Steel makers follow a precise recipe to ensure that each time they make a particular alloy it has correct properties. The recipes are known as Specifications, and they specify the amount of each alloy. Each alloy recipe or type is named according to a number convention.
Sandvik 12C27: Stainless steel made in Sweden. Known as a premium steel.
Easy to sharpen, plain carbon steel used in knife making.
D2 Steel: A high-carbon, high-chrome tool steel often used for blanking dies. This steel has excellent edge holding ability but is very difficult to process.
S30V: Developed primarily for the cutlery industry by Crucible Steel, S30V contains noticeably higher amounts of Carbon and Vanadium than does BG-42. This increase in Carbon and Vanadium provides superior edge-holding and abrasion resistance. S30V is the best blade steel available today.
BG-42: A proprietary alloy of Timken Latrobe Steel, BG-42 is a high-performance, bearing-grade martensitic stainless steel used in the aerospace industry. Because of its high strength and ability to reach high Rockwell hardness (Rc 61-62), BG-42 is well suited for blades that are subjected to extreme use.
154CM: 154CM is a very high carbon stainless steel with the addition of Molybdenum. Because 154CM provides better edge retention than standard cutlery (stainless) steels, it is a good choice for blades that require heavier cutting applications.
420HC: A higher carbon version of standard Type 420 martensitic stainless steel. The Carbon content, combined with the high Chromium content, provides good abrasion resistance and edge-holding.
420J2: A lower carbon content, general-purpose stainless steel. 420J2 has fair hardness and corrosion resistance and high ease of resharpening. 420J2 is suited for knife blades with light to medium use and routine applications.
17-7 PH: A Chromium/Nickel/Aluminum, precipitation-hardening, stainless steel. The alloy is used for high-strength applications requiring resistance to salt-water corrosion. 17-7PH offers a good compromise between Martensitic stainless steels and Austeniticstainless steels.
N690: A Martensitic stainless steels, can reach HRC 60 after twice heat treat. It contains 1.07％carbon, 17％ chromium, 1.50％ cobalt, 0.4％ manganes,' 0.4％ silico,' 1.1％molybdenum and 0.1％vanadium.
AUS stainless steel: AUS comes in several grades. AUS-4 is 0.40% to 0.45% carbon, but AUS-10 is 0.95% to 1.10% carbon. The level of chromium is 13% to 14.5%, less than the 440 varieties but still enough to ensure a stainless blade. Generally speaking, AUS-10 knives will be more expensive than the other three AUS varieties.
440 stainless steel: The most common type of stainless knife steel is 440. It comes in three varieties, which have different amounts of carbon and other metals they contain. On the low end is 440A, which has 0.65% to 0.75% carbon. On the high end is 440C, which has 0.95% to 1.20% carbon. All 440 steels are 16% to 18% chromium, which contributes to their stainless quality.