Steels?

[Sure Shot Rick]

BM 440C, Aus-8, 154CM, ATS34, CPM154, Scandinavian Steels VG10. SAMi laminated, what is it’s core steel? I am confused. I see where MB is replacing the 440C in some of their knives with 154CM. Seems to me, most of what I read, says that BM440C is great stuff and the majority of what I have read is only so so on 154CM. Seems to me most people rate ATS slightly ahead if 154CM. Then there is the CPM154 as used in the Speckbump. How does it compare to the SV30 that has replaced it, and what’s up with the Scandinavian Steels? I keep reading that they are under rated but the steel charts do not inspire me. What is in the core of Cold Steels laminated blades? Is it comparable to VG10? BM440C CPM154 or VG10 any preferences out there? Where does Aus-8 fall into things? Finally is Carbon V pronounced Carbon five or Carbon Ve and is it an improved 1095

 

[Alpha Knife Supply]

ATS-34 was a copy of 154CM. The quality of ATS-34 was high. Over time the quality of 154CM went down. Most custom knifemakers changed to ATS-34.

In the last few years several custom knifemakers have had problems with the quality of ATS-34. At the same time Crucible improved the quality of 154CM. Now lots of custom knifemakers are switching back to 154CM.

CPM154 is very similar to 154CM using the particle metallurgy process. It is a very high quality clean steel. It does not hold an edge as long ass S30V but it finishes nicer.

 

[bama_lou]

ATS-34 was a copy of 154CM. The quality of ATS-34 was high. Over time the quality of 154CM went down. Most custom knifemakers changed to ATS-34.

So, which one came first, ATS-34 or 154-CM? I thought that 154 was the American version of the ATS-34?

 

[me2]

Just looking at steel charts can be deceptive. The core of the current Cold Steel laminate is AUS 8 IIRC. The older stuff I dont know about. 154CM is fine for stainless, and it may push me to buy another BM 42, since they changed to 154CM from 440C, which was a change from Sandvic 12C27, probably my favorite stainless knife steel. AUS 8 as done by Benchmade in the Ambush series is impressive. They harden it higher than most companies and it shows when sharpening. The burr that forms is smaller, easier to remove and the edge is crisp and long lasting. These 2 knives have fairly thin edges as production folders go, so sharpening time shouldnt be an issue. I dont know much about ATS 34, as I've only had one knife from it and gave it to a buddy when he went into the Navy. The current concensus here in BF is that Carbon V (dont know what pronunciation) is 50100B = 0170-6, whatever Becker Knife and Tool uses. I will vouch for the edge holding and taking of Carbon V, whatever it is, as the edge on an old scalping knife was amazing, shaving steel at 15 degrees per side. And yes, it is an improvement over 1095, in terms of hardenability and strength, and possibly edge holding when done properly.

 

[mete]

154CM was developed by Climax Molybdenum Co, [thus the CM] Crucible bought the rights.154CM is an improvement over 440C. Hitachi copied it as ATS-34. Now Crucible also makes CPM 154 which may turn out to be a real winner. ....Though AUS-8 is a good steel CS could have picked a better steel for their laminate.....VG-10 is a japanese steel and an excellent one as I found in the Shun kitchen knives and now in a Fallkniven S-1.

 

[Cliff Stamp]

...what’s up with the Scandinavian Steels? I keep reading that they are under rated but the steel charts do not inspire me.

They have the ability to achieve full martensite hardness, high corrosion resistance and have very fine carbides, it has to do with the carbon/chromium balance, Verhoeven discusses this in detail. Unfortunately most leave the steel really soft so none of this is actually realized. Devin Thomas has a nice page on it as well.

-Cliff

 

[nozh2002]

Devin Thomas has a nice page on it as well.

-Cliff

I am curious about Devin Thomas page - he mention 79 Rocweel scale C, which is on my knowledge out of scale C range.

Thanks, Vassili.

 

[M Wadel]

and dont forget about the RWL-34 its the same as ATS34 and CPM154, but with a little V added. the CPM154 and RWL should be able to reach 62-63 hrc

 

[gud4u]

The performance characteristics of various steels are fine for assessing general performance characteristics, but blade-makers often modify performance properties to emphasize a particular characteristic, such as toughness or edge-holding.

For example, I have an early Spyderco Military 440V blade tempered to emphasize edge-holding (high hardness). The blade holds an edge very well for general slicing, but using it in the garden for a task such as root-cutting results in serious edge-chipping. Edge repair was a bitch.

I performed a similar task yesterday (planting 6 shrubs) with a Buck/Strider Tarani folder with ATS34 blade with no edge-chipping at all. Edge repair was quick and easy. A very nice combination of edge-holding and toughness.

Both blades are steeply beveled to about 22 - 25 degrees included angle.

Spyderco makes excellent folders - this early high-hardness 440V blade was a 'mistake' in that single early model only, soon corrected by Spyderco - just an example of how blade-makers can alter blade performance properties - intentionally or by error.

In the end, selecting a blade-maker on their performance reputation is at least as important as selecting a popular blade alloy material. Perhaps the best criteria for selection might be Cliff Stamps test-to-destruction reviews of a prospective knife model.

 

[Sal Glesser]

Hi Rick,

Steel used for knife blades is rarely made specifically for knives.

(I know Crucible, Hitachi, Takefu and Aichi do make blade specific steels. there are no doubt others as well, but in the world of steels, these are "small potatos").

So most steels used for knives will be "imported" from other industries. Steels that just happen to have the right properties to make good knife blades.

Steels like 52100 (carbon steel) and BG-42 (stainless) are both ball bearing steels. It seems ball bearing steels can make good knives.

154cm had added moly in stainless to prevent "high temperature creep" in Boeing's jet fins. The combination worked well for blades.

In knife steels, the major properties sought after are;
Edge retention (abrasive resistance), toughness, and corrosion resistance.

In custom knives, there is also the "look" of some steels when finished. Some steels will "get sharper" than others due to very fine grain structure, but most hardenable steels will get razor sharp.

Edge retention will determine how often you will need to sharpen the edge.

Toughness means it won't break.

Corrosion resistance means in will be less likely to rust or require less maintenance.

With that said,

makers are always trying to find the best "balance" of the above properties. The best usually cost the most to purchase and to process.

New technology (eg; particle metalurgy, nitrogen based steels, etc.) broaden the available materials. These new technologies, being in early stages of development are even more costly.

Manufacturers change steels or make a change in the process used to make their models for a number of possible reasons;

They are trying to improve the performance of the model.
They are trying to maintain a price point for a model and rising steels
costs take them past the requuired threshold.
They are having problems getting a particular steel.
They are having problems with the performance of the steel.
They are getting requests from their customers to make the change.

There are probably some I'm missing but I think you can see what I mean.

sal

 

[HoB]

How about hardenability. I know that even a moderate amount of carbon is sufficient max hardenability, but I though certain elements (and carbon) was added to improve hardenability?

 

[Cliff Stamp]

I am curious about Devin Thomas page - he mention 79 Rocweel scale C, which is on my knowledge out of scale C range.

Carbides and similar are often extrapolated off of the HRC scale just for reference.

-Cliff

 

[steeldust]

Thanks for the info Sal! "In knife steels, the major properties sought after are;
Edge retention (abrasive resistance), toughness, and corrosion resistance. "

As a ELU I find that ease of resharpening is very important. So I won't buy a knife in ATS-55 which I find hard to sharpen. I look for knives in 440c, VG-10, AUS-8, and AUS-10 that are easy to sharpen. Sal, Does the average ELU sharpen their knives?