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440A is a conventional stainless knife steel with useful corrosion resistance and modest abrasive edge retention. It can suit occasional cutting when the knife is well made and you are comfortable maintaining its edge. It is a distinct grade from 440C, with a different wear-and-corrosion balance rather than simply the same steel under a shorter name.
What Is 440A Steel?
440A belongs to the 440 family of martensitic stainless steels. The selected Carpenter specification gives carbon and chromium ranges and maximum limits for several other elements. A blade marked only 440 does not identify the suffix, so it should not automatically be described as 440A or 440C.
Performance Ratings
For the science, we turn to Dr. Larrin Thomas of Knife Steel Nerds, who has kindly allowed us to share his ratings here.
| Property | 440A |
|---|---|
| Abrasive edge retention | |
| Toughness | |
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
Explore 440A’s Tradeoffs
Choose a steel above to highlight its position and see all three exact ratings below. The full map fits your screen.
Stainless
440A
- Abrasive edge retention
- 3.5
- Toughness
- 3.5
- Corrosion resistance
- 8.5
Same position; corrosion ratings may differ:
All 48 rated materials. Numbers group steels at identical coordinates; colors describe stainless classification, not corrosion scores. Neither direction means a universally better knife.
440A’s ratings are shown above. Enable JavaScript to select another steel, or browse the full ratings table.
Edge Retention Compared with 440C
440A scores 3.5 for abrasive edge retention, compared with 440C at 4.5. That is a lower wear rating, so 440C may be more relevant when abrasive edge life is the priority. For small, occasional tasks, the quality of the edge and the design of the knife may matter more to you than that difference.
Our 440C profile looks at that different balance of wear and corrosion resistance.
Does Lower Carbon Mean More Toughness?
Not automatically. 440A and 440C both receive a toughness rating of 3.5 in this framework. The lower carbon range is not enough to claim that every 440A blade will be tougher. For resistance to edge damage, look at the complete knife and consider steels with a higher toughness rating if that is your main need.
Corrosion Resistance and Sharpening
440A has a corrosion-resistance rating of 8.5, higher than 440C's 7.5. That is a useful part of its balance for ordinary exposure to moisture. Clean and dry the knife after use, since residue and trapped water can still affect it.
Suitable conventional sharpening stones can be used for 440A. Keep a consistent bevel angle and remove the burr before deciding that more grinding is needed. For routine use, a simple maintenance approach can be enough; diamond abrasives are an option rather than a requirement imposed by the stainless label.
When Is 440A a Reasonable Choice?
440A can be reasonable in a sound knife at a price that makes sense for its design and quality. Inspect fit, edge condition and handle comfort instead of making the decision on the steel name alone. If the knife will do frequent abrasive cutting, a more wear-resistant grade may justify extra cost; for light use, you may not need that tradeoff. Our knife steel guide explains the alternatives.
Composition
Our steel composition guide explains what the elements do and how to read these values.
440A: Carpenter Type Analysis ranges and maxima, mass %. Iron is the balance; values describe this source rather than every producer’s material. Carpenter Technology: 440A alloy data sheet.
| Element | 440A |
|---|---|
| Carbon (C) | 0.6–0.75% |
| Chromium (Cr) | 16–18% |
| Molybdenum (Mo) | ≤0.75% |
| Manganese (Mn) | ≤1% |
| Silicon (Si) | ≤1% |
| Phosphorus (P) | ≤0.04% |
| Sulfur (S) | ≤0.03% |
