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Steel testing underway...
- Thread starter aarongough
- Start date
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Tonight I did some further testing on the blades, on tonight's agenda:
Tin can test:
This was suggested elsewhere, that I try the blades for opening tin cans.
I did use #1, #2, #5 to open a few cans as they were the only ones with tips remaining. The test did not prove to be informative though... The edge damage across the 3 blades was largely uniform. In each case the edge was rolled and probably not good for a whole lot afterwards.
Blade breakage test (ultimate toughness):
This is one I've been looking forward to. I use the word 'ultimate' here in the same sense as 'ultimate tensile strength', it's a measure of the last little bit of toughness or flexibility that the blade has to give. Not sure that it's the most accurate use of the term, but it gets the idea across.
I find this informative simply because it shows how much abuse the blade can take. I tell my customers not to use their knives as pry bars, but if push comes to shove then in an emergency they're going to do it... I want to make sure that the knife isn't going to fail on them without warning. Failure is fine, and to be expected when enough force is applied (anything will fail given enough force!), but the blade should tell them they're doing something bad well before it breaks!
Each blade was restrained in the rubber-padded jaws of a vise, 7" away from the butt of the test blade. A cheater bar was then attached and the blade was slowly and evenly bent until it broke. Here are the results:
Each one was recorded at 60 frames per second as it was tested, below are the images from the frame just before the blade failed:
Blade #5 - 60º
Blade #2 - 55º
Blade #4 - 30º
Blade #3 - 85º - Note the deformation near the ricasso
Blade #6 - 25º
Blade #1 - 15º
Finally, the blades as they are after the test, note that #3 is very bent:
Tin can test:
This was suggested elsewhere, that I try the blades for opening tin cans.
I did use #1, #2, #5 to open a few cans as they were the only ones with tips remaining. The test did not prove to be informative though... The edge damage across the 3 blades was largely uniform. In each case the edge was rolled and probably not good for a whole lot afterwards.
Blade breakage test (ultimate toughness):
This is one I've been looking forward to. I use the word 'ultimate' here in the same sense as 'ultimate tensile strength', it's a measure of the last little bit of toughness or flexibility that the blade has to give. Not sure that it's the most accurate use of the term, but it gets the idea across.
I find this informative simply because it shows how much abuse the blade can take. I tell my customers not to use their knives as pry bars, but if push comes to shove then in an emergency they're going to do it... I want to make sure that the knife isn't going to fail on them without warning. Failure is fine, and to be expected when enough force is applied (anything will fail given enough force!), but the blade should tell them they're doing something bad well before it breaks!
Each blade was restrained in the rubber-padded jaws of a vise, 7" away from the butt of the test blade. A cheater bar was then attached and the blade was slowly and evenly bent until it broke. Here are the results:
Code:
[FONT=Courier New]
Blade breakage test:
Best
#5 - 60º - lots of warning, even resistance throughout the pull, very energetic when it finally went, shrapnel all over!
#2 - 55º - lots of warning, even resistance throughout
#4 - 30º - resistance increased suddenly before breakage
#3 - 85º - plastic deformation from about 15º onwards, resistance went way down after about 15º, lots of bend remained in the blade, really not ideal
#6 - 25º - resistance increased suddenly before breakage
#1 - 15º - basically no warning, no resistance changes, just sudden brittle failure
Worst
[/FONT]Each one was recorded at 60 frames per second as it was tested, below are the images from the frame just before the blade failed:
Blade #5 - 60º
Blade #2 - 55º
Blade #4 - 30º
Blade #3 - 85º - Note the deformation near the ricasso
Blade #6 - 25º
Blade #1 - 15º
Finally, the blades as they are after the test, note that #3 is very bent:
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- Joined
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Thanks mate! I was and still am very happy with that knife! I may be sending him a new one after seeing the results of this test though, don't want him lugging about
inferior steel!
I'm probably going to unveil the steels next week after they've been Rockwell tested...
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I missed the "two 01 blades", just saw the home brew forge HT, didn't read careful enough.
Good testing man! Carry on...
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Excellent! I was worried I'd missed a good trick with the O1! Thanks for the feedback!
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Great test and thread. Now enough with the foreplay show us the results
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Great test and thread. Now enough with the foreplay show us the results
I know man, I'm excited too! I want to find out what steel blade #2 is!
I'm probably going 'unwrap my presents' tonight when I get to the shop... The only other tests are the hardness test and the corrosion test, and I don't see how either of those could be influenced by knowing which steel is which!
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supposedly O1's hardness/toughness/edge retention is at its best in the Rc60-64 range. the steel makers and some to the steel distributors say if Rc60 is too high, go with a different alloy. doing my own "testing" with O1 as kitchen knives, have had no issues yet with chipping. my thoughts on blades is get the steel hard and the edge thin, the angle low. very curious to see how the O1 blade did, besides being the easiest to work and HT, it is also the least expensive. my guess is that blade #3 is O1 with homebrew HT.
the old sailor
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Crucible says that O1 has roughly equal toughness from 58-63HRC (as shown here: http://www.crucibleservice.com/eselector/prodbyapp/tooldie/ketos.html). I don't think I've ever managed to get it into the upper range.
It would be worth a look at some point!
I can imagine that it's possible to get away with much higher hardnesses in kitchen knives than you could in wilderness/survival knives unfortunately. Getting that extra edge retetion would be nice though, so it's worth a shot at some point!
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After watching you video of you making a knife with file's and knowing how much time it most likely took you and it's a shame you had to take your blades all the way to destruction. But I guess that's the only way to get your answers. I use a lot of O1 I find it does get a little chippy in the higher RC range. I do a 58 and see good results for me. Well looking forward to seeing some answers.
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I actually received my new KMG grinder right before I started the process of making the test blades! It was very nice to get to take it a little easy... That's why these blades look a little less than optimal in some places, they're the first ones I've ever done on a grinder!
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Ok guys! I'm going to be unwrapping these test blades soon to find out which is which, but first I want to put together a summary of the blades. Each blade has been ranked against all the others for each test, then assigned points based on where it places against the other blades. 1st place = 60 points, 5th place = 10, 6th = 0 points, and so on... Each blade that survived the tip strength test was given an extra 30 points
If you spot a mistake please point it out!
Blade #1
Sharpening: 9:08 - 6th overall
Fine edge retention: 106 cuts - 4th overall
Coarse edge retention: good - 3rd overall
Impact toughness: excellent - 2nd overall
Tip strength: excellent
Bending toughness: 15º - 6th overall
Points: 0 + 20 + 30 + 50 + 30 + 0 = 130
Blade #2
Sharpening: 7:19 - 4th overall
Fine edge retention: 126 cuts - 2nd overall
Coarse edge retention: excellent - 1st overall
Impact toughness: excellent - 1st overall
Tip strength: good
Bending toughness: 55º - 2nd overall
Points: 20 + 50 + 60 + 60 + 30 + 50 = 270
Blade #3
Sharpening: 8:23 - 5th overall
Fine edge retention: 166 cuts - 1st overall
Coarse edge retention: good - 2nd overall
Impact toughness: average - 3rd overall
Tip strength: poor
Bending toughness: 85º (plastic deformation) - 4th overall
Points: 10 + 60 + 50 + 30 + 0 + 20 = 170
Blade #4
Sharpening: 6:21 - 1st overall
Fine edge retention: 100 cuts - 5th overall
Coarse edge retention: very poor - 6th overall
Impact toughness: poor - 6th overall
Tip strength: poor
Bending toughness: 30º - 3rd overall
Points: 60 + 10 + 0 + 0 + 0 + 30 = 100
Blade #5
Sharpening: 6:49 - 2nd overall
Fine edge retention: 120 cuts - 3rd overall
Coarse edge retention: ok - 4th overall
Impact toughness: average - 4th overall
Tip strength: good
Bending toughness: 60º - 1st overall
Points: 50 + 30 + 20 + 20 + 30 + 60 = 210
Blade #6
Sharpening: 6:51 - 3rd overall
Fine edge retention: 35 cuts - 6th overall
Coarse edge retention: poor - 5th overall
Impact toughness: poor - 5th overall
Tip strength: poor
Bending toughness: 25º - 5th overall
Points: 30 + 0 + 10 + 10 + 0 + 10 = 60
Overall ranking:
1st - Blade #2
2nd - Blade #5
3rd - Blade #3
4th - Blade #1
5th - Blade #4
6th - Blade #6
If you spot a mistake please point it out!
Blade #1
Sharpening: 9:08 - 6th overall
Fine edge retention: 106 cuts - 4th overall
Coarse edge retention: good - 3rd overall
Impact toughness: excellent - 2nd overall
Tip strength: excellent
Bending toughness: 15º - 6th overall
Points: 0 + 20 + 30 + 50 + 30 + 0 = 130
Blade #2
Sharpening: 7:19 - 4th overall
Fine edge retention: 126 cuts - 2nd overall
Coarse edge retention: excellent - 1st overall
Impact toughness: excellent - 1st overall
Tip strength: good
Bending toughness: 55º - 2nd overall
Points: 20 + 50 + 60 + 60 + 30 + 50 = 270
Blade #3
Sharpening: 8:23 - 5th overall
Fine edge retention: 166 cuts - 1st overall
Coarse edge retention: good - 2nd overall
Impact toughness: average - 3rd overall
Tip strength: poor
Bending toughness: 85º (plastic deformation) - 4th overall
Points: 10 + 60 + 50 + 30 + 0 + 20 = 170
Blade #4
Sharpening: 6:21 - 1st overall
Fine edge retention: 100 cuts - 5th overall
Coarse edge retention: very poor - 6th overall
Impact toughness: poor - 6th overall
Tip strength: poor
Bending toughness: 30º - 3rd overall
Points: 60 + 10 + 0 + 0 + 0 + 30 = 100
Blade #5
Sharpening: 6:49 - 2nd overall
Fine edge retention: 120 cuts - 3rd overall
Coarse edge retention: ok - 4th overall
Impact toughness: average - 4th overall
Tip strength: good
Bending toughness: 60º - 1st overall
Points: 50 + 30 + 20 + 20 + 30 + 60 = 210
Blade #6
Sharpening: 6:51 - 3rd overall
Fine edge retention: 35 cuts - 6th overall
Coarse edge retention: poor - 5th overall
Impact toughness: poor - 5th overall
Tip strength: poor
Bending toughness: 25º - 5th overall
Points: 30 + 0 + 10 + 10 + 0 + 10 = 60
Overall ranking:
1st - Blade #2
2nd - Blade #5
3rd - Blade #3
4th - Blade #1
5th - Blade #4
6th - Blade #6
Willie71
Warren J. Krywko
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I do O1 at rc60-61 for EEC and small skinners. No reports of chipping so far. I don't have a tester yet, but follow a pretty strict ht recipe for O1 and it should be in that range. I do O1 kitchen knives at rc 62-63 and they hold an edge like you wouldn't believe.
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Well, I just took a peek under the covers... Wow. I said in a previous post that it would be amusing if there was an upset, but I have to tell you I'm amazed (and maybe even a little disappointed) with the results. I'm very, very surprised to say the least.
Before I post the results, another disclaimer: These results are in my shop, with my heat-treatment, my sharpening, and when used in my design. Different designs, different heat-treats and different sharpening methods will all perform differently. I'm not slagging off anyone's choice of steel with these results, and your results may vary.
With that over, let's see some results. Drum-roll please...
Overall ranking:
6th place - Blade #6 - 440C
5th place - Blade #4 - O1 Kiln
4th place - Blade #1 - CPM154 (WTF?!?)
3rd place - Blade #3 - O1 backyard heat-treat
2nd place - Blade #5 - CPM3V
1st place - Blade #2 - A2
Wow.
As you can imagine I'm amazed by these results... I was expecting to see CPM154 or CPM3V in first place if I'm honest. I really wanted to see CPM154 in first place as I wanted to be able to offer stainless blades to my customers along with even better performance.
I'll be getting all these blades hardness tested next week to help verify that nothing went wrong during the heat-treat process. I didn't see any sign of decarburization on any of the blades after heat-treat except for the CPM3V where the decarb was ground off... All blades were shielded from oxygen in the kiln using ATP-641 anti-scale.
I'm somewhat dumbfounded to be honest, I did not get the results I was expecting! I guess that's what's great about doing tests blind... There's always room for surprises!
Before I post the results, another disclaimer: These results are in my shop, with my heat-treatment, my sharpening, and when used in my design. Different designs, different heat-treats and different sharpening methods will all perform differently. I'm not slagging off anyone's choice of steel with these results, and your results may vary.
With that over, let's see some results. Drum-roll please...
Overall ranking:
6th place - Blade #6 - 440C
5th place - Blade #4 - O1 Kiln
4th place - Blade #1 - CPM154 (WTF?!?)
3rd place - Blade #3 - O1 backyard heat-treat
2nd place - Blade #5 - CPM3V
1st place - Blade #2 - A2
Wow.
As you can imagine I'm amazed by these results... I was expecting to see CPM154 or CPM3V in first place if I'm honest. I really wanted to see CPM154 in first place as I wanted to be able to offer stainless blades to my customers along with even better performance.
I'll be getting all these blades hardness tested next week to help verify that nothing went wrong during the heat-treat process. I didn't see any sign of decarburization on any of the blades after heat-treat except for the CPM3V where the decarb was ground off... All blades were shielded from oxygen in the kiln using ATP-641 anti-scale.
I'm somewhat dumbfounded to be honest, I did not get the results I was expecting! I guess that's what's great about doing tests blind... There's always room for surprises!
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Given the somewhat counter-intuitive results I'm probably going to look into getting metallographs of the test blades taken as well. No point basing my decisions on testing/research that is wrong!
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Agreed. I was expecting the backyard O1 to be right down the bottom of the list. 440C is where I expected it to be, as it CPM3V. However I was very much expecting CPM154 to top the list.
Many of the steels in this test were actually cryo-treated, including the A2.
I will say though that the breakage test was really weird with the backyard O1. I have tested other blades heat-treated the same way to destruction in the same fashion and not had them deform like that.
I'll definitely be doing my best to make sure that I verify that the heat-treats on all steels were up to par! (through hardness tests and possibly metallographs)
Willie71
Warren J. Krywko
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This is pretty awesome!!! It just goes to show how the steel type is much less important than grind and heat treat. I'm not surprised to see A2 in the lead for a hard use knife ( I watched Nathan's A2 test video the other day, and WOW!!!) CPM 3v will start to show its advantages more as you push edge geometry more extreme. I am surprised by the O1 results. I suspect more refined HT would move it up a few notches, especially since the shot in the dark HT worked out better than the kiln HT. I have been progressively been moving to the lower end of the HT range with my blades as I get better control of the equipment. They perform better the more I push toward the lower boundary for austentizing rather than the higher boundary (1095, W2, O1 all well under 1500f- usually about 1465-1475).
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