An assessment of nickel-based alloys for high-temperature bolting applications
Alloy 80A (Ni-20Cr-2.4Al-1.4Ti) has been used successfully for up to 130,000 hours duration as a high-temperature bolting material in steam turbines. In this period only a few failures have occurred. Two of the most important failure mechanisms are stress corrosion cracking and intergranular fast fracture. Factors affecting these mechanisms have been examined, including atomic ordering, grain boundary segregation of phosphorus and precipitate size. Other Ni-based alloys have also been evaluated for their suitability as high-temperature bolting applications. It is concluded that Alloy 80A is a good bolting material with good service experience, but further improvements in the embrittlement and the SCC properties are considered attainable by controlling the impurity levels and by modifying the heat treatment.
Bibliographic Reference: EUR 13802 EN (1991) 70 pp., FS, ECU 6.25
ISBN: ISBN 92-826-3235-0
Record Number: 199210123 / Last updated on: 1994-12-02
Original language: en
Available languages: en