Finally ready. Just a few heats treat questions.

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panzerjunky

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Aug 13, 2022
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I realize this stuff has been gone over ad nauseum My simple question is what it actually means.


Normalize at 1550-1650°F for 10-15 minutes and air cool.

Anneal at 1400°F for 30 minutes, cool at 600°F/hr to 1200°F, air cool.

Austenitize at 1525°F for 10-20 minutes depending on stock thickness, quench in oil.

Temper at 300-450°F to desired hardness.


So, Ok my blade is cut out, primary grind done, file work done, Gimping done, holes drilled. ready to heat treat.
I have a brand new never used Even heat Lb 27 this will be the inaugural run.
what do they mean by Anneal is the knife blank already annealed? And where it says Austenitize That is simply running it up to Crit temp soak for 10 to 20 min then pull out and dunk in my parks 50 .Then Do I but it right back in the oven at 400 to 450 for an hour ( some folks say do that twice) or do I air cool it first then put it in the oven at 400 to 450??? the reason I ask that is if my Kiln is at say 1525 it will take a bit to drop ( I am assuming) to 450. Or am I dunking in parks 50 and slamming it in the wife's oven while still hot (she loves that wonder why her cakes taste like oil LOL) or do I have time to cool the kiln?? any clarification or tips would be appreciated.
Thanks Jerry
 
Like Hoss said steel is important.

If you’re forging annealing and grain refinement cycles are more crucial. If you’re looking to get the absolute most out of low alloy carbon steel then a DET anneal might be what you want to do.

So if it needs annealing and grain refinement do that. I like to coat the blade or foil wrap the blade to minimize decarb as much as I can.

Then bring your oven nearly to whatever temp you’re going to austenitize to. A couple hundred degrees before that temp is reached throw your blade in if oil quenching have that blade coated to minimize decarb. After soak and quench you can do a cold treatment if desired just clean the oil off your blade to help keep everything from getting gross.

You want your blade to come down to room temp as fast as you can without cracking the blade so I would say as long as it’s under 300 degrees then you’re fine.

Then I would personally wait for the oven to come back down to tempering temp which is usually several hours. I heat treat at night and temper in the morning. You’re gonna want for do at least 2 tempering cycles usually 2 hours each.

You could always temper 350 then 400 depending on what hardness you’re looking for.

I work with air hardening steels but here is what I do after the quench I unwrap my blades and get them into the liquid nitrogen as fast as I can for at least 30 min. I pull them out let them come back to room temp. In the morning I put them in the cool kiln and I have a slow ramp to bring the first temper to 300 for 2 hours. After the first temper I’ll test HRC and check for straightness. I’ll correct any warps or set up for a shim temper. Usually the shim temper will happen later after tempering all the other blades. I’ll then adjust my tempering temp based on what my HRC values are to try and reach my final target. I’ll temper a second time for 2 hours and check hardness values and might temper a 3rd time if I haven’t achieved my target hardness.
 
Ok, now we know that we are talking about 80CrV2, here is Larrin's recommendations for HT of a stock removal blade in a HT oven. This should work fine with no additional steps:


Stock Removal Blades Heat Treated with a Furnace - KnifeNerds

Austenitize at 1525°F for 10 minutes (longer with stock thicker than 1/8″),
quench in oil. (Parks 50 is good)

Temper at 300-450°F to desired hardness. (400° gives good hardness/toughness balance and 450° gives the best toughness/hardness balance)
 
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Stacy E. Apelt - Bladesmith said:
Ok, now we know that we are talking about 80CrV2, here is Larrin's recommendations for HT of a stock removal blade in a HT oven. This should work fine with no additional steps:


Stock Removal Blades Heat Treated with a Furnace - KnifeNerds

Austenitize at 1525°F for 10 minutes (longer with stock thicker than 1/8″),
quench in oil. (Parks 50 is good)

Temper at 300-450°F to desired hardness. (400° gives good hardness/toughness balance and 450° gives the best toughness/hardness balance)
Click to expand...
what is det anneal and where do I find info on that?
 
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panzerjunky said:
what is det anneal and where do I find info on that?
Click to expand...

D.E.T

"Divorced Eutectoid Transformation"

What is it?

A shortcut to fine sphereodizing the carbides by cooling from Ac1 at the proper cooling rate to allow carbon move from solution in austenite to undissolved carbides rather than nucleating at new sites or phases (pearlite)


This is the best video on 80CRV2 heat treatment.


DET is not required for stock removal 80CRV2 using a Evenheat furnace as explained in the video by Dr Larrin.

The steel is already in the sphereodized annealed condition although it is a coarser sphereodizing which is good for machining.
 
I edited my response now that we know the steel.
DET is not needed for a stock removal blade in 80CrV2 under most situations. The only reason would be if it was suspected to be highly spheroidized, like some NJSB steel. Even then it isn't crucial if Larrin's regimen is followed.

Just a few simple steps and you will have a good blade:

Austenitize at 1525°F for 10-15 minutes

Quench in oil. (Pretty much anything better than canola is good.)

Temper at 400-450°F to desired hardness. (400° gives the best hardness/toughness balance and 450° gives the best toughness/hardness balance)
Do the temper as soon as possible after the quench. I use the kitchen oven when I don't want to use my small HT oven for tempering. Temper twice at 400°F for 1 hour each cycle (2 hours for thicker blades). Cool in running tap water between tempers and at the end.

TIP:
Wash the blades well in soap and hot water to remove the oils and such before tempering in the kitchen oven. It will keep the wife happier. Buying a countertop convection oven is a good idea for the shop to use for tempering.


Additional info:
DET sounds fancy, but it is just a simple and practical method of annealing a blade of carbon steel before HT. It is necessary if the blade has been forged or is highly spheroidized as-received. Most stock removal blades don't need it.
Basically, you heat the blade to 1350°-1400°F and hold it for 30 minutes to an hour. Shut off the oven and let the blade remain for at least four hours, overnight is what most folks do.
 
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a DET step doesn't work by itself for turning coarse sphereodizing into fine sphereodizing.

Normalizing is what's used for breaking up coarse sphereodizing, DET is for fine sphereodizing after normalizing.

Have to go to Acm to fully dissolve coarse Fe3C not just to Ac1 and cool.
 
I was curuios so I ran a coupon of AKS 80CrV2 and one of NJSB 80CrV2. 1525°F austenetizing with 13 minute soak quenched in Parks 50. 2x tempering at 375°F for an hour per cycle.

The AKS sample is 60-61 Rc, heavy on the 61. The NJSB is 58-59 Rc, heavy on the 59.

When I run a batch of NJSB 80CrV2 I will normalize and run a DET cycle.
 
Thank all of you for your patience and advice.
I used to heat treat my 1095 by holding it in my forge till the magnet didn't stick .Dunk in parks 50 then slam it in my wife's oven at 450 for an hour. I am wanting to be a bit more predictable and scientific about this so.
I now have this beautiful Even heat Lb27 and TBH I'm a little intimidated but.... I know me and I'll just run it at yalls direction. I'll let ya know how it turns out. I am waiting for it to come up to 1525 as we speak.
after I'm done, I'll run my RC files and let y'all know where it ended up.
Again, thank you for all your help.
Jerry
 
Have another question?
When I am running up the temp for my Austenetizing Run. Do I put my blade in the kiln and let it slowly heat up with the kiln. Then once it reaches temp and runs its soak time pull out and Quench. Or do we let the kiln heat up them put in the blade. That is the rout I took, and it dropped like 50 deg. I just added a little time, so it was at the right temp the correct amount of time.
Thanks Again
 
panzerjunky said:
Have another question?
When I am running up the temp for my Austenetizing Run. Do I put my blade in the kiln and let it slowly heat up with the kiln. Then once it reaches temp and runs its soak time pull out and Quench. Or do we let the kiln heat up them put in the blade. That is the rout I took, and it dropped like 50 deg. I just added a little time, so it was at the right temp the correct amount of time.
Thanks Again
Click to expand...


Austenitizing* I want you sounding like a pro 🤙


If you're just running a single blade, running a hot furnace is not an issue and helps you control the soaking time better.

Bring the furnace up to the austenitizing temperature and let it equalize when you open the door to place your blade inside and close the door, the temp will drop but it will rebound quickly since the heat is well retained in the bricks.

Once your thermocouple shows the temperature has rebounded, you can start your soak time.


Congratulations on your Even Heat furnace.
Those are my favorite.

Keep up the enthusiasm, you'll be heat treating with the best of them in no time.
 
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