80CrV2 HT help

rustyrazor

rustyrazor

Joined
Oct 13, 2011
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I just got my coupons back after heat treating 80CrV2 and it was at best, horrible. Not only did it not get to the hardness i wanted to begin with, it's so inconsistent that i don't rightly know where to start problem solving this, so I'll describe what i'm doing with what equipment and see if one of you guys have any pointers. Note: I didn't get into amazing detail on the temps and whatnot because the pieces were so off that it's rediculous. in one coupon, it was tested in all four corners and it varied from HRC 33 to 45. all four coupons had wildly varying numbers and i'm baffled.

1. heat to critical, hold minimum 10.
2. quench in canola (warmed up with a hot piece of steel)
3. once cooled to bare hand touch, i stuck each one in a snowbank for 5 minutes just to cool them further. (will switch to plates or dry ice in the future)
4. tempered each coupon at a different temperature for 2 hours each x 2... as i intended on using these for testing, obviously this won't be the case.

Possible problems as i see it...
1. my kiln isn't calibrated right? it's new and i have no idea how to confirm if it's reaching the exact temps it's reading. (evenheat with rampmaster)
2. My quench oil isn't appropriate... Canola was recommended. is it good for 80CrV2?
3. My quench tank is too narrow (3' round pipe 18" deep)

These are the theories i have as of now... any help would be awesome.

Royce
 
Jason Fry said:
What's your "critical" temperature?
Click to expand...

Sorry, i'm at work right now so i'm not 100% sure, but it is based on a lot of threads of reputable makers, i'll post when i get home. I am pretty sure it's someting else i'm doing wrong unless the thermocoupler is not calibrated right on the oven. i keep thinking the tank needs to be bigger to allow room for the oil to move and dissipate heat better.
 
Decarb could definitely be an issue... i simply ground them "shiny" after i did the HT and sent them off to get tested. I'll put up the entire recipe when i get home. Apologies for not having all the info available. just thought someone might find a glaring issue with some of the things i thought could be the problem.
 
Too low aus temp or not fast enough quench. Too low aus temp sometimes caused by not enough soak time.

Hoss
 
Unless I'm mistaken, 80CrV2 doesn't require a fast quench, so I would think canola (which is pretty fast), even in a small container, would quench the steel rapidly enough. A fast quench steel, maybe not.

So I would guess this is either a temp or soak time problem.


Is it common to freeze 80CrV2 prior to the first temper? On many carbon steels it is advised to get them in the tempering oven while they are still warm to the touch.
 
Sometimes a slow quench is caused by to slow into the oil, too great a distance between the furnace and the quench.

According the the hrc, it is pearlite or badly under hardened.

Hoss
 
DevinT said:
Sometimes a slow quench is caused by to slow into the oil, too great a distance between the furnace and the quench.

According the the hrc, it is pearlite or badly under hardened.

Hoss
Click to expand...

it might be the temp... i know i'm quenching fast enough. it's in the canola literally within two seconds. the tank is set three feet away at a 90 deg to my right so i don't mess that up, lol it might be the only part i haven't messed up. i had a rush job last night as one of the military guys had to have his knife today to put in his kit to go away so that took my time up and i didn't get into the HT books to see the recipe. MY assumption is that if the aus temp wasn't high enough, i would get consistently low numbers though right? not HRC 33-47 in the same 2'' x 3" piece as i've got on my garbage coupons.
 
I know Karl, sorry... the four test coupons were split into two groups. two were Aus @ 1475 and the other two were 1500. the two at 1500 fared better but they still had variations in them in the readings of all four corners. the best one turned out at HRC54/56 with one corner getting 56 and the other three all getting 54. the worst one was 1475 tempered at 400, it varied from 33 at one corner to 50 at another... that's why i am baffled at it. if it was consistently horrible at least it would make sense, but with that much variation i figured it might be something massively wrong with one of my steps. that is what made me think it was my small quench tank causing too many gas pockets in the oil, or the wrong oil. if my temp was too low, wouldn't that just make the entire piece uniformly too soft|?
 
Are you sure it's 80crv2 and not 52100? If it isn't decarb, those results sound like 52100 that wasn't normalized.
 
Aldo's 80CRV2 came spheroidized which austenitizing temp wouldn't be enough to dissolve most carbon.

Try 1650F with 10+ minute soak before your regular normalizing cycle might help.
 
A couple of thoughts...
Not enough soak or time to come up to temp could produce results like that.

One time I got some 1084 from a well known guy that was so spheriodized that you had to take it up to 1600 or so and normalize before it would harden right at 1500 like it should.

Edit... the guy above me mentioned the spheriodization thing being in play with the 80CRV2. I'm guessing that's it.
 
Because I don't want to go chasing HT failure demons, and I'm sure you don't either, it would be best to do full normalization on these steels, every time......

1075, 80CrV2 (1080+), 1080, 1084, 1095, W2, 52100, and I'm going to throw in the 8670, even though I haven't tried that steel. There is no need to do it on O1. Or Cru Forge V, for that matter. CFV comes (came...no longer available) completely ready to harden, there is no need to normalize or cycle it if you're just stock removal. Most of us do normalize it anyway, just for that added peace of mind.
 
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ok.. i'll look it up. anyone have a recipe that has worked for them that i can take a shot at?
 
This will work quite well for many of the carbon steels....
To normalize, warm kiln to 1650f, once at temp, insert blade and soak for 20 minutes up to 30 if you like. Air cool to black heat or room temp.
Do this again, at a lower temp, 1550f
Do this again, at a lower temp, 1450f
Do this again, at a lower temp, 1350f
Now you're ready to harden, warm kiln to 1475f, once at temp, insert blade and soak for 20 minutes, quench in 130f canola oil or fast commercial oil. (since 80CrV2 is basically at the eutectoid point, you can use 1500f and a shorter soak, like 10 minutes. Use a soak regardless of the temp you choose, to help alloys come into solution).
Temper at 400f, twice, at least an hour each time, for around 61HRC.
 
Thanks chief... i'll try that before my next coupons. i'm hoping i get this right before i go broke or run out of steel, lol. nothing to kick you in the ego better than a complete failure or two here and there.

p.s. yep, Warren, it's definitely 80CrV2... i've never used 52100 and those coupons were right out of the box. i mark every piece of steel the entire length of it nowadays because of the possibility of mixing steel years ago.
 
If the steel is ID correctly, and the temps in your kiln are accurate, and you're STILL getting soft readings, make sure the decarb layer has been thoroughly removed. If you're not protecting the blade with some sort of anti-scale/anti-decarb, or running in a purged atmosphere etc, the decarb will need to be sanded thru before taking readings. The decarb layer can be thick. High temps, and long times at temp, contribute to decarb layer thickness.
 
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