There are many steel types out there so it is nice to know a bit about them before you buy a knife. Here are the types of steel that I carry in the shop, if you have any further questions please do not hesitate to contact me and I will do my best to answer any questions.
Generally, Japanese knives are made with harder steel than some of your more common western knives. This is great because it means you can sharpen to a more acute angle, and they get much sharper. The downside to having hard steel however, is that it can chip. I think this is a small price to pay if you want a proper sharp knife. Steel hardness is tested on the Rockwell scale. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. So the higher the number, the harder the steel.
VG10: A common steel type used in Japan, VG10 was designed for kitchen cutlery but has now made its way to sporting knives (hunting and fishing) as well. It is a stainless steel with a high carbon content. The metallurgy breaks down as such, 1% Carbon, 15% Chromium, 1% Molybdenum, 0.2% Vanadium, 1.5% Cobalt, and 0.5% Manganese. VG10 is a very versatile steel and a great one for beginners and experienced users. It is quite durable, so you need not worry about chipping if you treat it properly. It is easy to sharpen, and has great edge retention.
SLD: Designed by Hitachi as a steel used for dies to cut and punch other steels, it has also proven itself in the Japanese cutlery world. It’s composition looks something like this: Carbon 1.4-1.6%, Chromium 11.0-13.0%, Molybdenum 0.8-1.2% & Vanadium 0.2-0.50%. This translates to a stainless steel that is quite durable and holds a razor edge. So far in my experience sharpening and using SLD steel, I find it takes a very nice edge.
POWDERED STEELS: A relatively new way to produce steel, powder-metallurgical steel is becoming popular among knife makers. The manufacturing process allows for a more evenly spread distribution of elements in the alloy, which aids in having less weak spots so the knife maker can heat-treat the steel to higher temperatures and not have to worry so much about failure. It is quite wear resistant with an even finish, which means it is less prone to chipping.
WHITE CARBON STEEL (SHIROGAMI): White carbon is a near pure carbon steel. It takes a wicked edge, and holds it for an extremely long time. Rust can form on white carbon, however when cared for properly it will develop a beautiful patina, making your knife one of a kind. White carbon is a favourite among knife sharpeners (and chefs) for its ease of sharpening. White carbon steel has a very small temperature window for hardening, which means it requires a skilled hand in the forging process.
BLUE CARBON STEEL (AOGAMI): A highly sought after steel by knife makers for being more forgiving in the forging process then white carbon, blue carbon is not as pure as shirogami. Blue carbon steel adds tungsten and chromium for rust resistance and is more wear resistant. There are 3 types of blue steel: Blue #1, Blue #2, and Aogami Super or super blue steel. Aogami super is much more rich in chemical composition and includes vanadium & molybdenum. This helps boost its edge retention and is said to be a bit tougher than #1 & #2.
No matter which way you look at it, these carbon steels are a joy to sharpen and cut with. So it really is all about personal preference.