What is the production process of thick wall seamless pipe?

According to the production mode, the thick wall seamless pipe can be divided into three categories: hot rolling, welding and cold working. The hot-rolled seamless steel tube is a kind of steel tube with hollow section which is made by piercing and rolling a solid billet or ingot. Cold working seamless steel pipe is the secondary processing of steel pipe. Cold working is an important method to obtain high-precision and high-performance pipes, including cold rolling, cold drawing, cold tension reducing and cold spinning. Seamless metal tubes for high alloy steel are mainly produced by extrusion.

The raw material of large diameter thick wall seamless tube is round billet, which is heated in the furnace at a temperature of about 1200℃. The fuel is hydrogen or acetylene. The temperature control in the furnace is a key problem. After the round tube is discharged from the furnace, it needs to be pierced by a pressure piercer, which is generally a cone roller piercer. After piercing, the round tube blank is successively rolled, continuously rolled or extruded by three rollers. After extrusion, the tube shall be removed for sizing. The sizing machine uses a cone-shaped drill to drill holes into the steel embryo at high speed, forming a thick wall seamless pipe. The inner diameter of the thick wall seamless pipe is determined by the outer diameter length of the drill bit of the sizing machine.

After cooling by spraying water, the steel pipe will be straightened. After straightening, the steel pipe is sent to the metal flaw detector by the conveyor belt for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, they will be detected. After the quality inspection of thick wall seamless pipe, strict manual selection is also required. After the quality inspection of thick wall seamless pipe, paint the number, specification, production batch number, etc. And hoisted into the warehouse by crane.