Precipitation hardened nickel alloys are commonly used in oil and gas production equipment where materials must provide both outstanding mechanical strength and corrosion resistance. Additive manufacturing (AM) provides a new approach to the design and manufacture of components from metal powder and provides some unique advantages over traditional manufacturing. However, components produced by AM are not currently acceptable per NACE(1) MR0175/ISO(2)15156 since no AM alloys have been balloted and approved for inclusion. There are uncertainties and knowledge gaps around the performance of AM material in sour service. AM Alloy 718 (UNS N07718) test material was manufactured by laser powder bed fusion (LPBF) with final heat treatment per API(3) 6ACRA 150K designation by three suppliers. After benchmarking the basic mechanical properties in air, the AM Alloy 718 test material was evaluated by slow strain rate (SSR) testing and proof ring testing in sour environments similar to those used for the wrought Alloy 718 150K ballot for NACE MR0175/ISO 15156. The resistance to stress corrosion cracking (SCC) and galvanically induced hydrogen stress cracking (GHSC) were investigated and compared to the wrought Alloy 718 150K results.

Subject
Test methods, Materials, Fracture toughness, Materials performance, Nickel based alloys, Sour environments, Mechanical properties, Powders, Risk reduction, Heat treatment, Stress corrosion cracking, Wrought metals, Ductility
Keywords:
Additive Manufacturing, Alloy 718, 150K, UNS N07718, Sour Service
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2022
Association for Materials Protection and Performance (AMPP)
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