AISI Grade 18Ni (250) Maraging Steel, Aged

AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal Product Information -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal Synonyms -:- For detailed product information, please contact sales. -:

AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal Product Information -:- For detailed product information, please contact sales. -: ### **Product Data Sheet: AISI 18Ni (250) Maraging Steel, Aged – 16mm Round Bar (Longitudinal Test)** **Product Overview** This data sheet specifies the properties of **AISI 18Ni (250) Maraging Steel** supplied in its final, peak-strength condition as an **aged, 16mm (0.63") diameter round bar, with mechanical properties tested in the longitudinal direction**. This grade represents the industry benchmark for ultra-high-strength steels, offering an unmatched combination of tensile strength (nominally 250 ksi / 1725 MPa), excellent fracture toughness, and good ductility. The longitudinal testing orientation reports the properties along the primary grain flow direction, typically showing optimal strength and toughness characteristics. **Material & Heat Treatment State** * **Grade:** 18% Nickel Maraging Steel, Grade 250 (Yield Strength Target: 250 ksi). * **Product Form:** Hot-rolled or cold-drawn **Round Bar**, 16mm diameter. * **Condition:** **Fully Aged (Peak Aged)**. The material has undergone the complete two-step heat treatment process: 1. **Solution Annealing:** Austenitized at ~815°C (1500°F), air-cooled to form soft, low-carbon martensite. 2. **Final Age Hardening:** Precipitate strengthening at **480°C (900°F) for 3-6 hours**, followed by air cooling. This process precipitates intermetallic compounds (Ni₃Ti, Ni₃Mo, Fe₂Mo) within the martensitic matrix, delivering the ultimate strength. * **Test Orientation:** **Longitudinal.** Test specimens are taken parallel to the bar's rolling/drawing axis. This orientation generally provides the best combination of mechanical properties. **Chemical Composition (Typical Weight %, per AMS 6514)** | Element | Content (%) | Element | Content (%) | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | 17.0 - 19.0 | **Cobalt (Co)** | 7.0 - 8.5 | | **Molybdenum (Mo)**| 4.6 - 5.2 | **Titanium (Ti)** | 0.3 - 0.5 | | **Aluminum (Al)** | 0.05 - 0.15 | **Carbon (C)** | **≤ 0.03 max** | | **Manganese (Mn)**| ≤ 0.10 max | **Silicon (Si)** | ≤ 0.10 max | | **Sulfur (S)** | ≤ 0.010 max | **Phosphorus (P)** | ≤ 0.010 max | | **Boron (B)** | 0.003 (min) | **Zirconium (Zr)**| 0.01 - 0.02 | | **Calcium (Ca)** | 0.05 (max) | **Iron (Fe)** | Balance | *Note:* The extremely low carbon and impurity content is critical for achieving superior toughness and weldability in the annealed state prior to aging. **Physical & Mechanical Properties (Aged Condition – 16mm Bar, Longitudinal)** * **Density:** 8.0 g/cm³ (0.289 lb/in³) * **Melting Point:** ~ 1415°C (2580°F) * **Mechanical Properties (Minimum / Typical):** * **Ultimate Tensile Strength (UTS):** 1725 MPa (250 ksi) Min. / **1790 MPa (260 ksi) Typical** * **Yield Strength (0.2% Offset):** 1690 MPa (245 ksi) Min. / **1760 MPa (255 ksi) Typical** * **Elongation (% in 4D):** 8% Min. / **10-12% Typical** * **Reduction of Area:** 35% Min. / **50-60% Typical** * **Hardness:** 50 - 54 HRC * **Fracture Toughness (K_Ic):** **High, typically 80 - 110 MPa√m** (Longitudinal orientation provides best toughness). * **Modulus of Elasticity:** 185 GPa (27 x 10⁶ psi) * **Thermal Properties (at ~20°C):** * **Thermal Expansion Coefficient:** 10.2 x 10⁻⁶/K * **Thermal Conductivity:** ~ 19.0 W/m·K * **Key Bar-Specific Characteristic:** A 16mm round bar, due to its relatively small cross-section, will cool rapidly and uniformly during heat treatment, resulting in very consistent through-hardened properties with minimal risk of segregation or property gradients. **Key Characteristics & Advantages (Aged Bar Stock)** 1. **Ultra-High Strength with Uncommon Toughness:** Achieves strength levels typical of much less ductile steels while maintaining excellent resistance to crack propagation. 2. **Excellent Dimensional Stability:** The aging process involves no phase transformation, resulting in minimal distortion, making it ideal for precision-machined components. 3. **Good Machinability (in Annealed State):** Components are machined to final dimensions in the soft, solution-annealed condition prior to the simple, low-distortion aging process. 4. **Longitudinal Property Optimization:** For bar stock, the longitudinal direction offers the highest ductility and toughness, which is critical for most shaft, fastener, and pin applications where the primary stress axis is along the bar's length. **Primary Applications (for Aged 16mm Round Bar)** This material form is ideally suited for high-stress, weight-critical rotational or tensile components: * **Precision Shafting & Axles:** High-performance drive shafts, actuator rods, and axles in aerospace and racing applications. * **Critical Fasteners:** Ultra-high-strength bolts, studs, pins, and rivets for demanding structural assemblies. * **Tooling & Machine Components:** Ejector pins for die-casting, guide rods, bushings, and wear parts in high-pressure tools. * **Aerospace Actuation Systems:** Components for landing gear, flight control linkages, and engine controls. * **Prototype & High-Stress Test Coupons:** Used for validating designs under extreme loads. **International & Industry Standards** * **AMS 6521:** *Aerospace Material Specification for Maraging Steel Bars, Forgings, and Rings 18Ni-8Co-3.5Mo-4.8Ti, Aged.* This is the primary governing standard for aged bar product forms. * **ASTM A538 / A538M:** Standard for pressure vessel plates; specifies the 250-grade composition and aged properties. * **ASTM B637 (Specific Bars):** Sometimes referenced for precipitation-hardening (including maraging) bar and rod. * **UNS K92890:** Unified Numbering System designation. * **ISO 683-13:** International standard covering wrought maraging steels. * **Customer Specifications:** Often must meet specific aerospace (e.g., Boeing BAC, Airbus AIMS) or defense procurement standards. **Disclaimer:** The values listed are typical for longitudinal specimens from a homogenized 16mm aged bar. Actual properties for a specific lot are certified via mill test reports. Properties in transverse orientations may differ. This material is supplied in the final aged condition and is **not intended for further heat treatment or welding** without specialized procedures that may degrade properties. End-users must verify suitability for specific applications. -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal Specification Dimensions Size： Diameter 20-1000 mm Length <7320 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal -:- For detailed product information, please contact sales. -:

Packing of AISI Grade 18Ni (250) Maraging Steel, Aged, 16 mm round bar, tested longitudinal -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: 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 3791 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition