I Tested the Edge Retention of 48 Steels

I just listened to a 2 year old podcast you were interviewed on. Being dumb to the knife world, I assumed you were older and by results (volume of work published so far), more interested in the super steels personally as a favorite.

I heard your part about getting a melt of a mid level steel rather than trying to make a rex^2, and your discussion of geometry above heat treat above composition in terms of order (I don't want to put words in your mouth, that's how I heard it). Well done.

I've spent a fair amount of time in isolation here (also in Pgh) manipulating hardness and geometry to try to eliminate failure in woodworking without increasing cutting resistance (because that's where actual economy of effort is had - probably different than knives).

What ever came of your experimental melt? Presumably a stainless with more wear resistance than AEB-L, but less than the high vanadium steels and better toughness than the stylish super high carbide knife steels?
 
Larrin said:
Development is complete on NioMax but still waiting on commercial production.
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ah yes, the mysterious niomax, with yummy niobium, and low 6%ish carbide volumes... with toughness surpassing aeb-l, I like the sound of it very much

considering the patent was filed back in march, I figured you might provide more info on it = D
 
I googled the name (sorry, I'm new - I see you've been answering questions about this for over two years). I see elongated carbides, and am assuming they're somehow oriented with grain direction (as in, I'm assuming this going to be a traditional steel with a grain direction after it's rolled).

Question (this is partially from a woodworking perspective where we use grain direction to our advantage so that the edge is perpendicular to the grain direction) - are the carbides in the images on your blog parallel to the grain direction?
 
dirc said:
ah yes, the mysterious niomax, with yummy niobium, and low 6%ish carbide volumes... with toughness surpassing aeb-l, I like the sound of it very much

considering the patent was filed back in march, I figured you might provide more info on it = D
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There is no patent application on NioMax, I’m not sure what you’re referring to.
 
D-weaver said:
I googled the name (sorry, I'm new - I see you've been answering questions about this for over two years). I see elongated carbides, and am assuming they're somehow oriented with grain direction (as in, I'm assuming this going to be a traditional steel with a grain direction after it's rolled).

Question (this is partially from a woodworking perspective where we use grain direction to our advantage so that the edge is perpendicular to the grain direction) - are the carbides in the images on your blog parallel to the grain direction?
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The carbides are parallel to the rolling direction. There is some directionality in properties to all of the steels I have tested. When I do micrographs the horizontal is parallel to the rolling direction and the vertical is thickness. It’s a standard orientation, other directions can make carbides appear smaller than they are.
 
dirc said:
I thought this was you - doing it with Alpha knife supply?.... looks like they filed this in March of 2020? (sorry not patent, but trademark)
https://uspto.report/TM/88830731
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Ok well a trademark is just a name it doesn’t mean the product is ready to sell. No need to hype a product you can’t buy. If there was a patent it would be a little easier to talk details because the design would be public.
 
Is it fair to say that the average garage user starting with mill stock may (assuming carbon 1% or greater)
* end up with a better result if they heat quickly (just past critical, and not trying to hit it dead on and coming up short) and quench and then double temper - assuming nothing untoward with grain direction, vs
* attempting to hand work steel to death and then do a multiple quench process?

I ask this question because I've attempted to shape various high carbon bits (mostly files) and then finish shaping just as any color is gone from the item being forged, and any time I break something after quench, the more I've worked the steel (the longer I've worked it and the more times i heat it), the more prominent carbides become in it.

Geometry and hardness are my two main targets, not challenging toughness, so I can't see a final difference in use between any of them - just surprised that additional hammering sessions seem to yield more and more (and coarser) carbides when breaking a sample.

I have no controlled furnace or anything of the sort to normalize post-forging, just a propane forge.
 
D-weaver said:
Is it fair to say that the average garage user starting with mill stock may (assuming carbon 1% or greater)
* end up with a better result if they heat quickly (just past critical, and not trying to hit it dead on and coming up short) and quench and then double temper - assuming nothing untoward with grain direction, vs
* attempting to hand work steel to death and then do a multiple quench process?

I ask this question because I've attempted to shape various high carbon bits (mostly files) and then finish shaping just as any color is gone from the item being forged, and any time I break something after quench, the more I've worked the steel (the longer I've worked it and the more times i heat it), the more prominent carbides become in it.

Geometry and hardness are my two main targets, not challenging toughness, so I can't see a final difference in use between any of them - just surprised that additional hammering sessions seem to yield more and more (and coarser) carbides when breaking a sample.

I have no controlled furnace or anything of the sort to normalize post-forging, just a propane forge.
Click to expand...
When you break a piece of quenched steel and look at the fracture surface you are looking at the relative grain size not the carbides. You could be overheating the grain thus leading to a coarser appearance, or you could be decarburizing the steel so much that it is not longer fracturing in a brittle manner. Only brittle fracture reflects the grain size.

Grain refinement cycles are easy to do even in a propane forge, however. Just heat to nonmagnetic and air cool until it's magnetic again.
 
Thanks. That's essentially what I was doing, but quenching. I"ll try reheats. I only shape (for fear of increasing grain size) and don't heat to forging temperatures. The shaping is done just above critical (which doesn't last long) so I get multiple low temperature heats. I have pictures of the grain from samples, but this is tending toward (or is) your area of expertise and it'd be rude for me to pick at this as an amateur - I'm sure you could get paid to answer similar questions.

I'm just astounded at how fine and uniform something like a file is and then whatever I do afterwards, looking at a broken section at 150x under a metallurgical scope, the bits that reflect back are a bit larger (the bits between what look to me like carbides) are still fine and don't appear to have changed. I assumed it was formation of carbides due to the excess of carbon (and whatever else must be in files - as easily as they harden to extreme hardness, I'm guessing they have molybdenum in small amounts, and maybe vanadium.
 
You can message me separately to ask specific questions so that we aren’t off topic in the thread.
 
Hi Larrin! What do you think about Maxamet, how would it stack with these steels?

I think it is tough enough and can cut for weeks being used as my only do-it-all blade (EDC, kitchen, homestead/gardening etc roles). It is also easy to sharpen with DMT plates. The factory edge chipped only when i hit the edge of a steel barrel cut in half and it was a small chip that reduced in size with weeks of use and finally completely disappeared after the first sharpening three weeks later (PM2).
 
kobold said:
Hi Larrin! What do you think about Maxamet, how would it stack with these steels?

I think it is tough enough and can cut for weeks being used as my only do-it-all blade (EDC, kitchen, homestead/gardening etc roles). It is also easy to sharpen with DMT plates. The factory edge chipped only when i hit the edge of a steel barrel cut in half and it was a small chip that reduced in size with weeks of use and finally completely disappeared after the first sharpening three weeks later (PM2).
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Maxamet would be similar to Rex 86/Z-Max which was tested. We plan on doing Maxamet in the future. There is a blank that has been heat treated and is awaiting grinding.
 
back on topic with your data group. It looks like the O1 blade is slightly less hard than 1095, but underperformed fairly significantly on a relative basis. I don't have a parallel to compare with testing as I've only used water hardening irons of older laminated make, but will make a 1095 iron this weekend to compare. In plane testing, i saw edge life (in feet and weight planed from the same board, and rotating plane blades to minimize potential differences within the board) of O1 at about 80% of A2.

The water hardening steel that I did test (ward and payne laminated probably something 0.8-1% carbon) lasted about 55-60% of A2 footage planed. AEB-L and 1095 may be interesting to woodworkers if they can match O1 steel (since they have good edge stability and fine grain).

Is the poor relative comparison of O1 vs 1095 any surprise? I'd have guessed the relationship would be the reverse.
 
I believe O1 was briefly discussed in the article. O1 was expected to be similar to 1095 or slightly better.
 
Thanks for the reply - I read about everything I could read on your site too quickly and missed that detail. I'm super pleased that you offered all of this info, though. I've been able to point to your page with a few people who have hassled me about my data set, and I have a new steel to play with that I didn't even know existed (AEB-L), and am curious to see how well it will perform in a knife if I just give it a quick atmospheric heat to high temp and quench/freezer/double temp. Until I found your site, I was also under the misconception (due to bad info from other people - "nothing but liquid nitrogen will make a difference") that a freezer treatment prior to quench doesn't change the final result at all. Best of luck as you continue to make an important mark for the rest of us.
 
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