Alloy C276,Hastelloy C276,UNS N10276,E FORU

### **Alloy C-276 / Hastelloy® C-276 / UNS N10276** **Nickel-Chromium-Molybdenum Superalloy with Exceptional Corrosion Resistance** #### **1. Overview** Alloy C-276, most commonly known by the trademark **Hastelloy® C-276**, is a nickel-based superalloy renowned for its exceptional corrosion resistance in a wide range of severe environments. It is a versatile "workhorse" alloy designed to handle both oxidizing and reducing media. Its key characteristic is outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking. The low carbon content minimizes carbide precipitation during welding, making it highly suitable for fabricated chemical process equipment in the as-welded condition. It is often the material of choice for the most aggressive industrial applications. #### **2. Chemical Composition (Weight %)** The typical chemical composition of Alloy C-276 is outlined below. The balance is Nickel (Ni). | Element | Content (%) | Key Function | | :--- | :--- | :--- | | **Nickel (Ni)** | Balance | Forms the austenitic matrix, providing inherent corrosion resistance and stability. | | **Chromium (Cr)** | 14.5 - 16.5 | Confers resistance to oxidizing agents (e.g., Fe³⁺, Cu²⁺, hypochlorite). | | **Molybdenum (Mo)** | 15.0 - 17.0 | Provides resistance to reducing acids (e.g., HCl, H₂SO₄) and to pitting/crevice corrosion. | | **Tungsten (W)** | 3.0 - 4.5 | Enhances resistance to reducing acids and complements molybdenum's effects. | | **Iron (Fe)** | 4.0 - 7.0 | Balances cost and fabricability; controlled to maintain corrosion resistance. | | **Cobalt (Co)** | 2.5 max | - | | **Manganese (Mn)** | 1.0 max | - | | **Vanadium (V)** | 0.35 max | - | | **Silicon (Si)** | 0.08 max | Kept low to avoid formation of detrimental phases. | | **Carbon (C)** | 0.01 max | Kept very low to prevent sensitization and intergranular corrosion in heat-affected zones. | | **Phosphorus (P)** | 0.025 max | - | | **Sulfur (S)** | 0.01 max | - | #### **3. Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.89 g/cm³ (0.321 lb/in³) | | **Melting Range** | ~ 1325 - 1370 °C (2420 - 2500 °F) | | **Mean Coefficient of Thermal Expansion** | 20 - 200°C (68 - 392°F): **11.2 x 10⁻⁶/°C** (6.2 x 10⁻⁶/°F)
20 - 400°C (68 - 752°F): **11.9 x 10⁻⁶/°C** (6.6 x 10⁻⁶/°F) | | **Thermal Conductivity** | 11.1 W/m·K (77 Btu·in/hr·ft²·°F) at 100°C (212°F) | | **Specific Heat** | 427 J/kg·K (0.102 Btu/lb·°F) at 100°C (212°F) | | **Electrical Resistivity** | 1.30 μΩ·m at 21°C (70°F) | | **Modulus of Elasticity (Young's Modulus)** | 205 GPa (29.8 x 10⁶ psi) at 21°C (70°F) | | **Magnetic Permeability** | Typically < 1.001 (Essentially non-magnetic). | #### **4. Mechanical Properties (Typical for Annealed Condition)** | Property | At Room Temperature | At 315°C (600°F) | | :--- | :--- | :--- | | **Tensile Strength** | 790 MPa (115 ksi) min | 655 MPa (95 ksi) | | **Yield Strength (0.2% Offset)** | 345 MPa (50 ksi) min | 295 MPa (43 ksi) | | **Elongation (in 50 mm / 2 in)** | 40% min | 40% | | **Hardness (Rockwell B)** | 85 - 95 HRB | - | #### **5. International Standards** Alloy C-276 is covered by numerous international standards for various product forms: * **ASTM:** * **B 575:** Plate, Sheet, and Strip * **B 574:** Rod (Bar) * **B 622:** Seamless Pipe and Tube * **B 619/B 626:** Welded Pipe and Tube * **B 366:** Fittings * **ASME:** SB-575, SB-574, etc. (Approved for use in ASME Boiler and Pressure Vessel Code, Section VIII). * **UNS:** N10276 * **EN (European Standard):** 2.4819 (Material Number) * **DIN:** DIN 17744, DIN 17752 (Werkstoff Nr. 2.4819) #### **6. Product Applications** Alloy C-276 is a critical material in industries where corrosion is a primary failure mechanism: * **Chemical Processing Industry (CPI):** Reactors, vessels, heat exchangers, and piping systems handling sulfuric acid, hydrochloric acid, phosphoric acid, and chlorine environments. * **Pollution Control:** Key components in Flue Gas Desulfurization (FGD) systems like absorber towers, outlet ducts, and stack liners. * **Pulp and Paper Industry:** Digesters and bleach plants exposed to corrosive chlorine dioxide and chloride-containing liquors. * **Waste Incineration & Pharmaceutical:** Equipment handling harsh flue gases, acidic condensates, and aggressive process streams. * **Marine and Offshore:** Seawater system components like pumps, valves, and heat exchangers where resistance to pitting and crevice corrosion is critical. #### **7. Key Characteristics & Advantages** * **Exceptional Versatility:** Resists a wider range of corrosives than most other alloys. * **Superior Localized Corrosion Resistance:** Excellent resistance to pitting and crevice corrosion in chloride-containing environments. * **Excellent Weldability:** The low carbon content allows it to be used in the as-welded condition for most applications without post-weld heat treatment. * **Broad Industrial Application:** Proven performance from room temperature to moderately high temperatures in extremely aggressive media. --- **Disclaimer:** *Hastelloy® C-276 is a registered trademark of Haynes International. The values provided are typical and for informational purposes only. For critical applications, always consult the official material data sheets from the supplier and relevant design codes.*

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 1653 gallon liquid totes Special package is available on request.