A182 F5 F9 F11 F22 F91 socket weld forged fittings
A182 F91 Wrought alloy steel tubes, flanges, wrought fittings and valves and other components for high temperature use.
F91 is a kind of metamorphic steel formed by adding reinforcing elements V,Nb,N and so on on the basis of the original 9Cr-1Mo type steel. They are usually referred to as martensitic heat resistant steels (but those with less than 10% Cr in the US standard are listed as ferritic series, so the name in the standard is still ferritic type). It has excellent performance at room temperature, excellent durability and creep properties below 650¡æ and low linear expansion coefficient.