• th


Alloy 20 (Carpenter 20Cb3)


ALLOY20 is a low carbon, Nb stabilised austentic Ni-Fe-Cr alloy with alloying additions of Cu & Mo.

•excellent resistance to sulphuric and phosphoric acids
•good resistance to intergranular corrosion
•very good resistance to chloride-ion induced stress-corrosion cracking
•good resistance to pitting and crevice corrosion
•good mechanical properties at both ambient and elevated temperatures, up to approximately 500 ‹C (930 ‹F).

Corrosion resistance

ALLOY20has excellent corrosion resistance to sulphuric, phosphoric and organic acids and to aqueous solutions of their salts. Resistance to nitric acid is also good. Due to the controlled chemical composition, the alloy also has excellent resistance to such forms of corrosion as intergranular corrosion and stress corrosion. The molybdenum content ensures good resistance to pitting and crevice corrosion. Optimum corrosion resistance can only be obtained if the material is in the correct metallurgical condition and clean.


ALLOY20 is used in a wide variety of applications up to temperatures of approximately 500 ‹C (930 ‹F).

Typical applications are:

•equipment for the manufacture of sulphuric acid and for processes based on sulphuric acid
•extraction columns in the production of amines and the processing of pharmaceuticals
•production of plastics and synthetic fibres
•equipment for food processing to protect against contamination