Square pipe is a name for square pipes, that is, steel pipes with equal side lengths. Square tubes can be divided into seamless square tubes and welded square tubes according to the presence or absence of welds. Seamless square pipe is a square steel pipe with four corners. It is a square steel pipe formed by cold drawing and extrusion of seamless steel pipe. There is an essential difference between seamless square pipe and welded square pipe. Steel pipes have a hollow section and are used in large quantities as pipes for transporting fluids. Welded square tube is a square tube made of steel plate or strip steel after crimping and welding.

Stainless steel seamless pipe is a hollow long cylindrical steel, and its scope of application is used as a pipe for conveying fluid. Mainly widely used in petroleum, chemical, medical, food, light industry, mechanical instruments and other industrial pipelines and mechanical structural components. The stainless steel pipe is made of acid-resistant and heat-resistant steel billets, which are heated, pierced, sized, hot-rolled, and cut.

Natural gas pipelines refer to pipelines that transport natural gas (including associated gas produced in oil fields) from mining sites or processing plants to urban gas distribution centers or industrial enterprise users, also known as gas pipelines. The use of natural gas pipelines to transport natural gas is a way to transport large quantities of natural gas on land. Natural gas pipelines account for about half of the world's total pipeline length

Straight seam pipe is a kind of welded steel pipe, which refers to the steel pipe whose weld seam is parallel to the longitudinal direction of the steel pipe. The seam pipe is formed by rolling a long steel strip of a certain specification through a high-frequency welding unit and welding it with a straight seam. The specification of the straight seam pipe is represented by the nominal diameter, and can be divided into two types: thin-wall straight seam pipe and thick-wall straight seam pipe according to the wall thickness. According to the shape, it can be divided into round, square or special-shaped tubes.

The boiler tube is a seamless tube. The manufacturing method is the same as that of seamless pipes, but there are strict requirements on the steel types used in the manufacture of steel pipes. According to the operating temperature, it can be divided into general boiler tubes and high-pressure boiler tubes.

Spiral seam submerged arc welded steel pipe (SSAW) refers to a metal pipe with a spiral seam welded by submerged arc welding process. Widely used in water supply engineering, petrochemical industry (such as octg casing), chemical industry, electric power industry, agricultural irrigation, urban construction,