Alloy G3 Corrosion Resistant Alloy, UNS N06985，1

### **Product Datasheet: Alloy G-3 (UNS N06985)** **A Nickel-Chromium-Iron-Molybdenum Alloy for Severe Corrosion Environments** --- #### **1. Overview** **Alloy G-3** (UNS N06985) is a versatile, wrought **nickel-chromium-iron-molybdenum alloy** known for its exceptional resistance to a wide range of severe corrosive environments. It was developed as an advanced version of earlier alloys like G-2, offering superior performance, particularly in **sulfuric acid** and other aggressive chemical media. Its key characteristics include outstanding resistance to **pitting and crevice corrosion**, good resistance to **stress corrosion cracking (SCC)**, and high strength. The alloy's balanced composition allows it to handle both oxidizing and reducing conditions effectively. Furthermore, its low carbon content and stabilized chemistry provide excellent resistance to sensitization and intergranular attack during welding. #### **2. Chemical Composition (Typical Weight %)** The composition is engineered for a broad spectrum of corrosion resistance. | Element | Content (%) | Role in the Alloy | | :--- | :--- | :--- | | **Nickel (Ni)** | Balance (~44-46) | Provides inherent resistance to caustic solutions and reducing acids. | | **Chromium (Cr)** | ~21.0 - 23.5 | Confers resistance to oxidizing environments and general corrosion. | | **Iron (Fe)** | ~18.0 - 21.0 | The base element, providing a cost-effective matrix. | | **Molybdenum (Mo)** | ~6.0 - 8.0 | Enhances resistance to pitting, crevice corrosion, and reducing acids. | | **Copper (Cu)** | ~1.5 - 2.5 | Provides specific resistance to sulfuric acid and other reducing acids. | | **Tungsten (W)** | ~1.5 max | Contributes to resistance in reducing environments. | | **Niobium + Tantalum (Nb+Ta)** | ~0.50 max | Acts as a stabilizer to prevent sensitization. | | **Carbon (C)** | ≤ 0.015 | Kept very low to prevent carbide precipitation and sensitization. | | **Manganese (Mn)** | ≤ 1.00 | Aids in manufacturability. | | **Silicon (Si)** | ≤ 1.00 | Residual element. | #### **3. Physical Properties (Typical)** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.31 g/cm³ (0.300 lb/in³) | | **Melting Range** | ~1320 - 1400 °C (~2410 - 2550 °F) | | **Thermal Expansion Coefficient** | ~13.5 μm/m·°C (20 - 100°C) | | **Thermal Conductivity** | ~10.5 W/m·K (at 100°C) | | **Modulus of Elasticity** | ~205 GPa (29.7 x 10⁶ psi) at 20°C | #### **4. Mechanical Properties (Typical for Annealed Condition)** **At Room Temperature:** * **Tensile Strength:** ≥ 690 MPa (100 ksi) * **Yield Strength (0.2% Offset):** ≥ 310 MPa (45 ksi) * **Elongation:** ≥ 35% #### **5. Corrosion Resistance** Alloy G-3 is designed for superior performance in a wide range of corrosive media: * **Sulfuric Acid:** Excellent resistance over a broad concentration and temperature range. * **Phosphoric Acid:** Resists both pure and contaminated (e.g., with fluorides) acid. * **Localized Attack:** High resistance to **pitting and crevice corrosion** in chloride-containing solutions. * **Oxidizing Media:** Performs well in nitric acid and other oxidizing environments. * **Mixed Acids:** Particularly effective in complex, multi-acid environments like those found in pickling baths and chemical synthesis. #### **6. Product Applications** Alloy G-3 is widely used in industries where equipment faces severe chemical attack: * **Chemical Processing:** Reactors, vessels, heat exchangers, and piping systems for sulfuric and phosphoric acid production. * **Pollution Control:** Scrubbers, ducting, and fan components in Flue Gas Desulfurization (FGD) systems. * **Oil and Gas:** Downhole and surface equipment in sour (H₂S-containing) wells; components in acid stimulation. * **Pharmaceutical Industry:** Process equipment requiring high purity and corrosion resistance. * **Pickling Operations:** Tanks, heating coils, and racks. #### **7. International and Industry Standards** Alloy G-3 (UNS N06985) is covered by several ASTM standards for various product forms. * **UNS:** **N06985** * **ASTM Standards (U.S.):** * **ASTM B582:** Plate, Sheet, and Strip * **ASTM B581:** Welded Pipe and Tube * **ASTM B622:** Seamless Pipe and Tube * **ASTM B574:** Rod and Bar * **ASME:** Approved for use in ASME Boiler and Pressure Vessel Code Section VIII (e.g., SB-582 for Plate). * **ISO:** ISO 15156-3 (NACE MR0175) for use in sour service environments in oil and gas production. --- **Disclaimer:** The information provided herein is for reference purposes only. Properties can vary based on product form, size, and manufacturing process. Corrosion resistance is dependent on specific environmental conditions (temperature, concentration, presence of oxidizers, etc.). For design and procurement, the official, latest issue of the relevant material specification and the manufacturer's technical data must be consulted.

Packing of Standard Packing: 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 3374 gallon liquid totes Special package is available on request.