Shell of FC float collar is applied of 35 Cr Mo alloyconstructional steel.The float collar is applied to the casingassembly in general and used for guiding casing string into wellsuccessfully,it serves as an extra back pressure valve sealingagainst pressures from blow while running the assembly and afterthe cementing job.Internal parts are readily drillable,and itscapability of back-pressure is over 35Mpa.