Maraging 250,Maraging C250 Tube,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 Tube (UNS K92890)** --- #### **1. Product Overview** **Maraging Steel 250 Tube** (commercially designated as **Maraging C250 Tube**, **UNS K92890**) is a precision tubular product manufactured from ultra-high-strength maraging steel, designed for applications requiring exceptional strength-to-weight ratio in hollow sections with tight dimensional tolerances. This product combines the superior mechanical properties of Maraging 250 alloy with the precision of tubular manufacturing, providing optimal solutions for aerospace, defense, and instrumentation applications where reliability and dimensional accuracy are paramount. The "C250" designation indicates commercial grade optimization for enhanced manufacturability in tubular forms. --- #### **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 - **Fatigue Strength:** Excellent in cyclic pressure applications **B. Physical Properties** - **Density:** 8.00 g/cm³ (0.289 lb/in³) - **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 **C. Tube Specifications** - **Outside Diameter Range:** 6 mm - 150 mm (0.25" - 6") - **Wall Thickness:** 1 mm - 15 mm (0.04" - 0.6") - **Length:** 1,000 mm - 6,000 mm (3' - 20') - **Diameter Tolerance:** ±0.1 mm for precision grades - **Wall Thickness Tolerance:** ±5% to ±10% - **Straightness:** ≤ 0.5 mm/m for precision applications - **Surface Finish:** Smooth ID and OD surfaces --- #### **4. Product Applications** **Aerospace & Defense** - **Rocket motor cases** and launch tube assemblies - **Aircraft hydraulic** system tubing - **Missile guidance** system components - **Helicopter rotor** shafts and drive systems - **Space vehicle** structural members **Precision Instrumentation** - **High-pressure measurement** devices - **Scientific instrument** frames and structures - **Optical system** mounting tubes - **Vacuum chamber** components - **Laboratory equipment** precision tubing **High-Performance Industrial** - **Racing vehicle** drive shafts and components - **Hydraulic cylinder** barrels - **Process control** instrument tubing - **Medical device** components - **Semiconductor** manufacturing equipment --- #### **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 | | **ASTM** | A511 | Standard Specification for Seamless Stainless Steel Mechanical Tubing | | **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 | --- #### **6. Heat Treatment Process** **Solution Annealing (Before precision machining)** - **Temperature:** 820 ± 10°C (1,508 ± 18°F) - **Time:** 1 hour per 25 mm of wall thickness - **Atmosphere:** Protective atmosphere essential - **Cooling:** Controlled air cool **Aging Treatment (After final fabrication)** - **Temperature:** 480 ± 5°C (896 ± 9°F) - **Time:** 3-4 hours for thin-walled tubes - **Cooling:** Air cool to room temperature - **Distortion:** Minimal dimensional changes --- #### **7. Fabrication & Machining** **Precision Machining:** - **Optimal Condition:** Machine in solution-annealed state (28-32 HRC) - **Tooling:** Carbide tools with sharp cutting edges - **Tolerances:** Capable of holding tight dimensional tolerances - **Surface Finish:** Achieves excellent surface quality **Forming & Bending:** - **Bend Radius:** Minimum 2x tube diameter - **Mandrel Bending:** Recommended for thin-walled tubes - **Springback:** Predictable and consistent - **Heat Treatment:** Required after severe forming operations --- #### **8. Quality Assurance** **Standard Testing Protocol:** - **Dimensional Verification:** 100% inspection of critical dimensions - **Ultrasonic Testing:** Wall thickness and integrity verification - **Surface Quality:** Internal and external surface examination - **Straightness Verification:** Optical measurement methods **Advanced Quality Features:** - **Eddy Current Testing:** For surface defect detection - **Hydrostatic Testing:** Pressure testing to specification requirements - **Metallurgical Analysis:** Grain structure and inclusion rating - **Certification:** Full traceability and compliance documentation --- **Packaging & Handling:** - Individual protective packaging for each tube - Special care to prevent surface damage and denting - Clear identification with heat numbers and specifications - Custom cutting and end finishing available **Technical Support:** - Engineering assistance for design and application - Fabrication process recommendations - Heat treatment guidance - Quality assurance program development **Contact Information:** [Your Company Information] *Note: All mechanical properties are typical for material in the fully aged condition. Specific performance characteristics should be verified for critical applications. Maraging C250 Tube offers enhanced consistency and performance for precision tubular applications. Consult our technical team for detailed engineering 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 2590 gallon liquid totes Special package is available on request.