Off Topic Plate quench as an oil alternative?

Justin Schmidt

Justin Schmidt

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Feb 18, 2016
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So I follow a gentleman named Edward Braun aka ALEF forge. He's been testing plate quench as an oil alternative. I thought it was just for hypereuctoid steels but he said it's for everything. Anyway he's been getting some crazy high hardness. 67 from 1095 and about the same out of 52100.
These needed to get tested in a lab obviously and this is just preliminary stuff but I thought it was VERY interesting. What do you think?
 
plate quench is usually for air hardening steels like A2 or D2 or 440C. I have used it successfully with very thin, 1/32", O1 but have not tried on thicker stock. I guess if you had liquid cooled quench plates it might work, but building and maintaining quench plates like that would be a lot more trouble than maintaining a 5 gallon bucket of canola or commercial quench oil. see if he will tell you his HT procedure to get these results, if he says no, trade secret, run away quickly
 
Haha I'm not THAT gullible now Scott. This is a screen shot of one of the posts and he also has a video of the plate quench then another of the actual rc test. I believe he's up at NJSB doin these tests but i could be wrong.

7jycuuw.jpg
 
I have a hard time swallowing that. I have tryied plate quenching thin (.072 & .090) 15n20 and it gets hard but not anywhere near as hard as an oil quench. And 15n20 needs a slower quench then 1095. But that does not mean that he did not stumble apon something unique for what ever steel he is working with.
 
till i see data from a know and respected metallurgist i say snake oil. science must be proven and since i have seen more then once makers not even getting a good quench on air cooled steels anything with a 1 sec nose almost cant possibley work
 
I imagine that if Ed says he's getting those hardness numbers in those steels with that process, he's shooting straight. He's been studying up and practicing knife-related metallurgy pretty hard the last few years, and has been working with suppliers to test steel. As he says there, no claims are made at this point other than rockwell values... more testing will have to follow to determine if it's a suitable method for use with blades.
 
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Salem Straub said:
I imagine that if Ed says he's getting those hardness numbers in those steels with that process, he's shooting straight. He's been studying up and practicing knife-related metallurgy pretty hard the last few years, and has been working with suppliers to test steel. As he says there, no claims are made at this point other than rockwell values... more testing will have to follow to determine if it's a suitable method for use with blades.
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I think that's the key. Ed and I have talked, and I have no doubts he's getting that hardness. However I have my doubts its anything but a party trick. The fact that without growing the grain it hardened to the mid 40s doesn't inspire confidence.
 
In my testing the best performing blades have the finest grain. Grain refining reduces harden-ability. If you have to increase grain size in a steel like 1095 to harden in a plate quench, you might be going in the wrong direction. For me it would be more trouble to plate quench & much easier to just oil quench a blade?
 
for thin O1 blades, 1/16" or less, I have had good luck quench in oil till black then between quench plates to room temperature. i also agree that enlarging the grain with the long soak at 1650* and very long soak at 1480* combined with much higher levels of retained austenite that these temperatures cause will not give best result for a blade.
 
The facts are that quenching speed is always [slow to fast ] air, plate, oil, water , brine. I'd have to dig up the actual numbers . We can cheat a bit by quenching in water for some seconds then finish into oil for example but that takes experimentation and knowledge of metallurgy. We want a good martensite structure without pearlite etc. All things must be considered , grain size especially. For me I don't even like edge quenching .
 
Interested to hear the results of lab tests.

I have successfully plate quenched O1 steel - but only 1/16" thickness. My concern was with warping and de-carb on the thin 1/16" steel. I foil wrapped the blades and folder springs that were profiled only..... blades were not ground so they would have full contact with the plates. They were quenched while still in the foil. The hardened blades tested a pt. or two harder than similar 1/16" oil quenched blades. I broke test pieces to examine the grain and under low magnification it appeared fine and uniform all the way through.

I tested thicker O1 steel by foil wrapping together two pieces of 1/16"precision ground O1 to simulate a 1/8" thickness. After plate quenching, the two outside surfaces that were in contact with the plates were fully hardened, but the two inside surfaces were not.

Saludos

J

JD WARE KNIVES
 
I’ve done oil to black, then plate quenching on thin 15n20 or O1. Similarily, I’ve plate quenched z-wear last the nose than air cooled. The important thing is getting past the nose for optimum structures without creating excessive stress.
 
Willie71 said:
I’ve done oil to black, then plate quenching on thin 15n20 or O1. Similarily, I’ve plate quenched z-wear last the nose than air cooled. The important thing is getting past the nose for optimum structures without creating excessive stress.
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And I really don't know how he's going to get good grain structure from 1095. It's nose is something like 1 sec? I don't see how he is avoiding getting pearlite
 
1095 is a shallow hardening steel, so did the 1095 1/8" thick blade cross section fully hardened? Easy to surface grind and hrc test at 0.04" & 0.06" depths - this test the 'shallow' part. If 0.06" depth read below 63rc(case hardened), then near center/core isn't optimal for edge (maybe ok for single/chisel bevel edge). If 0.06" read 65+rc, slowly bend away from ground surface (stretch core, compress skin) until blade fracture/split. Check for evidence of plastic-flow (stretched/elongated) - if exists, then it has mixed phrase microstructure (pearlite+mart+bainite+etc.), which not optimal(after tempered) for edge tools. If highly intergranular fractured, easy to see fractured-grain size.

MHO - these ^ preliminary tests should be done(a few times) by ht tinkerer before thinking about Lab tests. At any rate, I am interested to see lab data.

*
Quench Your Brain With Heat Conduction Equation
Easy visual: youtube.com/watch?v=NHucpzbD600
Academic: cecs.wright.edu/~sthomas/htchapter02.pdf
*
 
Sounds like the long way around the barn to me. I'll just keep oil quenching and grinding off what little decarb I get. I always surface grind everything anyway. As far as controlling warping, I've done enough blades to know what to do and more importantly what NOT to do. I hardly ever get a warped blade and if I do it is easily fixed during the temper.
 
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