Maraging 300,Udimar 300,UNS K93120,E FORU

### **Maraging 300 / Udimar 300 / UNS K93120** **Ultra-High Strength Nickel-Maraging Steel for Demanding Aerospace Applications** --- #### **1. Overview** **Udimar 300**, commercially designated as **Maraging 300**, is an ultra-high strength, low-carbon nickel-maraging steel that achieves exceptional mechanical properties through a unique age-hardening process of martensitic transformation. This alloy represents the highest strength grade in the 18Ni maraging steel family, designed to provide an optimal combination of ultra-high strength (exceeding 2000 MPa), good fracture toughness, and excellent fabricability. The maraging process involves forming a soft, low-carbon martensite upon cooling from the solution treatment temperature, which is subsequently strengthened by precipitation of intermetallic compounds during aging. --- #### **2. Chemical Composition (Weight %)** The typical chemical composition of Maraging 300 is outlined below. The balance is Iron (Fe). | Element | Content (%) | Key Function | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Forms the martensitic matrix structure. | | **Nickel (Ni)** | 18.0 - 19.0 | Primary element enabling martensitic transformation and precipitation hardening. | | **Cobalt (Co)** | 8.5 - 9.5 | Enhances the formation of intermetallic compounds and significantly increases strength. | | **Molybdenum (Mo)** | 4.5 - 5.2 | Principal precipitation hardening element forming Ni₃Mo intermetallics. | | **Titanium (Ti)** | 0.5 - 0.8 | Forms Ni₃Ti precipitates contributing to secondary hardening. | | **Aluminum (Al)** | 0.05 - 0.15 | Aids in deoxidation and forms hardening precipitates. | | **Carbon (C)** | 0.03 max | Kept extremely low to improve toughness and weldability. | | **Manganese (Mn)** | 0.10 max | Controlled to minimize impurity effects. | | **Silicon (Si)** | 0.10 max | Controlled to minimize impurity effects. | | **Sulfur (S)** | 0.010 max | Kept at minimal levels to prevent hot shortness. | | **Phosphorus (P)** | 0.010 max | Minimized to prevent embrittlement. | | **Boron (B)** | 0.003 max | Trace addition to enhance hardenability. | --- #### **3. Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.10 g/cm³ (0.293 lb/in³) | | **Melting Point** | ~ 1410 - 1450 °C (2570 - 2640 °F) | | **Modulus of Elasticity (Young's Modulus)** | 185 GPa (26.8 x 10⁶ psi) | | **Poisson's Ratio** | 0.30 | | **Thermal Conductivity** | 19.0 - 21.5 W/m·K at 20-200°C | | **Mean Coefficient of Thermal Expansion** | 20 - 200°C: **10.3 x 10⁻⁶/°C** (5.7 x 10⁻⁶/°F) | | **Electrical Resistivity** | 0.65 μΩ·m at 20°C | | **Specific Heat Capacity** | 460 J/kg·K at 20°C | --- #### **4. Mechanical Properties (Typical for Aged Condition - 480°C/900°F)** | Property | Value at Room Temperature | | :--- | :--- | | **Tensile Strength** | 2000 - 2070 MPa (290 - 300 ksi) | | **Yield Strength (0.2% Offset)** | 1930 - 2000 MPa (280 - 290 ksi) | | **Elongation (in 50 mm / 2 in)** | 6 - 8% | | **Reduction of Area** | 35 - 40% | | **Fracture Toughness (K_Ic)** | 50 - 70 MPa√m | | **Hardness** | 52 - 54 HRC | | **Charpy V-Notch Impact** | 12 - 18 J (9 - 13 ft-lb) | | **Shear Strength** | 1170 - 1240 MPa (170 - 180 ksi) | --- #### **5. International Standards** Maraging 300 conforms to the following international specifications: * **AMS:** * **AMS 6514:** Steel Bars, Forgings, and Tubing 18Ni (300) * **ASTM:** * **A538:** Standard Specification for Maraging Steel Bars, Plates, and Forgings * **MIL:** * **MIL-S-46850:** Maraging Steel Plate, Sheet, and Strip * **UNS:** K93120 * **Aerospace Standards:** * Various proprietary specifications from major aerospace manufacturers --- #### **6. Product Applications** Maraging 300 is utilized in the most demanding aerospace and defense applications: * **Aerospace Structures:** * Rocket motor cases and missile bodies * Aircraft landing gear components * Space vehicle structural members * Helicopter rotor hubs * **Defense Systems:** * Weapon system components * Armor plate applications * Military aircraft critical parts * **Tooling and Manufacturing:** * High-performance die casting tools * Precision molds and fixtures * Extrusion rams and components * **Specialty Applications:** * High-performance racing components * Critical fasteners and bolts * Nuclear reactor components --- #### **7. Key Characteristics & Advantages** * **Ultra-High Strength:** Exceptional strength-to-weight ratio with yield strength exceeding 1930 MPa (280 ksi) * **Excellent Fracture Toughness:** Superior toughness compared to conventional high-strength steels at equivalent strength levels * **Good Fabricability:** Can be machined and formed in the solution-annealed condition * **Minimal Distortion:** Low thermal expansion and simple heat treatment minimize dimensional changes * **Superior Weldability:** Excellent welding characteristics without preheating or post-weld heat treatment requirements * **Simple Heat Treatment:** Age hardening at 480°C (900°F) provides consistent, reproducible properties * **Good Corrosion Resistance:** Better resistance to stress corrosion cracking than conventional high-strength steels * **Proven Reliability:** Extensive successful use in critical aerospace applications for decades --- **Disclaimer:** *Udimar is a registered trademark. The values provided are typical and for informational purposes only. For critical applications, always consult the official material data sheets from the supplier and relevant design codes. Proper solution treatment and aging cycles are essential for achieving optimal mechanical properties.*

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1698 gallon liquid totes Special package is available on request.