440C Vac Melt AMS 5618 stainless steel is known for its hardness capability and excellent wear resistance. It is a martensitic stainless steel vacuum melted to very high purity levels for demanding applications and minimum oxidation. It has a chromium content of 16-18% and around 1% carbon, which makes it a hard and strong alloy that’s ideal for applications where wear resistance and load bearing are the highest priorities.
440C VM AMS 5618 is employed extensively in friction applications, such as bearing materials. As a strong, corrosion-resistant aerospace-grade alloy, it’s also widely specified for many aircraft components. Other usages are seen in valve parts, medical devices, and kitchen equipment. It is sold in the annealed condition and can be heat treated to HRC 58-60.
| Property | Value | Notes |
|---|---|---|
| Material Type | Martensitic Stainless Steel | UNS S44004 |
| Density | 7.65 g/mm3 | 0.276 lb/in3 |
| Melting Point | ~1,480–1,510°C | ~2,700–2,750°F |
| Hardness (HRC) | 58-60 | After hardening by heat treatment |
| Tensile Strength | ~1,965 MPa | ~285,000 psi |
| Yield Strength | ~1,896 MPa | ~275,000 psi |
| Elongation at Break | ~1–5% | Very low ductility |
| Modulus of Elasticity | ~200GPa | ~29 x 10⁶ psi |
| Corrosion Resistance | Good | Some other grades of stainless have higher resistance |
| Magnetism | Magnetic | Results from the martensitic structure |
| Heat Treatment | Required for hardening and annealing | |
| Machinability | Moderate | Machine in the annealed state |
| Weldability | Poor | Not recommended unless annealed; post-weld heat treatment is critical |
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