Maraging 300 (18Ni-300): Ultra-High-Strength Steel for Aerospace Tooling
AMS 6514 / ASTM A538 · Published: 2026-06-02 · Updated: 2026-06-02
Maraging 300 achieves >2,000 MPa yield strength through Ni3Mo/Ni3Ti intermetallic precipitation during aging at 480°C for 3 hours. Unique: 2,000+ MPa strength with KIC >80 MPa√m toughness — no other steel matches this combination. For landing...
Maraging 300 achieves >2,000 MPa yield strength through Ni3Mo/Ni3Ti intermetallic precipitation during aging at 480°C for 3 hours. Unique: 2,000+ MPa strength with KIC >80 MPa√m toughness — no other steel matches this combination. For landing gear, rocket motor casings, extrusion tooling.
Quick Facts
| Category | Alloy Steel |
| Standard | AMS 6514 / ASTM A538 |
| Density | 8000 kg/m³ |
| Yield Strength | 1,930-2,070 MPa (aged) |
| Tensile Strength | 2,000-2,100 MPa |
Global Equivalents & Cross-Reference
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Frequently Asked Questions
Why so expensive?
18% Ni + 9% Co + 5% Mo = >/kg raw material. Double vacuum melting (VIM+VAR). But the strength-toughness combination is unmatched.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu