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The last letter in 440A or 440C matters. In Larrin Thomas’s ratings, 440C has higher abrasive edge retention while 440A has higher corrosion resistance; their toughness scores are equal. A listing that says only “440 stainless” leaves out the detail needed to make this comparison.
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 | 440C |
|---|---|---|
| Abrasive edge retention | ||
| Toughness | ||
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
Ask Which 440 Steel the Knife Uses
Carpenter’s specifications give 440A a carbon range of 0.60–0.75% and 440C a range of 0.95–1.20%. Both list 16–18% chromium. They are related stainless grades, not interchangeable labels.
Do not assume a knife marked simply 440 is 440C. If the maker does not identify the grade, a precise performance comparison is not supported by that listing.
Our 440A steel profile takes a closer look at its properties and care.
440C Favors Abrasive Edge Retention
The abrasive edge-retention scores are 4.5 for 440C and 3.5 for 440A. For repeated slicing, that makes 440C the more appealing choice when the other features are comparable.
Both receive 3.5 for toughness. The extra carbon in the published 440C range does not justify inventing a toughness advantage or disadvantage beyond the actual ratings.
Our 440C steel profile takes a closer look at its properties and care.
440A Has the Higher Corrosion Rating
440A rates 8.5 for corrosion resistance, compared with 440C at 7.5. Both are stainless steels, but the shared chromium range does not make their corrosion performance identical.
We would still wash off corrosive residue and dry either blade. A smooth finish and appropriate care matter even when the steel rates well.
The Grade Name Is Only the Starting Point
We would favor 440C for wear resistance and 440A when corrosion resistance is the stronger priority. Before buying, confirm the exact grade and look for a maker that clearly describes the knife.
These ratings cannot establish the quality of an unidentified low-cost blade. A clear specification and a useful design are more valuable than a vague premium-steel claim.
Composition
Our steel composition guide explains the elements and the differences between reported values, ranges and limits.
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.
440C: Carpenter Type Analysis ranges and maxima, mass %. Iron is the balance; values describe this source rather than every producer’s material. Carpenter Technology: 440C alloy data sheet.
| Element | 440A | 440C |
|---|---|---|
| Carbon (C) | 0.6–0.75% | 0.95–1.2% |
| Chromium (Cr) | 16–18% | 16–18% |
| Molybdenum (Mo) | ≤0.75% | ≤0.75% |
| Manganese (Mn) | ≤1% | ≤1% |
| Silicon (Si) | ≤1% | ≤1% |
| Phosphorus (P) | ≤0.04% | ≤0.04% |
| Sulfur (S) | ≤0.03% | ≤0.03% |
Compare Two Knife Steels
Sources and Update Notes
- Dr. Larrin Thomas: knife steel ratings · Property ratings; the scores describe steels rather than individual finished knives.
- Carpenter sheet
- Carpenter sheet
