Cold rolled seamless steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, as well as carbon thin-walled steel pipes and alloy thin-walled steel pipes.

The strength of thick-walled spiral steel pipes is generally higher than that of large-diameter straight seam steel pipes.

Seamless steel pipe penetration testing has simple principles, flexible methods, and strong adaptability. It can detect surface opening defects in any direction at one time.

The characteristics of plastic-coated composite steel pipe: It not only has the strength of steel pipe, but also has the advantages of plastic pipe corrosion resistance, wear resistance, and low fluid resistance. It is a new type of water supply and anticorrosion pipeline.

Large-diameter steel pipes are pickled using an acid solution to remove oxide scale and rust on the surface of steel, called pickling. Acids for pickling include sulfuric acid, hydrochloric acid, phosphoric acid and mixed acids.

Generally speaking, the appropriate petroleum cracking steel pipe should be selected from the three aspects of performance, economy and working conditions.