Lay down some knowledge on us! What's the difference between A2, O1, 1095CV, Infi, Elmax and Vanadis?
Well, they're all mostly iron
1095 and
O1 are classic, low-alloy, fairly simple "carbon" steels with very little carbide content. Their greatest attributes are fine grain, which makes them tough and easy to get a very crisp edge on, and the fact that they're inexpensive and easy to work with. They have essentially no corrosion-resistance as we think of it. I prefer O1, 1095CV and
52100 over plain 1095 because they do have a splash of added carbide-forming elements, which help with edge retention without sacrificing toughness or making them difficult to sharpen.
In the early-mid part of the 20th century, industry started adding more alloying elements like chromium, tungsten, vanadium, molybdenum etc. to steels, mainly in a quest to increase wear-resistance properties and stability at high temperatures ("hot hardness" or "red hardness"... meaning it doesn't lose its temper under stress/friction). This results in what we typically call "tool steels" today. (Not tools as in wrenches and screwdrivers, but cutting tools like mills and drill bits)
A2 is a very well-known tool steel, not all that different from the simpler steels except that it has around 5% chromium. At those levels the chrome is mostly tied up in carbides, which again adds wear-resistance. D2 is also a tool steel, but it has a lot more carbon and a lot more chrome, which makes for lots more carbides and much better wear resistance - but it sacrifices a lot of toughness.
INFI is an interesting alloy - as a proprietary alloy, it's hard to really get a handle on exactly what's in it; it kind of depends on whom you ask. But at the risk of over-simplifying things, it's "basically" a high-grade, high-speed tool steel. Although they're quite different chemically, INFI and
CPM-3V are very similar in performance, offering a great balance of very high toughness and very good wear-resistance, with moderate corrosion-resistance. Unless corrosion-resistance is a big issue, CPM-3V is my favorite steel.
Steels like
Elmax and
Vanadis 4 are really a whole 'nother ball of wax. They have very high levels of alloying elements, and rely on costly third-generation powder metallurgy manufacturing techniques to maintain a fine grain/carbide structure and thereby retain high levels of toughness. They are an outgrowth of "powder" steel technologies that gave us steels like CPM-154 and CPM-S35VN.
This technology has evolved to such an extent that we now have "stainless" steels like Elmax and
CTS-XHP that exhibit excellent edge-retention, can support very fine, keen edges, and levels of toughness that often meet or even exceed those of many plain "carbon" steels.
Which would be best(price, edge retention, etc) for a small slicer, by slicer I mean NOT a woods knife but an actual slicer.
For price, you can't beat 1095. For edge retention my choice would be Elmax at 62Rc... which has an added benefit of good corrosion-resistance. But honestly, all these steels will work
very well for a pure cutting implement... as long as the geometry is good and the HT is top-notch, you really can't go wrong with any of them.
Geometry cuts. Alloy selection and HT determine how long a knife
keeps cutting.