Hastelloy C-22HS Nickel Alloy,C-22HS alloy，1

### **Introduction to Hastelloy® C-22HS® (UNS N07022) Nickel Alloy** **Hastelloy® C-22HS®** is a nickel-chromium-molybdenum-tungsten alloy specifically engineered for **exceptional high-temperature strength** and outstanding corrosion resistance. The "HS" stands for "High Strength," which is its defining characteristic. While it shares the excellent corrosion resistance profile of the renowned C-276 and C-22 alloys, C-22HS is uniquely strengthened through a **precipitation-hardening heat treatment**. This combination makes it an ideal choice for demanding applications in the oil & gas industry where components must withstand extreme pressures, high temperatures, and aggressive corrosive environments simultaneously. --- ### **Chemical Composition (Weight %, typical)** The composition is balanced to provide both corrosion resistance and the ability to be age-hardened. | Element | Minimum | Maximum | Key Function | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | **Balance** | | Austenitic matrix; provides overall corrosion resistance and stability. | | **Chromium (Cr)** | 20.0 | 22.5 | Resistance to oxidizing media and localized corrosion. | | **Molybdenum (Mo)** | 12.5 | 14.5 | Resistance to reducing media and pitting/crevice corrosion. | | **Tungsten (W)** | 2.5 | 3.5 | Solid-solution strengthening; enhances pitting resistance. | | **Iron (Fe)** | 2.0 | 4.0 | - | | **Cobalt (Co)** | 2.0 | 4.0 | Contributes to precipitation hardening. | | **Aluminum (Al)** | 0.50 | - | Key age-hardening element. | | **Titanium (Ti)** | 0.50 | - | Key age-hardening element. | | **Manganese (Mn)** | - | 0.50 | - | | **Silicon (Si)** | - | 0.08 | Kept low to maintain toughness and corrosion resistance. | | **Carbon (C)** | - | 0.015 | Kept extremely low to prevent carbide precipitation. | | **Phosphorus (P)** | - | 0.025 | - | | **Sulfur (S)** | - | 0.010 | - | *The deliberate addition of Aluminum (Al) and Titanium (Ti) is crucial. During the aging heat treatment, they form the coherent gamma prime [γ'] precipitates (Ni₃(Al, Ti)) that give the alloy its high strength.* --- ### **Physical Properties (Typical)** * **Density:** 8.55 g/cm³ (0.309 lb/in³) * **Melting Range:** 1325 - 1370 °C (2415 - 2500 °F) * **Thermal Expansion Coefficient:** 12.3 μm/m·°C (20-100°C) * **Thermal Conductivity:** 10.9 W/m·K at 100°C * **Modulus of Elasticity (Young's Modulus):** 217 GPa (31.5 x 10⁶ psi) at 21°C --- ### **Mechanical Properties (Typical)** The properties of C-22HS are highly dependent on its heat treatment condition. The standard sequence is a solution anneal followed by an age (precipitation hardening) treatment. | Condition | Tensile Strength | Yield Strength (0.2% Offset) | Elongation | | :--- | :--- | :--- | :--- | | **Solution Annealed** | ~ 845 MPa (123 ksi) | ~ 395 MPa (57 ksi) | ~ 50% | | **Aged (Precipitation Hardened)** | **≥ 1241 MPa (180 ksi)** | **≥ 827 MPa (120 ksi)** | ≥ 15% | *The aged condition demonstrates a dramatic increase in strength while retaining sufficient ductility for service.* --- ### **Key Characteristics and Product Applications** #### **Key Characteristics:** 1. **Ultra-High Strength:** Its primary advantage is yield strength exceeding 120 ksi (825 MPa) after aging, which is significantly higher than non-age-hardenable nickel alloys like C-276 or 625. 2. **Excellent Corrosion Resistance:** Maintains good resistance to a wide range of corrosive media, including sour gas (H₂S), chlorides, and organic acids, making it suitable for oil & gas downhole environments. 3. **High-Temperature Capability:** Retains a significant portion of its strength at temperatures up to ~700°F (~370°C) and has good oxidation resistance. 4. **Age-Hardenable:** The properties are achieved through a controlled heat treatment, allowing for flexibility in manufacturing. #### **Primary Applications:** C-22HS is predominantly used in the Oil & Gas industry for critical, high-stress components: * **Downhole Equipment:** * **Production Tubing & Casing:** For deep, high-pressure, high-temperature (HPHT) wells where conventional materials lack the strength. * **Completion Tools:** Packers, hangers, and flow control devices. * **Wellhead and Christmas Tree Components:** For sour service applications. * **Valve Components:** High-strength stems, trim, and bodies for severe service valves. * **Fasteners:** High-strength bolts and nuts for critical connections in corrosive environments. * **Aerospace:** Specialized high-strength components requiring corrosion resistance. --- ### **International Standards** As a specialized, proprietary alloy, its standardization is specific. It is covered under ASTM specifications for its UNS number. | Product Form | Standard | Designation | Notes | | :--- | :--- | :--- | :--- | | **Bar, Wire, Forgings** | ASTM B574 (Low-Carbon) | UNS N07022 | This is the primary specification for the raw material forms used for downhole components. | | **Plate, Sheet, Strip** | ASTM B575 (Low-Carbon) | UNS N07022 | - | | **Pipe & Tube** | ASTM B622 / B619 | UNS N07022 | For seamless and welded pipe and tube. | | **Welding Consumables** | AWS A5.14 / A5.11 | **ERNiCrMo-17** / **ENiCrMo-17** | These are the matching filler metals for welding C-22HS. *Note: Weld metal is typically not age-hardenable.* | **Important Note on Welding:** While C-22HS can be welded using matching composition filler metals, the weld metal itself does not precipitation-harden. The Heat-Affected Zone (HAZ) will also have different properties than the aged base metal. Post-weld heat treatment (PWHT) strategies must be carefully considered in design. **Note:** "Hastelloy" and "C-22HS" are registered trademarks of **Haynes International, Inc.** For critical applications like those in the oil & gas industry, consultation with the manufacturer and thorough testing per specific service conditions are essential.

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 3258 gallon liquid totes Special package is available on request.