Practical differences between A2 and CPM 154

[gofastalot]

I know A2 is not "stainless" and CPM is, and I've seen the metal compositions, but beyond that what are the differences? I've searched all morning to learn about CPM 154 and A2 but haven't found much in the way of real-world differences between the two steels. Please help.

 

[Varulv]

you should get the A2 Bravo-1 lol it's less expensive but not stainless...

A little patina or rust don't hurt

 

[A.P.F.]

I know A2 is not "stainless" and CPM is, and I've seen the metal compositions, but beyond that what are the differences? I've searched all morning to learn about CPM 154 and A2 but haven't found much in the way of real-world differences between the two steels. Please help.

The true steel gurus on the forum will have more information, but in general, non-stainless steels are tougher than stainless steels, which make them well suited for hard use fixed blades such as combat knives. CPM154 is a 'Particle Metallurgy' stainless that has good toughness for a stainless as well as good wear resistance and a refined grain structure. CPM154 takes a fine edge and holds it for a long time, yet is not a bear to sharpen. You will find the CPM series of steels used extensively for folders.

 

[gofastalot]

you should get the A2 Bravo-1 lol it's less expensive but not stainless...

A little patina or rust don't hurt

So you knew I was asking about the Bravo 1.

It seems the CPM offers stainless and a little better edge retention but at the cost of toughness, although they "appear" to be close based on what I've been reading.

I was hoping someone had both and could offer some opinions based on real use instead of the theory, which I've been reading a lot of. If its just stainless and really not much other benefit, I have to decide if its worth a $80+ premium over A2

 

[AMRaider]

Generally A2 will be a bit tougher, and of course 154CM* will be more stain resistant. As for wear resistance, I would wager 154CM to be the winner. It has 4% Mo verses A2's 1.1% Mo which (assuming proper heat treatment) should take the place of Cr in forming carbides. Molybdenum carbides are harder than Chromium carbides (75 HRC vs 67 HRC, source: BladeMag June, 2009) and 154CM should have more of them than A2. Granted A2 does have some Vanadium (0.25%), but the quantity is so low, I suspect it's purpose is mainly for keeping the grain size small rather than forming carbides (Vanadium carbide hardness 80-85 HRC, source: BladeMag June, 2009).

Anyway, between the two steels you mentioned, if it's for a big fixed blade I'm going to thrash, my preference would be for A2. For a folder, 154CM. YMMV, of course.

*The CPM version of 154CM should exhibit a slight increase in toughness over the regular version. However, I would tend to doubt CPM 154CM's tougness would rival A2's. A2 at RC 60 will yield about 40 ft-lbs impact toughness versus 25-28 ft-lbs for regular 154CM in the high 50s RC.

 

[Jeff Clark]

A2 is a tool steel that is commonly used to make things like drill bits. You can buy drill rod that is made out of A2. It is on the tough side of the tool steel spectrum rather than the hardest side. It performs well at around 60 RC hardness. It takes a very fine edge, particularly compared to CPM154. So A2 will be tougher and get sharper than CPM154. The CPM154 is packed with hard carbides of a relatively fine size. It will hold its edge longer than A2, but will not take the kind of razor edge as A2. It is also stainless.

For many people CPM154 is a superior steel, I'm just not one of them.

 

[Neo]

If its just stainless and really not much other benefit, I have to decide if its worth a $80+ premium over A2

Jeff said it all

Did you go to the Bark River forum?
Mike Steward says in every day use you won't find much difference between a Bravo in A2 or CPM 154.
It all comes down to the stainless part and I personally find the patina of A2 adds character.