AISI Grade 18Ni (250) Maraging Steel, nominal anneale

AISI Grade 18Ni (250) Maraging Steel, nominal annealed properties Product Information -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (250) Maraging Steel, nominal annealed properties Synonyms -:- For detailed product information, please contact sales. -:

AISI Grade 18Ni (250) Maraging Steel, nominal annealed properties Product Information -:- For detailed product information, please contact sales. -: ### **Product Data Sheet: AISI Grade 18Ni (250) Maraging Steel (Nominal Annealed Condition)** **Product Overview** AISI 18Ni (250), also known as 18% Nickel Maraging Steel Grade 250, is a premier ultra-high-strength alloy from the maraging steel family. In its **nominal annealed (soft or solution-annealed) condition**, the material is supplied in a soft, low-carbon martensitic state. This condition provides excellent machinability, formability, and weldability, serving as the standardized pre-hardened state from which the full tensile strength of approximately 250 ksi (1725 MPa) is developed through a subsequent, simple age-hardening (aging) heat treatment. It is the most widely used grade within the maraging steel family. **Standard Condition: Nominal Annealed (Solution Annealed)** * **Typical Treatment:** Austenitized at **815°C (1500°F)** for 1 hour per inch of thickness, followed by **Air Cooling** to room temperature. * **Purpose:** This treatment dissolves the intermetallic-forming elements (Ti, Mo, Co) into solid solution within the austenitic structure, which then transforms to a soft, heavily dislocated, low-carbon **lath martensite** upon cooling. This structure is ductile and workable. * **Key Note:** The material in this condition is **not yet at its final high strength**. It is designed to be machined, formed, or welded in this soft state, and then aged to achieve its ultimate mechanical properties with minimal distortion. **Chemical Composition (Typical Weight %, per ASTM A538 / 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 | **Critical Feature:** Extremely low carbon and impurity (S, P) content is essential for maximizing toughness and weldability. **Physical & Mechanical Properties (In Nominal Annealed Condition)** * **Density:** 8.0 g/cm³ (0.289 lb/in³) * **Melting Range:** ~ 1415°C (2580°F) * **Mechanical Properties (Annealed):** * **Ultimate Tensile Strength (UTS):** 1030 - 1100 MPa (150 - 160 ksi) * **Yield Strength (0.2% Offset):** 1000 - 1070 MPa (145 - 155 ksi) * **Elongation (% in 4D):** 14 - 16% * **Reduction of Area:** 65 - 75% * **Hardness:** 28 - 32 HRC * **Machinability:** Good (approximately 40-45% relative to 1% carbon steel) * **Thermal Properties (Annealed):** * **Thermal Expansion Coefficient (20-100°C):** 10.2 x 10⁻⁶/K * **Thermal Conductivity:** ~ 19.5 W/m·K * **Properties After Standard Aging (480°C/900°F for 3-6 hrs):** * **Ultimate Tensile Strength (UTS):** 1725 - 1790 MPa (250 - 260 ksi) * **Yield Strength (0.2% Offset):** 1690 - 1760 MPa (245 - 255 ksi) * **Hardness:** 50 - 54 HRC **Key Characteristics & Advantages (Annealed State)** 1. **Superior Machinability & Formability:** The soft martensitic structure allows for relatively easy machining, cutting, and forming into complex shapes prior to final aging. 2. **Excellent Weldability:** Can be welded using common techniques (TIG, MIG) without preheating. Welding is performed in the annealed condition, followed by a full aging cycle to restore strength uniformly. 3. **Minimal Distortion Upon Aging:** The final strengthening is achieved by a low-temperature aging process that causes negligible dimensional change or distortion compared to quenching processes. 4. **Foundation for High Performance:** This annealed state is the essential precursor for developing the alloy's legendary combination of ultra-high strength, excellent fracture toughness, and good fatigue resistance after aging. **Primary Applications** The material is procured in the annealed condition for fabrication and then aged. Final applications include: * **Aerospace & Defense:** Critical structural components such as rocket motor casings, missile bodies, aircraft landing gear, helicopter drive shafts, and satellite components. * **Tooling:** High-performance plastic injection molds, die-casting dies, extrusion rams, and machine components requiring high strength and wear resistance. * **Precision Machinery:** High-load shafts, gears, fasteners, and springs in demanding environments. * **Racing & Automotive:** Critical safety components, transmission parts, and fasteners in Formula 1 and other elite motorsports. * **Specialty Fasteners:** Ultra-high-strength bolts and studs for critical assemblies. **International & Industry Standards** * **ASTM A538 / A538M:** *Standard Specification for Pressure Vessel Plates, Alloy Steel, 18% Nickel Maraging* (Covers 200, 250, 300, and 350 grades). * **AMS 6514:** *Aerospace Material Specification for Maraging Steel Bars, Forgings, and Rings 18Ni-8Co-3.5Mo-4.8Ti, Solution Annealed* (The primary spec for annealed 250-grade product forms). * **AMS 6521:** Specification for the same composition in the *Aged* condition. * **UNS K92890:** Unified Numbering System designation (shared with other 18Ni grades; grade is defined by heat treatment). * **ISO 683-13:** *Heat-treatable steels, alloy steels and free-cutting steels — Part 13: Wrought maraging steels*. * **MIL-S-46850 (Historical):** Military Specification often referenced. **Disclaimer:** The values provided are nominal and typical for standard sections. Actual properties may vary based on manufacturer, product form (bar, plate, forging), and exact thermal cycle. For design-critical applications, always refer to certified material test reports from the supplier or conduct independent verification testing. The annealed condition is an intermediate processing state; final part performance is achieved only after the prescribed aging heat treatment. -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (250) Maraging Steel, nominal annealed properties Specification Dimensions Size： Diameter 20-1000 mm Length <7319 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, nominal annealed properties Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Grade 18Ni (250) Maraging Steel, nominal annealed properties -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Grade 18Ni (250) Maraging Steel, nominal annealed properties -:- For detailed product information, please contact sales. -:

Packing of AISI Grade 18Ni (250) Maraging Steel, nominal annealed properties -:- 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 3790 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