440C
Blade steels
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 |
Comparison with Related Steels
| 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.
Sources
- Knife Steel Nerds: 440C – The Classic Stainless Steel