Classification of precision steel pipes | What is the specification of precision steel pipes?

First, the classification of precision steel pipes: precision steel pipe sub-precision steel pipe and welded precision steel pipe (with seam pipe) two categories. According to the shape of the section, it can be divided into round tubes and special-shaped tubes. Circular precision steel tubes are widely used, but there are also some special-shaped precision steel tubes such as square, rectangular, semi-circular, hexagonal, equilateral triangle and octagonal. For precision steel pipes subjected to fluid pressure, hydraulic tests are carried out to check the pressure resistance and quality. No leakage, wetting or expansion is allowed under the specified pressure. Some precision steel pipes are also required to be rolled according to the standard or the requirements of the purchaser. Side test, flare test, flattening test, etc.

Second, precision steel pipe: precision steel pipe is made of steel ingot or solid pipe blank through perforation, and then made by hot rolling, cold rolling or cold drawing. The specifications of precision steel pipes are expressed by the outer diameter * wall thickness in millimeters. Precision steel pipe is divided into hot rolling and cold rolling (dial) precision steel pipe. Hot-rolled precision steel pipes are divided into general precision steel pipes, low- and medium-pressure boiler precision steel pipes, high-pressure boiler precision steel pipes, alloy precision steel pipes, stainless steel precision pipes, petroleum cracking pipes, geological precision steel pipes and other precision steel pipes. Cold rolling (dial) precision steel pipe in addition to general precision steel pipe, low and medium pressure boiler precision steel pipe, high pressure boiler precision steel pipe, alloy precision steel pipe, stainless precision steel pipe, petroleum cracking pipe, other precision steel pipe, also includes carbon thin wall precision Steel pipe, alloy thin-walled precision steel pipe, stainless steel thin-walled precision steel pipe, special-shaped precision steel pipe. The outer diameter of hot-rolled seamless pipe is generally larger than 32mm, the wall thickness is 2.5-75mm, the diameter of cold-rolled precision steel pipe can reach 6mm, the wall thickness can reach 0.25mm, the outer diameter of thin-walled pipe can reach 5mm, the wall thickness is less than 0.25mm, cold rolling It has higher dimensional accuracy than hot rolling.

Third, the general use of precision steel pipe is to use 10, 20, 30, 35, 45 and other high-quality carbon steel 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other combined steel hot-rolled or cold rolled into of. Seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid conveying pipes. 45, 40Cr and other medium carbon steel seamless pipes are used to make mechanical parts, such as the force parts of automobiles and tractors. Generally, precision steel pipes are required to ensure strength and flattening test. The hot-rolled precision steel pipe is delivered in a hot rolled state or a heat-treated state; the cold rolling is delivered in a heat-treated state by heat.