The Mastiff wrote:Yes, Ed said that. Lets keep it in perspective though. What the competition chopper goes through does not compare in any way to what the folders we carry go through. I don't know what the impact would be in pounds per square inch but it must be pretty high considering the force, the speed of the swing, and the thinness of the edge making the impact with whatever it hits.
Edit: Found it
Even so the knives are lasting for what is a relatively long time before their work hardened edge causes it to need to be retired. Not many steels with the wear resistance of CPM M4 can take the stresses involved. 52100 has great edge stability but no way near the wear resistance of CPM M4. Apparently they can't sharpen the edges during a competition which is what caused them to look at M4 in the first place.
With the competition knives great care must be taken when making the knives to insure no stress fractures, bends or imperfections make it through. It also needs to be heat treated pretty precisely to keep it from warping, overheating, under heating, time at temp., as well as things like final hardness which is important too. I'm pretty sure more than a few perfect knives have been broken to look at the grain structure. I've left out a whole bunch of important things that I've forgotten, or don't even know about.
Is it any wonder that most of the really successful competitors are very advanced level knife makers themselves, often with sponsorships to help with the costs.
Ed was or is using a clad steel in his. I don't have any information about this and hope he gets involved in this thread. He is about as knowledgeable as one can be.
Typically the higher the wear resistance in a steel the higher the carbide fraction. Also, typically the higher the carbide fraction the lower the toughness and edge stability.
There are, I don't want to say exceptions. I'll call them "work arounds" . A clad steel custom made can be one. It can be pulled off by someone like Ed who has advanced knowledge of not only regular knifemaking, but also Damascus making , and "san mai" ( three layer) steels.
Anyways, I got slightly off topic. CPM M4 is not too weak for our uses. I have no problem keeping it rust and stain free. I too love that "bite" the carbides give it. It's another steel that can take a savage edge and I hope to see it in the regular lineup for a while.
If you hear the steel is not tough enough for competition choppers it doesn't mean anything about cutlery with normal uses. Competition choppers are to regular knives what Baja 500 tube frame "toyota" hand builds are to off the line Tundras.
By the way, I wasn't aware that 52100 is used in competition choppers. The edge stability is there but the wear resistance would be lacking in some of the really trying events. I've heard 3V is too, and it has better wear than 52100.
There is lots I need to learn about the sport. If I'm not mistaken a chip in the edge disqualifies you. Think about that when you see film of some of these thick wristed, huge forearmed guys getting amazing speed in their swings while cutting through everything from ping pong balls to framing lumber.
CPM M4 has done pretty well as have some other steels.
Joe
I agree, M4 is more then tough enough for my uses and I am sure many others as well. IMO it is one element that becomes over hyped out of a complete package. Like choclate chip cookies, it is not only the chip (toughnes) that is delicious, it is the complete package that makes it appealing.
:)
One element I think that might be of great importance for the cookie of M4 is
Molybdenum (Mo): A carbide former, prevents brittleness & maintains the steel's strength at high temperatures. Improves machinability and resistance to corrosion (Zknives.com).