Edge retention, an interesting video...

[Mo2]

I am most familiar with wood working. Birch, pine, etc. do not contain abrasive particles (some tropic wood contain abrasive inclusions), and for that reason, abrasive wear resistance is not important for me. So, I am not expert on abrasive wear, but I am very interested in other people test results. I suspect that maybe there is some hype with supersteels.

There is no hype.

 

[dirtvictim]

I always laugh at the next greatest steel to come along. Everyone scrambles to market a blade from it while it's a hot topic then quickly moves to the next one. I'll stick with my light saber.

 

[Natlek]

So, I am not expert on abrasive wear, but I am very interested in other people test results. I suspect that maybe there is some hype with supersteels.

Ok.................I can bet with you in anything you want that my super-duper knife /M42 steel/ will outperform YOUR knife from SIMPLE carbon steel TEN times in wear resistance . Maybe then you will become believer

 

[Natlek]

Some seem to be unhappy because their favorite supersteel was beaten by simple basic steels, and they argue that the test was wrong or not enough scientific. However, It was a good user's test and it showed one hard fact; one experienced knife user did not notice difference between S30V, 8Cr13MoV, and 1080 steel blades.

I quoted wrong post first time...........hey , you can buy two hacksaw blade for metal........one from carbon steel and one made from bi-metal .Cut some steel and see what is super steel and WHY they are super steel .No need to cut all day rope ...............

 

[me2]

This testing and results are not unprecedented or an isolated event. They confirm what I found several years ago. If everything is constrained and controlled the differences can frequently be seen, but not always. In actual use, where things aren't as controlled, the differences aren't obvious, at least on rope or cardboard.

 

[Juha Perttula]

Once a week my wife complains something like this: "We have a blade enthusiast in house and our all kitchen knives are always dull".
Do you think, If I bought for her a chef knife made of the very best supersteel, she would say: "Wow, this is amazing, my knife is still sharp".

 

[Natlek]

Once a week my wife complains something like this: "We have a blade enthusiast in house and our all kitchen knives are always dull".
Do you think, If I bought for her a chef knife made of the very best supersteel, I would hear: "Wow, this is amazing, my knife is still sharp".

Yes , you will hear her much less often complains ............

 

[microbe]

Somebody needs to come up with a very though and course cutting material, a rig with pressure measurement and a fixed test blade shape, all designed specificity for knife testing, and come up with a scale, like Rockwell did when he came up with his hardness test.

 

[Twindog]

Somebody needs to come up with a very though and course cutting material, a rig with pressure measurement and a fixed test blade shape, all designed specificity for knife testing, and come up with a scale, like Rockwell did when he came up with his hardness test.

They already have. It's called the CATRA edge retention test, and it uses steel blanks of steel alloys that are all the same size and geometry and heat treated to similar hardness. Then the blanks are used to cut silica-impregnated (abrasive) cards until a cutoff level of dullness is reached. The scale is the number of cuts it takes to reach that level of dullness.

So M390 at 61 Rc gets 958.6 cuts.
D2 at 61 Rc gets 665.8 cuts.

Wear resistant steels like 10V would do even better. Less wear resistant steels would do much poorer.

http://www.bucorp.com/media/CATRA_Test2.pdf

 

[BluntCut MetalWorks]

I did learned from test below and would conduct this test better today. Results would move around drastically, esp if using my current ht. A HydroSilicateDynamic (sandy water flow impacting/blasting edge at various angles) would be cool and effective.

===

In 2013, I conducted wear resistance test for 12 steels - cutting palm frond, 0.5" sisal rope and sand.
Conclusion: Palm & Rope cuttings were not useful (ok, a failed!).

https://www.bladeforums.com/threads/wear-resistance-test-for-12-different-steels.1122510/

Results at end point:

Palm frond Results - #s of cut:
Final:
15N20 - 480
Mora carbon - 570
14C28N - 1425
1084 - 1425
zdp189 - 1965
s35vn - 2280
cpm-154 - 2325
cpm-m4 - 2475
k110/d2 - 2550
s30v - 2850
52100 - 5250
k390 - 6100

0.5" sisal rope Results - #s of cut:
On going (then abandoned)
1084 - 2500
K390 - 1700
14C28N - 1700
52100 - 1700


Cutting sand results - #s of cut:
Box cutter - 10 (which mean after 10 cuts this knife no longer cleanly slice newsprint with grain at 30-45* angle)
Mora carbon - 10 | 4
Opinel #9 carbone - * | 5
15N20 - 10
1084 - 20 | 10
Zdp-189 - 20
S30V - 20
K110/D2 - 20
S35VN - 20 | 17
14C28N - 30
CPM-154 - 30
52100 - 40
CPM-M4 - 50
K390 - 60

AS NOTED in thread
**Shamelessly** I ignore minor variables at play for this test: edge geometry + blade profile + other variables + forces + vectors + reproducibility +

 

[microbe]

They already have. It's called the CATRA edge retention test, and it uses steel blanks of steel alloys that are all the same size and geometry and heat treated to similar hardness. Then the blanks are used to cut silica-impregnated (abrasive) cards until a cutoff level of dullness is reached. The scale is the number of cuts it takes to reach that level of dullness.

So M390 at 61 Rc gets 958.6 cuts.
D2 at 61 Rc gets 665.8 cuts.

Wear resistant steels like 10V would do even better. Less wear resistant steels would do much poorer.

http://www.bucorp.com/media/CATRA_Test2.pdf

Thanks, I was not aware of this. So if CATRA gives an index for each steel, the only remaining discussion is blade shape and grind depending. It will be my knife cuts better then your knife forever. Facepalm.

 

[me2]

CATRA has some issues. The total cut count, tcc, doesn't tell the whole story. The graphs tell much more, if available.

 

[Gaston444]

Came across this on a CATRA related thread:

" It thus can be determined for example that in 440A stainless, with an optimal soak, 0.48% of carbon is in solution and thus a maximum hardness of 60 HRC can be obtained.

Note the high carbide steels actually decrease the hardness usually because they are not balanced to produce hardness but they are created to produce a large volume of primary carbides and thus they are very far to the right of the carbon saturation line. As noted, this is because for the purposes they are created, a high wear resistance is required. But again in the tool industry, this isn't a difficult problem, the steels used for knives never have a high primary carbide aggregate as this doesn't assist edge retention at high sharpness. Steels designed for retaining a high sharpness are steels such as the F series, the tungsten grades, the white/blue series, etc. . However there is a very curious thing which happened in the cutlery specific industry which I have never seen anyone explain, or even source how it happened.

If you read books from some time ago and look at the edge angles they are all very low, even axes have very low angles. As a specific example, in Cook's book (1921) you will see the edge angles of a swamper axe at 17.5 dps. If you scan modern small folders, 17.5 dpi would be considered a low angle - however this is a full size swamping axe, and these were the utility axes used to cut limbs roots, etc. which were ground with steep angles because they were not meant to cut well, but be durable. A full size felling axe would be ground to 15 dps, and again this is a full size felling axe swung by able bodied men and slamming into traditional NA woods. Note as well that this was the final apex angle, it quickly swept back into a lower angle to provide relief. When I started years ago writing about edge angles on chopping knives in the 8-10 dps range and 12-14 micro-bevels I received quite a lot of flak as this was quite in opposite to current convention thinking. The reason this happened is because now the steels used on all knives, even large ones are extremely idiotic choices in general. They are ultra brittle, extremely high carbide steels which have forced the more than doubling of edge angles on cutlery.

...and thus a move towards using materials which, while not working well at a high sharpness, do work very well at a low sharpness as once very large angles are used and once a tolerance for very low sharpness is acceptable - then the solution is no longer F2 it is D7 ."

http://www.cliffstamp.com/knives/forum/read.php?5,2040

Gaston

 

[Frotier76]

Some seem to be unhappy because their favorite supersteel was beaten by simple basic steels, and they argue that the test was wrong or not enough scientific. However, It was a good user's test and it showed one hard fact; one experienced knife user did not notice difference between S30V, 8Cr13MoV, and 1080 steel blades.

Some seem to be unhappy because their favorite supersteel was beaten by simple basic steels, and they argue that the test was wrong or not enough scientific. However, It was a good user's test and it showed one hard fact; one experienced knife user did not notice difference between S30V, 8Cr13MoV, and 1080 steel blades.

That is very true.Every time a new steel surfaces you hear a gamut initially of praise and hoopla saying it outperforms this other older premium steel and so forth.Or 'oh my gosh AUS-6...hmph...AUS-8 is the lowest I go'...that's a hilarious one.Sometimes I think we just have our blades stamped 'STAINLESS' and drop the BS altogether...let the consumer market figure if it's 'premium' or not in good old-fashioned real world use.

 

[ShannonSteelLabs]

That is very true.Every time a new steel surfaces you hear a gamut initially of praise and hoopla saying it outperforms this other older premium steel and so forth.Or 'oh my gosh AUS-6...hmph...AUS-8 is the lowest I go'...that's a hilarious one.Sometimes I think we just have our blades stamped 'STAINLESS' and drop the BS altogether...let the consumer market figure if it's 'premium' or not in good old-fashioned real world use.

That may be true. Especially in the case of some Ultra high carbide steels. (MAXAMET, CPM REX 121) these steels are not actually designed for knives we use. They have excellent edge holding and wear resistance.

But moving back to stainless I feel that isnt correct. I have used several steels for stainless and I have seen a difference. Say Zfinit/LC200N vs. AUS-8. Zfinit is much more stainless and tougher. It likely has better edge holding. I havent directly compared the 2, but I didnt like AUS8, when I had it.

Being a maker I have found that

Some people dont need the most advanced super steel for an EDC. But some people l oi ie and want that. I have seen people who actually need a stainless with great edge holding for work. Lesser steels just dont hold up.