Hyperduplex grades offer significantly improved resistance to pitting, crevice and stress corrosion cracking and increased strength compared to super duplex grades.
Approximate Composition - 27-32% Cr, < 0.030% C, 7.0% Ni, 3.5-5% Mo, 0.4-0.5% N
These grades combine the following characteristics:
- Excellent resistance to pitting and crevice corrosion – PREN ~50
- Excellent stress corrosion cracking resistance in chloride and sulphide
- Minimum 0.2% PS 700-800 MPa
These grades are used in extreme sea water conditions e.g. high temperatures and high chlorination levels.
Offshore oil and gas e.g. deep water umbilicals, desalination plants, heat exchangers, process industries.