440A
Data verified440A is the lowest-carbon member of the 440 high-carbon martensitic series, trading a little attainable hardness for toughness and corrosion resistance. It is used for cutlery and dental and surgical instruments.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.60–0.75 |
| Si | ≤1.00 |
| Mn | ≤1.00 |
| P | ≤0.040 |
| S | ≤0.030 |
| Cr | 16.00–18.00 |
| Mo | ≤0.75 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Delivery condition | Annealed (hardened for use) |
| Hardness (hardened) | 55–58 HRC |
| Tensile strength | 725–1930 MPa (condition dependent) |
| Density | 7.70 g/cm³ |
| Magnetic | Yes |
Heat treatment
Anneal 845–900 °C slow cool; harden 1010–1065 °C oil/air; temper 150–370 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| aisi | 440A |
| jis | SUS440A |
| gb | 68Cr17 |
Compare side by side: 440A vs 440B · 440A vs 440C
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Cutlery, surgical instruments, bearings for mild environments, valve parts.
Processing: High carbide content makes grinding and machining slow; corrosion resistance is best hardened, tempered and polished; not weldable in practice.
Need 440A from stock?
Steel.Wiki is sponsored by Shenzhen NewAsia Special Steel (Nasteel), a special-steel stockholder in Shenzhen stocking mold, tool and alloy steels with EN 10204 3.1 certification.
Ask for a quotationVisit NasteelSource: ASTM A276 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.