Where does ATS-55 stand?

Joined
Feb 6, 2000
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Well, as you may know, ATS-55 was created to get ATS-34 performance at a much cheaper price. This was a partial success. While ATS-55 is cheaper (maybe much cheaper) than ATS-34, it also has quite a bit less edge retention. So, it's a comprimise between price and performance. I'm pretty sure it has better edge holding than AUS-8. Maybe edge-holding along the lines of between 440-B and 440-C . A good bang for the buck, I'd say. Spyderco uses it quite extensively.

This came from the Bladeforums knowledge base on steel types:

"ATS-55
Similar to ATS-34, but with the moly removed and some other elements added. Not much is known about this steel yet, but it looks like the intent was to get ATS-34 edge-holding with increased toughness. Since moly is an expensive element useful for high-speed steels, and knife
blades do not need to be high speed, removing the moly hopefully drastically decreases the price of the steel while at least retaining ATS-34's performance. Spyderco is using this steel."

I think that if you do a search for ATS-55 , you'll get plenty of information. I think I remember reading a post that wasn't too kind about ATS-55's performance, but I may be wrong.

Hope that helps!
 
Joined
Jan 28, 2000
Messages
131
My Wayne Goddard Lwt. has been my EDC since
November 99,and Wegner is also my EDC.
Honestly,I can't tell the difference between Wegner and Wayne Goddard Lwt. regarding edge-holding ability.
 
Joined
Feb 18, 1999
Messages
6,209
I find the edge-holding is better than AUS-8. I find that on some of my ATS-55 knives the blades pick up rust very easily. On other knives of the same steel they don't. (Both types would be satin finished).

ATS-55 is also pretty easy to resharpen, but that could also have to do with the fact the knives I had to resharpen with ATS-55 were beveled in such a way that back-beveling was unnecessary.
Jim
 
Joined
May 26, 2000
Messages
1,922
<font face="Verdana, Arial" size="2">"ATS-55: Similar to ATS-34, but with the moly removed and some other elements added. Not much is known about this steel yet, but it looks like the intent was to get ATS-34 edge-holding with increased toughness. Since moly is an expensive element useful for high-speed steels, and knife
blades do not need to be high speed, removing the moly hopefully drastically decreases the price of the steel while at least retaining ATS-34's performance. Spyderco is using this steel."
</font>

I read this "knives don't need to be high speed" comment somewhere also. It is a simple and misleading comment in relation to the knives this forum is typically interested in (stuff you hold in hand, not that you chuck up in a milling machine) and ignores carbide content and hardness (and not attributable to Andrew Lynch, he's just quoting from elsewhere).

What typically makes a "high speed" steel suitable for high speed machining is excellent red-hardness, a property related to a materials' ability to stay hard at red-hot temperatures sometimes involved in high speed machining of other hard materials. Red hardness typically requires significant tungsten content for true high speed steels (the "M" series stuff, M2, M4, M7, etc), but apparently vanadium and molybdenum may be required along with tungsten to achieve red-hardness. These steels tend to also make good knife blades if corrosion resistance isn't a prime consideration (as the high speed steels typically don't have enough chromium to be near "stainless").

Given identical blade geometry, edge holding for slicing and general abrasion resistance seems to be a function of two things, to generalize:
1st overall steel matrix hardness
2nd content of hard carbides embedded in the steel matrix (or Cobalt-Chrome matrix in case of Stellite/Talonite).

There is significant evidence that steel matrix hardness is a primary contributor, and carbide content is a secondary but significant contributor to edge holding (i.e. soft vanadium carbide bearing materials don't hold an edge well, but simple hard steels like 1095 and 52100 will).

But the secondary benefits of hard carbides are exactly what separate the vanadium/moly bearing steels (D2, BG-42, CPM3V/10V/440V/420V, Vascowear), the tungsten/Vanadium/Moly bearing (M2), and the Moly bearing steels (ATS-34/154CM) from the more ordinary steels.

From Crucible:

"Carbide particles vary in their hardness, depending on the type of carbide:

60-65 hardened steel
66-68 Rc for chromium carbides
72-77 Rc for molybdenum and tungsten carbides
82-84 Rc for vanadium carbides."

If you believe the concepts that Crucible and others espouse (I do), that of hard carbides being a good way to increase a blades wear/abrasion resistance, and therefore increase edge retention for some (slicing) cutting tasks, then to remove Molybdenum from ATS-34 (what they did to make ATS-55) is to make a steel that is very ordinary in slicing performance, about exactly like AUS-8/10, 440B/C, GIN-1/G2, etc.

See AG Russell's and Spyderco's steel matrix for background on alloy content. Knock the 4% moly out of ATS-34 and see the similarities to AUS-8/10 and 440B/C, GIN-1:

http://www.agrussell.com/steel/index.html
http://www.spyderco.com/education/steelchart.asp


[This message has been edited by rdangerer (edited 04-24-2001).]
 
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