The main production process of large-diameter seamless steel pipe is hot-rolled large-diameter seamless steel pipe and heat-expanded diameter seamless steel pipe. The maximum size of heat-expanded seamless steel pipe is 325mm-1220mm and the thickest is 200mm.

The heat treatment of seamless pipe or welded pipe refers to a metal thermal processing process in which the chemical composition and organization of the surface or interior of the material are changed by means of heating, heat preservation and cooling in the solid state to obtain the required properties.

The quality of steel pipes is assessed by inspecting the technological properties of seamless or welded steel pipes. Master the test method of steel pipe bending (cold bending) performance and the uation method of steel pipe quality, and use instruments and equipment correctly.

In order to improve the service life of seamless pipes or welded pipes, steel pipe manufacturers often choose to galvanize steel pipes. There are two types of galvanized pipes: hot-dip galvanizing and electric galvanizing. Hot-dip galvanizing has a thick galvanized layer, which has the advantages of uniform coating, strong adhesion, and long service life. The cost of electro-galvanizing is low, the surface is not very smooth, and its corrosion resistance is much worse than that of hot-dip galvanized pipes.

Oxygen blowing pipes are used for steelmaking oxygen blowing pipes. Generally, small-diameter welded steel pipes are used, and the specifications range from 3/8 inch to 2 inch.

Geological pipe is a steel pipe used for core drilling by geological departments. It is a type of seamless pipe. It is a steel pipe with a hollow section and no seams around it. According to the application, it can be divided into drill pipe, drill collar, core pipe, casing and sedimentation pipe, etc.