80CRV2 Heat Treat help/suggestions

J. Hoffman

Dealer - Purveyor
I just recently got some 80CRV2 and started playing with it. I broke the spine when grinding one knife and just used it as heat treat test. That blade was brought to 1575° with a 10 minute soak, and quenched in Parks 50, tempered at 400° for one cycle and then snapped. I was impressed because the blade almost bent 90° before snapping. The grain was a little courser than I liked, but the Rc was right at 60.

I did some reading and found people are austenizing at 1500° with good results. So I did two more samples. The first one got a thermal cycling treatment. 1600° for two minute soak then 1500°, 1450° and 1400°. It was cooled in vermiculite after each heat. I then austenized two samples, the one that had the cycling and one that did not. I did both at 1500° for 10 minutes with a quench into Parks. I did a 400° temper on both. The non-cycled piece came in at 60 Rc and the other came in at 57 Rc again. Both pieces are very short and I'm having a hard time snapping them to get the grain size. I need a longer lever to snap it. I'm curious as to why the one is so much softer than the other.

Any suggestions would be appreciated.
 
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Did you grind the surface before the hardness check? If not I guess you had some decarbonization on the cycled piece. Also I think you soak to long. I've used some 80CRV2 and I get best results with soaking between 3 and 5 minutes at 1520-1530.
 
The cycling conditioned the carbides for quicker solution on austenitizing, it is pretty much the same treatment I prescribe for folks having trouble getting proper solution in heavily spheroidized steels, particularly with chrome. it is not surprising as I am seeing some awfully high numbers being recommended for the CrV2, for its chemistry. BTW, you are aware that the Parks #50 is made for water hardening steels, and the CrV2 is a deep hardener? IT could very well account for your cracking. You want an 11 to 14 second oil for CrV2.
 
Thanks for the replies. I assumed the crv2 would prefer the faster quench, I'll try again today with the slower oil. Kevin, if the cycling allowed for quicker solution, did that mean the cycled piece soaked too long at 10 minutes? I guess I would assume conditioned carbines would have gotten harder than unconditioned. I've seen some claiming a 30 minute soak which seems way too long.
 
So this morning I redid some pieces. Did an anneal at 1600° then cycles of 1500,1450 and 1400°. I cool in the air instead of vermiculite between cycles. Austenized at 1500° and quenched in 11-second oil. I broke one sample and had great structure, I'm very pleased. Rc out of quench was 61. I was expecting a little higher. I'm doing a snap temper right now at 350°. I'm hoping to end up with 59-60 Rc.

2 Hour temper at 350° gave me a consistent 60 Rc on four different spots. I'm very happy with that. Now to do a blade and sharpen it, and see what kind of performance I can get from it. Thanks for the help.
 
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not sure which steel you ended up with. here is a discussion on HF about heat treating 80CrV2/1080+ from AKS. http://www.hypefreeblades.com/forum/viewtopic.php?f=4&t=640&p=5336&hilit=80crv2#p5336 again, this was 3/32" thick 1080+ from Alpha Knife. heat furnace to 1475F/800C, blade in, once blade is same color as thermocouple, 5 minute soak. quench in 12 second oil, wipe. two 15 minute tempers at 375F with cold water quench in between. Rc62-63. the post has Roman Landes logic for using a short tempering time.
more links to suppliers and information
http://knifedogs.com/showthread.php?34557-80Crv2-and-AlphaKnifeSupply-1080
 
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