High Performance New Ni-Base Alloy AF955 (AF955) for Oil and Gas Industry

摘要

A precipitation hardened Ni-base alloy has been developed to fulfil the recent stringent requirements of the oil and gas industry. The new alloy is commercially designated as AF955 and the Unified Numbering System (UNS) assignment of N09955. The new alloy is patented and accepted for inclusion in NACE MR0175/ISO 15156. It is produced at strength levels of 827 MPa (120 ksi) 0.2% offset minimum yield strength (MYS) and 965 MPa (140 ksi) MYS with very good ductility and toughness, and with a microstructure characterized by fine γ' and γ" strengthening precipitates, uniform and equiaxed grain size distribution, minimized secondary phase precipitation and free of continuous grain boundary precipitates. It exhibits good corrosion resistance and low susceptibility to hydrogen embrittlement. These properties make alloy AF955 a very promising material for widespread applications from oil and gas industry to power generation, chemical applications and many others. Details of the manufacturing process and properties of AF955 are presented and discussed in this paper.