8670 from AKS

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shqxk

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I have bought over 30 pieces for this steel from AKS in the past several months and have been using several range of heat treatment. From the reccomended 1500F to 1550F but none of these temp get the me the edge durability I expected so I tried austenitizing at 1600F and it definitely provides the best performance. I have sold several bar to others knifemakers and they all have the same experience as me that 1500F is too low and 1600F gave much better result.
 
Did you normalize it by cycling down first? It may be spheroidized as-received.
 
If you look at the AKS website they recommend an aus temp of 1600 so you're results make sense.
 
When I ran coupons on AKS 8670 I settled on 1525 with a 15 minute soak to get the AQ hard hardness to where I felt it needed to be. This was with an older batch of 8670 so potentially different results.

I perosnaly find low alloy oil quench steels to be a pain as they seem to vary enough from melt to melt to make a difference in how I heat treat so now I make sure to buy a bunch of steel at once and run coupons for each steel order.
 
Is there a difference from the material from Pops?

I use both suppliers, and was thinking of trying this steel soon.
I'd like to know what to tell the heat treaters? Depending on where I order

Thanks
 
Check out ..8670 heat treat coupon results.. thread by Willie71. 2018 thread that lists good tests for this steel. Looks like he spent a good deal if time and effort in playing to get those results
 
Crag the Brewer said:
Is there a difference from the material from Pops?

I use both suppliers, and was thinking of trying this steel soon.
I'd like to know what to tell the heat treaters? Depending on where I order

Thanks
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AKS is a European steel source and Pops is USA sourced. From Larrin's testing the AKS version might have higher impact toughness.

From talking to a Swiss maker he contends he has often seen European steels being tougher compared their US equivalent.

My last 8670 purchase was from Pop's as it is one of the cheapest steels but I have yet delved into running coupons.
 
In mine and Warren’s testing 1525F was more than enough for full hardness. So I would be looking at other issues in your process.
 
There is only ~0.4% chromium in 8670. There is no need for a 1600°F austenitizing temperature. I tried some of the first 8670 when AKS received it, and found 1525°F to be the sweet spot. Hardened as received, no normalizing or cycling.
 
shqxk said:
I have bought over 30 pieces for this steel from AKS in the past several months and have been using several range of heat treatment. From the reccomended 1500F to 1550F but none of these temp get the me the edge durability I expected so I tried austenitizing at 1600F and it definitely provides the best performance. I have sold several bar to others knifemakers and they all have the same experience as me that 1500F is too low and 1600F gave much better result.
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"Edge durability I expected"
"Definitely provides the best performance"
"Gave a better result"

How are we supposed to know what any of that means?

With there being so much scatter in people's anecdotal experiences is there anything in empirical we can observe to get an idea of what you are drawing these conclusions from?
 
I don't have scientific test to provide since this are based on my own experience and reports from other makers who use this steel which I think it might benefit who having the similar issue (1500F range doesn't get as hard as expected) with this steel.

The HT recipe are pretty much the same, 1600F normalize, 1450F grain refinement and 1200F temper annealing.

Most of the test are done by cutting some hard wood, bone or bamboo which you can watch it here but all the video are in Thai tho.

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shqxk said:
I don't have scientific test to provide since this are based on my own experience and reports from other makers who use this steel which I think it might benefit who having the similar issue (1500F range doesn't get as hard as expected) with this steel.

The HT recipe are pretty much the same, 1600F normalize, 1450F grain refinement and 1200F temper annealing.

Most of the test are done by cutting some hard wood, bone or bamboo which you can watch it here but all the video are in Thai tho.

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It would make this thread more interesting if you complied the pictures/videos to show more what you're asking. It would be more engaging for discussion.

We (the audience) would be able to see empirically if the cause for the concern is temperature related or just a goofy, poor test.

8DyMUJ3.png
 
DeadboxHero said:
It would make this thread more interesting if you complied the pictures/videos to show more what you're asking. It would be more engaging for discussion.

We (the audience) would be able to see empirically if the cause for the concern is temperature related or just a goofy, poor test.

8DyMUJ3.png
Click to expand...

There are like 5 makers who did some testing on this steel and all of them have digital control gas oven and low temperature salt bath (for tempering) they are also very familair with steel like SUJ2 (52100) or K460 (O1) and 4 of them said it doesn't get as hard as expected with 1500F austenitizing or at least it's noticable softer compare to 52100 which is kinda weird result. So I tell them to use the temperature AKS suggest in their site and the got much better result with 1600F austenitizing. I will have some coupons for HRC test very soon.
 
DeadboxHero said:
It would make this thread more interesting if you complied the pictures/videos to show more what you're asking. It would be more engaging for discussion.

We (the audience) would be able to see empirically if the cause for the concern is temperature related or just a goofy, poor test.

8DyMUJ3.png
Click to expand...

If the heat treat recipe numbers that I gave above seems off and can be the cause of this problem feel free to lets me know.
 
shqxk said:
There are like 5 makers who did some testing on this steel and all of them have digital control gas oven and low temperature salt bath (for tempering) they are also very familair with steel like SUJ2 (52100) or K460 (O1) and 4 of them said it doesn't get as hard as expected with 1500F austenitizing or at least it's noticable softer compare to 52100 which is kinda weird result. So I tell them to use the temperature AKS suggest in their site and the got much better result with 1600F austenitizing. I will have some coupons for HRC test very soon.
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Keep in mind that tempering temp will vary between 8670 and 52100, if you tempered both steels at the same temp 52100 will be a point or two harder. I heat treat 8670 at 1525F and temper at 350F for 62rc
 
Johnson-Mehl said:
If you want the data me and Larrin can get from JMatPro 7 - it's called ask. I believe you know who I am. I'll spend the time with you - he won't. (He can't, in his defense.)

If not my contact information is jason@veraxknives.com or +4127268610, please don't contact me unless you are seriously interested in learning immense amounts of information in physics chemistry and mathematics as most people do.
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Jason... you'd probably be taken seriously if you weren't such a cunt.
 
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