AISI 440C is a high-carbon martensitic stainless steel capable of achieving high hardness and excellent wear resistance through heat treatment. It is commonly used for precision bearings, high-hardness components, and wear-resistant industrial parts.
AISI 440C is a high-carbon chromium stainless steel developed for applications requiring high hardness, wear resistance, and useful corrosion resistance. Its ability to respond to hardening and tempering makes it suitable for components operating under demanding contact, friction, and wear conditions.
The material is commonly used for precision bearing components, valve parts, cutting components, wear-resistant machine elements, and other applications requiring a hard surface. Corrosion resistance depends on the material’s heat-treated condition, surface finish, and exposure environment. Appropriate material certification and heat-treatment specifications are important when selecting this grade for critical components. Typical Applications: Precision bearings, wear-resistant components, valve parts, cutting components, and high-hardness machine parts.Final chemical, mechanical properties, dimensions and tolerances are confirmed against the governing specification and purchase order.
| Element | Symbol | Min (%) | Max (%) | Nominal Target |
|---|---|---|---|---|
| Carbon | C | 0.95% | 1.20% | 1.05% |
| Chromium | Cr | 16.00% | 18.00% | 17.00% |
| Manganese | Mn | — | 1.00% | 0.50% |
| Silicon | Si | — | 1.00% | 0.50% |
| Molybdenum | Mo | — | 0.75% | 0.50% |
| Phosphorus | P | — | 0.040% | Max 0.040% |
| Sulfur | S | — | 0.030% | Max 0.030% |
| Iron | Fe | Balance | Balance | ~80.2% |
| Condition / Thermal State | Tensile Strength (Rm) | Yield Strength (Re) | Elongation (A5) | Hardness (HBW / HRC) |
|---|---|---|---|---|
| Annealed | 730 – 800 MPa | 440 – 500 MPa | 12% – 18% | 230 – 269 HBW (98 HRB) |
| Cold Drawn (Annealed Stock) | 800 – 900 MPa | 550 – 650 MPa | 8% – 14% | 250 – 285 HBW |
| Quenched & Tempered (315°C) | 1,900 – 2,050 MPa | 1,800 – 1,900 MPa | 2% – 5% | 56 – 58 HRC |
| Quenched & Tempered (150°C Max Hardness) | 2,000 – 2,150 MPa | 1,900 – 2,000 MPa | 1% – 3% | 58 – 60 HRC (650 – 700 HB) |
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