Hastelloy C-22 Alloy 22 (UNS N06022; W. Nr. 2.4602; NiCr21Mo14W) is a fully austenitic advanced corrosion-resistant alloy that offers resistance to both aqueous corrosion and attack at elevated temperatures. This alloy provides exceptional resistance to general corrosion, pitting, crevice corrosion, intergranular attack, and stress corrosion cracking. Alloy 22 has found numerous applications in the chemical/petrochemical processing, pollution control (flue gas desulfurization), power, marine, pulp and paper processing, and waste disposal industries.

Alloy 22 is nickel-base and typically contains 22% chromium, 14% molybdenum, and 3% tungsten. Iron is normally limited to less than 3%. The alloy’s high content of chromium gives it good resistance to wet corrosion by oxidizing media (e.g., nitric acid and ferric and cupric salts). Its contents of molybdenum and tungsten give the alloy resistance to wet reducing media (e.g., sulfuric and hydrochloric acids). Alloy 22 exhibits excellent resistance to corrosive attack by seawater under stagnant and flowing conditions.

At elevated temperatures, the high chromium level of Hastelloy C-22 Alloy helps it resist oxidation, carburization, and sulfidation. Since it is nickel-base, alloy 22 resists high temperature attack by halides (e.g., chlorides and fluorides). With these attributes, the alloy is widely used to protect steel tubes and other components in coal-fired and waste-to-energy boilers.

Hastelloy C-22 Available Product Forms:

Pipe, tube, fitting, flange, sheet, strip, plate, round bar, flat bar, fastener, forging stock, hexagon and wire


Hastelloy C-22 Alloy Steel Tube

Hastelloy C-22 is a Ni-Cr-Mo alloy, which has strong resistance to pitting corrosion, crevice corrosion, intergranular corrosion and stress corrosion cracking. The joint action of Ni, Cr, Mo and W makes Hastelloy C-22 alloy have excellent corrosion resistance in a larger oxidizing and reducing environment. Hastelloy C-22 alloy has outstanding corrosion resistance in most harsh environments. It has resistance to the precipitation of intergranular carbides and the generation of multiple phases during welding or forging operations.

Therefore, Hastelloy C-22 alloy is widely used Used in industrial fields such as flue gas desulfurization systems, bleaching systems in the pulp and paper industry, waste incinerators, chemical plants, pharmaceutical plants, and radioactive waste storage. Hastelloy C-22 alloy has high strength, good ductility, weldability and formability, so it has a consistent detailed description in the ASME and ASTM standards. Its material product forms include plates, strips, pipes, bars and forgings. Hastelloy C22 alloy is a versatile nickel-chromium-molybdenum tungsten alloy, which has better overall corrosion resistance than other existing nickel-chromium-molybdenum alloys, including Hastelloy C276, C4 alloy and 625 alloy.

Hastelloy C22 alloy has good resistance to pitting corrosion, crevice corrosion and stress corrosion cracking. It has excellent resistance to oxidizing water media, including wet chlorine, nitric acid, or mixed acids of oxidizing acids containing chloride ions. At the same time, Hastelloy C22 alloy also has ideal resistance to reducing and oxidizing environments encountered during the process. Relying on this omnipotent performance, it can be used in some troublesome environments, or used in factories for multiple production purposes. Hastelloy C22 alloy has exceptional resistance to various chemical environments, including strong oxidizing substances, such as ferric chloride, copper chloride, chlorine, thermal pollution solutions (organic and inorganic), formic acid, acetic acid, acetic anhydride, sea water and Salt solution, etc. Hastelloy C22 alloy has the ability to resist the formation of grain boundary precipitation in the welding heat-affected zone, so that it can be adapted to many chemical process applications in the welding state.

Hastelloy C-22 Chemical Composition:

.010 max20-22.52.5 max2.0-6.00.50 max12.5-14.5Balance0.02 max0.08 max0.02 max2.5-3.50.35 max

Hastelloy C-22 Mechanical Properties:

Product FormTensile (ksi)0.2% Yield (ksi)Elongation %Hardness (HRb)
Plate (0.25”-1.75”)112536289
Sheet (0.038”-0.15”)122635493
Bar (0.50”-5.50”)115556089

Hastelloy C-22 Application:

Hastelloy C22 alloy has been widely used in the chemical and petrochemical fields, such as in components and catalytic systems that contact chloride-containing organics. This material is especially suitable for use in high temperature, mixed with impurities of inorganic and organic acids (such as formic acid and acetic acid), and seawater corrosive environments.

Mainly used to manufacture the following types of equipment or parts:

  • Acetic acid/acetic anhydride
  • Acid leaching
  • Cellophane manufacturing
  • Chlorination system
  • Complex mixed acid
  • Rolls of electro-galvanized tank
  • Expansion bellows