Plate Quenching?

[David Loukides]

Hi,
What is Plate Quenching?
Why is it Better for 154cm stainless?
I am going to try this stainless for the first time.What is the standard proceedure in Heat treatment.
Thanks A lot

 

[Stacy E. Apelt - Bladesmith]

Plate quenching is cooling the stainless blade between two thick plates of metal,usually aluminum. It cools the blade rapidly,evenly,and prevents warping.
I will assume you are using a standard heat treating oven (it is about the only way for stainless,other than salt pots),like a Paragon, to do your HT.
Wrap the blade in one layer of plain brown paper.Wrap that in a "packet" of Heat Treating foil,making sure the edges are crimped and sealed air tight. The paper is to burn and remove any oxygen in the packet,thus preventing the blade from decarb.Pre-heat the oven to 1400F and insert the packet.Hold for two hours.Ramp to 1950F and hold for 20-30 minutes. Remove packet,tear open and plate quench blade ( a big vise is a good idea). Cool in the plates until room temperature.Snap temper in an oven at 200 for an hour,cryo at -100F or lower (liquid nitrogen is best) for at least one hour,re-temper at 450F(one to two hours),re-cryo,then one last temper at 450F (one to two hours).That will produce the best you can get from 154CM. If you don't have the liquid nitrogen or other cryo materials available,just go directly to the double temper after cooling the blade.
Stacy

 

[butcher_block]

thats about how i do it also
but i dont use paper in the foil
foil wrap blade put in kiln cold
full ramp 1475 10 min
full ramp to 1975 hold 45 min
pull from kiln and right between the plates i dont take out of the foil till i can handle it by hand
over night in Ln then first temper at 400 2 hours then 2nd temper also at 400 for 2 hours
that has me around 60-61 Rc last time i ran a batch the first batch i did i tempered at 500 and the Rc was a little lower
but all this said everyone does it there own way all take the good info here and use it as a base and work to get what you want out of it
rember also that my 1975 could be the same as stacys 1950 depending on the kiln and how the readings run

 

[David Loukides]

Thanks for the help Guys.:thumbup:
I use a evenheat oven and the high temp foil wrap.
I have the alluminium plate and the vice.
I will have to substitute the liquid nitrogen with dry ice and acitone. I guess I can't have everything.

 

[Rob!]

No Need to be upset about dry ice and acetone. It is at exactly the temperature that crucible specifies for cryo. The reason Liquid nitrogen is preferred is convenience. It can be kept in a dewar for up to two months or so depending on how much it is used. The dry ice will likely be all gone overnight. Take some solace in the safety factor. If you spill a handful of dry ice in your lap, it will start to get cold before too long. If you spill Liquid nitrogen in your lap, your woo-hoo will fall off!

Rob!

 

[David Loukides]

Thanks for the info and the good laugh.
How much acetone do you recomend per block of dry ice?

 

[mete]

Don't bother to take the blade out of the foil to plate quench. Liquid nitrogen gives you -300 F and dry ice/acetone gives you -100 F .

 

[Rob!]

You only need enough acetone that the knife is completely submersed (for better contact). As for the difference in temp, Mete is right but this is from the Crucible website spec sheet on 154CM.

"

Recommended Heat Treat Practice​

To completely transform any retained austenite, a
freezing treatment with dry ice at -100°F (-74°C) is
recommended"....

Dry ice will do just fine - but sooner or later, you'll be looking for a dewar and LN.

Rob!​