AISI Grade 18Ni (200) Maraging Steel Sheet,Plate

AISI Grade 18Ni (200) Maraging Steel Sheet/Plate, Annealed Product Information -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (200) Maraging Steel Sheet/Plate, Annealed Synonyms -:- For detailed product information, please contact sales. -:

AISI Grade 18Ni (200) Maraging Steel, Annealed Product Information -:- For detailed product information, please contact sales. -: # **Product Name: AISI Grade 18Ni (200) Maraging Steel, Annealed** ## **Introduction** AISI Grade 18Ni (200) Maraging Steel in the annealed condition is a special class of ultra-high-strength steel characterized by its unique metallurgical system. Unlike conventional steels hardened by carbon, maraging steels achieve their exceptional strength through a combination of a low-carbon, iron-nickel martensitic matrix and age-hardening via intermetallic compound precipitation. The **annealed (also called solution-annealed or soft) condition** provides a **ductile, machinable, and weldable state** with moderate strength, which is then transformed into an ultra-high-strength state through a simple, low-distortion aging heat treatment. This makes 18Ni (200) a premier material for aerospace, tooling, and critical structural applications requiring a combination of extreme strength, toughness, and dimensional stability during heat treatment. ## **Key Features** * **Ultra-High Strength Potential:** Following aging, it achieves nominal yield strengths of **200 ksi (1380 MPa)** with excellent fracture toughness, far exceeding conventional quenched and tempered steels of similar strength levels. * **Superior Processability in Annealed State:** In the annealed condition, it exhibits **good ductility, excellent machinability, and outstanding weldability**, allowing complex components to be fabricated relatively easily. * **Simple, Low-Distortion Aging:** The final strengthening is achieved by a low-temperature (around 480°C / 900°F) aging process that causes minimal dimensional change, warping, or scaling, unlike the severe quenching required for traditional high-strength steels. * **Excellent Combination of Properties:** After aging, it maintains good toughness and fatigue resistance at very high strength levels, and offers high resistance to crack propagation. --- ## **1. Chemical Composition (Typical Weight %)** The composition is designed for a martensitic transformation upon cooling from the solution temperature and subsequent age-hardening. | Element | Content (%) | Primary Role | | :------------- | :------------ | :-------------------------------------------- | | **Nickel (Ni)**| **17.0 - 19.0**| Primary alloying element; promotes formation of a soft, low-carbon martensite upon air cooling from the solution temperature. | | **Cobalt (Co)**| **8.0 - 9.0** | Reduces the solubility of molybdenum in the matrix, promoting precipitation hardening during aging. | | **Molybdenum (Mo)**| **3.0 - 3.5** | Primary hardening element; forms intermetallic precipitates (Ni₃Mo) during aging. | | **Titanium (Ti)**| **0.15 - 0.25** | Secondary hardening element; forms Ni₃Ti precipitates. | | Aluminum (Al) | 0.05 - 0.15 | Aids in deoxidation and contributes to aging. | | Carbon (C) | **≤ 0.03 (max)** | Kept extremely low to ensure good martensitic toughness and weldability. | | Silicon (Si) | ≤ 0.10 | | | Manganese (Mn) | ≤ 0.10 | | | Sulfur (S) | ≤ 0.01 | | | Phosphorus (P) | ≤ 0.01 | | | **Iron (Fe)** | **Balance** | | --- ## **2. Physical & Mechanical Properties** ### **Properties in the ANNEALED Condition:** This is the *fabricable* state of the material. | Property | Value / Range (Typical, Annealed) | | :-------------------------------------------- | :--------------------------------------- | | Density | 8.1 g/cm³ | | Modulus of Elasticity | ~190 GPa | | **Tensile Strength (Rm)** | **1000 - 1150 MPa** | | **Yield Strength (Rp0.2)** | **830 - 970 MPa** | | **Elongation (A)** | **≥ 15 %** | | Hardness (Rockwell C) | **28 - 34 HRC** | | **Machinability** | **Good** (relative to its strength). Similar to annealed 4340. | | **Weldability** | **Excellent** for an ultra-high-strength steel. Pre- and post-weld heat treatment often not required for thin sections. | ### **Properties in the AGED Condition (Typical, for reference):** | Property (Aged) | Value / Range | | :-------------------------------------------- | :--------------------------------------- | | **Tensile Strength (Rm)** | **~2000 MPa** | | **Yield Strength (Rp0.2)** | **~1380 MPa (200 ksi)** | | **Elongation (A)** | **~10 %** | | **Fracture Toughness (K_IC)** | **~80 - 110 MPa√m** | | Hardness (Rockwell C) | **50 - 54 HRC** | --- ## **3. Product Forms & Applications** **Available Product Forms (Annealed):** * **Bar and Rod:** For machining into critical components. * **Plate and Sheet:** For structural applications. * **Forgings:** For high-strength, complex shapes. * **Billet:** For further processing. **Primary Applications:** The annealed material is fabricated into components that are later aged to achieve their final properties. * **Aerospace & Defense:** **Rocket motor cases**, aircraft landing gear components, helicopter undercarriages, missile skins, and critical fasteners. * **Tooling & Molds:** **Injection molds** for plastics, die-casting tooling, and extrusion dies where high pressure and wear resistance are required. * **High-Performance Racing:** Gears, shafts, and suspension components. * **Precision Machinery:** Critical parts requiring dimensional stability after heat treatment and high strength-to-weight ratios. --- ## **4. International Standards & Approvals** 18Ni (200) is covered by several international and proprietary specifications. | Standard Type | Standard Number & Designation | Notes | | :------------------ | :--------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------- | | **AISI / SAE (USA)**| **Grade 18Ni (200)** | Common U.S. designation. The number indicates the nominal yield strength in ksi after aging. | | **Unified Numbering System (UNS)** | **K92890** (for the 18Ni maraging steel family). Specific grades may have variations. | | | **AMS (Aerospace Material Spec)** | **AMS 6512** (Solution Heat Treated Condition)
**AMS 6514** (Aged Condition) | The primary procurement specifications for aerospace applications. | | **ASTM (USA)** | **ASTM A538** (Standard Specification for Maraging Steel Grades 200, 250, 300, and 350) | Covers bar, plate, and sheet. | | **MIL-Spec** | **MIL-S-46850** | U.S. military specification. | | **Proprietary** | Vendor-specific grades like **VascoMax® 200** (Carpenter Technology). | Often have tighter controls or proprietary processing. | --- ## **Critical Technical & Procurement Note** **Maraging steel is a process-sensitive material. Its performance is entirely dependent on strict adherence to specified heat treatments.** 1. **Procurement Specification:** Always specify the **condition** (e.g., **"Annealed" or "Solution Annealed"**) and the intended **final aged strength level** (e.g., Grade 200). Referencing an AMS or ASTM standard is crucial. 2. **Heat Treatment Cycle:** * **Solution Annealing:** Typically 820-850°C (1500-1550°F) for 1 hour per inch of thickness, followed by **air cooling**. This produces the soft, martensitic structure. * **Aging (Final Hardening):** Typically 480°C (900°F) for 3-6 hours, followed by air cooling. **This step is performed by the end-user after all machining and welding is complete.** Aging causes a **predictable, slight growth** (~0.04% linear). 3. **Fabrication in Annealed State:** * **Machining:** Can be machined using techniques for alloy steels. Material work-hardens, so sharp tools and positive rake angles are recommended. * **Welding:** Can be welded in the annealed condition using matching or nickel-based filler wires (e.g., AWS ERNiMo-3). Welds are typically aged along with the base metal. For optimum properties in the weld zone, a full re-solution anneal after welding may be required. 4. **Certification:** Require a **material test certificate** confirming chemistry and mechanical properties **in the supplied condition (annealed)**. For critical applications, additional tests for grain size or cleanliness may be specified. 5. **Distinct Advantage:** The primary advantage over conventional high-strength steels is the ability to fabricate a complex, high-tolerance component in a **soft, stable state**, and then achieve ultra-high strength with a simple, low-temperature aging treatment that minimizes distortion and eliminates the risk of quench cracking. -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (200) Maraging Steel, Annealed Specification Dimensions Size： Diameter 20-1000 mm Length <7311 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 (200) Maraging Steel, Annealed Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Grade 18Ni (200) Maraging Steel Sheet,Plate, Annealed -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Grade 18Ni (200) Maraging Steel Sheet,Plate, Annealed -:- For detailed product information, please contact sales. -:

Packing of AISI Grade 18Ni (200) Maraging Steel Sheet/Plate, Annealed -:- 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 Sheet/Plate 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 3782 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