exclude diamond, gold and silver, but a block of copper would not be out of the question.

If water cooling was used, then the speed of quenching could be controlled by the speed of water flow through the pipes. Another advantage is that the plates would cool quickly after quenching allowing better production flow of blades through the quench system, as you wouldn't have to wait for the plates to come back down to room temperature.

Ideally, the copper block should not be too thick or you would have less fine control, so you would have a copper plate or thin block with a milled pattern of water channels in it clamped tight to a flat copper plate and edge braised in place. A copper water pipe would be inset and braised onto the water inlet and outlet orifices. I would then attach a set of these plates to each side of a large vise. Rubber tubing would used to convey water from a faucet to the plates and to evacuate the heated water from the block to a bucket below.

There are many possible enhancements. Shaped copper plates could be attached to the plumbed plates to allow differential quenching. Perhaps the edge bevel angle could be accomodated too. Also, a hole for a thermocouple
would be useful.

It sounds very elaborate, but copper is easy to mill. Assuming you had all the copper, tubing and connections to hand, the basic system could be easily be built and running in an afternoon. It'd be cheap too; easily cheaper than a salt bath.
 
thermal conductivity at 20°C, W/(m*°C)
copper = 390
aluminium = 225
iron = 75
magnesium = 155

but then i found another thing, Thermal Capacitivity (heat capacity??)20-100°C, J/(kg*°C)

anyway the figures are
copper 390
aluminium 900
iron 450
magnesium 1050

density:
copper 8,9 kg/dm3
aluminium 2,7
iron 7,9
magnesium 1,7



it might be so that copper can actually store more thermal energy since its heavier but aluminium can get rid of it faster. could be all backwards tho. can anyone verify this?
 
I can't answer the questions about capacity or conductivity, but I too wondered about non-air-hardeneing steels. I know one of the issues is to quench at the proper speed - not necessarily the fastest speed. I had some old bandsaw blade around (L6 I believe) so I made a couple blades for kitchen use. I quenched one in oil and the other was plate quenched. Both read RHC 62 after quenching and both tempered to RHC 60. Now this is very thin steel ~ 1/16 so the results may not apply elsewhere - but it seems to have worked for me so far.

Rob!
 
a milled pair of copper plates set up like a huge water cooled computer cooler
i thought about that when this thread was first started i just didnt have the mill to do it
also i dont think that using tap water would be best a recirculation tank of say antifreeze would be better to keep from a boil off/ blow off inside the plates from happening im not too sure if even with water cooled plates you could get quench speed on par with oil
if it was that fast i think i would have to set one up for the less mess factor
any more input and if it sounds likely to work i have a favor or 2 from a friend in metal shop might have to do some testing
so mete what say you with 2 pumps pushing coolent through 2 copper plates set up in a press do you think i could get the speed i need to do say 3/16 O1
thanks
butch
 
With circulating water you'd never get any steam.Hard to say if you could do O-1 with plates . Maybe one of those that uses plates could do some experiments.
 
thanks mete maybe the only benefit would be getting away with smaller plates since you would not be overloading them with heat
so instead of doing 2 blades and having to wait till the plates cooled to do any more you should be able to keep right on quenching
so just how fast can real quenching oil suck heat out of a blade
thanks
butch
 
I am getting ready to try the aluminum plate set-up in combination with a "Vortec" cold air gun (supposed temp of -40*F using your compressor as the air supply)In Bob Terzoula's book "Tactical Folder" he simply uses a fan while holding ATS34 so that the Fan Blast hits from the edge.(To avoid warpage)(as I'm sure you all know.)I thought of taking this one further by using the plate and cold gun set-up and ironically this thread pops up (great timing)I thought of leaving a little exposed edge for the cold gun blast and now after reading about slotting the plates that might be a better option as far as directing the cold gun blast directly over the edge.Cold gun is on the way and I have a few Blades (4) ATS34 Blades and (3) 154CM Blades that I am going to try and perfect this method on. Thanks guys for the thread ( not the panty hose stuff IG & Dan ) Ah heck , that was fun too. In a sick kinda way :barf: :D
 
RJ,

Sorry if I am being obtuse, but saying "flat" does that mean you do all your HT prior to grinding, thus quenching a perfectly flat piece of steel?

Thanks,

John Frankl
 
mete said:
Steve , the cooling must be uniform, the same on both sides of the blade, no gapes between blade and foil or foil and plate. Clamp it !
Click to expand...

I have always used two heavy flat steel plates salvaged from a press die. About 1 1/2" thick x 6 x 12, or so.

Each piece weighs about 25 pounds, so sandwiching the blade between the two heavy steel plates sucks the heat out and places enough weight on top that no clamps are required. I put the blade on one end and a small piece of material the same thickness as the blade on the other to keep the plates parallel and balanced.

The heavy steel sucks the heat out so fast I can pick the blade up with my bare hands within a minute.

So, guys, the moral of my story is "it ain't gotta be aluminum".;)
 
I use two aluminum plates, 14"X8"X7/8" and have had no problem with quenching ground blades. Try the straight plate quench first, then worry about the fancy additions later if you are not satisfied with the results. I have not done anything but air quenching steels, however. A2, D2 and S30V all quench well this way. I usually quench them down into the Martensite range with the plates and then unwrap them and let them go to room temp in air.

The plates will pull the heat out conductively faster than any cold air gun can possibly affect. Any gas or liquid quench medium will have convective effects at the surface of the heated material, which will slow down the heat transfer. Conduction transfers heat faster by orders of magnitude than convection, period. The ground edge will cool faster through conduction out the flat part of the blade than it will in any convective medium.
 
So Shgeo , Are you essentially saying to use my "Cold Air Gun" on my mill where it was originally engineered to be ? What you are saying makes sense-But-My thoughts were to combine the 2. No ? Still (and always learning here) so all of the posts here are interesting to me.It would seem that "Cold" plates would draw the Heat from the Blade faster "initially" till they too heated up than a set of plates at ambient temp.I hope that you post back an "answer" to this most interesting thread.I am going to do some research today and respond again to your last post.I am currently reading "Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel" by John D. Verhoeven" (Thanks Mete) a very interesting piece of work, and hope to get some answers to Heat Treat Techniques from that too.Thanks everyone!! Thanks for starting it rlinger!:thumbup:
 
If you're going to use cold plates just put them in the refrigerator of freezer.I would like someone to do tests with something like O-1 and see if it would work with plates .Cold plates might work.
 
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