ER90S-B9 is a 9% Cr-1% Mo wire modified with niobium (columbium) and vanadium designed to provide creep-rupture strength, toughness, fatigue life, oxidation and corrosion resistance at elevated service temperature (1040-1112°F) and high pressures (up to 4,000 psi). 

ER90S-B9, when subjected to proper welding procedures and post-weld heat treatment, yields deposits that result in a deposit structure of tempered martensite with precipitation of FeCr Carbides (M22C6) and vanadium-rich carbon-nitrides. This allows higher operating steam temperatures and pressures, and provides higher long-term creep rupture properties.

This wire is suitable for 9% Chromium steels such as P91, T91, F91 and ASTM A-213, A-335, A-387. Applications include fabrication of turbines, header systems, steam piping, electric generation, and petrochemical equipment. Controlled preheat, interpass and post heat treatment may be needed to avoid cracking.