Seamless steel tubes are produced by puncturing steel ingots or solid tube billets to form a blank, which is then subjected to hot rolling, cold rolling, or cold drawing. With a hollow cross-section, seamless steel tubes are extensively used as fluid transmission pipelines. Compared to solid steel materials such as round bars, seamless steel tubes offer a lightweight alternative while maintaining similar bending and torsional strength, making them an economical steel section widely employed in the manufacturing of structural components and mechanical parts, including steel scaffolding for oil drilling operations.
Development History of Seamless Steel Tubes
The production of seamless steel tubes has a history spanning nearly 100 years. In 1885, the German brothers Mannesmann invented the two-roll skew rolling piercing mill, followed by the invention of the periodic pipe rolling mill in 1891. In 1903, the Swiss inventor R.C. Stiefel introduced the automatic pipe rolling mill (also known as the plug mill). Subsequent advancements led to the emergence of continuous pipe rolling mills, plug mills, and various other extension machines, marking the formation of the modern seamless steel tube industry.
During the 1930s, the adoption of three-roll pipe rolling mills, extruders, and periodic cold rolling mills improved the variety and quality of steel tubes. In the 1960s, improvements in continuous rolling mills, the introduction of three-roll piercing mills, and particularly the successful application of stretch reducing mills and continuous casting billets boosted production efficiency and strengthened the competitiveness of seamless tubes against welded tubes.
By the 1970s, seamless and welded tubes were neck-and-neck in development, with the global steel tube output increasing at a rate of over 5% annually. In China, since 1953, there has been a focus on developing the seamless steel tube industry, which has preliminarily established a production system capable of rolling various large, medium, and small-diameter tubes.
Copper tubes typically undergo similar processes, including skew rolling perforation of ingots or billets, rolling with pipe mills, and coiling and drawing processes.
Uses and Classification of Seamless Steel Tubes
Uses: Seamless steel tubes, as an economical steel section, play a crucial role in the national economy. They are widely utilized in various sectors such as petroleum, chemicals, boilers, power stations, shipbuilding, machinery manufacturing, automobiles, aviation, aerospace, energy, geology, construction, and military industries.
Classification:
By Cross-Section Shape: Round tubes, irregularly shaped tubes
By Material: Carbon steel tubes, alloy steel tubes, stainless steel tubes, clad pipes
By Connection Method: Threaded pipes, welded pipes
By Production Method: Hot-rolled (extruded, plugged, expanded) pipes, cold-rolled (drawn) pipes
By Application: Boiler tubes, oil well tubes, line pipes, structural tubes, fertilizer tubes
