High-Nickel Ductile Iron Wire, heat-resistant ductile Iron Wire, 20% Ni

High-Nickel Ductile Iron Wire, heat-resistant ductile Iron Wire, 20% Ni Product Information -:- For detailed product information, please contact sales. -: High-Nickel Ductile Iron Wire, heat-resistant ductile Iron Wire, 20% Ni Synonyms -:- For detailed product information, please contact sales. -:

High-Nickel Ductile Iron, heat-resistant ductile iron, 20% Ni Product Information -:- For detailed product information, please contact sales. -: ## **Product Introduction: High-Nickel (20% Ni) Heat-Resistant Ductile Iron** High-Nickel (20% Ni) Heat-Resistant Ductile Iron is a specialized austenitic nodular iron, engineered to deliver unparalleled dimensional stability and corrosion resistance under severe thermal cycling and moderately high-temperature conditions. With a nominal nickel content of 20%, this alloy forms a stable austenitic matrix that is immune to the phase transformations that cause growth and distortion in standard ferritic ductile irons. It is designed for continuous service in the **700°C to 850°C (1290°F to 1560°F)** range, excelling in applications where resistance to thermal fatigue, oxidation, and certain corrosive atmospheres are simultaneously required. This material fills the critical performance gap between ferritic Si-Mo ductile irons (excellent for thermal fatigue but limited to ~800°C) and higher-nickel superalloys, offering a balanced solution for complex components that must withstand both mechanical stress and aggressive thermal-chemical environments. --- ### **1. Chemical Composition (Nominal 20% Ni Grade)** The composition is centered on achieving a fully austenitic structure with 20% nickel as the primary stabilizer, often augmented with chromium and silicon for enhanced performance. **Typical Composition Range (e.g., D-2M / Type D-2):** | Element | Content (%) | Primary Function in Heat Resistance | | :--- | :--- | :--- | | **Nickel (Ni)** | **18.0 - 22.0** | **Fundamental Austenite Stabilizer.** Creates and maintains a stable, non-magnetic austenitic matrix from room temperature to service conditions. This eliminates ferritic transformation, providing exceptional resistance to thermal growth and distortion. Imparts inherent toughness and ductility. | | **Chromium (Cr)** | **1.75 - 2.50** | **Enhances Oxidation Resistance.** Forms a protective chromium oxide (Cr₂O₃) layer within the surface scale, significantly improving resistance to scaling, oxidation, and mild sulfidation at high temperatures. Also provides solid solution strengthening. | | **Silicon (Si)** | **1.00 - 3.00** | **Synergistic Oxide Former.** Promotes the formation of a dense, adherent silicate-rich oxide scale. Raises the scaling temperature and improves overall oxidation and growth resistance. Typically kept moderate in 20% Ni grades to balance castability and machinability. | | **Carbon (C)** | **2.30 - 2.90** | Ensures full nodularization. Provides graphite for thermal shock resistance and machinability. Content is controlled to avoid excessive primary carbides. | | **Manganese (Mn)** | 0.50 - 1.50 | Supports austenite stability and acts as a deoxidizer. | | **Magnesium (Mg)** | 0.04 - 0.08 | Essential nodularizing element for spheroidal graphite formation. | | **Copper (Cu)** | ≤ 1.50 (Optional) | Sometimes added to further enhance corrosion resistance in specific atmospheres and provide mild strengthening. | | **Iron (Fe)** | Balance | Base metal. | **Microstructural Note:** The target microstructure is a **fully austenitic matrix** with a uniform, non-interconnected distribution of **well-formed spheroidal graphite (Type VI, >80% nodularity)**. The matrix should be free of ferrite, pearlite, and undesirable massive carbides. --- ### **2. Physical & Mechanical Properties at Room & Elevated Temperature** This alloy is characterized by its stability, maintaining good strength and excellent ductility over a wide temperature range. | Property | Typical Value / Description | | :--- | :--- | | **Microstructure** | Austenitic matrix with spheroidal graphite. | | **Density** | ~7.3 - 7.4 g/cm³ | | **Tensile Strength (Room Temp)** | **450 - 550 MPa (65 - 80 ksi)** | | **Yield Strength (0.2% Offset, Room Temp)** | **240 - 310 MPa (35 - 45 ksi)** | | **Elongation (Room Temp)** | **8 - 20%** – Retains significant ductility. | | **Hardness (Room Temp)** | **140 - 200 HB** | | **Impact Resistance (Charpy V-Notch)** | **20 - 35 J (15 - 26 ft-lbf)** at room temperature. | | **Maximum Service Temperature** | **Up to 850°C (1560°F)** in oxidizing atmospheres. Optimal for long-term cyclic service between 700-800°C. | | **Growth Resistance** | **Exceptional.** Exhibits minimal permanent growth (<0.05% after 1000h at 750°C) due to the invariant austenitic structure, superior to all ferritic grades. | | **Oxidation/Scaling Resistance** | **Very Good.** The Ni-Cr-Si alloying promotes a protective, adherent oxide scale. Performance is superior to unalloyed ductile iron and comparable to many cast steels in this temperature range. | | **Thermal Conductivity** | Moderate (~12-15 W/m·K). Lower than ferritic ductile irons. | | **Thermal Shock Resistance** | **Excellent.** The austenitic matrix provides high ductility and fracture toughness, while the nodular graphite effectively arrests crack propagation, making it highly resistant to thermal fatigue. | | **Creep & Rupture Strength** | Good. Adequate for many loaded applications at temperature, though lower than advanced ferritic Si-Mo grades at the very top of their range. | | **Magnetic Properties** | **Essentially non-magnetic.** A key advantage for specific applications. | --- ### **3. Key Product Advantages & Characteristics** * **Ultimate Dimensional Stability:** The austenitic structure provides near-zero growth under thermal cycling, critical for precision fixtures and housings. * **Superior Thermal Fatigue Resistance:** Excellent for components subjected to severe and repeated thermal shocks. * **Combined Heat & Corrosion Resistance:** Performs well not only in high temperatures but also in corrosive atmospheres (e.g., containing combustion condensates, mild acids, or salts), outperforming ferritic grades. * **Good Weldability and Machinability:** Generally weldable with appropriate Ni-based filler rods and machinable with standard tools, though work-hardening tendencies require care. * **Non-Magnetic Property:** Essential for applications in electrical systems or where magnetic interference must be avoided. --- ### **4. Product Applications** This material is specified for high-integrity components in demanding, cyclic thermal environments where dimensional stability and corrosion are concurrent challenges. * **Turbocharger & Exhaust Systems:** **Turbocharger housings** for large marine, locomotive, and stationary engines where exhaust gas corrosion (sulfidation) is a concern. High-performance exhaust manifolds and components. * **Power Generation:** High-temperature valve bodies, pump casings, and turbine components in waste heat recovery and combined cycle plants. * **Heat Treatment & Industrial Furnaces:** Fixturing, trays, jigs, and fan housings subject to repeated heating and cooling cycles. * **Petrochemical:** Components for reformers, heaters, and transfer lines handling high-temperature process streams. * **Marine & Offshore:** High-grade pump and valve components for high-temperature service on ships and platforms. --- ### **5. International Standards** The 20% Ni heat-resistant ductile iron is covered under austenitic ductile iron standards, with specific types defined for their balanced properties. | Standard | Title / Scope | Common Designations / Notes | | :--- | :--- | :--- | | **ASTM A439** | *Standard Specification for Austenitic Ductile Iron Castings* | **Type D-2** is the most common grade corresponding to ~20% Ni, 2% Cr chemistry. It is the primary reference standard for this material. | | **ISO 2892** | *Austenitic cast irons* | Designations such as **JS/HR/ANi20Cr2** (Spheroidal Graphite / Heat Resistant / Austenitic with 20% Ni, 2% Cr). | | **EN 13835** | *Founding – Austenitic cast irons* (European) | **EN-GJSA-XNiCr20-2** (Material Number). The designation explicitly indicates a spheroidal graphite (GJS) austenitic iron with ~20% Ni and 2% Cr. | | **JIS G5513** | *Austenitic spheroidal graphite iron castings* (Japanese) | **FCD-NiCr202** (indicating Ni-Cr type with 20% Ni, 2% Cr). | | **GB/T 27748** | *Heat resistant austenitic cast iron* (Chinese) | May include grades similar to **QTNi20Cr2** under the austenitic nodular iron category. | **Specification Note:** For procurement, specifying **ASTM A439 Type D-2** or its equivalent in other standards is standard practice. For critical applications, supplementary requirements for **high-temperature tensile testing, oxidation resistance tests, or strict microstructural analysis (nodularity, carbide limits)** are often added to the purchase agreement. --- ### **Conclusion** High-Nickel (20% Ni) Heat-Resistant Ductile Iron is a premium engineering alloy that masterfully balances **austenitic stability, thermal fatigue resistance, and environmental durability**. Its **20% nickel-based austenitic matrix** delivers **unrivaled growth resistance and dimensional stability**, making it the ideal choice for precision components that undergo thousands of severe thermal cycles. While it may not offer the peak high-temperature strength of specialized ferritic Si-Mo grades, its **broader resistance to combined thermal and corrosive attack** positions it as the superior and often essential material for advanced turbo-machinery, exhaust systems, and high-temperature process equipment where long-term reliability under complex stressors is non-negotiable. -:- For detailed product information, please contact sales. -: High-Nickel Ductile Iron, heat-resistant ductile iron, 20% Ni Specification Dimensions Size： Diameter 20-1000 mm Length <6487 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. -: High-Nickel Ductile Iron, heat-resistant ductile iron, 20% Ni Properties -:- For detailed product information, please contact sales. -:

Applications of High-Nickel Ductile Iron Wire, heat-resistant ductile Iron Wire, 20% Ni -:- For detailed product information, please contact sales. -: Chemical Identifiers High-Nickel Ductile Iron Wire, heat-resistant ductile Iron Wire, 20% Ni -:- For detailed product information, please contact sales. -:

Packing of High-Nickel Ductile Iron Wire, heat-resistant ductile Iron Wire, 20% Ni -:- 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 Wire 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 2958 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