1. Introduction of seamless coil

Seamless coil is a kind of round, square, rectangular hollow seamless steel pipe. Seamless steel coils are formed by inserting ingots or solid billets into capillaries and then hot, cold or cold rolled. Compared to solid steels such as round bars, seamless steel coils have the same bending and torsional strength and are lighter in weight. It is an economical steel, widely used in the manufacture of structural parts and mechanical parts such as oil drilling steel scaffolding.

2. Development history of seamless coil

Seamless coil production has been around for nearly 100 years. The German Mannismann Brothers first invented the two-roll cross-rolling piercing machine in 1885, and invented the periodic tube rolling mill in 1891. In 1903, the Swiss Stiefel invented the automatic pipe rolling machine (also known as the plugging machine). Later, various extension machines such as continuous pipe rolling mills and pipe jacking machines appeared, and the modern seamless coil industry began to form. In the 1930s, the variety and quality of steel pipes were improved due to the adoption of three-roll mills, extruders and periodic cold-rolling mills. In the 1960s, due to the improvement of continuous rolling mills and the emergence of three-roll piercing machines, especially the success of tension reducers and continuous casting slabs, production efficiency was improved and the competitiveness of seamless and welded pipes was enhanced. In the 1970s, seamless pipes and welded pipes kept pace, and the world’s steel pipe production increased by more than 5% every year. Since 1953, my country has attached great importance to the development of the seamless coil industry, and has initially formed a production system for rolling various large, medium and small-sized pipes. Generally, copper tubes also adopt the processes of billet skew rolling, piercing, tube rolling, and coil drawing.

3. The use and classification of seamless coils

Application: Seamless coil is a kind of economical section steel, which occupies an important position in the national economy. Widely used in petroleum, chemical, boiler, power station, shipbuilding, machinery manufacturing, automobile, aviation, aerospace, energy, geology, construction, military and other industries.

Classification:

According to the shape of the section: round section tube, special-shaped section tube

② According to the material: carbon material steel pipe, alloy steel pipe, stainless steel pipe, composite pipe

③ According to the connection management method: threaded connection pipe, welded pipe

④Divided by production method: hot-rolled (extrusion, top, expansion) pipe, cold-rolled (drawn) pipe

⑤Divided by use: boiler tube, oil well tube, line tube, structural tube, fertilizer tube.

4. Production process of seamless coil

①The main production process of hot-rolled seamless coil (main inspection process):

Tube blank preparation and inspection → tube blank heating → perforation → tube rolling → waste tube reheating → diameter determination (reduction) → heat treatment → finished tube straightening → finishing → inspection (non-destructive, physical and chemical, Taiwan inspection) → storage

②Main production process of cold rolled (drawn) seamless coil

Billet preparation→pickling lubrication→cold rolling (drawing)→heat treatment→straightening→finishing→inspection