440C Steel is a high-carbon martensitic stainless steel that was the industry standard for high-end knives for decades before the arrival of modern "super steels." Even today, it remains a highly respected and reliable choice for quality blades.
It is the most carbon-rich grade in the 440 series (which includes 440A and 440B).
Key Characteristics
High Hardness: It can reach a hardness of 58–60 HRC, which provides excellent edge retention.
Great Wear Resistance: Because of its high carbon and chromium content, it resists abrasion and holds its shape well under use.
Excellent Corrosion Resistance: It is highly resistant to rust from water, food acids, and the atmosphere, making it a favorite for kitchen and outdoor use.
Good Polishability: It can be ground and polished to a beautiful mirror finish, which is why it is popular for custom and decorative knives.
Chemical Composition
440C is defined by its high levels of Carbon and Chromium:
Carbon (C): 0.95% – 1.20% (High carbon for hardness)
Chromium (Cr): 16.0% – 18.0% (Very high for superior rust resistance)
Manganese (Mn): 1.0%
Molybdenum (Mo): 0.75% (Increases toughness)
Common Equivalents
9Cr18MoV: The Chinese equivalent, often seen in high-quality budget knives.
N690: An Austrian steel that is essentially 440C with added Cobalt to improve edge stability.
Common Applications
Classic Pocket Knives: Still used by many traditional makers and brands like Boker.
Mid-Range Kitchen Knives: Especially those requiring a balance of sharpness and low maintenance.
Industrial Components: Used for ball bearings, valve parts, and surgical instruments due to its hardness and stainless properties.