New Knife Steel Ratings by Knife Steel Nerds

[Josh1973]

I am - again - surprised how relatively "bad" REX45/HAP 40 fares. Especially how really not spectacular its toughness actually is. Of course I don't doubt the results at all (!), but this is different to what - also experienced - knife users always tend to say and also different to my own experience.
M4 seems to be the clearly better choice here: About the same edge retention, noticeable tougher.

…

I think Spyderco ran their Rex 45 too hard. Larrin tried to replicate the Spyderco heat treatment, which basically means that it wasn’t tempered for long enough to achieve an more optimal level of toughness. Tempering REX45 to 64-65 HRC would have resulted in a better balance of properties, in my opinion. If Larrin ever decides to optimize the heat treatment for REX 45, I think you will see a more desirable balance of properties.

I think most Japanese knife makers that use HAP40 (Hitachi equivalent of REX 45) temper it down to about 65 HRC. So, Spyderco’s heat treatment is going to result in much lower toughness than what is commonly achieved with the steel, and I have no idea why they decided to do that.

Well put and agreed. Some people on this forum act like REX45 is garbage steel on here. Well I have a Native Chief that has still yet to need sharpening from EDC use Involving cutting branches and breaking down cardboard boxes. But I don't use my folders to stab steel drums or baton oak logs anyways. So I am not concerned with the toughness issue of REX45 at higher Rockwell. It does not take a metallurgist to know that running a steel at high Rockwell will result in better edge retention but sacrifice toughness. And running a lower Rockwell will result in the exact opposite. I do agree that perhaps Spyderco should have ran the REX45 3-4 points lower on the Rockwell.
I never thought I would see the day junk 8CR13MOV would be praised on this forum while REX45 would be shamed.

I'm on this forum several time per day I don't think I've ever seen anyone imply that REX45 is garbage steel. I have no clue where you got that impression. You're all welcome to express your thoughts and opinions but, if I recall correctly, everyone was excited and happy that Spyderco was running REX45 at a higher hardness. It actually felt like HAP40 was now inferior because it couldn't be run as hard due to the SUS410 outer cladding. I like HAP40 and I've never felt that way but I'm pretty easy to please. This is the first time I've actually seen anyone complain that they're running REX45 too hard. So it would seem to me that we have the best of both worlds. You can buy knives with REX45 at a higher hardness or HAP40 with more toughness. How fabulous is that?

Thanks for commenting Sir. I will be glad to try to defend my position. And yes garbage was a bad choice of words on my part. I should have stated subpar or overrated for the price in place of garbage. I will eat my words on that one statement.

Here is how I feel. Entirely too many people have gone on about how toughness in REX 45 is lacking because Larrin did some testing on a steel that was ran at 67-68 Rockwell. And determined that REX45 was not very tough and implied it was overrated. I dare to respectfully disagree with both users of REX 45 and even Larrin himself. Who I hold in high regard and respect what he has taught me and the knife community concerning metallurgy. That is to be commended.
However, I disagree with him on REX45 lacking toughness. When he tested REX45 at maximum Rockwell. Which is
Any steel ran at higher Rockwell will be trading off some toughness for edge retention. And HAP40 which is a REX45 substitute ran at 64-65 Rockwell was a lot tougher than REX45.
Any steel run maximum Rockwell sacrifices some toughness.
And vice versa.

Until I see REX45 ran at a 61 to 64 Rockwell. then toughness tested. I am not taking claims of it's lack of toughness seriously. Or fact. And yes I would like to see it tested at a lower Rockwell to verify it's toughness results.

I got a REX 45 Native Chief I use every day landscaping and cutting copper wire. Rockwell 68. And I got the S30V version of the Chief. With a VG10 Endura. And a Byrd hawkbill in the all mighty 8cr13mov garbage that should have died off 20 years ago. Guess which one has chips and needs more sharpening. It sure is not REX45.

I dropped my REX45 from a ladder a bit over a story on the ground tip first on the pavement. No tip damage other than a bit of rolling. And fixed with a ceramic rod in under a minute.
I dropped my Byrd 8cr13mov 6 feet onto the ground. Lost half an inch of tip.
I dropped my Endura VG10 from a wrist flick losing grip on my knife. 2 good chips and quarter inch of tip snapped off hitting a wood floor. I have even chipped my Endura and s30V Native Chief from cutting big zip ties.

Please tell me once again how brittle and non tough REX45 is. Despite the fact it has a higher Rockwell than any other steel I mentioned. I am no Metallurgist. Just someone who actually uses knives for a living. And the real world is my experiment on steel. REX45 has not failed me yet.

As far as those who detract from REX45. I have seen REX45 naysayers here and on various social media forums. I do go on forums also. And I pay those claims about as much credence as I do to a fake Rolex being the genuine thing.

[GautamGoel]

Looking at Larrin's article, a few things jump out at me:

1. VG-10 is a pretty underrated steel. It has the same toughness and edge-retention as s30v, with only a bit worse edge retention. Yes, it's not a supersteel, but anyone who uses VG-10 need not be embarrassed by it.

2. Similarly, M390/20cv is overrated; it is only slightly better than s30v in edge retention (and slightly worse in toughness). Some people speak about M390 as it its the greatest invention since sliced bread - actually, you'll probably never discern any difference between M390 and s30v in real-world use.

3. Cruwear and S90v seems to be the best all-around supersteels, given that they both have good edge retention and reasonable toughness and corrosion resistance. Picking between them comes down to whether you value toughness more (Cruwear wins) or edge retention and corrosion resistance (S90v excels at both).

4. Maxamet and REX-121 are the most "lopsided" steels, having insane edge retention but lousy toughness and corrosion resistance. ZDP-189 offers a similar (but less extreme) tradeoff.

5. I hear a lot about M4, but looking at the chart, I don't really see why you'd want it - there are many steels that outperform M4 in multiple dimensions.

6. None of the carbon steels (52100, etc) are anything special in edge retention or corrosion resistance; the only reason you would ever pick one is if you value toughness (or sharpenability, in the case of 52100). Most people can safely ignore this class of steels.

TL, DR: s30v and VG-10 are perfectly fine for day-to-day use; true steel connoisseurs will probably pick s90v or Cruwear.

[RamZar]

M390/20cv is overrated; it is only slightly better than s30v in edge retention (and slightly worse in toughness). Some people speak about M390 as it its the greatest invention since sliced bread - actually, you'll probably never discern any difference between M390 and s30v in real-world use.

M390/20CV/204P is a great choice for small folders where Edge Retention and more importantly Corrosion Resistance matter most. It trumps S30V for those two criteria.

Larrin: “With my standard 1% saltwater test, there was no corrosion visible on the [MagnaCut] steel after 72 hours, while a couple small spots were visible on 20CV and significant rusting on everything else but Vanax. MagnaCut is listed as “new steel” in the image below.”

[Karl_H]

Looking at Larrin's article, a few things jump out at me:

...

Larrin's tables do not include hardness. I think your conclusions might change, when you consider hardness (resistance to deformation/rolling).

People value M4, 4V, Cruwear, and Magnacut because of the relatively high toughness at high achievable hardness.

[Naperville]

Everyone has a different intended use for their knives. The tests and charts are very useful for everyone. The steel you buy and it's attributes should rest on intended use.

- Some like to whittle wood.
- Some cut cardboard and plastic films.
- Some plan to use the knife for self defense.
- Some have to cut hundreds of zip ties every week.
- Others only plan to use their knives in food prep.

[nerdlock]

Looking at Larrin's article, a few things jump out at me:



2. Similarly, M390/20cv is overrated; it is only slightly better than s30v in edge retention (and slightly worse in toughness). Some people speak about M390 as it its the greatest invention since sliced bread - actually, you'll probably never discern any difference between M390 and s30v in real-world use.

As stated by RamZar above, you're overlooking one pretty important aspect of the M390-class steels: corrosion resistance. I've had S30V which is pretty stainless rust in the tropical humidity where I'm located, even without being exposed to salty water at all; but my M390/20CV/204P blades have yet to develop any form of rust or even patina whatsoever. That alone does not make these classes of steel overrated.

[vivi]

. Wish H1 was included like others in the corrosion resistant 10 rating: LC200N and Vanax. I have some knives in H1 and LC200N but not Vanax yet.

Same here. H1 doesn't get much coverage from him.

[RamZar]

. Wish H1 was included like others in the corrosion resistant 10 rating: LC200N and Vanax. I have some knives in H1 and LC200N but not Vanax yet.

Same here. H1 doesn't get much coverage from him.

This is what Larrin said in regard to H1:

It would be interesting to see a side by side comparison of Vanax SuperClean, LC200N and H-1 just in terms of extreme corrosion resistance.

My standard saltwater corrosion tests failed to corrode Vanax or LC200N so I would need different tests to differentiate them. There are a few options but I'm not excited about any of them. H1 I don't have in flat stock so that would be more challenging to compare.

[TkoK83Spy]

I honestly don't care what the stats say. Everyone cuts different material, at different geometry, different finishes, different sharpening abilities. Too many people rely on this stuff instead of doing their own personal testing and figuring out what works best for THEM. No disrespect to Larrin, but many sheep read these graphs and just go with it blindly without any of their own experiences.

Some of these comments I've read blow my mind and honestly make me wonder if people have ever actually sharpened a knife (hitting the Sharpmaker on the browns or white rods IS NOT SHARPENING)...or used it consistently through various materials to really even be able to form an honest opinion on the capability or traits of all these steels.

[BornIn1500]

1. VG-10 is a pretty underrated steel. It has the same toughness and edge-retention as s30v, with only a bit worse edge retention.

That's a strange way to write it. It's not the same edge retention. On a scale of 0-10, he has VG-10 as a 4.5 and S30V as a 6. That's a substantial jump in edge retention. I would have assumed VG-10 would at least be a little more tough, but it's not. Larrin proves that there really is no benefit for using VG-10 over S30V other than the lower price.

1.5 points on the edge retention scale isn't small. To say a 4.5 is basically a 6 isn't realistic. That's like saying 8cr at 3 is the same as Vg-10 at 4.5.... cause it's only 1.5 difference....

EDIT: maybe you meant "it has the same toughness and corrosion resistance " and made a mistake. In that case the sentence makes sense.

[James Y]

VG-10 is a good steel. It may not be “super,” but in some ways I’ve liked it more than S30V, even though the latter steel is harder.

Every single steel used in every knife doesn’t have to be the “latest-greatest super steel.” For those who seek that, there are plenty of examples available.

Jim

[Vaugith]

[...]

I got a REX 45 Native Chief I use every day landscaping and cutting copper wire. Rockwell 68. And I got the S30V version of the Chief. With a VG10 Endura. And a Byrd hawkbill in the all mighty 8cr13mov garbage that should have died off 20 years ago. Guess which one has chips and needs more sharpening. It sure is not REX45.

[...]

I have similar experiences with rex45. There is something missing here, and I can't quite put my finger on it. Most of my tougher steels chip when gouging copper but rex45 does not. When I figured out how I like to sharpen it, it does not chip at all. I cannot get similar performance out of AEBL. Maybe the graphs that Larrin produces that include a range of edge retention or toughness results over a range of hardnesses is actually much more useful than a flat number.

[vivi]

1. VG-10 is a pretty underrated steel. It has the same toughness and edge-retention as s30v, with only a bit worse edge retention.

. Larrin proves that there really is no benefit for using VG-10 over S30V other than the lower price.

numbers on a graph aren't the be all and end all.

VG10 sharpens up faster and takes a high polish edge with more ease.

Sharpening response is very important. All the edge holding in the world won't matter if you can't get a good baseline edge to begin with.

[GautamGoel]

1. VG-10 is a pretty underrated steel. It has the same toughness and edge-retention as s30v, with only a bit worse edge retention.

That's a strange way to write it. It's not the same edge retention. On a scale of 0-10, he has VG-10 as a 4.5 and S30V as a 6. That's a substantial jump in edge retention. I would have assumed VG-10 would at least be a little more tough, but it's not. Larrin proves that there really is no benefit for using VG-10 over S30V other than the lower price.

1.5 points on the edge retention scale isn't small. To say a 4.5 is basically a 6 isn't realistic. That's like saying 8cr at 3 is the same as Vg-10 at 4.5.... cause it's only 1.5 difference....

EDIT: maybe you meant "it has the same toughness and corrosion resistance " and made a mistake. In that case the sentence makes sense.

Yes, that's what I meant to write.

[Fireman]

Dr. Larrin, can you please add S7 to the new charts? S7 is a steel being used to make knives and so I assert that it has merit enough to be a part of the party. It is my “Zombie Apocalypse” steel of choice.

[Karl_H]

. Wish H1 was included like others in the corrosion resistant 10 rating: LC200N and Vanax. I have some knives in H1 and LC200N but not Vanax yet.

Same here. H1 doesn't get much coverage from him.

Larrin wrote a very comprehensive article on H1. It would get a 10 rating for corrosion resistance (no visible rust in salt spray test). If you want a knife steel that will not corrode in seawater, you essentially have 3 choices in production knifes: H1, LC200N, and Vanax.

https://knifesteelnerds.com/2019/06/24/ ... -it-works/

Larrin seems to be willing to test knife steels, as long as people can provide him with the raw material. Keep in mind that it requires time, money, and special equipment to do all of the testing that Larrin does. His work shouldn’t be taken for granted. If you really want him to do testing on a particular steel, check out: https://knifesteelnerds.com/how-you-can-help/

[vivi]

. Wish H1 was included like others in the corrosion resistant 10 rating: LC200N and Vanax. I have some knives in H1 and LC200N but not Vanax yet.

Same here. H1 doesn't get much coverage from him.

Larrin wrote a very comprehensive article on H1. It would get a 10 rating for corrosion resistance (no visible rust in salt spray test). If you want a knife steel that will not corrode in seawater, you essentially have 3 choices in production knifes: H1, LC200N, and Vanax.

https://knifesteelnerds.com/2019/06/24/ ... -it-works/

Larrin seems to be willing to test knife steels, as long as people can provide him with the raw material. Keep in mind that it requires time, money, and special equipment to do all of the testing that Larrin does. His work shouldn’t be taken for granted. If you really want him to do testing on a particular steel, check out: https://knifesteelnerds.com/how-you-can-help/

I'm at work so I only had time to glance back over it, but IIRC he didn't mention anything about SE vs PE in this article, did he?

I'll check out the second link later tonight.