Hot extrusion technology of seamless steel tube

When producing seamless steel tubes by hot extrusion, the tube blank must be a hollow billet. One is a hollow blank in which a forged billet or a billet is made into a hole, and the other is a hollow billet which is centrifugally cast. Perforation of billet or billet, depending on the type of steel and specifications, three different perforation methods can be used: solid tube blank perforation in the vertical punch; pre-drill a small hole in the center of the tube (also called guide Hole), perforating on the pressure puncher; drilling a large hole with a diameter slightly larger than the extruded core rod in the center of the tube blank, and directly feeding it to the extruder for extrusion. When the solid tube blank is perforated on a vertical perforating machine, the tube blank is heated and descaled, and a layer of glass powder is adhered to the surface and loaded into the perforated cylinder. The temperature of the hollow shell after perforation has been reduced and must be reheated to achieve the desired extrusion temperature. The hollow tube blank is heated and the temperature rises to 1180~1250 degrees Celsius to achieve plastic deformation. The heated tube blank is first descaled, then rolled on the glass powder, and a layer of glass powder is adhered. The glass powder acts as a lubricant and heat insulation. The tube blank is loaded into a cylindrical extrusion barrel of a horizontal extruder, and an extrusion die and a glass pad are arranged at the bottom of the extrusion barrel; a round core rod (also called a perforated needle) is inserted into the extrusion rod to the mold. In the hole. The squeeze rod enters the extrusion tube, and the tube blank is pressed toward the die hole end through the pressing pad. As the applied pressure is continuously increased, the tube blank is first thickened to eliminate the between the tube blank and the inner wall of the extrusion tube. The gap is then extruded from the die hole. During the extrusion process, the glass mat between the tube blank and the extrusion die melts, covering the surface of the steel to act as a lubricant.