Steel pipe
A steel pipe (also hollow profile ) is a tubular profile steel with a concentric , rectangular , oval or other closed cross-section, the wall of which is made of steel . Steel pipes are used to convey liquid, gaseous or solid substances, or are used as static or structural elements.
Steel pipe is available from diameters in the millimeter range ( brake lines , hydraulic lines , etc.) up to several meters ( pipeline systems , etc.)
According to their manufacturing process, steel pipes are divided into:
- seamless steel pipes . These are formed by the perforation of solid material ( blooms , billets , slabs primarily etc.) in rolling mills by hot rolling generates and subsequent processing steps.
- longitudinally welded steel pipes . These are first formed from steel strips ( steel strip ), wide band ( coils ), sheet steel , etc. into a tubular body and the strip edges are then welded together in the longitudinal direction to form a closed steel tube.
- spiral welded steel pipes . These are helically wound from steel strips, shaped and welded at the edges of the band to form a closed pipe body (spiral pipe production).
Ventilation ducts such as folded spiral ducts (made of spirally wound sheet metal strips connected by a longitudinal fold), rainwater downpipes and other thin-walled pipes made from sheet metal are not counted among the steel pipes in the narrower sense .
history
Fire-welded pipes were first manufactured in England in 1825, followed by Germany in 1845. In fire or fire pressure welding, rolled sheet metal strips are bent into profiles with a round cross-section using forming tools and butt welded or overlapped. This started the industrial production of steel pipes.
In 1886 Max and Reinhard Mannesmann developed the cross rolling process for the production of seamless tubes. This development is seen as the beginning of large-scale pipe production.
Two elements are essential in skew rolling: First, a pair of rollers with axles arranged at an angle to one another, which rotate in the same direction and thus pull the steel block, which can be up to 1300 degrees Celsius, through the system. And secondly, a thorn that punctures the glowing round block.
The cross-rolling process of 1886 was initially hardly suitable for industrial production. The Mannesmann brothers did not succeed in producing a commercially available thin-walled tube in a single rolling pass. It took them four years until they finally combined skew rolling with the so-called pilgrim step process in 1890 . The concept of the Mannesmann process established itself for the combination of the two technologies. The material is released for a short time during rolling with an asymmetrical roller, rotated through a certain angle and pushed back for the next step. "This movement - back and forth - owes the process, based on the Echternach jumping procession, the name pilgrim rolling".
In addition to this process, other processes for the manufacture of seamless tubes developed at the end of the 19th century. These coexisted for some time. After the property rights had expired , the methods were often combined. The common procedures developed from this:
- Pipe contouring and push bench method for dimensions from approx. 21 to 178 mm.
- Tube contouring process with controlled moving mandrel bar or the plug rolling process with an outside diameter of 140 to 406 mm.
- Cross rolling pilger step process for dimensions from 250 to 660 mm outside diameter.
standardization
Steel pipes are to European standards for the manufacturing system standardized . The following standards are currently valid:
- EN 10210 - Hot-finished hollow profiles for steel construction made from unalloyed structural steels and fine-grain structural steels (two parts) - formerly DIN 17120… DIN 17125, DIN 59410
- EN 10219 - Cold-finished welded hollow profiles for steel construction made of unalloyed structural steels and fine-grained structural steels (2 parts) - formerly DIN 17119, DIN 17120, DIN 17123, DIN 17125, DIN 59411
- EN 10305 - Precision steel tubes (six parts) - formerly DIN 2385, DIN 2391, DIN 2393 ... DIN 2395
- EN 60423 and EN 61386 for armored steel pipes (Stapa pipes) that are used in electrical installations
All named European standards are valid in Germany as DIN standards .
See also
Web links
swell
- ↑ a b Johannes Groß-Weege, Axel Kulgemeyer, Christina Träger, Production of steel pipes , Salzgitter Mannesmann Forschung GmbH, Duisburg Production of steel pipes ( Memento from December 13, 2014 in the Internet Archive ) (PDF; 672 kB)
- ↑ a b c d e f g Karl-Heinz Brensing and Baldur Sommer; Manufacturing process for steel pipes ; published by Mannesmannröhren-Werke AG, Mülheim an der Ruhr
- ↑ Jürgen Schreier; Tube production - Skew rolling celebrates its 125th birthday ; dated January 29, 2010 on www.bleendung.com; accessed on July 14, 2016.