Wear resistance test for 12 different steels

Somewhere a knife sharpener is rolling in his grave... Make sure to take good before and after photos to show how the finish changed.
 
I was thinking why not slicing sandpaper, all new from same brand, same grit (preferably high sothe impact is more uniform)? This way it will be totally measurable without impact blunting.

Sand is cheaper though. However, the abraded steel will be left in the sandbox, contributing to next knife test (more like polluting)???
Perhaps 12 fresh box for each?
With this test, you can make edge geometry the same for all, another factor eliminated.
 
Sand paper is good for planar interactions, while sandbox volume interaction offers more uniformity interaction for the whole edge. Polluting/swarf matter is small in compare to the volume of sand and sand particles size. It would takes quite a bit of swarf to mostly coat sand particles as they freely rotate & move about. I don't think blade profile + edge (profile & geometry) play important role, since apex has direct impact with the sand, dulling it which exactly the aspect we are looking for.

I did a pilot test of 4 knives & a box cutter, dulling were fast and severe. May be all 12 knives testing can be done in a not super long boring video. Of course this test will favor high alloy knives. Surprise factor I want to examine/extrapolate (if possible) is grain & matrix structure, whether it has advantage in wear resistance or not.

Oh are you saying I am cheap? ;) heeheheh

Chris "Anagarika";12861748 said:
I was thinking why not slicing sandpaper, all new from same brand, same grit (preferably high sothe impact is more uniform)? This way it will be totally measurable without impact blunting.

Sand is cheaper though. However, the abraded steel will be left in the sandbox, contributing to next knife test (more like polluting)???
Perhaps 12 fresh box for each?
With this test, you can make edge geometry the same for all, another factor eliminated.
Click to expand...
 
dkb45 said:
Seems that this test is more about proof in method of cutting more than what is being cut. Obviously some things will wreck an edge, but the rope and fronds are close to what many knife users see (mostly cutting food or opening packages), and almost all of the wear seems to have come from hitting the cutting board.
Click to expand...

Yeah, to be honest I do try to minimize having to use a backing or having my edge come into contact with anything besides what I'm cutting so you do have a point in the validity of it in that respect.

bluntcut,

I really like the sand idea, I just wonder if it won't be too abrasive... Some people I know sharpen their blades on sandstone, so it will be like dulling an edge almost immediately won't it? Plus I do think that the geometry will still have a bit of a factor in this, because if one knife is easier to draw through the sand doesn't this mean the pressure on its edge caused by the abrasives are less? Not to poke holes in the idea...

I'm just wondering if any of the low alloy steels won't fail after just one draw through the sand. Guess the only way to tell is to find out.
 
I had to hurry through the sand cutting test, so test slice newsprint after every 10 cuts through the sand. I am not really looking forward to re-sharpen 12 knives for round 2 where newsprint test after every single/1 cut.

Result:

Box cutter - 10 (which mean after 10 cuts this knife no longer cleanly slice newsprint with grain at 30-45* angle)
Mora carbon - 10
15N20 - 10
S35VN - 20
Zdp-189 - 20
S30V - 20
K110/D2 - 20
1084 - 20
14C28N - 30
CPM-154 - 30
52100 - 40
CPM-M4 - 50
K390 - 60

20 minutes video - thanks for watching & comments.
[video=youtube_share;mYAPD_8_VO8]http://youtu.be/mYAPD_8_VO8[/video]
 
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For round 2 of sand cutting, where I test slice newsprint after every cut.

Mora carbon: 4
1084: 10
S35VN: 17

I'd checked that all result edges(from round 1 & round 2) are plain dulled. i.e. not rolled nor deformation in any shape/form.
 
I'm downloading. Will watch soon!

Edit to add:
Some has nice rings going through the sand. Also I'd say this test is quite focus, only measuring the abrading factor. Perhaps we can use this as standard?

You seems also to have mastered 52100 HT (mostly Cr carbides?) as it comes near the champs with lots of V carbides.
 
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Yes, this test seem highly focus on just wear resistance. You mentioned the word 'standard', forced :cool: me to re-watched the video a few times. There were variations in rate of movement and angle (slight tilt from vertical). To have a fair test, perhaps we can control the rate (I'm not going to do this due to constraints) by having the knife on a track move at fixed speed, vertically dip into sand and take out at certain distance, repeat until fail. Having said this, for the top 3 knives, rate of movement mostly were equal and or faster than others, so will keep this result.

I tested 2 knives with substantially slow rate of movement, it took 3x more cuts to dull them. hence rate impact abrasion matter...

Chris - thanks your vote on my 52100 recipe. I would like to improve 52100 by an additional 20% - 50%. OK, I'm dreaming but out of dream/hobby time budget for now:p

Chris "Anagarika";12865647 said:
Some has nice rings going through the sand. Also I'd say this test is quite focus, only measuring the abrading factor. Perhaps we can use this as standard?

You seems also to have mastered 52100 HT (mostly Cr carbides?) as it comes near the champs with lots of V carbides.
Click to expand...

When time permits, I will add a few more knives to this test:
Production:
spyderco endura vg-10
Opinel carbone

Yet made (super & magnum = fun words, it they don't live up to name, well then 'wimp' & 'dud') - hahaha:
S90V
cpm-20cv (m390 equiv)
Elmax
M2
D2 super
D2 magnum
52100 super
52100 magnum
...

OT - what is a good way to test cutting-performance test knives? cutting-performance is roughly the sum of (wear resistance + efficiency + durability). I am leaving out rust&stain resistance and ease of sharpening.
 
Tough question.

Slicing? Push cutting? Balance between two?
What being cut? Hanging or on cutting board?

If you're thinking EDU (borrowing Martin's term) then Ankerson's kind of test is similar. However you mention performance, meaning also comfort during test, simplified to amound of pressure required to do so to eliminate handle comfort factor.

Seems a jig is required.

Having said that, for real EDU, handle comfort is important, so at the end, it's subjective.

PS: the K390 responded well to end grain cardboard strop + fresh autosol;) practically shaved with it although not as smooth as the small paring 52100.
 
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Hi bluntcut, I have to keep complementing you for doing this! My favorite steel 52100 seems to perform quite well. I just noticed however that there is no 3V steel in the test? What is your expectation how it would perform?
 
Hi Andy,

I've a paring knife in 3V (very thin 0.05") still in foil to be ht - however table it for when not too busy with work. I expect (my or production) 3V survives 15-20 sand cuts. 3V known for high toughness (~60rc) and keen edge but average in wear resistance. I retested my 52100 2nd try: got 41. 3rd try got 43. I have doubt in my own result, my 52100 is good but can't be that good. There must be biases and or flawed in my setup and or execution.

awestib said:
Hi bluntcut, I have to keep complementing you for doing this! My favorite steel 52100 seems to perform quite well. I just noticed however that there is no 3V steel in the test? What is your expectation how it would perform?
Click to expand...

A better sand test would be. Sand pouring down (funnel perhaps) from particular height onto a section of the edge, 1 unit (could be a liter) of sand per pour, repeat until the impacted edge section fail to slice(or push) newsprint. Gravity will ensure fairly consistence & uniform velocity of impact. Hypothetically, if 52100 get any where close to s30v/s35vn of wear resistance, although I would be ecstatic but still not convince. lol - I could add a 'v' notch baton cross grain on 2x4 + uniform cardboard test. Will do more when time permits, humbug works interfere with knife hobby ;)
 
Ankerson's test is limited to a particular knife steel+geometry, how it wedge(rope) & backing impact(edge grain wood). Can it generalize to steel at given good ht at given hardness? Sorry no, geometry plays major role here. also a fixed 30* inclusive angle is a good compromised but far from optimal per steel&ht&geometry. Performance is quite complex, exact reason for this thread to focus on just wear-resistance.

I am surprised that k390 responded well to stropping on autosol. When I stropped on non-diamond/cbn, I get a wire-edge for my k390. otoh, 52100 edge would get very sharp.

Chris "Anagarika";12868602 said:
Tough question.

Slicing? Push cutting? Balance between two?
What being cut? Hanging or on cutting board?

If you're thinking EDU (borrowing Martin's term) then Ankerson's kind of test is similar. However you mention performance, meaning also comfort during test, simplified to amound of pressure required to do so to eliminate handle comfort factor.

Seems a jig is required.

Having said that, for real EDU, handle comfort is important, so at the end, it's subjective.

PS: the K390 responded well to end grain cardboard strop + fresh autosol;) practically shaved with it although not as smooth as the small paring 52100.
Click to expand...
 
@hank,

Your question caused me to think further. Maybe wear resistance needs better definition. Cutting paper/cardboard is a continuous force applied to the apex. Cutting sand is one after another sand grain colliding with the apex thus maube this causing zdp to microchip?

@Bluntcut,

Really a good quest, perhaps need to relook at cutting other medium. Sandpaper might not be a good idea as the apex will also collide with the individual abrasive grain embedded to the paper.

Which brought us back to basic question : wear resistance against what substance and how to test.

K390: will test further. Maybe it's wire edge now but a tough wire :confused:
 
All resultant edges were plain dulled. Used a loupe 15x & 22x, I didn't see any microchip from any knife. I think the sand just abraded the apex (steel matrix) away. As for zdp-189, I am wag-ing (beyond hand waving) here... although the steel matrix is extra hard but lack of toughness amplified the abrasion force, sometime a little flex help. e.g. analogy - a hammer strike against brick vs punching bag. Furthermore, its abundant CrC and some WC are perhaps too fine to absorb collision force, so the matrix took the brunt of the force. And there is extra Cr hang around for rust&corrosion resistance maybe actually weaken the steel lattices, which translate to a slightly weaker grain boundary.

Chris "Anagarika";12876998 said:
@hank,

Your question caused me to think further. Maybe wear resistance needs better definition. Cutting paper/cardboard is a continuous force applied to the apex. Cutting sand is one after another sand grain colliding with the apex thus maube this causing zdp to microchip?
Click to expand...

Make a blade look like a propeller, use a fixed rpm motor to churn muddy/sandy water/liquid rate on elapse time ;)

K390 - a first few stroke on strop with white/autosol/green would clean the steel matrix but won't do much to VC & WC. So as more subsquence strokes only to weaken the matrix support for carbide, especially the area right below the apex. hahaha speaking as if I am personally stand on the apex :p

edit: area below the apex because 1. high carbides volume will protect the apex from soft abrasive. 2. thin apex will flex (amt depend on force exert) away from abrasive
@Bluntcut,

Really a good quest, perhaps need to relook at cutting other medium. Sandpaper might not be a good idea as the apex will also collide with the individual abrasive grain embedded to the paper.

Which brought us back to basic question : wear resistance against what substance and how to test.

K390: will test further. Maybe it's wire edge now but a tough wire :confused:
Click to expand...
 
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Very interesting tests. I like the sand testing the best. It appears to be the most consistent.

I think we need to figure out a way to isolate and determine Abrasion Resistance and Toughness separately.

Also I think we need to have some small knives made that are all identical in size , thickness and edge geometry. And heat treated to the same impact resistance level (Based on the manufactures guidelines , say heat treated so that the blade has an impact resistance of 85ft/pds , based on crucibles toughness charts) And then all sharpened on a jig to matching finishes and angles. Say finish on Diamond or CBN loaded strops so that that carbide size is not a variable.

Again , I like your tests , but I feel that there are still some variables that make it inconclusive.
 
Good point :thumbup:

To take toughness influent out of the test, we could cut through sub-micron white alumina powder instead of sand. Kind of costly to buy a gallon of that stuff. Or cheaper just to use fine sandy semi-liquid mud, but cut count will be high and messy too.

I don't think geometry matter much in these type of test. while ht in term of hardness does but can't really normalize (common denominator for) other ht aspects. So there are many variables involves, so we take relevant results (or aspects of) and toss low confident/correlation data away.

I like to keep this test simple, so it can be easily reproduce/replicate by others. Plus tailor test knives to their interest.

Sadden said:
Very interesting tests. I like the sand testing the best. It appears to be the most consistent.

I think we need to figure out a way to isolate and determine Abrasion Resistance and Toughness separately.

Also I think we need to have some small knives made that are all identical in size , thickness and edge geometry. And heat treated to the same impact resistance level (Based on the manufactures guidelines , say heat treated so that the blade has an impact resistance of 85ft/pds , based on crucibles toughness charts) And then all sharpened on a jig to matching finishes and angles. Say finish on Diamond or CBN loaded strops so that that carbide size is not a variable.

Again , I like your tests , but I feel that there are still some variables that make it inconclusive.
Click to expand...
 
a question then: do you think zdp 189 blades are ground too thin and sharpening bevels too acute? should bevels be thicker and edges more convexed?
 
iirc over a year ago I zero grinded my Stretch CF but went nut cut a sardine can, lost about 3mm of the blade height/width. So behind the edge is not too thin now. For palm frond & sand cutting, I sharpened this knife around 40* inclusive in avoid micro-chipping. There were minor micro-chip in frond cutting but that occurs after 1500 cuts, so I don't know whether from nasty impacts or repeat stress fatigued the edge lead to mini-fracture. As for sand test, it just plain dulled, I can see the light reflected back the entire length of the edge. Geometry play very minor role as long as the apex strength/support is not a liability.
 
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