440C Special Steel (UNS S44004)
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440C Stainless Steel (ASTM A240/ ASTM A276)
Alloy 440C is a high-carbon, high-chromium martensitic stainless steel that is highly valued for its excellent hardness, wear resistance, and moderate corrosion resistance. It is one of the highest carbon-content stainless steels in the martensitic class, which allows it to achieve a very hard, durable, and corrosion-resistant surface when heat treated.
Features of 440C:
- High Hardness: Capable of achieving hardness levels of 58-60 HRC after heat treatment, making it ideal for wear-resistant and cutting-edge applications.
- Good Corrosion Resistance: Offers moderate resistance to corrosion in atmospheric and mildly corrosive environments, particularly when polished.
- Wear and Abrasion Resistance: Exceptional performance in environments subjected to wear, abrasion, and mechanical stress.
- Edge Retention: Retains sharp edges well, making it suitable for cutting tools and surgical instruments.
- Heat Treatable: Can be heat treated to achieve high strength, hardness, and durability.
Specifications of 440C:
Applicable Standards:
- ASTM A240, ASTM A276, UNS S44004
Mechanical Properties:
| Property | Value |
|---|---|
| Tensile Strength | ~760 MPa |
| Yield Strength | ~490 MPa |
| Elongation | ~12% |
| Hardness (BHN) | 450-500 |
| Density | 7.75 g/cm³ |
Applicable Standards:
- Melting Range: 1400-1450°C
Chemical Composition:
| Element | Percentage (%) |
|---|---|
| Chromium (Cr) | 16.0-18.0 |
| Nickel (Ni) | ≤0.75 |
| Manganese (Mn) | ≤1.0 |
| Silicon (Si) | ≤1.0 |
| Carbon (C) | 0.95-1.20 |
| Phosphorus (P) | ≤0.04 |
| Sulfur (S) | ≤0.03 |