Steel pipe refers to steel with openings at both ends and a hollow section, and its length is relatively large compared to the surrounding area. According to its production method, it can be divided into seamless steel pipe and welded steel pipe. The specification of the steel pipe is represented by the external dimension and wall thickness, and its size ranges from a small capillary tube to a large diameter tube with a diameter of several meters.

Pipeline engineering is the construction of pipelines for transporting oil, natural gas and solid slurry. Including pipeline line engineering, station depot engineering and pipeline ancillary engineering. In a broad sense, pipeline engineering also includes the supply of equipment and equipment.

Double-sided submerged arc welded spiral steel pipe is more and more popular in oil and gas, slurry transportation, urban construction and other industries due to its high pressure bearing capacity, small resistance, low temperature resistance, corrosion resistance, and convenient installation and maintenance.

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.