AISI Grade 18Ni (300) Maraging Steel, Aged

AISI Grade 18Ni (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm Product Information -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm Synonyms -:- For detailed product information, please contact sales. -:

AISI Grade 18Ni (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm Product Information -:- For detailed product information, please contact sales. -: # AISI Grade 18Ni (300) Maraging Steel, Aged ## Round Bar | 16 mm Diameter | Longitudinal Testing --- ### **Product Overview** This product is a **precipitation-hardened (aged) round bar** of ultra-high-strength AISI Grade 18Ni (300) Maraging Steel. The material has undergone the complete solution annealing and aging heat treatment cycle to achieve its final mechanical properties. The **16 mm (0.63 in) diameter** and **longitudinal testing orientation** are critical specifications, indicating the product form and the direction in which its mechanical properties are guaranteed and most favorable. --- ### **Chemical Composition (Weight %, Typical)** | Element | Min (%) | Max (%) | Key Function | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | 18.00 | 19.00 | Forms the primary martensitic matrix; essential for toughness. | | **Cobalt (Co)** | 8.50 | 9.50 | Reduces solubility of Mo in matrix, enhancing precipitation hardening. | | **Molybdenum (Mo)** | 4.60 | 5.20 | Forms key intermetallic precipitates (Ni₃Mo) for strength. | | **Titanium (Ti)** | 0.55 | 0.80 | Forms Ni₃Ti precipitates; contributes significantly to strength. | | **Aluminum (Al)** | 0.05 | 0.15 | Deoxidizer; forms minor strengthening precipitates. | | **Carbon (C)** | - | 0.030 | Kept very low to ensure toughness and weldability. | | **Manganese (Mn)** | - | 0.10 | Residual. | | **Silicon (Si)** | - | 0.10 | Residual. | | **Boron (B)** | 0.003 | 0.005 | Enhances hardenability and grain boundary strength. | | **Zirconium (Zr)** | 0.01 | 0.02 | Grain refiner; improves toughness. | | **Sulfur (S)** | - | 0.010 | Impurity, tightly controlled. | | **Phosphorus (P)** | - | 0.010 | Impurity, tightly controlled. | | **Iron (Fe)** | Balance | | Base element. | *Note: This composition is standardized to achieve the characteristic aging response.* --- ### **Standard Heat Treatment** The bar is supplied in the fully aged condition, having undergone the following standard process: 1. **Solution Anneal:** 815°C ± 15°C (1500°F) for 1 hour per inch of thickness, followed by air cooling. 2. **Aging (Precipitation Hardening):** 480°C ± 5°C (900°F) for 3 hours, followed by air cooling. --- ### **Physical & Mechanical Properties** *Properties are guaranteed in the **longitudinal direction** of the 16 mm round bar.* | Property | Typical Value (Longitudinal) | Notes / Standard | | :--- | :--- | :--- | | **Ultimate Tensile Strength (UTS)** | 2000 - 2070 MPa (290 - 300 ksi) | | | **0.2% Yield Strength (YS)** | 1900 - 2000 MPa (276 - 290 ksi) | Very high yield-to-tensile ratio (>0.95) | | **Elongation at Break (A₅₀)** | 10 - 12 % | Measured on a 50 mm gauge length | | **Reduction of Area (Z)** | 50 - 60 % | Excellent for this strength level | | **Hardness** | 50 - 54 HRC | | | **Fracture Toughness (K_IC)** | 70 - 90 MPa√m | Superior to conventional HSLA steels | | **Modulus of Elasticity** | ~185 GPa (26.8 x 10⁶ psi) | | | **Density** | 8.0 g/cm³ (0.289 lb/in³) | | | **Thermal Conductivity (20°C)** | ~19 W/(m·K) | | | **Coefficient of Thermal Expansion (20-100°C)**| 10.5 x 10⁻⁶ /°C | | **Key Implications of 16 mm Diameter & Longitudinal Testing:** * **Uniform Properties:** A 16 mm diameter ensures rapid and uniform cooling during heat treatment, resulting in consistent microstructure and properties throughout the cross-section. * **Optimal Directional Strength:** Longitudinal properties (tested parallel to the rolling/forging direction) represent the **maximum achievable strength and ductility**. Transverse properties are typically 5-10% lower in ductility and toughness. * **Bar Stock Application:** This form is ideal for machining into **high-stress axial components** like shafts, pins, bolts, and actuators, where the primary load aligns with the bar's length (longitudinal direction). --- ### **International & Industry Standards** This product meets or exceeds the requirements of the following standards for aged 18Ni (300) maraging steel: | Standard Body | Standard Number | Title / Specification | | :--- | :--- | :--- | | **ASTM** | ASTM A538 / A538M | Standard Specification for Precipitation-Hardening Alloy Steel Bar, Forging, and Forging Stock for High-Strength Service | | **AMS (Aerospace)** | AMS 6521 | Steel Bars, Forgings, and Tubing 18.5Ni-9.0Co-4.9Mo-0.65Ti (0.020C) (Maraging 300) Solution and Precipitation Heat Treated | | **UNS** | UNS K92890 | Unified Numbering System designation | | **ISO** | ISO 683-13 | Heat-treatable steels, alloy steels and free-cutting steels - Part 13: Wrought precipitation-hardenable stainless steels | | **Proprietary/Common** | Maraging 300, 18Ni300, Grade 300 | Industry common names | --- ### **Typical Applications** The **aged 16 mm round bar** is specified for critical, weight-sensitive components requiring the ultimate combination of strength, toughness, and dimensional stability. * **Aerospace & Defense:** * **Actuator Shafts & Torque Tubes:** For landing gear, flight controls. * **High-Strength Fasteners:** Special bolts, pins, and studs. * **Rocket Motor Components:** Cases, fastening elements. * **Missile Guidance System Parts.** * **Precision Tooling & Machinery:** * **Extrusion & Die-Casting Punches and Pins:** Resists fatigue and thermal checking. * **Precision Shafts & Spindles:** In high-performance CNC machinery. * **Gears and Bearing Races** for specialized applications. * **High-Performance Automotive & Racing:** * **Connecting Rod Bolts, Head Studs.** * **Lightweight Suspension Components.** * **Nuclear & Marine:** * **Components for Instrumentation** requiring non-magnetic, high-strength properties (in specific conditions). --- ### **Fabrication & Handling Notes (Aged Condition)** * **Machining:** Difficult; requires rigid setups, sharp carbide or CBN tools, and low feed rates. Best machined in the annealed condition before final aging. * **Grinding:** Acceptable for final sizing; use proper coolants to avoid thermal stress. * **Welding:** Not recommended in the aged condition. Welding should be done in the solution-annealed state, followed by a full re-aging treatment. * **Corrosion Protection:** While more resistant to stress corrosion cracking than many high-strength steels, it is not stainless. Appropriate plating (e.g., electroless nickel) or coating is required for corrosive environments. ### **Disclaimer** The information provided is for general reference. For critical applications, always consult the official certified material test report (CMTR/EN10204 3.1) for the specific heat lot and verify properties against the governing project or design specification. -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm Specification Dimensions Size： Diameter 20-1000 mm Length <7334 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 (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Grade 18Ni (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Grade 18Ni (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm -:- For detailed product information, please contact sales. -:

Packing of AISI Grade 18Ni (300) Maraging Steel, Aged, round bar, tested longitudinal, 16 mm -:- 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 3805 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