Large diameter thick wall seamless steel pipe
Thick-walled seamless pipes can be divided into three types: hot rolling (extrusion), welding and cold working. A hot-rolled seamless steel pipe is a steel pipe in which a solid pipe blank or a steel ingot is perforated and rolled into a hollow section, and the basic process is perforation and rolling. Cold-worked seamless steel tubes are secondary processing of steel pipes (including thick-walled seamless pipes and secondary processing of thin-walled seamless steel pipes). Cold working is an important method to obtain high-precision, high-performance pipes, including cold rolling, cold drawing, cold tension reduction and cold spinning. High-alloy steel grades are mainly produced by extrusion of extruded metal seamless pipes.
The raw material of the large-diameter thick-walled seamless pipe is a round tube blank, and the production process is as follows: the billet is sent to the furnace for heating at a temperature of about 1200 °C. The fuel is hydrogen or acetylene. Temperature control in the furnace is a key issue. After the round billet is released from the furnace, it is subjected to a through-hole punching machine. Generally, the common punching machine is a conical roller punching machine. After perforation, the round billet is successively rolled, rolled or extruded by three rolls. After extrusion, the tube should be sizing. The sizing machine is rotated at a high speed by a conical drill bit into a steel core to form a thick-walled seamless pipe. The inner diameter of the thick-walled seamless pipe is determined by the outer diameter of the sizing machine drill bit.
The thick-walled seamless pipe enters the cooling tower and the steel pipe is sized. After cooling by water spray, the steel pipe is straightened after being cooled. After the steel pipe is straightened, it is sent to a metal flaw detector (or water pressure test) by a conveyor belt for internal flaw detection. If there are cracks inside the steel pipe, bubbles and other problems will be detected. After thick wall seamless pipe quality inspection, it must be carefully selected by hand. After the quality inspection of thick-walled seamless pipes, spray the numbers, specifications, production batch numbers, etc. with paint. It is hoisted into the warehouse by a crane.
