Type 347 (UNS S34700)
Type 347 is a niobium stabilized chromium nickel austenitic stainless steel with corrosion resistance similar to 304/304L. This grade is typically used in the 800-1500˚F temperature range where it is stabilized against chromium carbide precipitation by the addition of niobium, which results in the precipitation of niobium carbides. Type 347 has excellent intergranular corrosion resistance after exposure to this temperature range, and this grade resists oxidation up to 1500˚F and has higher creep and stress rupture properties than 304/304L. It also possesses good low temperature toughness and is non-magnetic in the annealed condition.