PDA

View Full Version : Chilling Plates



Lerch
09-01-2011, 08:38 PM
Hi all

When plate quenching stainless steel is there any benefit to chilling the aluminum plates in a fridge before you quench the steel? I have done this some times and sometimes not, i thought maybe it would help when doing 2 or 3 blades on one set of large blocks

just wanted to know if there was a pro or con to this or if it is pointless

thanks
steve

Knifemaker.ca
09-01-2011, 09:43 PM
I don't think it benefits or harms the quench. It may allow more quenches before the plates get too hot to handle. I have cooled off plates in a snowbank between quenches. Similar idea.

Justin King
09-02-2011, 07:24 AM
I have used chilled/frozen plates to accelerate the quench when HTing 3v, it does not seem to reach full hardness with a standard plate quench unless the stock is very thin. Still comes out about a half a point harder when I send them to Peter's.

Dan Pierson
09-02-2011, 07:58 AM
I find it unlikely that cooling plates from, say 60-80 F (room temp) to below 32 F will
make much difference to steel at something like 1800 F, especially given that the
critical temperature you have to get the still passed is around 800-1000 F. Maybe
I'm wrong, but the difference in plate temp just doesn't seem very significant in
this scale of things.

Cooling plates in between quenches is clearly a different matter because they're
going to be warmer then.

Note that this isn't the same question as warming quenching oil because the warming
reduces the viscosity of the oil and makes it work better.

Lerch
09-02-2011, 02:54 PM
Ya i didnt figure in the scheme of things a 20deg plate would have much effect on a 1950deg blade so i figured it was probably a waste anyway,

just thought i would ask, i guess i was probably more worried it could have some kind of detrimental effect

thanks
steve

scherar
09-02-2011, 03:19 PM
I put mine in the chest freezer for about an hour beforehand, but I have no proof that it makes it better or more effective. I started doing this because I had a couple instances where one of two/three blades didn't come out fully hardened after the quench. I seem to have better luck now that I am freezing them a little now. Why or how, I don't know. It is just working for me. If you are getting good results without doing it, I would continue with what you are doing.

ArtinNC
09-17-2011, 02:03 PM
I have thought about using a fish tank pump and running water through the plates. But I do have another set of plates that I use when the first plates get warm. Here is my setup.
http://img.photobucket.com/albums/v643/ArtinNC/100_1356.jpg

franklin
09-18-2011, 06:37 AM
sweet art,im trying to do the same thing but cant seem to find a vice, what kind is yours?

ArtinNC
09-18-2011, 08:28 AM
I got the quick release wood working vice from Harbor Fright. I like the quick release.

Lerch
09-18-2011, 10:18 PM
Well I dont have anything as elaborate as your vise, what i have been doing is chilling the plates in my freezer from when i start the oven to heat treat. Place the blades down on the plates and then typically i stand on the plates in my drive way so he south or north wind can blow a little between them. As long as the blades arent overly large ( 8" or under) i can usually hand hold the blades by the 2 minute mark.

If anyone thinks this is not enough please let me know what else i can do

thanks
steve

Knifemaker.ca
09-19-2011, 07:27 AM
What you are doing is pretty close to what we do here. We use heavy plastic clamps instead of standing on them and our wind is generally east west - but that doesn't matter cause the shop door is closed. :-)

The vice thing is really cool, but our pates are 1 ft x 2 ft, so I think I'd have to design a hydraulic damper to handle the weight. Too much tinkerin'..... :-)

Your process is also the same as what we do here. The only ones that get triple temper are ones that the manufacturer specifies it (like CPM3V) or if a maker specifically asks for a third temper.

Sounds like you've got it nailed Steve.

Lerch
09-19-2011, 11:58 AM
I guess i will just keep on keeping on then, thanks!!

steve

Lerch
09-19-2011, 11:58 AM
I guess i will just keep on keeping on then, thanks!!

steve

ArtinNC
09-19-2011, 07:21 PM
Well that is one way to do it. I think that is enough pressure, but I don't to stand there for two minutes. With my vice I don't tighten it with a lot of pressure just enough for ssolid contact.

Lerch
09-19-2011, 09:58 PM
well my first thought was to place a 45lb bench press weight on the plate to add some weight but i figured iron on top would only add to any heat storage. in all honesty i think the weight of the plates is more than likely enough to ensure and rigidity of the foil is compressed down into the plate but i thought the added weight of my 200lb butt might help to flatten out any possible bend in some of the thinner blades i have done but straightness would only be limited to thickness of the spine so that idea was out anyway.

steve

ArtinNC
09-20-2011, 08:25 AM
The solid contact on the blade will help remove the heat from the blade faster. That is why you want some wieght on it.

Scott Kauffman
03-04-2014, 06:27 PM
the photo is not showing for me. any way you can show a new Pic of your set up?

rhinoknives
03-04-2014, 06:56 PM
I have no idea about the original question but I can share that there are many inexpensive post surgery pumps on the market for chilling things down.
http://www.ebay.com/itm/Aqua-Relief-System-ARS-2000D-Hot-Cold-Therapy-Pump-With-Pad-Instructions/111289898032?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%2 6asc%3D163%26meid%3D5259965219583526684%26pid%3D10 0005%26prg%3D1088%26rk%3D1%26rkt%3D4%26sd%3D251464 376325%26

scott.livesey
03-05-2014, 08:56 AM
I have no idea about the original question but I can share that there are many inexpensive post surgery pumps on the market for chilling things down.
http://www.ebay.com/itm/Aqua-Relief-System-ARS-2000D-Hot-Cold-Therapy-Pump-With-Pad-Instructions/111289898032?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%2 6asc%3D163%26meid%3D5259965219583526684%26pid%3D10 0005%26prg%3D1088%26rk%3D1%26rkt%3D4%26sd%3D251464 376325%26

but only if you have your cutting done at a high class place. when my knee was done by Duke, got a nice one that plugs in the wall. when other knee was done by UNC, got a cheapy you have to pump by hand. guess that is why Duke won't take my current heath insurance. lol.

Freds Edge
03-05-2014, 09:50 AM
I got my plates from the local scrap yard , what I bought was a piece of bar stock 4' x 3.5'' x 3.5'',cut it in 1/2 and now have 2 plates each 2' x3.5'' x 3.5''.They act as one heck of a heat sink.

tomwatson
03-08-2014, 06:30 PM
Sorry to be a rock in the road, but all you think is happening with cold plates is not happening. I've been heat treating over 26 years with all types of metal and after several trips to college in Michigan on metallurgy, welding, and being a x-ray welder for 40 years, there is a lot for you to learn. In air hardened metals you get some benefit from plate quenching, maybe 1/2 to 1 point of hardness. I do it because it speeds up the quench over still air and allows me to get on with tempering. Plate quenching came about because machinists were having to make parts that were getting thinner and thinner. Plate quenching helped to keep the parts flat. Here are a few other things you don''t have to do.

1. Don't use a hammer to seal the seams if using SS tool wrap. A wood roller is made just for this. Closing the seams with a hammer can crack a seam inside where you don't see it.

2. You don't have to put a piece of paper in the bag to burn up the oxygen. Nor do you have to put a hole in the bag to do the same. You can ask the big heat treaters and they will tell you the same. When the oven begins to heat up, the foil being as thin as it is, absorbs the heat first and the O2 bonds with the 309 foil and becomes inert. This leaves the majority of the air in the bag as nitrogen which is a totally inert gas. The other gases left are very minor.

3. You do not have to put anything on the blades while they are inside the bag. If your blades are sticking to the bag, then you have had an overheat or you have been at holding temp with the wrong type of material.

4. You can quench the blades right in the bag using quench plates.

There are a lot of other things I could tell you, but I'm tired. Respond if you wish, but be nice to me.

KenH
03-08-2014, 07:24 PM
Well Tom, I don't see why anyone wouldn't be anything but nice to you. All your points are well taken, and pretty much what I've learned in my meager short time reading/learning about HT'ing. I hadn't thought about the O2 bonding with the SS foil, but have used a tad of paper, but most of time I don't and can't tell any real difference..... Other than brown paper makes the steel black.

Please feel free to share more knowledge,

Ken H>

tomwatson
03-08-2014, 07:52 PM
I will continue to share especially on heat treating. I am not trying to do anything but educate. I try to be as funny as a 67 year old man can be. Anyway, we all play with sharp and hot things. If I can find the time I will write a small treatise on steel aging.

KenH
03-08-2014, 09:07 PM
Well Tom, I guess us 67 yr old men gotta hang together:) Steel aging? That sounds intriguing - looking forward to it.

Ken H>