AKS 8670

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AKS 8670

Postby scott.livesey » Sat Jul 15, 2017 3:48 pm

Just bought a couple of pieces to try, some for kitchen utility knives and one cleaver. has anyone else tried this steel? any heat treat tips?
Here is composition:
C: 0.71
Cr: 0.43
Mn: 0.50
Ni: 0.88
Si: 0.28
I was thinking 1550F, soak for 5 to 7 minutes, quench in oil. temper at 300F for utility and 400F for cleaver
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Re: AKS 8670

Postby Stuart Davenport » Sun Jul 16, 2017 1:27 pm

I use it, Scott. Heck, if it's oil quenching I use it! ha ha! Great steel, VERY VERY tough even at 63HRC. Very clean steel, too, works like butter even hard. Sharpens to an excellent edge. Not hardly any wear resistance, obviously, but that's not what this steel is about. Hard and tough...that's this steel's forte.

I do 1525F, 10 minutes, P50 quench with no issues. Leaving edges thick these days now that I have the grinder to thin down post HT, so I haven't had issue using fast oil on this steel.....yet. I'm doing 350F tempers for kitchen knives and hunters both, coming in at ~63HRC. Spec sheet calls for very high austenitizing temps, not sure why, tho. Cr doesn't begin to go into solution until 1650F, IIRC, so I don't get why the recommended high aus temps. I wouldn't go above 1530F on any simple carbon steel anyway, that's just me. No vanadium, so I would keep the aus temps down. Plus, coming from AKS, no normalizing or cycling needed. Austenitize, quench, temper, done.

You'll like that steel. I like that it comes in good thickness...or should I say more properly....good THINNESS. .084" is very handy for most all what I make.
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Re: AKS 8670

Postby scott.livesey » Sun Jul 16, 2017 11:57 pm

thanks Stuart. replied on KD
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Re: AKS 8670

Postby Kevin R. Cashen » Mon Jul 17, 2017 7:32 am

8670, also sold at other outlets as 8670M is a pretty good steel, I have used it in a few projects that would not tolerate all out L6 in the mix. It is sort of like a beefed up 5160. It is, however, an oil hardening steel, which means its cooling curves are not optimally matched with #50 oil which is made to meet the needs of water hardening steels and is overkill on this alloy. Just about any regular (not accelerated) quench oil of the 11 to 15 second range will work very well with this alloy.
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Re: AKS 8670

Postby scott.livesey » Mon Jul 17, 2017 12:15 pm

Kevin R. Cashen wrote:8670, also sold at other outlets as 8670M is a pretty good steel, I have used it in a few projects that would not tolerate all out L6 in the mix. It is sort of like a beefed up 5160. It is, however, an oil hardening steel, which means its cooling curves are not optimally matched with #50 oil which is made to meet the needs of water hardening steels and is overkill on this alloy. Just about any regular (not accelerated) quench oil of the 11 to 15 second range will work very well with this alloy.


thank you Kevin. this is my first use of lower carbon steel and I wanted to get HT temperature right. I guess with carbon at 0.7%, 1500F should be fine. with 0.125" material, will an 8 to 10 minute soak time be enough?
if I decide to sell the finished product, 8670 sounds ordinary, was thinking 72NiCrMo4-2 would sound more exotic to customers.
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Re: AKS 8670

Postby Stuart Davenport » Mon Jul 17, 2017 12:18 pm

Call it "ScottSmelt"
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