Maraging 250,Udimar 250 ,,E FORU

British Specs:BS S162，American Specs:AMS 6512 Bar, Tube, Forgings AMS 6520 Sheet, Strip and Plate ASTM A646 MIL-S-46850 Type 3，German Specs:WS 1.6359

### **Product Datasheet: Maraging Steel 250 / Udimar 250** --- #### **1. Product Overview** **Maraging Steel 250** (also known commercially as **Udimar 250**) is an ultra-high-strength martensitic-age-hardening steel characterized by its exceptional combination of high strength, excellent toughness, and good dimensional stability during heat treatment. The term "maraging" derives from **martensitic** and **age-hardening**, describing its unique strengthening mechanism. This nickel-cobalt-molybdenum steel achieves its superior properties through a low-temperature aging process that precipitates intermetallic compounds, providing outstanding mechanical properties without the need for rapid quenching, thus minimizing distortion. --- #### **2. Chemical Composition (Weight %)** | Element | Min (%) | Max (%) | Balance | |---------|----------|----------|---------| | **Nickel (Ni)** | 17.00 | 19.00 | - | | **Cobalt (Co)** | 7.00 | 8.50 | - | | **Molybdenum (Mo)** | 4.50 | 5.20 | - | | **Titanium (Ti)** | 0.30 | 0.50 | - | | **Aluminum (Al)** | 0.05 | 0.15 | - | | **Iron (Fe)** | - | - | Balance | | **Carbon (C)** | - | 0.03 | - | | **Manganese (Mn)** | - | 0.10 | - | | **Silicon (Si)** | - | 0.10 | - | | **Sulfur (S)** | - | 0.01 | - | | **Phosphorus (P)** | - | 0.01 | - | --- #### **3. Physical & Mechanical Properties** **A. Mechanical Properties (After Solution Annealing & Aging)** - **Tensile Strength:** 1,720 - 1,790 MPa (250 - 260 ksi) - **Yield Strength (0.2% Offset):** 1,655 - 1,725 MPa (240 - 250 ksi) - **Elongation:** 10 - 14% - **Reduction in Area:** 45 - 55% - **Hardness:** 48 - 52 HRC - **Fracture Toughness (K_Ic):** 70 - 90 MPa√m - **Impact Toughness (Charpy V):** 25 - 35 J **B. Physical Properties** - **Density:** 8.00 g/cm³ (0.289 lb/in³) - **Melting Point:** 1,430 - 1,450 °C (2,606 - 2,642 °F) - **Modulus of Elasticity:** 185 GPa (26.8 × 10⁶ psi) - **Poisson's Ratio:** 0.30 - **Thermal Conductivity:** 19.0 - 21.0 W/m·K - **Thermal Expansion Coefficient:** 10.5 - 11.0 × 10⁻⁶/°C (20 - 100°C) - **Electrical Resistivity:** 0.60 - 0.65 μΩ·m --- #### **4. Product Applications** **Aerospace & Defense** - **Rocket motor casings** and missile components - **Aircraft landing gear** components - **Helicopter rotor** shafts and components - **Critical fasteners** and high-strength bolts - **Ordnance components** and gun barrels **Tooling & Industrial** - **Precision molds** for injection molding - **Die-casting tools** and cores - **Extrusion screws** and barrels - **High-performance gears** and shafts - **Test equipment** and fixture components **Specialized Applications** - **High-performance racing** components - **Surgical instruments** and medical devices - **Marine components** requiring corrosion resistance - **Nuclear reactor** components - **Optical instrument** mounts and frames --- #### **5. International Standards & Specifications** | Standard Body | Specification Number | Title/Description | |---------------|----------------------|-------------------| | **AMS** | AMS 6512 | Steel Bars, Forgings, and Tubing 18Ni (250) | | **ASTM** | A538 | Standard Specification for Precipitation-Hardening Steel | | **UNS** | K92890 | Unified Numbering System Designation | | **MIL** | MIL-S-46850 | Steel, Maraging 250 Grade | | **ISO** | 683-13 | Heat-treatable steels, alloy steels, and free-cutting steels | | **AWS** | A5.14 | Specification for Nickel and Nickel-Alloy Welding Electrodes | --- #### **6. Heat Treatment Process** **Solution Annealing** - **Temperature:** 820 ± 10°C (1,508 ± 18°F) - **Time:** 1 hour per 25 mm of thickness - **Cooling:** Air cool (minimizes distortion) **Aging Treatment** - **Temperature:** 480 ± 5°C (896 ± 9°F) - **Time:** 3 - 6 hours (depending on section size) - **Cooling:** Air cool to room temperature **Key Advantages of Heat Treatment:** - Minimal distortion and dimensional changes - No decarburization concerns - Simple furnace equipment requirements - Excellent reproducibility of properties --- #### **7. Fabrication & Machining** **Machining Recommendations** - **Annealed Condition:** Optimal for heavy machining - **Tooling:** Carbide tools recommended - **Coolant:** Required for high-speed operations - **Aged Condition:** Grinding or EDM preferred **Welding Considerations** - **Weldability:** Excellent compared to other ultra-high-strength steels - **Processes:** TIG, MIG, and plasma arc welding suitable - **Filler Metal:** Matching composition recommended - **Post-Weld Heat Treatment:** Required to restore full properties --- #### **8. Technical Advantages** **Key Benefits:** - **Ultra-High Strength:** Exceptional strength-to-weight ratio - **Excellent Toughness:** Superior fracture resistance - **Simple Heat Treatment:** Minimal distortion during processing - **Good Weldability:** Easily welded without pre-heat - **Dimensional Stability:** Minimal size changes during aging - **Corrosion Resistance:** Better than conventional high-strength steels **Comparative Advantages:** - Superior to conventional quenched and tempered steels - Better toughness than most ultra-high-strength steels - Simpler heat treatment than secondary hardening steels - Excellent combination of strength and ductility --- **Quality Assurance:** - Full traceability to melt source - Certified chemical and mechanical properties - Non-destructive testing available - Compliance with aerospace quality requirements **Contact Information:** [Your Company Information] *Note: All mechanical properties are typical for material in the fully aged condition. Actual properties may vary based on specific processing parameters and section size. Consult technical data sheets for application-specific recommendations.*

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 2573 gallon liquid totes Special package is available on request.