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Seamless steel pipe is made from steel ingot or solid billet by piercing into a rough tube, and then made by hot rolling, cold rolling or cold dialing. Seamless steel pipe has a hollow cross-section and is used in large quantities as a pipeline for transporting fluids. Compared with solid steel such as round steel, steel pipe is lighter in weight when the bending and torsion strength is the same, and it is a kind of economic cross-section steel, which is widely used to make structural and mechanical parts, such as steel scaffolding for oil drilling.

Seamless steel pipe development history

Seamless steel pipe production has a history of nearly 100 years. German Mannesmann brothers in 1885 first invented the two-roll slanting mill piercing machine, 1891 and the invention of the cycle rolling mill, 1903 Swiss Stiefel (R.C. Stiefel) invented the automatic rolling mill (also known as the top type rolling mill), and later appeared in the continuous rolling mill and the top of the pipe machine and other extensions to begin to form a modern seamless steel pipe industry.

In the 1930s, due to the use of three-roll mill, extruder, periodic cold rolling mill, improve the quality of the varieties of steel pipe.

In the 1960s, due to the improvement of continuous rolling mill, the emergence of three-roll piercing machine, especially the application of tension reducer and the success of continuous billet casting, improved production efficiency, enhanced seamless pipe and welded pipe competition.

Seamless pipe and welded pipe in the 70s are running neck and neck, the world steel pipe production to more than 5% per year rate of increase. After 1953, China attached importance to the development of seamless steel pipe industry, has initially formed a variety of large, medium and small pipe rolling production system.

Copper tube is also generally used ingot billet slant rolling perforation, rolling mill rolling, coil stretching process.

The use and classification of seamless steel pipe

Use: Seamless steel pipe is a kind of economic section steel, has a very important position in the national economy, widely used in petroleum, chemical industry, boiler, power station, shipbuilding, machinery manufacturing, automobile, aviation, aerospace, energy, geology, construction and military and other various sectors.

Classification:

According to cross-section shape: round cross-section pipe, shaped cross-section pipe

According to material: carbon steel pipe, alloy steel pipe, stainless steel pipe, composite tube

According to the connection mode: threaded pipe, welded pipe

According to the production mode: hot-rolled (extrusion, top, expansion) tube, cold-rolled (drawn) tube

By application: boiler pipe, oil well pipe, pipeline pipe, structural pipe, fertilizer tube