What is C22?
What does C22 alloy mean?
C22 alloy is a nickel-chromium-molybdenum-tungsten alloy that has excellent resistance to pitting, stress corrosion cracking and crevice corrosion. It has excellent resistance to a wide range of chemicals, seawater, brine solutions, and both oxidizing and reducing media. In addition, it has good weldability and resistance to intergranular corrosion, making it ideal for chemical processing equipment, papermaking, marine, power and waste treatment industries.
Gnee Steel Explains C22 Alloy
The composition percentages of C22 alloy are: Carbon 0.005%, Cobalt 1.5%, Chromium 2.2%, Iron 3%, Manganese 3%, Molybdenum 1.3%, Nickel 5.6%, Silicon 0.5%, Vanadium 0.25% and Tungsten 3%. Nickel-chromium-molybdenum-tungsten alloy has superior overall corrosion resistance compared to most nickel-chromium-molybdenum alloys. The iron, chromium, molybdenum and tungsten contents enhance the material's resistance to uniform and localized corrosion in a variety of environments, including flowing and stationary seawater. These alloying elements contribute to the material's resistance to a wide range of industrial chemicals and oxidizing and reducing media. The high chromium content contributes to the material's resistance to oxidizing media, while tungsten and molybdenum enhance the material's resistance to reducing media.
C22 Alloy Features:
Resistant to stress corrosion cracking, pitting and crevice corrosion
Excellent resistance to oxidizing and reducing media
Excellent resistance to chemical process environments such as ferric acid, seawater, acetic anhydride, brine solutions, etc.
No grain boundary precipitates form in the weld heat affected zone
Excellent weldability
This moderate to difficult to machine alloy hardens rapidly, generates a lot of heat, and may weld to the cutting tool surface, while its high shear strength makes it resistant to metal stripping. However, it must be fully machined using conventional methods. The alloy has good ductility, making it easy to cold work. However, due to its higher hardness than austenitic stainless steels, the energy required for cold forming is also higher.
Available forms include plates, sheets, bars, tubes, pipes, strips, wires, billets and coated electrodes, seamless pipes, welded tubes, forgings, fittings and flanges.
The alloy has excellent corrosion resistance in strong acidic and oxidizing environments and is suitable for a wide range of process equipment. Its application areas include:
Chemical process industries
Galvanizing line equipment
Chlorination systems
Acid production
Complex acidic and chemical environments
Alloy filler wires and cladding consumables
However, the alloy should not be used above 1250°F (700°C) as harmful phases may form at higher temperatures.
