Alloy 22,Hastelloy C-22,UNS N06022,E FORU

### **Alloy 22 / Hastelloy C-22 (UNS N06022) - Product Introduction** **Overview** **Hastelloy® C-22®** (UNS N06022) is a versatile, nickel-chromium-molybdenum-tungsten alloy renowned for its outstanding, all-around corrosion resistance. It is considered one of the most resilient nickel-based alloys for handling severely corrosive and oxidizing environments. Developed to overcome the limitations of earlier "C-type" alloys, Alloy 22 is specifically designed with an optimized balance of chromium, molybdenum, and tungsten to provide superior resistance to pitting, crevice corrosion, and stress corrosion cracking. A key feature of Alloy 22 is its ability to withstand both oxidizing and reducing media, making it highly effective in mixed acid and multi-chemical environments, such as those containing sulfuric acid and oxidizing salts. Its excellent weldability further enhances its suitability for critical industrial applications. --- #### **1. Chemical Composition** The chemical composition (in weight %) is meticulously balanced for maximum corrosion resistance. | Element | Content (%) | Role & Benefit | | :--- | :--- | :--- | | **Nickel (Ni)** | Balance | Provides the fundamental austenitic matrix and inherent resistance to corrosion. | | **Chromium (Cr)** | 20.0 - 22.5 | Confers exceptional resistance to oxidizing environments (e.g., nitric acid, ferric chloride, hypochlorite). | | **Molybdenum (Mo)** | 12.5 - 14.5 | Provides primary resistance to reducing environments (e.g., sulfuric acid, hydrochloric acid) and to pitting/crevice corrosion. | | **Tungsten (W)** | 2.5 - 3.5 | Synergistically enhances the protective effect of molybdenum against pitting and crevice corrosion. | | **Iron (Fe)** | 2.0 - 6.0 | An inherent element from the melting process, kept at a low level to optimize corrosion resistance. | | **Cobalt (Co)** | ≤ 2.5 | Controlled impurity. | | **Vanadium (V)** | ≤ 0.35 | Controlled impurity. | | **Carbon (C)** | ≤ 0.015 | Kept at an extremely low level to minimize carbide precipitation during welding, enhancing resistance to intergranular attack. | | **Silicon (Si)** | ≤ 0.08 | Kept very low to improve thermal stability and corrosion resistance. | | **Manganese (Mn)** | ≤ 0.50 | Aids in deoxidation during melting. | | **Sulfur (S)** | ≤ 0.02 | Impurity element, controlled to a very low level to improve hot workability and corrosion resistance. | | **Phosphorus (P)** | ≤ 0.02 | Impurity element, controlled to prevent embrittlement. | *Note: "Hastelloy" and "C-22" are registered trademarks of Haynes International Inc.* --- #### **2. Physical Properties** These properties are essential for engineering design and fabrication. | Property | Typical Value | | :--- | :--- | | **Density** | 8.69 g/cm³ (0.314 lb/in³) | | **Melting Range** | 1357 - 1399 °C (2475 - 2550 °F) | | **Specific Heat (20°C)** | 423 J/kg·K | | **Thermal Conductivity** | 10.8 W/m·K (at 100°C) | | **Mean Coefficient of Thermal Expansion (20-100°C)** | 12.5 μm/m·°C | | **Modulus of Elasticity (Tensile)** | 206 GPa (29.9 x 10⁶ psi) | | **Magnetic Permeability (Annealed)** | Typically < 1.001 (Essentially non-magnetic) | --- #### **3. Mechanical Properties (Typical for Annealed Condition)** Alloy 22 offers a robust combination of strength and ductility. | Property | Room Temperature Value | | :--- | :--- | | **Tensile Strength** | 690 MPa (100 ksi) min. | | **Yield Strength (0.2% Offset)** | 315 MPa (46 ksi) min. | | **Elongation (in 2 inches / 50mm)** | 45% min. | | **Hardness (Rockwell B)** | ≤ 100 HRB | --- #### **4. Product Applications** Hastelloy C-22 is a critical material in industries where equipment failure due to corrosion is not an option. * **Chemical Processing Industry (CPI):** * Reactors, vessels, and columns for production of acetic and formic acid. * Heat exchangers, piping, and pumps handling mixed acids and halogenated hydrocarbons. * **Pollution Control:** * Flue gas desulfurization (FGD) systems: absorber towers, dampers, ducting, and fan components. * **Pharmaceutical Industry:** Process equipment requiring high purity and resistance to aggressive cleaning agents and process streams. * **Pulp and Paper Industry:** Digester and bleach plant components exposed to corrosive liquors and chlorides. * **Nuclear Waste Treatment:** Selected for high-level nuclear waste containment due to its exceptional long-term corrosion resistance in complex chemistries. * **Marine and Offshore:** Critical components exposed to seawater and sour gas (H₂S) environments. --- #### **5. International Standards** Hastelloy C-22 (UNS N06022) is specified in various international standards for different product forms. | Product Form | Standard Specification | | :--- | :--- | | **Plate, Sheet, and Strip** | ASTM B575 / ASME SB575 | | **Seamless Pipe and Tube** | ASTM B622 / ASME SB622 | | **Welded Pipe and Tube** | ASTM B619 / ASME SB619, ASTM B626 / ASME SB626 | | **Pipe Fittings (Butt-weld)** | ASTM B366 / ASME SB366 | | **Bar, Rod, and Wire** | ASTM B574 / ASME SB574 | | **Forgings** | ASTM B564 / ASME SB564 | | **European Material Designation** | **EN 2.4602** (NiCr21Mo14W) | --- **Summary** **Hastelloy C-22 (Alloy 22 / UNS N06022)** stands as a benchmark for corrosion resistance among nickel-based alloys. Its optimally balanced chemistry provides unparalleled defense against a vast spectrum of corrosive threats, including pitting, crevice corrosion, and stress corrosion cracking in both oxidizing and reducing conditions. Governed by a comprehensive set of ASTM/ASME and other international standards, it is the material of choice for the most critical and demanding applications across the chemical processing, pollution control, and pharmaceutical industries, ensuring maximum equipment longevity and operational 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 1707 gallon liquid totes Special package is available on request.