Maraging 250，Vascomax C250 Bar(Round bar, Flat bar)，UNS K92940

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

Maraging 250 (Vascomax C250 Wire, UNS K92940) - Introduction with Composition, Properties, Applications and Product Forms

Maraging 250, commercially known as Vascomax C250 and designated by UNS K92940, is a high-performance ultra-high-strength martensitic steel alloy celebrated for its exceptional balance of high tensile strength, excellent toughness, and superior dimensional stability. This precipitation-hardening alloy achieves its remarkable mechanical properties through a specialized "maraging" heat treatment process—solution annealing followed by aging—which avoids the carbon-based hardening of conventional steels, resulting in minimal distortion and outstanding weldability. It is available in a comprehensive range of forms to meet diverse industrial needs, including Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock. Vascomax C250 Wire, in particular, is valued for its impressive strength-to-weight ratio, flexibility, and precision, making it ideal for intricate high-stress components in aerospace, defense, and precision engineering industries. Below is a detailed overview of its chemical composition, key properties, practical applications, and available product forms.

Chemical Composition

The precisely engineered chemical composition of Maraging 250 (Vascomax C250, UNS K92940) is the foundation of its exceptional strength and toughness. The typical composition (by weight) is as follows:

Iron (Fe): Balanced (approximately 70-75%) (primary matrix element, forming the martensitic structure)

Nickel (Ni): 17-19% (critical for forming the martensitic phase and enabling precipitation hardening)

Cobalt (Co): 7.0-8.0% (enhances hardening response and strengthens the martensitic matrix)

Molybdenum (Mo): 3.0-4.0% (forms intermetallic precipitates during aging, contributing significantly to strength)

Titanium (Ti): 0.3-0.8% (aids in precipitation hardening by forming Ni₃Ti intermetallic compounds)

Aluminum (Al): 0.05-0.15% (improves toughness and refines grain structure)

Carbon (C): ≤ 0.03% (kept extremely low to avoid carbide formation, ensuring high toughness and weldability)

Manganese (Mn): ≤ 0.1% (minimized to prevent grain boundary embrittlement)

Silicon (Si): ≤ 0.1% (controlled to maintain purity and avoid oxide inclusions)

Sulfur (S): ≤ 0.01% (strictly limited to ensure high toughness and reduce the risk of cracking)

Phosphorus (P): ≤ 0.01% (kept low to prevent grain boundary embrittlement)

This carefully balanced composition, combined with the maraging heat treatment, delivers the alloy's signature high strength, excellent toughness, and dimensional stability, making it suitable for demanding high-stress applications where reliability is critical.

Key Properties

Maraging 250 (Vascomax C250 Wire, UNS K92940) and its various forms exhibit exceptional properties that make them indispensable in applications requiring high strength and reliability:

Mechanical Properties (after aging at 480°C for 3 hours):

Tensile strength: 1700-1900 MPa (246,600-275,600 psi) — among the highest for structural alloys with excellent toughness

Yield strength (0.2% offset): 1500-1700 MPa (217,600-246,600 psi)

Elongation (in 50 mm): 12-18% (superior ductility for an ultra-high-strength material, enabling forming and bending)

Reduction of area: 45-55% (indicative of excellent toughness and resistance to brittle fracture)

Charpy impact toughness (unnotched): ≥ 70 J (51.6 ft-lb) at room temperature (exceptional toughness for such high strength)

Hardness: 44-48 HRC (Rockwell hardness, reflecting high surface hardness and wear resistance)

Physical and Thermal Properties:

Density: 8.1 g/cm³ (0.292 lb/in³) — lower than many high-strength steels, contributing to an excellent strength-to-weight ratio

Thermal conductivity: 16.0 W/(m·K) at 20°C (68°F)

Coefficient of thermal expansion: 12.0 μm/(m·K) (20-100°C) — low expansion, ensuring dimensional stability during temperature changes

Modulus of elasticity: 188 GPa (27,300 ksi) at room temperature

Melting point: 1420-1460°C (2588-2660°F)

Magnetic permeability: Ferromagnetic, with high magnetic saturation (useful in aerospace and defense applications requiring magnetic properties)

Processing Properties:

Weldability: Excellent weldability using conventional methods (TIG, electron beam), with minimal loss of strength in the heat-affected zone (HAZ) when properly post-weld aged

Machinability: Good machinability in the solution-annealed condition (soft state); more challenging in the aged (hardened) condition but manageable with carbide tools

Formability: Excellent formability in the solution-annealed condition, allowing for complex shapes to be formed before aging to final strength

Dimensional stability: Minimal distortion during heat treatment, ensuring tight tolerances in precision components

Product Forms

Maraging 250 (Vascomax C250, UNS K92940) is manufactured in a diverse range of forms to accommodate specialized high-stress industrial processes across aerospace, defense, and precision engineering sectors:

Bar: Available as Round bar (diameters from 6 mm to 200 mm) and Flat bar (thickness 5 mm to 150 mm, width 15 mm to 500 mm), ideal for machining into high-strength fasteners, shafts, and structural components.

Ribbon: Thin, flat strips (thickness 0.1 mm to 2 mm, width 5 mm to 100 mm) used in precision springs, sensor components, and lightweight structural elements.

Wire: Vascomax C250 Wire (diameters 0.1 mm to 10 mm) offers exceptional strength and flexibility, making it suitable for high-tension springs, cables, and intricate wire forms in aerospace and defense systems.

Rods: Solid cylindrical rods (diameters 3 mm to 50 mm) suitable for structural supports, actuator components, and precision shafts in high-stress machinery.

Tube and Pipe: Seamless options (outer diameter 6 mm to 100 mm, wall thickness 0.5 mm to 10 mm) for lightweight high-pressure vessels, hydraulic lines, and structural tubing in aerospace applications.

Foil: Ultra-thin sheets (thickness 0.01 mm to 0.1 mm) used in lightweight armor, precision diaphragms, and thin-walled components requiring high strength.

Plate and Sheet: Flat forms (plate: thickness 4 mm to 100 mm; sheet: 0.2 mm to 4 mm) for fabricating aerospace structural parts, missile components, and high-strength brackets.

Strip: Narrow, flat strips (thickness 0.1 mm to 3 mm, width 10 mm to 200 mm) for precision manufacturing in springs, clips, and high-strength electrical contacts.

Forging Stock: Billets and ingots for hot forging into complex shapes such as aircraft landing gear components, rocket motor casings, and defense hardware.

Applications

The exceptional strength and toughness of Maraging 250 (Vascomax C250 Wire, UNS K92940) across its various forms make it a critical material in industries requiring high performance under extreme stress:

Aerospace and Aviation:

Aircraft structures: Landing gear components, wing spars, and actuator rods (from bar, forging stock, and plate) leveraging the alloy’s high strength-to-weight ratio.

Rocket and missile systems: Motor casings, nozzle components, and structural frames (from forging stock, tube, and plate) for launch vehicles and ballistic missiles.

Satellite components: High-strength fasteners, antenna supports, and deployment mechanisms (from wire, bar, and rod) requiring minimal weight and maximum strength.

Defense and Military:

Armament: Gun barrels, missile guidance components, and armor plating (from plate, forging stock, and foil) offering superior ballistic resistance.

Naval systems: Torpedo components, submarine structural parts, and high-strength fasteners (from bar, rod, and forging stock) resisting corrosion and extreme pressure.

UAVs and drones: Lightweight structural frames and high-tension components (from sheet, wire, and strip) maximizing payload capacity.

Precision Engineering and Medical:

High-performance springs: Torsion springs, tension springs, and wave springs (from wire, ribbon, and strip) for aerospace and industrial machinery requiring extreme fatigue resistance.

Tooling and dies: Extrusion dies, blanking dies, and precision molds (from plate and bar) offering long service life under high stress.

Medical devices: Orthopedic implants, surgical instruments, and high-strength components (from wire and bar) combining strength with biocompatibility.

Motorsports and High-Performance Vehicles:

Racing components: Suspension parts, drive shafts, and chassis components (from bar, sheet, and forging stock) reducing weight while increasing strength.

Spacecraft and hypersonic vehicles: Thermal protection system components, structural brackets, and fasteners (from plate, bar, and tube) withstanding extreme temperatures and stress.

Specialized Applications by Form:

Wire: High-tension cables, precision springs, and wire ropes for aerospace and defense systems.

Tube/Pipe: Lightweight hydraulic lines, high-pressure vessels, and structural tubing in aircraft and rockets.

Plate/Sheet: Aerospace structural panels, armor plating, and missile casings requiring maximum strength.

Bar/Forging Stock: Landing gear components, rocket motor casings, and high-strength fasteners for the most demanding applications.

In summary, Maraging 250 (Vascomax C250 Wire, UNS K92940) — available in forms from Bar and Wire to Plate and Forging Stock — delivers exceptional high strength, superior toughness, and dimensional stability. Its diverse product forms enable tailored solutions across aerospace, defense, and precision engineering sectors, establishing it as a critical material in applications requiring high performance under extreme stress.

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 2601 gallon liquid totes Special package is available on request.