Additive manufacturing (AM), specifically Laser Powder Bed Fusion (LPBF), brings benefits to the Oil & Gas industry in the areas of better performance, inventory management, and cost reduction. However, selection of AM alloy UNS(1) N07718 (AM 718) face uncertain material capabilities for critical applications such as sour service, when compared to its wrought counterpart specified in API(2) 6ACRA (oilfield 718). This study reveals that AM 718 of modified solution treatment combined with standard API 6ACRA age hardening are capable of meeting the yield strength, tensile strength, elongation, and hardness requirements of API 6ACRA, with reduction of area of only 120K condition below the spec limit. AM 718 of modified solution treatment and API 6ACRA 120K age hardening shows resistance to environmentally assisted cracking (EAC) equivalent to oilfield 718 in slow strain rate (SSR) test per NACE TM0198-2020 at 300°F (149°C) in H2S-containing environment. The performance of AM 718 does not appear to be influenced by the powder conditions investigated. Results of this study provides data-supported clarity to the selection of AM 718 material conditions and production routes for Oil & Gas application and the H2S-service qualification.

Subject
Scanning electron microscopy, Hardening, Materials, Manufacturing, Microstructure, Fractures, Mechanical properties, Powders, Oilfields, Risk reduction, Hardness, Grain, Oil
Keywords:
UNS N07718, Additive Manufacturing, Laser Powder Bed Fusion, Slow Strain Rate Test, Hydrogen Sulfide, Mechanical Properties, Powder, Solution Treatment
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2022
Association for Materials Protection and Performance (AMPP)
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