Application Of Superalloys In Petrochemical And Marine Sectors In India

Abstract

Around the world, oil and gas development activities are increasing due to the growing demands for energy. Increasingly hostile environments involving deep offshore wells, higher pressure and temperature conditions, sour wells etc are encountered during exploration / development. This necessitates use of construction materials with high strength and resistance to corrosion in the severe conditions associated with production/refining. Superalloy grades such as 825, 625 and 718 have been deployed with success to meet these challenges. Technology to produce various millforms / critical components of superalloy grade 718 for aeronautical applications has been established in India. Work has also been carried out in the Country to develop superalloy grades 825 and 625 with no specific reference, however, to petrochemical applications.

The high strength nickel-base superalloy grades 686 and 725 have proved to be excellent candidate materials for a variety of marine applications — fasteners, springs etc. The Ni-base superalloy grade C276, exhibiting excellent corrosion resistance to seawater especially under crevice corrosion conditions, is similar to superalloy grade 686. Superalloy grade C276 has been successfully produced in India in different millforms.

The paper gives an overview of the development work done in India on superalloy grades 718, 625, 825 and C276 and prospects of using these materials in petrochemical and marine sectors in the country.