AISI Grade 18Ni (200) Maraging Steel, Aged

AISI Grade 18Ni (200) Maraging Steel, Aged, 16 mm round bar, tested in longitudinal direction Product Information -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (200) Maraging Steel, Aged, 16 mm round bar, tested in longitudinal direction Synonyms -:- For detailed product information, please contact sales. -:

AISI Grade 18Ni (200) Maraging Steel, Aged, 16 mm round bar, tested in longitudinal direction Product Information -:- For detailed product information, please contact sales. -: # **Product Name: AISI Grade 18Ni (200) Maraging Steel, Aged Condition - 16 mm Round Bar (Longitudinal Test Direction)** ## **Introduction** This specification details **AISI Grade 18Ni (200) Maraging Steel in its fully aged, ultra-high-strength condition**, supplied as a **16 mm diameter round bar** with mechanical properties certified in the **longitudinal direction**. The material has undergone the complete heat treatment cycle: solution annealing followed by the critical aging process. This state represents the final, service-ready condition of the alloy, delivering its signature combination of **extremely high strength (nominal 200 ksi / 1380 MPa yield), excellent fracture toughness, and dimensional stability**. The round bar form, tested longitudinally, is ideal for machining into high-stress components such as shafts, fasteners, and actuators where the maximum unidirectional mechanical performance is required. ## **Key Features** * **Ultra-High Strength with Toughness:** Achieves a yield strength of approximately **1380 MPa (200 ksi)** while maintaining superior fracture toughness compared to conventional quenched and tempered steels of equivalent strength, due to its low-carbon martensitic matrix strengthened by intermetallic precipitates. * **Minimal Distortion from Heat Treatment:** The aging hardening process occurs at a relatively low temperature (~480°C), resulting in negligible distortion, scaling, or the risk of quench cracking associated with traditional high-strength steels. * **Longitudinal Performance Optimization:** Testing in the longitudinal direction demonstrates the material's best possible strength and ductility along the primary working axis of the bar, which is critical for components subjected to tensile or bending loads aligned with their length. * **Ready-for-Service Condition:** Supplied in the aged condition, the bar is ready for final machining (grinding, honing) or direct use, with no further heat treatment required by the end-user. --- ## **1. Chemical Composition (Typical Weight %)** The composition is designed for age-hardening of a low-carbon, nickel-rich martensite. | Element | Content (%) | Primary Role | | :------------- | :------------ | :-------------------------------------------- | | **Nickel (Ni)**| **17.0 - 19.0**| Forms the soft, lath martensite matrix upon air cooling from solution annealing. | | **Cobalt (Co)**| **8.0 - 9.0** | Drives molybdenum out of solution to enhance precipitation hardening during aging. | | **Molybdenum (Mo)**| **3.0 - 3.5** | Primary hardening element; forms Ni₃Mo precipitates. | | **Titanium (Ti)**| **0.15 - 0.25** | Secondary hardening element; forms Ni₃Ti precipitates. | | Aluminum (Al) | 0.05 - 0.15 | Contributes to aging response and deoxidation. | | Carbon (C) | **≤ 0.03 (max)** | Kept extremely low to ensure martensite 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 (Aged Condition - Longitudinal)** *Properties are guaranteed minima or typical ranges for the aged, longitudinal condition of a 16 mm round bar.* | Property | Value / Range (Aged, Longitudinal) | Test Standard (Typical) | | :-------------------------------------------- | :--------------------------------------- | :-------------------------------- | | Density | 8.1 g/cm³ | | | Modulus of Elasticity | ~190 GPa | | | **Tensile Strength (Rm)** | **≥ 1930 MPa** | ASTM E8 / ISO 6892-1 | | **Yield Strength (Rp0.2)** | **≥ 1380 MPa (200 ksi)** | ASTM E8 / ISO 6892-1 | | **Elongation (A in 4D / 5D)** | **≥ 10 %** | ASTM E8 / ISO 6892-1 | | **Reduction of Area (Z)** | **≥ 40 %** | ASTM E8 / ISO 6892-1 | | Hardness | **50 - 54 HRC** | ASTM E18 | | **Fracture Toughness (K_IC)** | **80 - 110 MPa√m** (Typical) | ASTM E399 | | **Impact Toughness (Charpy V-notch, Longitudinal)** | **≥ 25 J at 20°C** (Typical) | ASTM E23 / ISO 148-1 | **Note on Directionality:** Properties tested in the **transverse direction** would typically show **reduced ductility and toughness** compared to longitudinal values. The longitudinal direction represents the most favorable orientation. --- ## **3. Product Forms & Applications** **Product Form & Condition:** * **Form:** **16 mm Diameter Round Bar**. * **Condition:** **Fully Aged (Solution Annealed & Aged)**. * **Surface:** Centerless ground, peeled, or hot-rolled finish as specified. * **Test Direction:** **Longitudinal** (parallel to the rolling/drawing direction). **Primary Applications:** This specific product is used for high-performance components where the longitudinal properties are critical: * **Aerospace:** High-strength **fasteners** (bolts, studs), **actuator shafts**, **landing gear pins**, and **rocket motor case fittings**. * **Precision Machinery:** **Drive shafts**, **spindles**, and **hydraulic piston rods** requiring high stiffness and fatigue resistance. * **Tooling:** **Ejector pins** for die-casting and injection molding, **punches**, and **mandrels**. * **Oil & Gas (Downhole):** **Critical pins and connectors** for downhole tools where high strength and resistance to hydrogen embrittlement are required. * **Racing & High-Performance Automotive:** **Suspension components**, **gears**, and **drive train elements**. --- ## **4. International Standards & Approvals** The aged condition of 18Ni (200) is covered by rigorous aerospace and industrial standards. | Standard Type | Standard Number & Designation | Notes | | :------------------ | :--------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------- | | **AISI / SAE (USA)**| **Grade 18Ni (200)** | Nominal designation based on aged yield strength (200 ksi). | | **AMS (Aerospace Material Spec)** | **AMS 6514** (Bar, forgings, and rings, 18.5Ni-9.0Co-4.9Mo-0.65Ti, maraging, consumable electrode melted, aged) | **The primary procurement specification for aged bar stock.** Defines chemistry, heat treatment, and property requirements. | | | **AMS 6512** (Solution heat treated condition) | For material to be aged by the user. | | **ASTM (USA)** | **ASTM A538** (Standard Specification for Maraging Steel Grades 200, 250, 300, and 350) | Covers aged bar, plate, and sheet. | | **MIL-Spec** | **MIL-S-46850** | U.S. military specification for maraging steels. | | **Proprietary** | **VascoMax® 200** (Carpenter Technology), **Cryo-Tuf® 200** | Proprietary grades with specific processing for enhanced cleanliness and properties. | --- ## **Critical Technical & Procurement Note** **Procuring maraging steel in the aged condition requires precise specification and understanding of its limitations.** 1. **Explicit Procurement Specification:** The order must state: * **Material:** **AISI 18Ni (200) Maraging Steel**. * **Condition:** **Aged (per AMS 6514)**. * **Form & Size:** **16 mm Round Bar**. * **Test Direction:** **Mechanical properties to be reported in the Longitudinal direction**. * **Standard:** **AMS 6514** (or equivalent). 2. **Machining in the Aged Condition:** **Extremely difficult.** The hardness of 50-54 HRC requires grinding, honing, or EDM for final sizing. All significant machining (turning, milling, drilling) **must be completed in the annealed condition** before the final aging treatment. 3. **Heat Treatment History:** The material is supplied with its final properties. **No further high-temperature heat treatment (welding, re-aging at higher temperature) is permitted**, as it will over-age the material, significantly reducing strength. 4. **Sensitivity to Over-Aging and Exposure:** Prolonged exposure to temperatures above ~400°C can cause over-aging and softening. Care must be taken during any post-aged processes (e.g., coating) that involve elevated temperatures. 5. **Certification:** Demand a comprehensive **Material Test Report (MTR)** that includes: * Heat chemistry. * **Full mechanical properties from longitudinal tests** (Tensile, Yield, Elongation, R.A., Hardness). * **Heat treatment record** confirming the full cycle (Solution Anneal + Aging times and temperatures). * For critical applications, **fracture toughness (K_IC) or Charpy impact data** may also be required. 6. **Justification:** This product is used when the component design **requires the final ultra-high-strength geometry to be held to tight tolerances that would be distorted by the aging process**, or when the end-user lacks aging furnace capability. It is more expensive than annealed stock due to the added processing and testing. -:- For detailed product information, please contact sales. -: AISI Grade 18Ni (200) Maraging Steel, Aged, 16 mm round bar, tested in longitudinal direction Specification Dimensions Size： Diameter 20-1000 mm Length <7312 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, Aged, 16 mm round bar, tested in longitudinal direction Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Grade 18Ni (200) Maraging Steel, Aged, 16 mm round bar, tested in longitudinal direction -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Grade 18Ni (200) Maraging Steel, Aged, 16 mm round bar, tested in longitudinal direction -:- For detailed product information, please contact sales. -:

Packing of AISI Grade 18Ni (200) Maraging Steel, Aged, 16 mm round bar, tested in longitudinal direction -:- 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 3783 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