Maraging 250,Maraging C250 ,UNS K92890,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 / Maraging C250 (UNS K92890)** --- #### **1. Product Overview** **Maraging Steel 250** (also known as **Maraging C250** and designated as **UNS K92890**) is an ultra-high-strength martensitic age-hardening steel from the 18Ni maraging steel family. The "C250" designation typically refers to commercial variations with optimized processing for specific applications. This steel achieves its exceptional mechanical properties through a precipitation-hardening mechanism that occurs at relatively low temperatures (around 480°C), minimizing distortion and making it ideal for complex components requiring high strength and dimensional stability. --- #### **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 | - | **Key Characteristics:** - Ultra-low carbon content minimizes carbide formation - Nickel content ensures martensite formation - Cobalt and molybdenum enable precipitation hardening - Titanium and aluminum form intermetallic compounds during aging --- #### **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 - **Fatigue Strength:** Excellent high-cycle performance **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 cases** and missile components - **Aircraft landing gear** components - **Helicopter rotor** shafts and components - **Ordnance components** and gun barrels - **Space vehicle** structural members **Tooling & Manufacturing** - **Precision molds** for injection molding - **Die-casting tools** and cores - **Extrusion screws** and barrels - **High-performance gears** and shafts - **Fixture components** and jigs **Energy & Industrial** - **Nuclear reactor** components - **Oil and gas** drilling tools - **High-pressure** vessel components - **Marine applications** requiring corrosion resistance - **Heavy machinery** critical components **Specialized Applications** - **High-performance racing** components - **Surgical instruments** and medical devices - **Optical instrument** mounts and frames - **Test equipment** structural components - **Research and development** applications --- #### **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 - **Atmosphere:** Air or protective atmosphere - **Cooling:** Air cool to room temperature - **Resulting Hardness:** 28-32 HRC **Aging Treatment** - **Temperature:** 480 ± 5°C (896 ± 9°F) - **Time:** 3 - 6 hours (depending on section size) - **Cooling:** Air cool to room temperature - **Final Hardness:** 48-52 HRC **Heat Treatment Advantages:** - Minimal distortion and dimensional changes - No decarburization concerns - Simple furnace equipment requirements - Excellent reproducibility of properties - No quenching required --- #### **7. Fabrication & Machining** **Machining Recommendations** - **Annealed Condition:** Optimal for heavy machining (28-32 HRC) - **Tooling:** Carbide tools recommended for production - **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 - **Pre/Post Heat Treatment:** Solution anneal after welding, age after all fabrication --- #### **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. Maraging C250 may have minor compositional variations optimized for specific applications. 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 2586 gallon liquid totes Special package is available on request.