What is the difference between Hastelloy C22 and C276?
The composition of Hastelloy C22 is 00Cr22Ni60Mo13W3. The composition of Hastelloy C276 is 00Cr15Ni60Mo16W4. The difference in CR content and MO content affects the heat resistance and corrosion resistance of the material.
Hastelloy c-22/UNS N06022/ NS338/ NS3308/
W.N. 2.4602/00Cr22Ni60Mo13W3/NiCr21Mo14W
Metallographic structure:
Hastelloy C22 has a face-centered cubic lattice structure.
characteristic:
Hastelloy C22 alloy is a versatile nickel-chromium-molybdenum-tungsten alloy that 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 oxidation in aqueous media, including wet chlorine, nitric acid or a mixture of oxidizing acids containing chloride ions. At the same time, Hastelloy C22 alloy also has the ideal ability to resist the reducing and oxidizing environments encountered during the process. Relying on this versatile performance, it can be used in some troublesome environments or applied in factories for multiple production purposes. Hastelloy C22 alloy has exceptional resistance to various chemical environments, including strongly oxidizing substances such as ferric chloride, copper chloride, chlorine, thermal pollution solutions (organic and inorganic), formic acid, acetic acid, acetic anhydride, seawater and Salt solution, etc. Hastelloy C22 alloy has the ability to resist the formation of grain boundary precipitation in the welding heat affected zone, which makes it suitable for many chemical process applications in the welding state.
Application areas:
Hastelloy C22 alloy has been widely used in the chemical and petrochemical fields, such as in components and catalytic systems that come into contact with chloride-containing organic matter. This material is especially suitable for use in high temperature, inorganic and organic acids mixed with impurities (such as formic acid and acetic acid), and seawater corrosion environments.
It can be mainly used to manufacture the following types of equipment or parts:
1. Acetic acid/acetic anhydride; 2. Acid leaching; 3. Cellophane manufacturing; 4. Chlorination system; 5. Complex mixed acids; 6. Rollers of electro-galvanizing tanks;
7. Expansion bellows; 8. Flue gas cleaner system; 9. Geothermal well; 10. Hydrogen fluoride furnace cleaner; 11. Incineration cleaner system;
12. Nuclear fuel regeneration; 13. Pesticide production; 14. Phosphoric acid production; 15. Pickling system; 16. Plate heat exchanger; 17. Selective filtration system;
18. Sulfur dioxide cooling tower; 19. Sulfonation system; 20. Tubular heat exchanger; 21. Overlay welding valve.
HastelloyC276 is based on HastelloyC to reduce C and SI in order to solve the problem that HastelloyC is not resistant to intergranular corrosion in the welding state. However, the thermal stability of the alloy is not good.
HastelloyC22 is based on C276, which increases the chromium content of the alloy and reduces molybdenum and tungsten, in order to improve the corrosion of C4 and C276 in strong oxidizing media. Although the corrosion resistance of oxidizing media is improved. However, the resistance to pitting corrosion and crevice corrosion has not been significantly improved. The corrosion resistance is better than C276, C4, and 625 alloys, especially suitable for environments with a large amount of chlorine and oxidants.
