1. Introduction of seamless steel pipe




The seamless steel pipe is a round, square, rectangular hollow steel pipe with no seams around it. Seamless steel tubes are perforated in steel ingots or solid tube blanks and then hot rolled, cold rolled or cold drawn. The seamless steel tube is a hollow section for conveying fluid. Compared with solid steel such as round steel, steel pipe has the same bending and torsional strength and light weight. It is an economical steel and is widely used in structural manufacturing. Parts and mechanical parts, such as steel scaffolding for oil rigs.




2. History of seamless steel tubes




Seamless steel tube production has a history of nearly 100 years. The German Mannesmann brothers first invented the twin-roll cross-rolling puncher in 1885 and invented the circulating mill in 1891. In 1903, Switzerland's Retreat invented the automatic pipe rolling machine (also called the rolling head machine). Machines, and later various types of extension machines, such as continuous pipe mills and pipe jacking machines, began to form the modern seamless steel pipe industry. In the 1930s, the quality of steel pipes was improved by the use of three-roll mills, extruders and periodic cold-rolling mills. In the 1960s, due to the improvement of continuous rolling mills, three roller machines, especially the use of tension reducing machines and continuous casting blanks, increased production efficiency and enhanced the competitiveness of seamless pipes and welded pipes. In the 1970s, seamless pipes and welded pipes were operated in parallel, and the world's steel pipe production increased at a rate of more than 5% per year. After 1953, China attached great importance to the development of the seamless steel pipe industry, and initially formed a rolling production system for various large, medium and small pipes. Copper pipes are also generally used for rolling perforations, rolling mill rolling, and roll stretching of steel ingots.




three. Use and classification of seamless steel tubes




use:




Seamless steel pipe is an economical steel that plays an important role in the national economy and is widely used in petroleum, chemical, boiler, power station, shipbuilding, machinery manufacturing, automobile, aviation, aerospace, energy, geology, construction, military and other fields. . Every department.




classification:




1 according to the sectional shape: circular section tube, profiled section tube




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




3 according to the connection method: threaded pipe, welded pipe




4. According to the production mode: hot rolling (squeezing, topping, expanding) tube, cold rolling (pull) tube




According to the use: boiler tube, oil well tube, line tube, structural tube, fertilizer tube...




4. Seamless steel pipe production process




1. Main production process of hot rolled seamless steel pipe (main inspection process):




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




2 cold rolling (drawing) seamless steel pipe main production process




Blank preparation→acid washing lubrication→cold rolling (pulling)→heat treatment→straightening→finishing→inspection