It contains 7.75 percent chromium, so it is not stainless, but is reasonably corrosion resistant. Cruwear is right in the middle of toughness, wear resistance, and corrosion resistance. It falls between simple carbon steels and super powder metallurgy steels. It's one of the few blade steels that can boast it has a good standing in all three of those categories.
Crucible calls it an air hardening tool steel. It can be considered an improved D2, the big improvement being the addition of vanadium, but they also add tungsten. CPM Cruwear is made via particle metallurgy, and is what knife makers like Spyderco use. Cruwear does seem to be (or was once) available in ingot form, but if so, this is moot since knife makers seem to exclusively use CPM Cruwear.
To sum it up, it is "well balanced" -- and a dream to sharpen.
From the above link:(from elena86:)
My all time favorite steel for plain edges. It exibits almost perfect balance of properties: excellent toughness, very good edge stability, it sharpens like a dream and has more than decent corrosion resistence.
(from The Mastiff:)
It's tougher than the stainless steels like S30V, M390, S90/S110V etc.
It's more wear resistant than the tough steels S7, L6, 5160 on up through A2 to about 3V.
It's between D2 and S30V in wear resistance but tougher than either.
It is less corrosion resistant than the stainless steels but more corrosion resistant than the 1% carbon steels like 1095, 52100, etc.
I does better with thinner edges than the stainless steels that have greater wear resistance like S30V, M390, etc.
It compares favorably to 3V and some choose it over 3V for a "hard use" folder. It seems that the Spyderco Mule is the only production knife, if you can call a mule a production knife.
Tom's Knife Info / tom@mmto.org