Need advice on heat treating 80CRV2

Taz said:
I did normalizing, grain refinement and a DET on 1/8" 80CRV2 that was around .135" thick. But the time I ground the decarb off, it was down to around .095" thick! YIKES. I learned to put the blades into a foil pouch for the cycles, then use ATP641 for the austentizing/quenching to not have to worry about decarb and scale!
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Yes, I noticed a lot of decarb, too. I am planning on purchasing foil soon! I quench mine at full thickness and grind bevels afterwards for that reason!
 
Cypress Creek Knives said:
I highly recommend a hardness tester. Without it, you never know how hard your steel is and you can't be sure of your HT protocols.

I'm a few hours away from you but I have an old Wilson hardness tester that I'm not using anymore. It's yours if you want to make the drive, though you will need to make a weight stack for it.
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Thanks, you guys have convinced me to get a hardness tester. I was able to pay off my kiln so I can start saving for a tester!
That is incredibly kind! I'm in northeast Ohio. Where are you located? I'm not sure if you're actively trying to unload it, but my family will be traveling in June on a big trip out west. If you're that direction I bet my family would make a stop to visit you and get it. I don't know anything about weight stacks. I'll do some research!
 
Thescrawnylumberjack said:
I’ve used the house made blade racks and they certainly impact heat treat. I ran coupons to confirm.
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I'm glad I'm not the only one who noticed this. I used a magnet to see when the blade transformed to nonmagnetic austenite compared to the handle (which was not in the rack). The blades in the rack took 5 minutes compared to the handle which was only 2 minutes. Not a huge difference, but still enough that I'm giving it more time to heat up.
 
Was the rack fully heated when the blades went into it? I would think if is was heated fully to the same temp as the kiln before blades were put in, it wouldn't have much effect? Or are the blades cooling the rack down when they go in, slowing the heating process?
 
I know this sounds somewhat elitist, but I feel a minimum size quench tank should hold 5 gallons of oil and have at least 4" clearance all around the blade.

Of course, smaller tanks will work, but for absolute consistent quenches of blades, this is the gold standard.
I use my parks at whatever the temperature it is outside. Normally, that is between 50 and 90. If it is winter and 35°F outside, then I warm it with a large block of steel welded on the end of a 48" length of 1/2" rod. It was Bill Moran's quench warmer. I stick it in the forge and get it red, then quench and stir. One or two quenches gets the oil above 50°F.

A 24X8" round tank woks perfect for most of us.
In a modern production knife shop, 10 to 30 gallons is used in large vats that look like large fry vats from a fast-food place. Many pros use a surplus fry vat.

Quench tanks can be easy to find/make.
I don't use it often but have a 1/4" thick aluminum 30-gallon pot with lid, left over from my cooking days. I put it on a turkey fryer base and fill it with quench oil. Easy warm up if needed, plenty of volume and thermal mass. for everything but a sword.
For swords, I cut the top off an old size 50 oxygen tank to make an 8" wide tank that is 48" tall. I welded it to a 24" metal plate for stability. It holds 10 gallons.
Cut off gas cylinders are cheap or free and make perfect quench tanks.
 
I have a local machine shop I scrounge through to look for quench tank possibilities and look for cut off gas cylinders at work. The 6" x 24" I use for AAA works pretty well, but after a few knives in the summer, it gets pretty warm. Plus with my new oven that I can fit a 27" blade into, I want to be able to oil quench something that long. I already have 30" x 4" x 1" aluminum quench plates :)
 
Yeah, I am looking for old gas tanks like the size 50 you mentioned. No plans to make anything oil hardening that big...yet! When I agitate a 14 or 16" OAL blade in my current tanks, I can hit the bottom if not careful! I have a harbor Freight Dolly to mount the new tanks on as well to make moving them around easier.
 
Heh, tempting! I work at a College and they get rid of old tanks frequently. Going to ask the guy who does that to save a couple for me when they go through and get rid of the old ones! That's how I snagged my 18L Wharton Taylor XT18 Nitrogen Dewar; it was in a dumpster. Just needed the foam core plug
:)
 
Keanen said:
Thanks, you guys have convinced me to get a hardness tester. I was able to pay off my kiln so I can start saving for a tester!
That is incredibly kind! I'm in northeast Ohio. Where are you located? I'm not sure if you're actively trying to unload it, but my family will be traveling in June on a big trip out west. If you're that direction I bet my family would make a stop to visit you and get it. I don't know anything about weight stacks. I'll do some research!
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I'm likely a bit out of the way. I'm in central IL. I am trying to move it asap as I need to free up some space in the shop, and it sounds like a couple other guys are interested in it as well. I'd recommend checking facebook marketplace. You can find a nice old Wilson for not too much money
 
Yeah, I picked up a Wilson 1JR for $325 last winter on Fb marketplace! $23 cheap indenter, some tuning and it's dead on. Got a few anvils and test blocks with it, too! Look for ones that have the entire weight stack, or make your own "stack" and hanger. Indenters are easy to pick up, too. Amazon and Ebay have them all over.

I have scans of several older manuals that talk about the calibration/adjustments to make, too!
 
Taz said:
Was the rack fully heated when the blades went into it? I would think if is was heated fully to the same temp as the kiln before blades were put in, it wouldn't have much effect? Or are the blades cooling the rack down when they go in, slowing the heating process?
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Brought to temp with the oven. It was impacting my results about 2 hrc which too much when running high hardness heat treats
 
Oh wow! I was surprised it would have any effect, especially when it's already pre-soaked.
 
I can't see the rack affecting hardness either. Was the timing of the soak started when you put the blades in or when the oven rebounded to target temp?
 
Stacy E. Apelt - Bladesmith said:
I can't see the rack affecting hardness either. Was the timing of the soak started when you put the blades in or when the oven rebounded to target temp?
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Time starts when the oven rebounds after putting the blades in. I also didn’t think it would affect anything. However, when I switched back to the even heat fixture my coupons were on target again.
 
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