I don't see any advantage of M2 over A2 in regards to knife steels as its primary advantage is of no use (it retains high abrasion resistance at extreme temperatures). Comments by knifemakers in regards to ELU advantages are welcomed. As for A2 over 440V it depends on if you want high toughness or abrasion resistance. Both factor into edge holding depending on what you cut. High toughness (charpy value) means the edge will resist rolling, impacting and chipping strongly and can be taken to a much lower included angle. High abrasion resistance simply means it takes longer for the edge to wear away.
Something to think about :
A2 : 60 RC : Charpy 21 : Wear resistance : 2-3
CPM-440V : 56 RC : Charpy 18 : Wear resistance 15/25
CPM-440V : 58 RC : Charpy 13 : Wear resistance 20/30
CPM-440V : 59 RC : Charpy 12 : Wear resistance ?
CPM-440V : 60.5 RC : Charpy 11 : Wear resistance ?
These are straight from the CPM sheets :
I assume that 3-4 and 20/30 are ranges.
You can see that A2 would have a much tougher edge (and a much higer yeild strength) and that 440V would have much better wear resistance. Deciding between the two means that you have to figure out how much of each property you need. For example if the extra toughness of A2 is of no use then obviously you get 440V. However if 440V chips out during regular use its high abrasion resistance is of no value.
Note in regards to CPM-440V, while people have commented on its weakness before (broken tips mainly) Sal Glesser has stated that is as as tough as any other steel they have used
For me, that means that the gloves are off when my new Military comes in.
Another aspect to consider is the kind of edge that each takes. According to MPS, A2 scores very high in this respect. It is better than Boye's 440C, which is saying something.
[This message has been edited by Cliff Stamp (edited 19 May 1999).]