A new alloy, designated UNS S35115, has been developed with the composition:
50%Fe-24%Cr-21%Ni-2% Mo-1.2% Si-0.24% N. It was originally designed for automotive
flexible coupling applications; however, corrosion tests showed it has good general corrosion,
pitting, and crevice corrosion resistance. Alloy 865 also resists chloride stress corrosion
cracking. Depending on the acid concentration and temperature, it is corrosion-resistant to
sulfuric, hydrochloric, nitric, and phosphoric acids. It is very corrosion-resistant to some water
environments contaminated with chlorides. This paper presents the results of an extensive
corrosion program to qualify alloy 865 for applications in the Chemical Process Industry (CPI)
and other related process industries.
Keywords: Alloy 865, Fe-Cr-Ni-Mo alloys, fatigue, corrosion, pitting, crevice, chloride, stress
corrosion cracking, sulfuric, hydrochloric, nitric, phosphoric, acid, chemical, water