Seamless elbow pipe because of the manufacturing process is divided into two kinds of seamless hot-rolled (extrusion) elbow pipe and cold drawn (rolled) seamless elbow fittings. Cold drawn (rolled) tube circular tube shaped tube is divided into two kinds. Rolling seamless elbow fittings raw tube round tube embryos to go through to the cutting machine cutting growth of about one meter blank, and sent by conveyor furnace heating. The billet is fed into the heating furnace, the temperature is about 1200 degrees Celsius. Fuel for hydrogen or acetylene. The furnace temperature control is a key issue. The tube round baked to wear empty after pressure puncher. Generally more common punch tapered roller punch, high this puncher production efficiency, product quality, perforated large flaring can wear a variety of pipe fittings. Perforated tube round has been a three-roll cross rolling, rolling or extrusion. Squeeze detached sizing. Sizing mill through the cone drill bit high speed rotation Billet punch to form a pipe. Executive Standard: GB/T12459-2005