440C Steel

Description

440C is one of the most well-known stainless knife steels. Developed in the 1950s, 440C was the standard for high-quality stainless knives for decades. Still widely used in pocket knives, kitchen knives, and medical instruments.

Composition

Element	Content
Carbon (C)	1.0 %
Chromium (Cr)	17 %
Molybdenum (Mo)	0.75 %
Manganese (Mn)	0.5 %

Properties

Property	Value	Rating (1-10)
Hardness	58–61 HRC	—
Toughness	5–6 ft-lbs at 60 HRC	5/10
Corrosion Resistance	Good (Cr in solution ~12–13 %)	7/10
Edge Retention (CATRA TCC)	~400–450 mm at 60 HRC	5/10
Carbide Volume	~15–17 % (chromium carbides Cr₇C₃)	—
Grindability	Good	7/10

Microstructure

440C contains mainly chromium carbides (Cr₇C₃) with a carbide volume of about 15–17 %. The high carbide volume leads to good wear resistance but moderate toughness.

Heat Treatment

Step	Temperature / Duration
Austenitizing	1040–1065 °C
Quench	Oil
Tempering	150–200 °C (2×)
Achievable Hardness	58–61 HRC

Steel	C	Cr	Hardness	Corrosion
440A	0.7 %	17 %	56–58 HRC	9/10
440B	0.85 %	17 %	58–60 HRC	8/10
440C	1.0 %	17 %	60–61 HRC	7/10
N690	1.05 %	17 %	58–60 HRC	7/10
VG10	1.0 %	15 %	59–61 HRC	8/10

Pros and Cons

Pros:

Good corrosion resistance
Proven performance for decades
Widely available
Easy to grind
Good wear resistance

Cons:

Limited toughness due to high carbide volume
Moderate edge retention compared to modern PM steels
Not suitable for extreme applications

Conclusion

440C remains a solid all-round steel for stainless knives. While modern steels like S35VN, MagnaCut, and 14C28N offer better property combinations, 440C is still a reliable choice for many applications.