Soak temp and time for 52100 and 5160?

B

B.V.

Joined
Dec 27, 2007
Messages
194
I just heat treated 3 blades (2 of 52100 and 1 of 5160) and soaked them at 1515 Deg. for 15 min. 2 times each. Will that do, or did I miss the mark somewhere?

Brad
 
I quenched them in ATF (I know but thats what I have) and then tempered them 3X at 400 for 2 hrs each time, cooling in between.

When I opened the Evenheat....I could see the recalesence/decalesence on the blades. Later I began to wonder if I should have been a little hotter to get above it?
 
man I need an even heat

and some pizza

pizza would be sweet right now

errrrr

'ahh

anywho


52100
Hardening: Austenitize from 1475°F to 1550 °F soak for 5 minutes or so (still wondering through alot of posts on this one)

5160
Hardening: Austenitize at 1525 soak for 10 minutes
 
Thanks Karl and Dave! The thing that threw me for the loop was seeing the flicker in the steel. Looks like I'm good then.

Yeah, I wish I had and oven of my own. It belongs to Rob Thomas...he is a good friend of mine. It is very nice to work with....less guessing.

And pizza does sound good!!

Brad
 
having a ez-bake knife oven is great and it really lets you get the HT you want

start with close to known HT and work it into what works best for you after all all kilns will read temps a bit different (when you change temp probes its changed too)
 
Seems to me 400 is too low for 52100, and too high for 5160. Did you take hardness readings from the blades?
 
Thanks for all the help guys.

I don't have the ability to get a hardness reading. I got the 400 from a google search but it was already my target temp from Mr. Fowlers research. However...I may go a bit higher since a file will barely cut into it still. Maybe my little oven thermometer is off a little.

I haven't tempered the 5160 blade yet though. It appears I may need to heat treat it again to got it a little hotter prior to quenching. I plan to temper it at 350.

Brad
 
if you have a tool and die shop near you you may be able to get some blades tested for a few bucks. it can be a big help
 
Hey Butch! Good to hear from you again. I just realized it was you....I will look into that. Thanks for the input...I wouldn't have thought of doing that.
 
BV: just a suggestion, try the edge flex on a steel or brass rod, if the edge chips you need to temper higher. A 15 degree increase in tempering temp can result in dramatic results.
 
Ed i have made razors that were tested at 64RC that had no problem flexing at the edge more then .030 with ought chipping out

i can also take a new file and grind an edge on it and have it not flex at all and not chip out ether

as much as i hate the "file skate test" it tells you more about the steels hardness then the edge flex does
 
Yes: but how does it cut? While RC and cut are correleatred high positive, - Not always.
the more tests you do, the more you can learn.
 
Ed Fowler said:
Yes: but how does it cut? While RC and cut are correleatred high positive, - Not always.
the more tests you do, the more you can learn.
Click to expand...

more tests sure Ed but the brass rod is more for geometry of the edge the poster is asking about HT and soak times not "how it will cut" he will grind the edge to fit the use of the blade (be it chopper rope cutter or shaver )

the key to it all is getting the HT right
is the same hardness for a kitchen knife the same as a chopper, no but if you get a good soak at the proper temp and a proper quench for the steel being used you can slowly narrow your temper temp to that that is fitting to your intended use

this is why kilns are great for getting the most out of your steel (even if you insist on multi quenching your steel) you can pick your temps and ajust from there
 
Why do you want the file to be able to cut the steel?
It should skate before the temper, and kinda want to bite, but not quite after temper for best edge holding. A very light bite for a chopper.

Mike
Maker
The Loveless Connection Knives
 
My suggestion is that RC is not always the best index for cut. I have seen a blade that tested RC 58 - 59 out cut a blade that tested RC 61 -62.

RC is but one tool or variable we can measure.

What I don't like about kilns is that it is hard to keep from hardening the tang. One very early rule I learned is that I should never harden the tang, I tried to temper back tangs that had been hardened and have never achieved the toughness of one that was not hardened. Just my experience, everyone is free to do as they wish. When using a torch you do not get the tang hot enough that it has the ability to harden.

I fully agree about getting the heat treat right.
 
With all due respect Ed, How can you possibly get a consistent soak at a consistent temperature with a torch? I can see if it is all someone has doing a simple steel like 1084 with a torch, but a more complex alloy that needs a soak at temperature really wants an even heat at a temperature that will get things appropriately into solution without inducing grain growth and carbide growth

-Page
 
Keeping in line with the question you asked:
One of the fine ingredients of cut and all around performance is fine grain.
From the first heat all forging thermal cycles are no hotter than 1625 f. Multiple thermal cycles and low temp forging (5160 and 52100) starting with large round bars allow a large degree of reduction by forging and sets the table for fine grain.

The finer the grain is, the lower the temperature at which it can grow.
Thus our desire to keep time above critical at a minimum.

Multiple quench cycles using a torch to heat the bottom third of the blade to just above critical can achieve a complete transformation to martensite with out long soak times, Rex has found no measurable retained austenite in the hardened portion of our blades so we know it works.

From an annealing temperature of 988 f. (3 heats) we know the tang is as tough and strong as it needs to be. The tang is never heated to critical temp during the hardening cycles, thus it remains strong and tough. Never have we had a tang break, we can drill them, cut them with a hack saw just like mild steel. This is important to us.

Thus preserving the fine grain we have been working for. Bill Moran taught me how to harden a blade with a torch, I practiced for months with a torch and mild steel developing my ability to harden with a torch.

The lab Rex works in just did an experiment using multiple quench to increase the toughness of some steel they were working with. It was very interesting, the cycles down through critical were timed,
first quench - 15 seconds
second quench - 7 seconds
third quench - 2 seconds.
Increase in strength, 20,000 psi.

Just another little experiment on multiple quench and a chance to watch a variable we had not been able to study before.

Heat control with a torch can be learned it just takes time, a student at present seminar just hardened his first 6 blades for the first time, he is learning fast.

Never apologise for asking questions.
 
for those keeping up with all this i need to add i cant HT with a torch worth a dam but i can edge quench a a blade from a kiln in oil and keep the tang out of the quenchant (if thats what i wanted in a blade ) to keep the tang soft

all the while i can scientifically monitor the temp i quenched the steel from and not by eye
 
Ed Fowler said:
Keeping in line with the question you asked:
One of the fine ingredients of cut and all around performance is fine grain.
From the first heat all forging thermal cycles are no hotter than 1625 f. Multiple thermal cycles and low temp forging (5160 and 52100) starting with large round bars allow a large degree of reduction by forging and sets the table for fine grain.
Click to expand...

What is the grain size after forging and before normalizing, annealing, or hardening? What is the mechanism that allows finer grain to cut better/longer?
 
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