Hastelloy C-22 flange is a premium nickel-chromium-molybdenum alloy component (UNS N06022, W.Nr.2.4602) for piping connections, boasting excellent corrosion resistance in both oxidizing and reducing environments and stable mechanical properties for harsh industrial applications.
Chemical Composition
Hastelloy C-22 is an improved nickel-based corrosion-resistant alloy in the Hastelloy C series, with a strictly controlled chemical composition that ensures its superior performance. The main elements and their content ranges (by weight) are as follows: Nickel (Ni) is the base element (balance), providing the alloy with fundamental corrosion resistance and structural stability. Chromium (Cr) accounts for 20.0% to 23.0%, enhancing resistance to oxidizing media. Molybdenum (Mo) ranges from 12.5% to 14.5%, strengthening resistance to reducing environments and local corrosion. Tungsten (W) is 2.5% to 3.5%, improving resistance to pitting and crevice corrosion. Trace elements include Iron (Fe) 2.0% to 6.0%, Manganese (Mn) ≤ 2.0%, Silicon (Si) ≤ 0.08%, Carbon (C) ≤ 0.015%, Sulfur (S) ≤ 0.02%, and Phosphorus (P) ≤ 0.03%[12]. Strict control of these trace elements avoids embrittlement and ensures the alloy’s weldability and corrosion resistance.
Mechanical Properties
Hastelloy C-22 flange maintains excellent mechanical properties in room temperature and extreme environments, with performance optimized after solution heat treatment. In the solution-treated state, its typical room-temperature properties include: tensile strength of 758 MPa (110 ksi) minimum, yield strength of 363 MPa (53 ksi) minimum, elongation of 40% minimum, and Brinell hardness of ≤ 217 HB[10]. The alloy has a density of 8.69 g/cm³, elastic modulus of 205 GPa, and melting point ranging from 1325°C to 1370°C (2417°F to 2498°F). It retains good toughness and strength at sub-zero temperatures and can operate stably in high-temperature environments up to 649°C (1200°F), making it suitable for high-temperature and high-pressure working conditions.
Key Functions
As a key connecting component in industrial piping systems, Hastelloy C-22 flange serves three core functions. Firstly, it achieves detachable connection of pipes, valves, pumps, heat exchangers and other equipment, facilitating installation, maintenance and replacement of pipeline components. Secondly, it ensures the airtightness and pressure-bearing capacity of the pipeline system, preventing leakage of corrosive media (liquid or gas) in high-pressure and harsh environments. Thirdly, it transfers loads between pipeline components, dispersing stress to avoid local damage and ensuring the stable operation of the entire pipeline system[10]. Additionally, its excellent corrosion resistance and mechanical stability extend the service life of the pipeline system and reduce maintenance costs.
Application Scenarios
Benefiting from its superior corrosion resistance, high strength and good weldability, Hastelloy C-22 flange is widely used in various harsh industrial fields that require resistance to complex corrosive media.
Chemical Processing Industry: It is widely applied in reactors, heat exchangers, storage equipment and pipeline connections for handling aggressive chemicals such as formic acid, acetic acid, hydrofluoric acid and sulfuric acid, as well as in PTA, fluorine chemical and fine chemical production.
Oil and Gas Industry: Used in offshore drilling platforms, oil refineries and hydrocarbon processing equipment, it adapts to high-temperature, high-pressure and sour gas environments, resisting corrosion from hydrogen sulfide and other corrosive media.
Marine Engineering: Suitable for seawater desalination systems, offshore oil rigs and marine pipeline connections, it can effectively resist seawater and brackish water corrosion, avoiding stress corrosion cracking.
Other Fields: It is also used in power plant desulfurization and denitrification systems, pharmaceutical equipment, paper pulp and papermaking industry (cooking and bleaching equipment), nuclear power secondary loop systems and aerospace equipment.
Additional Advantages
Hastelloy C-22 flange has excellent weldability and processability, supporting various welding methods such as gas tungsten arc welding, plasma arc welding and metal inert gas welding[10]. It can be customized into slip-on, blind, threaded, weld neck and other types according to engineering needs. It complies with international standards such as ASTM B564, ASME SB564 and ANSI B16.5, with size ranges from 1/2" to 24" (DN15 to DN600) and pressure ratings from 150# to 2500# (PN20 to PN420). Compared with other Hastelloy C series alloys, it has better corrosion resistance in oxidizing environments and improved weld zone performance, making it a cost-effective choice for high-demand corrosion-resistant pipeline connections.
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