According to different production processes, seamless steel pipes can be divided into hot-rolled seamless steel pipes, hot-expanded seamless steel pipes, and cold-drawn seamless steel pipes. Four categories of cold-rolled seamless steel tubes.

The hot-rolled seamless steel pipe is a round steel that is pierced into a tube blank by a piercing machine and then passed through a hot-rolling mill to set the tube blank to a specification outside diameter to be formed into a hot-rolled seamless steel tube. The process is simple and the price is relatively low, but the dimensional precision is not high.

Hot-expanded seamless steel pipes are formed by using seamless steel pipe blanks or finished seamless steel pipes to be burned to a temperature above 1050 degrees in an electric furnace with an alloy core head to expand to a certain outer diameter inside. After being expanded into a thermally expanded seamless steel pipe, the wall thickness is thinner than the raw material, the length is shortened, and the outer diameter is larger.

Cold drawn seamless steel pipe(astm a53) is a seamless steel pipe that is formed by drawing a seamless steel pipe blank or finished seamless steel pipe through the mold of a cold drawing machine. It coincides with the hot expansion process. The drawn finished pipe is longer than the raw material , The wall thickness is thinner, and the outer diameter is smaller. The drawing process does not require heating, and it can be formed at room temperature, and it can also be re-annealed. Sometimes it is not necessary to anneal.

The cold rolling process is also produced at room temperature like the cold drawing process, but the cold rolling mill is different from the cold drawing machine. The cold drawing machine is formed by a mold, and the cold rolling mill is gradually formed by the mold, so the cold rolling process is produced It is slower than cold-drawn process production.