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Thick wall seamless pipe can be divided into three categories: hot rolling (extrusion), welding and cold processing according to production mode. Hot rolled seamless steel tube is a steel pipe that is perforated and rolled into a hollow section by solid tube or ingot. The basic procedure is piercing and rolling. Cold working seamless steel tube is the two processing of steel pipe (also includes two times processing of thick wall seamless pipe and thin wall seamless steel tube). Cold working is an important method to obtain high precision and high performance pipes, including cold rolling, cold drawing, cold stretch reducing and cold spinning. Extruded metal seamless tubes for high alloy steel are mainly produced by extrusion.

The raw material of large caliber thick wall seamless pipe is round tube billet. The production process is as follows: billet is heated into the furnace, and the temperature is about 1200 degrees centigrade. The fuel is hydrogen or acetylene. The temperature control in the furnace is a key problem. When the round billet is out of the furnace, the piercing mill must pass through the pressure piercing machine, and the piercing mill is generally used as the piercer. After piercing, the round billet is successively rolled, rolled or pressed by three rollers. After extrusion to remove pipe sizing. The sizing machine passes through the cone bit and rotates into the steel embryo at high speed to form a thick wall seamless pipe. The inner diameter of thick wall seamless pipe is determined by the outer diameter length of the sizing machine.

The thick wall seamless pipe enters the cooling tower, and the steel tube is fixed. By spraying cooling, the steel tube will be straightened after cooling. After straightening, the steel pipe is sent to the metal flaw detector (or water pressure experiment) by the conveyor belt for internal flaw detection. If there are cracks in the steel pipe, bubbles and other problems will be detected. Quality inspection of thick wall seamless pipe should be carried out through strict manual selection. After the quality inspection of the thick wall seamless pipe, spray with the paint on the number, specifications, production batch number, etc.. It is hoisted into the warehouse by crane.