What is Hastelloy C22?

Hastelloy C22 (also known as Alloy 22, corresponding to grades UNS N06022 and W. Nr. 2.4602) is a fully austenitic advanced corrosion-resistant alloy exhibiting outstanding corrosion resistance in both high-temperature and aqueous environments. This alloy demonstrates exceptional comprehensive corrosion resistance, including resistance to uniform corrosion, pitting corrosion, crevice corrosion, intergranular corrosion, and stress corrosion cracking.

Alloy 22 is a nickel-based material with a typical composition of 22% chromium, 14% molybdenum, and 3% tungsten, with iron content usually controlled below 3%. Its high chromium content confers excellent resistance to wet corrosion in oxidizing media.

Characteristics

· Excellent resistance to corrosion in stagnant or flowing seawater

· Good resistance to oxidizing aqueous media

· Outstanding resistance to both reducing and oxidizing media

· C22 excels in pitting resistance

· Excellent weldability

· Maximum expose temperature: 677°C / 1250°F

Applications

Hastelloy 22 finds extensive applications across multiple industrial sectors, including chemical and petroleum processing, pollution control (such as flue gas desulfurization), power generation, offshore engineering, pulp and paper manufacturing, and waste treatment. In high-temperature environments, its high chromium content enables the alloy to effectively resist oxidation, carburization, and sulfidation.

Simultaneously, its nickel-based properties confer excellent resistance to high-temperature corrosion from halides, such as chlorides and fluorides.

Based on these comprehensive properties, the alloy is extensively used in coal-fired boilers and waste incineration boilers as a critical material for protecting steel pipes and other key components.

Such as the fields of

• Chemical Processing

• Chlorination systems

• Food Processing

• Pharmaceutical industry

• Oil & Gas

• Power Generation

• Pulp & Paper Industries

• Acetic acid production

• Fine chemicals

Specifications

Hastelloy C-22 is covered by ASME . Plate, sheet, strip, bar, tubing, and pipe are covered by ASME specifications SB-574, SB-575, SB-619, SB-622 and SB-626 and by ASTM specifications B-574, B-575, B-619, B-622 and B-626. The UNS number is NO6022.

Similar brand

Chemical composition of Hastelloy C-22 bolt

Physical properties of Hastelloy C-22 bolts

Minimum mechanical properties of Hastelloy C-22 bolt alloy at room temperature

Corrosion Resistance in the As-Welded Condition

Hastelloy C-22 (Alloy C-22) is a versatile nickel-chromium-molybdenum alloy with superior overall corrosion resistance compared to other commonly used nickel-chromium-molybdenum alloys such as Hastelloy C-276, C-4, and A625. This alloy demonstrates exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking. It exhibits outstanding corrosion resistance in oxidizing aqueous media, including oxidizing acids containing oxidizing agents, wet chlorine environments, nitric acid, or oxidizing acid mixtures containing chloride ions.

Alloy C-22 exhibits outstanding corrosion resistance in both reducing and oxidizing media, offering high versatility for production facilities subject to fluctuating operating conditions or multiple applications. It withstands diverse chemical process environments, including strong oxidizing agents (e.g., ferric chloride, cupric chloride), contaminated hot media (organic and inorganic), chlorine gas, formic and acetic acids, acetic anhydride, and seawater/brine solutions.

Furthermore, Hastelloy C-22 effectively suppresses grain boundary precipitation in the weld heat-affected zone, enabling it to meet most chemical process equipment manufacturing and operational requirements directly in the as-welded condition.