AUS-10 (often labeled as AUS-10A) is the top-tier, high-carbon grade in the Japanese AUS stainless steel series from Aichi Steel.
It is designed to be a high-performance competitor to steels like 440C and VG-10. In the "Cr" series hierarchy we discussed earlier, it is functionally equivalent to the premium 9Cr18MoV or 10Cr15CoMoV.
Key Characteristics
High Edge Retention: With approximately 1% carbon, it can be hardened to 58–61 HRC. This allows it to hold a sharp edge significantly longer than AUS-8.
Excellent Sharpness: Like all AUS steels, it has a fine grain structure. It can be ground to a very thin, aggressive edge that excels at slicing.
Good Toughness: Despite its high hardness, the addition of Vanadium and Nickel gives it better toughness (resistance to chipping) than many other steels in the 1% carbon range.
Reliable Corrosion Resistance: With 13%–14.5% Chromium, it is a true stainless steel. It resists rust well, though it requires slightly more care than the lower-carbon AUS-6.
Chemical Composition
The high carbon and alloy mix gives it its "premium" status:
Carbon (C): 0.95% – 1.10% (Very high; for maximum hardness and wear resistance).
Chromium (Cr): 13.0% – 14.5% (For stainless properties).
Vanadium (V): 0.10% – 0.27% (Refines grain and improves wear resistance).
Molybdenum (Mo): 0.10% – 0.31% (Increases strength).
Nickel (Ni): 0.49% (Improves toughness).
Common Applications
High-End EDC Knives: Frequently used by Cold Steel (as an upgrade to AUS-8 in models like the AD-15 or Recon 1) and Spyderco.
Japanese Kitchen Knives: A popular choice for professional chef knives because it offers a "VG-10-like" performance but is often considered slightly tougher and less prone to chipping.
Tactical Folders: Where the user needs a balance of a very sharp edge and a blade that won't snap under pressure.
AUS-8 vs. AUS-10
If you are choosing between the two:
AUS-8 is better for "hard use" where you might hit staples or wood, as it is tougher and easier to fix.
AUS-10 is better for "slicing" and everyday cutting (cardboard, rope) because it stays sharp much longer.