ASTM A439 Austenitic Ductile Iron Rod/Bar type D3A

ASTM A439 Austenitic Ductile Iron Rod type D3A Product Information -:- For detailed product information, please contact sales. -: ASTM A439 Austenitic Ductile Iron Rod type D3A Synonyms -:- For detailed product information, please contact sales. -:

ASTM A439 Austenitic Ductile Iron type D3A Product Information -:- For detailed product information, please contact sales. -: # **Product Technical Data Sheet: ASTM A439 Austenitic Ductile Iron – Type D-3A** --- ## **1. Product Overview** **ASTM A439 Type D-3A Austenitic Ductile Iron** is a **silicon-modified variant of the high-nickel Type D-3**, engineered specifically to provide **exceptional corrosion resistance to hot concentrated sulfuric acid and other reducing acids**. By significantly increasing the silicon content beyond that of standard Type D-3, this alloy develops a highly stable, silicon-enriched passive film that dramatically improves its performance in aggressive, non-oxidizing acidic environments. It retains the fully austenitic matrix, non-magnetic properties, and good mechanical characteristics of the D-3 family while offering a specialized corrosion profile that makes it indispensable in specific severe chemical processing applications. --- ## **2. Governing Standards & Specifications** This alloy is a defined variant within the ASTM A439 standard, optimized for a specific corrosion environment. * **Primary Standard:** * **ASTM A439** - *Standard Specification for Austenitic Ductile Iron Castings* * **International & Commercial Equivalents:** * **ISO 2892:** *Austenitic cast irons* – Type D-3A corresponds to **L-NiSiCr 20 5 3**. * **EN 13835:** *Austenitic cast irons* – Designated as **EN-JS 2035**. * **Common Trade Name:** **Ni-Resist® Type D-3A**. * **Key Referenced Testing Standards:** * **ASTM E8:** Tensile Testing * **ASTM E10:** Brinell Hardness * **ASTM A247:** Microstructure Evaluation * **ASTM G31:** Immersion Corrosion Testing (especially in sulfuric acid) --- ## **3. Chemical Composition Requirements (per ASTM A439)** The elevated silicon content is the critical modification that defines Type D-3A's performance. | Element | Composition Range (wt.%, ASTM A439) | Functional Role & Metallurgical Rationale | | :--- | :--- | :--- | | **Carbon (C)** | 2.40 - 2.90 | Controlled at the lower end of the D-3 range to improve castability with high Si and reduce the carbon available for potential carbide formation. | | **Silicon (Si)** | **4.50 - 5.50** | **The Defining Addition.** This high level promotes the formation of a tenacious, silicon-rich oxide film (SiO₂) on the surface, which is highly stable in reducing acids like sulfuric. It provides **outstanding corrosion resistance in concentrated H₂SO₄ across a wide temperature range**. Also strengthens the austenitic matrix via solid solution. | | **Nickel (Ni)** | **28.00 - 32.00** | **Primary Austenite Stabilizer.** Ensures a fully austenitic, ductile, and non-magnetic matrix even with the high Si content. Provides inherent corrosion resistance. | | **Chromium (Cr)** | **2.50 - 3.50** | Provides resistance to oxidizing conditions and improves general passivity. Balances the alloy for environments that may alternate between reducing and mildly oxidizing. | | **Manganese (Mn)** | 0.50 - 1.50 | Austenite stabilizer and sulfur control. | | **Copper (Cu)** | ≤ 0.50 | Kept low, as copper can be detrimental in sulfuric acid service. | | **Magnesium (Mg)** | ≥ 0.07 (min., residual) | Ensures spheroidal graphite formation. | | **Phosphorus (P)** | ≤ 0.08 | Kept low. | | **Sulfur (S)** | ≤ 0.03 | Kept low. | --- ## **4. Physical & Mechanical Properties** Type D-3A shares the base characteristics of high-nickel austenitic irons, with specific nuances from its high silicon content. | Property | Typical Value / Range for D-3A | Key Characteristics & Comparison with D-3 | | :--- | :--- | :--- | | **Tensile Strength, min.** | **414 MPa (60,000 psi)** | Similar minimum, but the high Si provides solid solution strengthening, often resulting in higher typical UTS (450-550 MPa). | | **Yield Strength (0.2% offset), min.** | **207 MPa (30,000 psi)** | Similar minimum, with typical values also elevated. | | **Elongation, min.** | **10%** | **Reduced compared to D-3 (15%).** The high silicon content increases strength but decreases ductility and impact toughness. | | **Hardness (Brinell, HBW)** | **160 - 220 HBW** | **Higher than D-3** due to significant solid solution strengthening from silicon. | | **Modulus of Elasticity** | **~105 - 115 GPa** | Slightly lower than D-3 due to higher alloying. | | **Impact Resistance** | **Moderate.** Lower than standard D-3 due to reduced ductility. Suitable for static or slowly loaded parts, not for high shock. | | **Corrosion Resistance** | **Specialized & Exceptional:**
• **Outstanding resistance to sulfuric acid (H₂SO₄)** across a wide range of concentrations and temperatures, including hot concentrated acid. This is its **primary application domain.**
• Good resistance to phosphoric acid (H₃PO₄).
• **Poor resistance to hydrofluoric acid (HF)** and hot concentrated alkalis, which attack the SiO₂ film.
• Good resistance to seawater and atmospheric corrosion. | | **Maximum Service Temperature** | **~800°C (1470°F) Continuous** | Slightly lower than D-3 due to potential embrittlement from high-temperature exposure with high Si. | | **Non-Magnetic Property** | **Excellent.** Fully austenitic. | | **Machinability** | **Fair.** More difficult than D-3 due to higher hardness and abrasiveness from the silicon-strengthened matrix. Carbide tooling is essential. | --- ## **5. Product Applications** Type D-3A is a specialist material, primarily deployed in sulfuric acid and related chemical service. * **Sulfuric Acid Production & Handling (Primary Market):** * **Pump casings, impellers, valve bodies, and pipe fittings** for concentrated sulfuric acid. * **Acid coolers, concentrators, and storage tank components.** * **Pickling line equipment** in steel and metal finishing. * **Chemical Processing:** * **Reactors, columns, and heat exchangers** for processes involving sulfuric or phosphoric acid. * **Equipment for fertilizer production** (e.g., phosphate processing). * **Petrochemical & Refining:** * **Alkylation unit components** where sulfuric acid is used as a catalyst. * **General Acid Service:** * **Components for chemical dosing and neutralization systems.** --- ## **6. Fabrication & Processing Notes** * **Condition:** Typically supplied **as-cast and solution annealed**. A high-temperature anneal (~1050-1100°C) followed by rapid cooling is critical to dissolve any silicon-rich carbides or intermetallics that may form during casting, ensuring optimal corrosion resistance and ductility. * **Casting Considerations:** The high silicon content significantly increases the melt's fluidity but can also promote shrinkage and microporosity. Expert gating and risering design is required. The alloy is more prone to reaction with molding materials; use of neutral or basic refractories is recommended. * **Machinability:** **Fair to Difficult.** The hard, abrasive matrix causes rapid tool wear. **Carbide or ceramic tooling with positive rake is mandatory.** Cutting speeds should be moderate to low, with ample coolant. * **Weldability:** **Poor to Fair (Requires Extreme Care).** The high Si and Ni content make it prone to hot cracking and microfissuring. Welding is **not generally recommended** for corrosion service. If repair is unavoidable: * Use **matching or over-alloyed Ni-Cr-Mo filler metal** (e.g., ENiCrFe-3). * Employ **low heat input** (GTAW preferred). * **Pre-heat and maintain interpass temperature** (~150-200°C). * **Post-weld solution annealing is absolutely essential** to restore corrosion resistance, but may not fully eliminate HAZ defects. --- ## **7. Ordering Information** **Specify:** **"Austenitic Ductile Iron Castings, ASTM A439 Type D-3A (Ni-Resist D-3A equivalent), Solution Annealed."** **Critical Details to Provide:** * **Applicable Standard & Grade** (ASTM A439 D-3A). * **Mandatory Heat Treatment:** "Solution Annealed" condition must be specified. * **Part Drawing & Specification.** * **Exact Corrosive Service Environment:** Acid type, concentration, temperature, and presence of oxidizers or contaminants. * **Certification Requirements:** MTR with full chemical analysis (verify high Si), mechanical properties, and heat treatment records. For critical acid service, **corrosion test coupons** exposed to the actual or simulated process fluid may be required for approval. --- ## **8. Summary: D-3 vs. D-3A Selection Guide** | **Criterion** | **Choose ASTM A439 Type D-3 when:** | **Choose ASTM A439 Type D-3A when:** | | :--- | :--- | :--- | | **Primary Corrosion Need** | Resistance to **hot concentrated alkalis (caustics)**, seawater, and oxidizing acids. | Resistance to **sulfuric acid** and other **reducing acids** is the paramount requirement. | | **Key Alloy Feature** | High Ni (28-32%) for general corrosion resistance. | High Ni **plus High Si (4.5-5.5%)** for acid-specific passivation. | | **Mechanical Focus** | Better ductility (15% min Elongation) and impact toughness. | Higher as-cast strength and hardness, but lower ductility (10% min Elongation). | | **Cost Consideration** | High (due to Ni). | Very High (due to Ni + specialized Si addition and processing). | | **Application** | Caustic evaporators, seawater pumps, general severe service. | Sulfuric acid pumps, valves, pickling equipment. | **ASTM A439 Type D-3A is a purpose-built, premium engineering material. It offers an irreplaceable solution for handling concentrated sulfuric acid—one of the most ubiquitous and corrosive industrial chemicals—where few other cast materials provide reliable, long-term service.** -:- For detailed product information, please contact sales. -: ASTM A439 Austenitic Ductile Iron type D3A Specification Dimensions Size： Diameter 20-1000 mm Length <6555 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 A439 Austenitic Ductile Iron type D3A Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A439 Austenitic Ductile Iron Rod type D3A -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A439 Austenitic Ductile Iron Rod type D3A -:- For detailed product information, please contact sales. -:

Packing of ASTM A439 Austenitic Ductile Iron Rod type D3A -:- 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 Rod 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 3026 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