Alloy 20 / 020,Incoloy 020,,E FORU

### **Alloy 20 / 020 / Incoloy 020 (UNS N08020) - Product Introduction** **Overview** Alloy 20, also commonly designated as Alloy 020 and marketed under the trade name **Incoloy 020**, is a nickel-iron-chromium super-austenitic stainless steel renowned for its exceptional resistance to sulfuric acid and many other aggressive chemicals. It was developed to address corrosion issues in the chemical processing industry where standard stainless steels like Type 316 fail. The alloy's composition is optimized with the addition of copper and molybdenum for corrosion resistance, and is stabilized with columbium (niobium) to prevent sensitization (carbide precipitation at grain boundaries) during welding, thereby maintaining its integrity in corrosive environments. Its key advantages include excellent resistance to stress corrosion cracking (SCC), pitting, and crevice corrosion, making it a premium material for demanding applications. --- #### **1. Chemical Composition** The chemical composition (in weight %) is the foundation of Incoloy 020's performance. | Element | Content (%) | Role & Benefit | | :--- | :--- | :--- | | **Nickel (Ni)** | 32.0 - 38.0 | Provides the fundamental austenitic structure, enhances toughness, and provides basic corrosion resistance. | | **Chromium (Cr)** | 19.0 - 21.0 | Imparts resistance to oxidizing environments (e.g., nitric acid, hot oxidizing gases). | | **Iron (Fe)** | Balance | The base element of the alloy. | | **Molybdenum (Mo)** | 2.0 - 3.0 | Increases resistance to pitting and crevice corrosion in chloride-ion containing solutions. | | **Copper (Cu)** | 3.0 - 4.0 | Key element that provides superior resistance to sulfuric acid and other reducing acids. | | **Columbium (Cb) [Niobium]** | 8 x %C min. - 1.00 max | Stabilizes the alloy by combining with carbon to prevent chromium carbide precipitation during welding (sensitization). | | **Manganese (Mn)** | ≤ 2.0 | Aids in deoxidation during the steelmaking process. | | **Silicon (Si)** | ≤ 1.0 | Enhances resistance to oxidation. | | **Carbon (C)** | ≤ 0.07 | Kept at a low level to minimize the formation of chromium carbides. | | **Phosphorus (P)** | ≤ 0.045 | Impurity element, controlled to prevent embrittlement. | | **Sulfur (S)** | ≤ 0.035 | Impurity element, controlled to improve hot workability and corrosion resistance. | *Note: "Incoloy" is a registered trademark of Special Metals Corporation (now part of Haynes International). "Incoloy 020" is their specific brand of UNS N08020.* --- #### **2. Physical Properties** These properties are critical for equipment design, including thermal and structural calculations. | Property | Typical Value | | :--- | :--- | | **Density** | 8.08 g/cm³ (0.292 lb/in³) | | **Melting Range** | 1443 - 1499 °C (2625 - 2730 °F) | | **Specific Heat (20°C)** | 500 J/kg·K | | **Electrical Resistivity** | 0.95 μΩ·m | | **Thermal Conductivity** | 12.9 W/m·K (at 100°C) | | **Mean Coefficient of Thermal Expansion (20-100°C)** | 15.1 μm/m·°C | | **Modulus of Elasticity (Tensile)** | 186 GPa (27 x 10⁶ psi) | | **Magnetic Permeability (Annealed)** | Typically < 1.02 (Essentially non-magnetic) | --- #### **3. Mechanical Properties (Typical for Annealed Condition)** Incoloy 020 offers a robust combination of strength and ductility. | Property | Room Temperature Value | | :--- | :--- | | **Tensile Strength** | 620 MPa (90 ksi) min. | | **Yield Strength (0.2% Offset)** | 300 MPa (44 ksi) min. | | **Elongation (in 2 inches / 50mm)** | 30% min. | | **Hardness (Rockwell B)** | ≤ 95 HRB | --- #### **4. Product Applications** Incoloy 020 is a workhorse material in industries that handle highly corrosive media. * **Chemical Processing Industry (CPI):** * Sulfuric acid pickling tanks, heaters, and piping. * Reactors, distillation columns, and heat exchangers handling phosphoric acid and chlorinated solvents. * **Pharmaceutical Industry:** Process vessels, mix tanks, and transfer lines requiring high purity and resistance to cleaning agents and process chemicals. * **Plastic & Synthetic Fiber Manufacturing:** Components in processes involving acetic acid, formic acid, and other aggressive chemical intermediates. * **Oil and Gas Refining:** Heat exchangers and piping handling "sour" crude oils (with H₂S) and other corrosive process streams. * **Food and Dairy Processing:** Evaporators and piping for highly acidic products like citrus juice and vinegar. * **Pulp and Paper Industry:** Digesters and bleach plant equipment. --- #### **5. International Standards** Incoloy 020 (UNS N08020) is specified in various international standards for different product forms. | Product Form | Standard Specification | | :--- | :--- | | **Plate, Sheet, and Strip** | ASTM B463 / ASME SB463 | | **Seamless Pipe and Tube** | ASTM B729 / ASME SB729 | | **Welded Pipe and Tube** | ASTM B775 / ASME SB775 | | **Pipe Fittings (Butt-weld)** | ASTM B366 / ASME SB366 | | **Forgings** | ASTM B462 / ASME SB462 | | **Bar, Rod, and Wire** | ASTM B473 / ASME SB473 | | **European Material Designation** | **EN 2.4660** (NiCr20CuMo) | --- **Summary** **Incoloy 020 (Alloy 20 / UNS N08020)** is a premier, nickel-based alloy specifically engineered to withstand one of the most challenging industrial chemicals: sulfuric acid. Its balanced chemistry, featuring chromium, molybdenum, copper, and columbium stabilization, provides a unique defensive profile against a wide range of corrosive threats, including stress corrosion cracking and pitting. Governed by a comprehensive set of international standards like ASTM and ASME, it is a trusted and specified material for critical components across the chemical, pharmaceutical, and energy sectors, ensuring long-term reliability and safety.

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 1703 gallon liquid totes Special package is available on request.