New Discoveries found in 8Cr13MoV testing
- Deadboxhero
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New Discoveries found in 8Cr13MoV testing
Dr Larrin did some extensive testing on 8Cr13MoV which helps put this budget material into perspective in its capabilities compared to other materials.
While there was lots of talk about real world testing being more important than controlled testing. There was something very fascinating that occurred with controlled testing that could only be ruled out with good control.
In the video at 17:27.
The harder HRC steel surprisingly had lower total cards cut in millimeters compared to the softer HRC steel.
61.0rc 395mm*
62.5rc 376mm
Both the hardness and CATRA testing are averaged from multiple tests.
A higher TCC in mm translates to higher slicing edge retention.
How is this possible?
It seems the 61.0rc condition had more carbide banding.
In the community sharpening thread, It was observed that cast ingot steels will have more carbide banding at the edge bevel itself which translates to areas of low carbide volume and high carbide volume in longitudinal bands which can terminate at the apex.
Image of 10Cr15CoMoV Chinese equivalent to VG10, large longitudinal bands of carbides moving parallel along the edge bevel.
So technically, we could have different amounts of wear and toughness at the edge itself especially since the actual apex is such a small cross-section.
While there wasn't any testing to look at this behavior before, now we have this 8CR13MOV testing and we got to see the behavior show itself and even overtake the higher HRC condition.
This information is quite thought provoking and really shows another previously hidden variable to be accounted for that can even show in real world testing and the importance of averages for making definitive statements and cut testing when comparing "A" to "B."
Re: New Discoveries found in 8Cr13MoV testing
Always felt Spyderco's 8Cr13MoV was a tad bit underrated.
- Deadboxhero
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Re: New Discoveries found in 8Cr13MoV testing
I don't feel like my opinions have changed about 8Cr13MoV. It grinds easy but it doesn't apex as well as other steels.
I did feel the testing put other steels in a better light rather than elevating 8Cr13MoV.
14C28N looks even better now.
Re: New Discoveries found in 8Cr13MoV testing
Yes please to BBB HT protocols optimizing Sandvik steels for Spyderco.
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Re: New Discoveries found in 8Cr13MoV testing
The information about banding is fascinating! It was also very interesting to see where 8Cr13MoV landed on the charts.
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- Deadboxhero
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Re: New Discoveries found in 8Cr13MoV testing
As of late 2022 its no longer called Sandvik anymore.
They changed the name to Alleima
https://www.alleima.com/en/products/str ... knowledge/
Re: New Discoveries found in 8Cr13MoV testing
I would choose 14C28 over 8Cr13MoV anytime, but it's just nice to know that 8Cr is not the junk everybody seems to promote especially Spyderco's 8 Cr.
Re: New Discoveries found in 8Cr13MoV testing
Whoa! Thanks Shawn. That's a bit surprising, it's been around a long time.Deadboxhero wrote: ↑Sat Jan 13, 2024 10:06 pmAs of late 2022 its no longer called Sandvik anymore.
They changed the name to Alleima
https://www.alleima.com/en/products/str ... knowledge/
- Deadboxhero
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Re: New Discoveries found in 8Cr13MoV testing
I had assumed 8cr13MoV would perhaps do better on CATRA then it did given the larger carbides and more carbide volume. That's always the best part about testing, expectations versus a closer glimpse of reality.Wandering_About wrote: ↑Sat Jan 13, 2024 10:05 pmThe information about banding is fascinating! It was also very interesting to see where 8Cr13MoV landed on the charts.
Here's one of the micrographs I did on 8Cr13MoV for Dr Larrin, we can see a lot of banding in this micrograph also, interestingly a large primary carbide has a crack in it. It seems the larger primary carbides are very delicate.
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Re: New Discoveries found in 8Cr13MoV testing
Than, not then.
Thanks for that. I find it a little surprising. What could be the reason? Are the long carbide bands acting like serrations? Why not with the steel run harder? Weird, but I am no metallurgist.
Edit to add: I like 14C28N and which we had some knives in it from Spyderco. Everyone dotes on 13C36, but 14C28N is a very much improved version.
Thanks for that. I find it a little surprising. What could be the reason? Are the long carbide bands acting like serrations? Why not with the steel run harder? Weird, but I am no metallurgist.
Edit to add: I like 14C28N and which we had some knives in it from Spyderco. Everyone dotes on 13C36, but 14C28N is a very much improved version.
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Follow the Christ, the King,
Live pure, speak true, right wrong, follow the King--
Else, wherefore born?" (Tennyson)
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Re: New Discoveries found in 8Cr13MoV testing
Wish not which.
I like 14c28n, too, and wish spyderco had a sprint run with it.
I have a couple tenacious that have held up well four me with 8cr13mov, though. Use a serrated version to open boxes, etc.
I like 14c28n, too, and wish spyderco had a sprint run with it.
I have a couple tenacious that have held up well four me with 8cr13mov, though. Use a serrated version to open boxes, etc.
- Deadboxhero
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Re: New Discoveries found in 8Cr13MoV testing
We must understand carbides are harder than the surrounding steel matrix.
The areas of carbide banding also have a higher volume of these harder particles than areas of no banding. So, banded areas at the edge will resist edge wear better.
Image: Stainless ingot steel edge after etching to reveal carbides at edge.
1. The micrographs between the two samples after evaluation showed less carbide banding with the 62.5rc sample versus the 61rc sample.
2. The austenitizing temperature was higher on the 62.5rc sample so it is possible more of the secondary carbides were dissolved. Another clue was that there was also more significant grain growth in the 62.5rc sample which could be due to not only higher temperature increasing grain growth but also less undissolved carbides remaining to pin grains.
In 2016, Ralph Bush did a study on the optimization of 440C, Well obviously this is a different steel than 8Cr13MoV however, they have the same carbide types. Ralph has a nice graph of both simulated and experimental carbide volume measurements at different austenitizing temperatures.
In summary, when we go hotter to go harder, we reduce carbide volume in some cases.
The typical chromium carbide dissolution temperature is around ~900C.
In the graph, we do see a significant drop in volume from 750C to 1000C, however, we see a rapid drop in volume near the typical austenitizing temperature for 440C and this behavior is also similar for many simple high carbon stainless ingot steels like 8Cr13MoV/AUS 8
So, it is possible that the edge on the softer, lower austenitized condition had more significant banding at the actual edge thus increasing the edge carbide volume which resisted edge wear better than the harder HRC condition which probably didn't have as significant of a band of carbides at the edge during testing.
This is all exciting because it is a deeper dive into the bizarre, non-intuitive world of microscopic properties at the edge actually making macro differences we can measure and experience with use.
Re: New Discoveries found in 8Cr13MoV testing
Byrd lineup and Chinese model sales go up 500% Sunday morning now because of this.
Very interesting find though. Never stop learning!
Very interesting find though. Never stop learning!
Last edited by TkoK83Spy on Sun Jan 14, 2024 9:34 am, edited 1 time in total.
15 's in 10 different steels
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1 - Bradford Guardian 3 / Vanadis 4E Wharnie
1 - Monterey Bay Knives Slayback Flipper / ZDP 189
1 - CRK Small Sebenza 31/Macassar Ebony Inlays
1 - CRK Large Inkosi Insingo/ Black Micarta Inlays
1 - CRK Small Sebenza 31 Insingo/Magnacut
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- araneae
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Re: New Discoveries found in 8Cr13MoV testing
Happy that the good Dr was able to shine some light on what must be the most maligned steel on the market. I have found 8Cr13 to be a perfectly serviceable steel. In my younger years, it was what I could afford. I cut a lot of cardboard working retail through high school and college. Byrds and some old AUS8 Spydies were doing most of it (along with some Chinese made Kershaws). 8Cr didn't hold the best edge, but remained serviceable and touched up easily. This is exactly why so many rave about 14C28N nowadays.
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Re: New Discoveries found in 8Cr13MoV testing
That was a good article, seemed pretty much in line with what's been said on 8CR before, but of course with the science to back it up. The most interesting part to me was that the Byrd manufacturer initially tried to pass their 8CR off as 440C to Spyderco until Spyderco tested the composition. I wonder how much of the chinesium "440C", "D2", or even 9CR out there in various brands is actually 8CR that no one bothered to test. Or maybe verifying composition on imported knives is a standard practice these days, it would be interesting to know.
Re: New Discoveries found in 8Cr13MoV testing
Really interesting article. I was eyeing the Alcyone for a long time - really like the design. Now seeing that the 8Cr is about comparable to BD1N I may actually give it a try. Still - I would love to see the Alcyone to come out in a different steel.
... I like weird ...
Re: New Discoveries found in 8Cr13MoV testing
My sample group of 8CR consists of 3 Kershaws. I was impressed with none of them. Edge holding was less than my VG10 Spydercos or 154CM Benchmades. Sharpening them was easy enough, but occasionally they seemed to develop a burr that I'd have to get past to get a good edge. I gave 2 away & held onto the CQC7K to use as a beater.
Not used any of Spyderco's knives in 8CR. I'm tempted by the Astute, but my experience with Kershaw's 8CR knives kind of put me off the steel.
Not used any of Spyderco's knives in 8CR. I'm tempted by the Astute, but my experience with Kershaw's 8CR knives kind of put me off the steel.
Re: New Discoveries found in 8Cr13MoV testing
14c28n is my favorite budget steel. I haven't bought a budget Spyderco (or Byrd) in a long time. My go-to for that category is Kershaw in 14c28n. The Leek is probably the best value in folding knives at the moment.
I've definitely had better experiences with Spyderco's 8cr than with Kershaw's 8cr. I just feel like Kershaw is in the sweet spot for price/performance with their 14c28n.