8670 hardeness after quench.

DeadboxHero

DeadboxHero

Knifemaker / Craftsman / Service Provider
Joined
Mar 22, 2014
Messages
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I'm curious from those of you with better equipment and more experience how hard are you guys getting 8670 after quench?

What Aus temp and soak time you guys using?

I've been playing around with some, I like the steel but I'd like to get it harder.

No I don't have any fancy equipment but I can hit the temps I need
 
I get 65 Rc as quenched, no soak time, heated with forge or torch.
Temper at 400 twice for a 60 Rc. They perform very well.
 
Thanks Don, do you need a faster quenchent for this steel? Or does warm canola work?

Are you quenching at orange color or bright red orange?
 
Don, I was looking at the graph on Chuck's website and it says 1600 austenizing tempwill get you like 62 AQ hardness and 400F will give you like 57Rc max. How are you getting that bump in AQ hardness?
 
Speaking of better equipment, does anyone recommend those portable ames hardness testers? I see some floating around on eBay for $300.00 just don't know if they are legit or not.
 
I don’t know about AQ hardness, but I’m austenitizing at 1550f, and tempering at 250f for kitchen knives, and I get Rc63 with this regime.
 
DeadboxHero said:
Speaking of better equipment, does anyone recommend those portable ames hardness testers? I see some floating around on eBay for $300.00 just don't know if they are legit or not.
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I have the same style, but a different brand. They work fine if used right. There’s more room for user error but once you learn the machine, you can get accurate results.
 
Willie71 said:
I don’t know about AQ hardness, but I’m austenitizing at 1550f, and tempering at 250f for kitchen knives, and I get Rc63 with this regime.
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Are you soaking at all Willie or just straight to quench, also what oven and quenchent you using? Do you use any decarb paste on the blade?
 
As a eutectoid steel little soaking is needed. there should be little decarb problem with that short soak.
With a 400F temper HRc 60 is reasonable performance.
Any hardness tester should be used with a test block especially as you learn to use it .
 
jdm61 said:
Don, I was looking at the graph on Chuck's website and it says 1600 austenizing tempwill get you like 62 AQ hardness and 400F will give you like 57Rc max. How are you getting that bump in AQ hardness?
Click to expand...
Different steel I guess. I'm using old saw mill blades, some tested like 8670, but don't test them all. Guess some of these blades are like a 1080 with a bit more alloy. I should have said this in the first post.
 
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Thanks guys, this place is a great resource for guys like me that are on there own.

I know in the past I got my balls busted for asking questions and not having projects that I was working on so before Stacy comes in here :D yes I've got blades to show


Just playing around still nothing exciting.

This is the temp I quench at in warm Canola.
OW1B0yA.png


Draw temper to light straw. Then dunk in tepid water. I repeat that twice.

Slightly under 0.020 behind the edge and 0.090 stock with 15 dps edge.
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This is the test.

nrATRpe.jpg


I beat it through 1/4" aluminum rod to check the stability.

Too soft
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I can pass at 0.023 behind the edge but under 0.020 I get this.

I need more hardeness. But I don't have the money or equipment for other steels now.
That's why I thought to ask so I can save time and materials from trail and erroring every possiblity.

Do you guys think a faster quenchent would help? Brine quench? Thremal cycling? Higher austenizing temperatures? Longer soak at temp? Dry ice alcohol subzero treatment after quench? My mind is racing with possibly but my wallet says no hahaha
 
jdm61 said:
Don, I was looking at the graph on Chuck's website and it says 1600 austenizing tempwill get you like 62 AQ hardness and 400F will give you like 57Rc max. How are you getting that bump in AQ hardness?
Click to expand...

That chart seems off to me based on my experience, which is limited to five blades at this point. Chuck sent me a couple sticks to try out in my last order. He had a video posted with a kitchen knife in 8670 ar Rc63 hammering through brass rods without a problem. I had to temper a bit higher than him to stay at Rc63, which for me was 250f. I like this steel at Rc63 in the kitchen. I sent one blade to an amateur chef who I made a full set of W2 kitchen knives a couple years ago, and he sees no deficits compared to what he’s used to. Might have to sharpen a bit more often than W2, but not by much.

I did a camp knife at Rc60. It’s tough as nails, but the edge holding is just ok. I think it’s much like 15n20, take advantage of the toughness and run it a bit harder than you think you should. I like it above Rc62, but I make finer slicing tools mostly. It’s plenty tough if you need that sort of thing. I suspect this steel is shallow hardening enough to get extra hardness with fast oil. I think some tests are in order, but I’m pretty short on time right now.
 
DeadboxHero said:
I need more hardeness. But I don't have the money or equipment for other steels now.
That's why I thought to ask so I can save time and materials from trail and erroring every possiblity.

Do you guys think a faster quenchent would help? Brine quench? Thremal cycling? Higher austenizing temperatures? Longer soak at temp? Dry ice alcohol subzero treatment after quench? My mind is racing with possibly but my wallet says no hahaha
Click to expand...
Temp in your photo looks good, but photos are not accurate. Might try a tad hotter. Faster quench should help, but brine is risky, maybe not so bad on a blade that small. Subzero will help also. Keep testing.
 
Those austenizing temperatures seem kinda high. Is anyone trying lower temperatures, 1475 to 1525 F or so?
 
me2 said:
Those austenizing temperatures seem kinda high. Is anyone trying lower temperatures, 1475 to 1525 F or so?
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I wanted to experiment with that, but haven’t had the time lately. I went with the low end of the recommended range. I’m curious as to the optimum austenitizing temp.
 
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