UNS N08830 is a new Ni-Fe-Cr-Mo-N superaustenitic alloy. It is a non-magnetic single phase, non-precipitation hardenable alloy with exceptional pitting and crevice corrosion resistance, while achieving high strength, excellent toughness and wear resistance in the strain hardened condition. This solid solution strengthened alloy has additions of Cu, W, Co and Mn resulting in improved microstructural stability as compared to other alloys with similar corrosion resistance, allowing for manufacturing productivity in a greater number of sizes and product forms.

This paper will introduce the alloy with a microstructural evaluation as well as corrosion and mechanical test results. Corrosion testing includes requirements to NACE MR0175 / ISO 15156 sour service testing, stress corrosion cracking testing in boiling sodium chloride, and pitting and crevice corrosion in ferric chloride. Mechanical testing included through-thickness analyses to determine a profile of the strength gradient for a strain hardened bar.


Today's oil and gas production is characterized by a variety of well conditions ranging from mild to aggressive in terms of temperatures, pressures, and corrosive conditions. The materials used for well construction have to be applicable to various combinations of mechanical and environmental conditions as well as meet cost expectations. With this in mind, ATI 830TM Alloy (UNS N08830) was developed for severe environment oil and gas applications where high strength and toughness combined with a high degree of corrosion resistance are required.

The design goals to satisfy these severe well environments included maintaining a near-surface yield strength of 1035 MPa (150 ksi) through strain hardening, while holding an allowable variation target of 69 MPa (15 ksi) across the diameter. These attributes make the alloy of interest for drilling, completions and subsea applications where super-duplex stainless steels fall short with respect to strength and resistance to H2S in some high pressure, high temperature (HPHT) well environments, and where the use of higher cost precipitation-hardened nickel alloys may be “over-kill”.

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