Delivery status of seamless steel pipe

Posted by chase Liu on August 30th, 2023

Seamless pipes can be divided into four categories according to the delivery status: hot-rolled, hot-expanded seamless tubes, cold drawn seamless tubing, and cold-rolled seamless tubes.

The hot-rolled seamless steel pipe is that the round steel is pierced into a tube blank by a piercer, and then the tube blank is set to a specified outer diameter by a hot rolling mill to form a hot-rolled seamless steel pipe product. The process is simple and the price is relatively low, but the dimensional precision is not high. According to domestic production technology, seamless steel pipes with an outer diameter of 60mm to 600mm can be hot-rolled.

The heat-expanded seamless steel pipe is formed by using the seamless steel pipe billet or the finished seamless steel pipe to be fired in an electric furnace to above 1050 degrees, and then expanded to a certain outer diameter with an alloy core head inside. After expanding into heat-expanded seamless steel pipe, the wall thickness is thinner than the original material, the length becomes shorter, and the outer diameter becomes larger

Cold-drawn seamless steel pipe is a seamless steel pipe formed by drawing the seamless steel pipe blank or the finished seamless steel pipe through the abrasive tool of the cold drawing machine. It is exactly opposite to the thermal expansion process. The drawn finished tube is longer than the raw material, the wall thickness is thinner, and the outer diameter is smaller. The drawing process does not require heating, forming at room temperature, and can also be annealed, sometimes it is not necessary to anneal.

The cold rolling process is also produced at room temperature like the cold drawing process. It's just that the cold rolling mill is different from the cold drawing machine. The cold drawing machine is formed by a mold once, while the cold rolling mill is gradually formed by the abrasive tool, so the production of the cold rolling process is slower than that of the cold drawing process.

Seamless pipe is a metal pipe with seamless structure, which is widely used in petroleum, natural gas, chemical industry, electric power, aerospace and other fields. Compared with welded steel pipes, seamless pipes have higher strength and pressure resistance, so they perform well in high pressure and high temperature environments.