300M Steel (UNS K93120)
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Maraging 300 (AMS 6514, AMS 6521)
Maraging 300 or UNS K93120, is a high-performance iron-based alloy engineered for applications requiring extremely high strength, excellent toughness, and dimensional stability. Unlike traditional steels that gain strength through carbon content, maraging steels achieve their exceptional mechanical properties through a unique combination of alloying elements and age-hardening treatment.
Chemical Composition:
| Property | Value |
|---|---|
| Molybdenum (Mo) | 4.6–5.2 % |
| Nickel (Ni) | 18.0–19.0 % |
| Cobalt (Co) | 8.5–9.5 % |
| Titanium (Ti) | 0.5–0.8% |
| Manganese (Mn) | ≤ 0.10 |
| Phosphorus (P) | 0.010% max |
| Aluminum (Al) | 0.5-0.15% |
| Carbon (C) | 0.3% max |
| Silicon (Si) | 0.10% max |
| Sulfur (S) | 0.010% max |
Mechanical Properties:
| Property | Value |
|---|---|
| Tensile Strength (Ultimate) | 280000 |
| Yield Strength | 80-105 ksi (552-724 MPa) |
| Hardness | 52 HRB |
Physical Properties:
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ (0.289 lb/in³) |
| Melting Point | 1413–1454 °C |
| Thermal Conductivity | 25 W/m·K |
| Specific Heat Capacity | 460 J/kg·K |
| Electrical Resistivity | ~80 µΩ·cm |
Heat Treatment:
- Solution treat at 820°C and age at 485°C
Applications:
- Aerospace components (landing gear, actuators)
- Missile and rocket motor casings
- Tooling and dies
- High-performance motorsports components
- Fasteners and high-strength shafts
Corrosion Resistance
- Moderate resistance to corrosion in atmosphere and mild environments
- Not suitable for marine or highly corrosive conditions without protective coatings