ASTM A874 Ductile Iron Sheet,Plate Composition

ASTM A874 Ductile Iron Sheet/Plate Composition Product Information -:- For detailed product information, please contact sales. -: ASTM A874 Ductile Iron Sheet/Plate Composition Synonyms -:- For detailed product information, please contact sales. -:

ASTM A874 Ductile Iron Composition Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: ASTM A874/A874M Corrosion-Resistant Ferritic Ductile Iron** **ASTM A874/A874M** is a standard specification for **ferritic ductile iron castings** alloyed with **silicon** to provide **superior corrosion resistance, particularly in high-temperature aqueous and mild acidic environments**. This alloy is often referred to as **"Si-Ductile"** or **high-silicon ductile iron**. Its primary value lies in its ability to withstand corrosive media (like sulfuric acid, acidic mine water, and chloride solutions) at elevated temperatures where standard ductile iron or even some stainless steels would fail, while retaining the good castability, machinability, and mechanical properties of ductile iron. It is a cost-effective alternative to high-nickel alloys for many applications. --- ### **1. Key International Standards & Designations** * **Primary Standard:** **ASTM A874/A874M - Standard Specification for Ferritic Ductile Iron Castings Suitable for Low-Temperature Service** * *(Note: The title emphasizes "low-temperature service" due to its excellent toughness at sub-zero temperatures, a direct result of its fully ferritic matrix. However, its dominant application is corrosion resistance.)* * **UNS Designation:** **F45000** (This is the UNS number specifically for the high-silicon, corrosion-resistant ferritic ductile iron covered by A874). * **Common Trade Names:** Si-Ductile, Duriron (when referring to high-Si white iron), Corrosion-Resistant Ductile Iron (CRDI). * **Related Standards:** * **ASTM A536:** Covers standard grades of ductile iron. A874 is a specialized subset with a specific chemistry for corrosion resistance. * **ASTM A897/A897M:** For austempered ductile iron (ADI), offering high strength. * **ISO 1083/JS:** While no direct equivalent exists, its properties align with high-silicon, ferritic grades within this international standard. --- ### **2. Chemical Composition (Requirements per ASTM A874)** The composition is precisely controlled to achieve a **fully ferritic matrix** with **spheroidal graphite** and a high silicon content for passivation. | Element | Requirements (% by Weight) | Purpose & Rationale | | :--- | :--- | :--- | | **Carbon (C)** | 2.90 - 3.70 | Provides the base carbon for graphite formation. Controlled to balance strength and castability. | | **Silicon (Si)** | **3.50 - 4.00** | **The defining alloying element.** At this high level, it: 1) Promotes a fully ferritic matrix, 2) Forms a stable, protective silicon dioxide (SiO₂) surface layer in corrosive environments, 3) Increases strength and hardness of the ferrite. | | **Manganese (Mn)** | **0.30 Max** | Kept very low to prevent the formation of pearlite or carbides, which would impair toughness, machinability, and corrosion resistance. | | **Phosphorus (P)** | **0.04 Max** | Extremely low limit to prevent brittle phosphide networks at grain boundaries. | | **Sulfur (S)** | **0.015 Max** | Extremely low limit is critical for successful nodularization (spheroidal graphite formation) and overall soundness. | | **Magnesium (Mg)** | 0.03 - 0.06 (Typical) | **The essential nodulizing element.** Must be present to ensure graphite forms as spheres, not flakes. Often reported as residual. | | **Chromium (Cr)** | **0.06 Max (Reported)** | Strictly limited. Chromium is a strong carbide former and would destabilize the required fully ferritic structure. | | **Copper (Cu)** | **0.40 Max (Reported)** | Limited. While it can improve corrosion resistance in some media, excess copper can promote pearlite. | | **Nickel (Ni)** | **0.40 Max (Reported)** | Limited for the same reason as copper and manganese. | **Key Takeaway:** The hallmark of A874 is the **high silicon (3.5-4.0%)** combined with **very low manganese, chromium, and copper** to guarantee a carbide-free, pearlite-free ferritic structure. This is fundamental to both its corrosion resistance and low-temperature toughness. --- ### **3. Mechanical & Physical Properties** The high silicon content in solid solution significantly strengthens the ferrite, resulting in properties distinct from standard ferritic ductile iron (e.g., ASTM A536 60-40-18). **A. Mechanical Properties (Minimums, as-cast or heat-treated to achieve ferritic structure):** * **Tensile Strength:** **70 ksi min (485 MPa min)** * **Yield Strength (0.2% Offset):** **50 ksi min (345 MPa min)** * **Elongation (% in 2 inches / 50mm):** **10% min** * **Hardness (Typical Range):** 217 - 269 HB (Approx. 95 - 25 HRB) * **Impact Toughness:** Excellent, even at low temperatures (e.g., Charpy V-Notch values often exceeding 20 ft-lb at -40°F/-40°C). **B. Typical Physical Properties:** * **Density:** Slightly lower than standard ductile iron, ~7.0 - 7.1 g/cm³, due to high silicon. * **Melting Range:** ~1150 - 1200 °C * **Modulus of Elasticity:** ~24 x 10⁶ psi (165 GPa) * **Coefficient of Thermal Expansion:** ~6.0 x 10⁻⁶ /°C (20-200°C) – Lower than standard ductile iron. * **Thermal Conductivity:** Lower than standard ductile iron due to high silicon content. * **Machinability:** **Fair to Poor.** The high silicon content significantly hardens the ferrite, causing increased tool wear. Special tooling and slower speeds are required. --- ### **4. Corrosion Resistance & Key Characteristics** * **Excellent Corrosion Resistance:** Particularly outstanding in **sulfuric acid (H₂SO₄) across a wide range of concentrations and temperatures**, phosphoric acid, nitric acid, and acidic salt solutions. It forms a tenacious, self-healing SiO₂-rich passive film. * **Oxidation Resistance:** Good resistance to scaling and oxidation at elevated temperatures (up to ~800°C / 1470°F in air). * **Fully Ferritic Matrix:** Provides exceptional **low-temperature impact resistance** and eliminates galvanic micro-cells between ferrite and pearlite, enhancing uniform corrosion resistance. * **Graphite Morphology:** The spheroidal graphite minimizes stress concentration points compared to flake graphite, improving both mechanical properties and corrosion fatigue resistance. --- ### **5. Typical Applications** ASTM A874 is specified where corrosion is the primary failure mode, especially in chemical process, geothermal, and mining industries. * **Chemical Process Industry (CPI):** * **Pump Casings, Impellers, and Volutes** handling sulfuric acid, mixed acids, and corrosive slurries. * **Valve Bodies and Components** (e.g., plug valves, check valves) for corrosive service. * **Pipe Fittings, Elbows, and Tees** in acid waste lines. * **Geothermal Energy:** * **Wellhead Components, Brine Piping, and Separator Parts** exposed to high-temperature, chloride-rich geothermal fluids. * **Mining & Mineral Processing:** * **Slurry Pump Parts, Hydrocyclones, and Wear Plates** in acidic environments. * **Pollution Control:** * **Scrubber Components, Ductwork, and Fans** in flue gas desulfurization (FGD) systems. --- ### **6. Summary** **ASTM A874/A874M (UNS F45000) defines a specialized, high-silicon, fully ferritic ductile iron engineered for maximum corrosion resistance in aggressive aqueous and acidic environments.** Its balanced composition sacrifices some machinability and raw strength to achieve unparalleled performance in corrosive media—often outperforming stainless steels in specific chemical services—while maintaining the cost and casting advantages of ferrous metals. It is a critical material for engineers in the chemical, energy, and resource extraction sectors designing durable equipment for harsh service conditions. -:- For detailed product information, please contact sales. -: ASTM A874 Ductile Iron Composition Specification Dimensions Size： Diameter 20-1000 mm Length <6599 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. -: ASTM A874 Ductile Iron Composition Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A874 Ductile Iron Sheet,Plate Composition -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A874 Ductile Iron Sheet,Plate Composition -:- For detailed product information, please contact sales. -:

Packing of ASTM A874 Ductile Iron Sheet/Plate Composition -:- 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 3070 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