Q: What is the difference between Inconel 718 standard and NACE 718?
A: NACE stands for the National Association of Corrosion Engineers. This group puts forth standards for corrosion resistant materials and when the NACE certification is asked for, the user is typically asking for NACE MR0175. Inconel 718 that meets NACE MR0175 specs is produced in accordance with the American Petroleum Institute, specifically for the oil & gas industry, and geared to minimize stress corrosion cracking.
NACE Inconel 718 have slightly different chemistry and mechanical properties than standard UNS N07718, ASTM or AMS Inconel 718. The chemistry has a tighter element range and mechanically the material is less brittle and more ductile. As a result, the tensile, yield and hardness of NACE Inconel 718 are lower.