I had the pleasure to chat extensively with a Bohler-Uddeholm rep at the BLADE show this weekend, and (among other things) I asked him lots of questions about Calmax, specifically as it might be used in knives, and how it might compare to CPM-3V.
With regards to the advantages over 3V, from what I understand it is way tougher, very easy to grind when it does suffer damage...
The B-U rep I spoke with did
not claim that Calmax is tougher than 3V, nor does their published info on the Charpy tests claim that. In fact, in B-U's own published testing literature, at normal knife hardnesses like 58Rc and 61-2 Rc, Calmax is noticeably
less tough than CPM-3V (according to Crucible's reports). Both are still far tougher than D2, but less tough than S7.
Grindability indeed looks to be quite high; that also means edge-retention will be correspondingly low.
...does not have the carbides 3v has making it more suitable for thinner and more acute edges.
It's pretty clear that Calmax was not designed with fine edges in mind. It's a punch and die steel, not a cutting steel.
Let's keep in mind that CPM-3V has a fairly low percentage of carbides, and they are quite small and evenly-distributed. We're not talking about D2-type chunks of carbides here. I have never had a problem getting a very fine crisp edge on CPM-3V, and neither have independent parties who've tested my knives and others'. Let's also consider that those fine, very hard carbides add a good deal of wear-resistance without sacrificing superior toughness.
What I heard from the rep is that Calmax was not designed for cutlery at all, and quite frankly he was not one bit enthused about using it for knives. He was somewhat surprised that I was even considering it. In fact, after hearing that I'm accustomed to using 3V and Elmax, and looking over one of my standard models with an acute bevel and thin edge, he pretty much talked me out of even bothering with Calmax... he just didn't see any advantage to it.
Bohler-Uddeholm does indeed make several other alloys that are
excellent for knife blades, including M390 and Elmax. They also have other grades forthcoming, that may prove to be very interesting for knifemaking purposes.