SK-5 is not an equivalent of 1080. While SK-5 has a smigde more carbon, it is further alloyed with other elements.
http://www.zknives.com/knives/steels/steelgraph.php?nm=1080
http://zknives.com/knives/steels/sk5.shtml
As for Carbon V, my understanding is that it was Sharon Steel 170-06. It’s what Kabar is currently calling “1095 CroVan”.
http://www.zknives.com/knives/steels/Sharon_Steel/1095_cro-van.shtml
So how I heard it, was that Camillus was making Cold Steel’s US Made Carbon V knives. When Camillus went belly up, Coldn Steel went to China/Taiwan for manufacturing, and switched to SK-5. Kabar bought up Camillus’ remaining Sharon Steel. Looking at the alloying elements, SK-5 is further alloyed than simple 1095.
http://www.zknives.com/knives/steels/steelgraph.php?nm=1095
SK-5 is closer to 1095 CroVan, than it is to 1095, 1080, or 1075.
The Sharon steel has more carbon and chrome, with Vanadium for toughness, but SK-5 gets there with Nickel. The Sharon Steel will have the edge (pun intended) in higher hardinability-but at the same Rockwell, the steels would be virtually indistinguishable to the user.
Bottom line, SK-5 is an alloyed Steel, where as 10XX are pure Carbon Steels.
And Carbon V is an alloyed Steel.
As for Aus8a (Cold Steel used annealed Aus8) it will commonly get compared to 440B because of the Carbon levels, but 440B has more chromium. Aus8 has Nickel and Vanadium, which 440B does not. I notice that AUS8 both gets sharper, and holds its edge better than 440B. It’s also more prone to staining, but is tougher.
Cold Steel’s heat treat of Aus8 is 2nd to none as well.
If I had to choose between the Japan made AUS8 SRK, and the Taiwan made SK-5 SRK, I’d choose the AUS8 blade (not that the SK-5 SRK is a lacking knife in the least). More stain resistant/less maintenance. Similar edge retention at its hardness, and adequately tough-it can withstand extensive gross abuse. There have been some nasty destruction tests of the 8A SRK, and the blade just shrugged it off.