Important technical terms
For the bending test, a bending sample with rectangular, circular or polygonal cross section is bent quickly in a bending device, until either a certain bending angle is achieved or the formability is exhausted. The test is then positive, when a determined bending angle (compared with the unloaded sample) is achieved without occurrence of an incipient crack.
Beveling means the chamfering of edges of plates, tube or steel bar ends by planing, milling, turning or flame-cutting. For bar ends it facilitates the entry into the tensioning tools, for plates and tubes it serves as welding edge preparation.
The preliminary material for the production of seamless stainless steel tubes is delivered in bars with a certain diameter. Of these preliminary material bars, billets with a certain length are sawn off, according to dimension and length of the desired finished tubes, which are pressed to seamless stainless steel tubes on the extruding press.
Billet heating of billets is executed in a rotary hearth furnace, in which heating from room temperature to forming temperature (approx. 1100 °C) takes place.
In billet preparation, the preliminary material bar is sawn up into billet length, a center bore is drilled, the frontal area of the billet is faced and the corners are chamfered. Following the billet greasing there is one last visual check after which the billets are heated.
Today, the preparation of warm water mostly takes place in combination boilers, in which the boiler water is heated directly, the water for industrial use, however, is heated indirectly by the boiler water by means of a heat exchanger (boiler). The heat energy of the boiler water is transferred to the water for industrial use by thermal conduction. While the boiler water circulates in a closed cycle and supplies the water for industrial use with the energy won from combustion of coal and oil in the heating boiler, it is used for washing, bathing and drinking.
For mandrel drawing, drawing soaps (stearates) are used as lubricant, which are applied to the tube surface by immersion into a soaping bath at approx. 70 °C. Before soaping, the tubes are provided with a substrate, the so-called drawing bonder, which is applied by immersion into a heated oxalic acid solution (70 - 80 °C). Neutralization has to be performed between bonderizing and soaping.
In general, a brand is a medium used in business dealings for marking of goods or services of a certain company with the target to distinguish these products from those of others. E.g.: A200 is a steel brand of the company SBER, whose chemical composition corresponds various standardized materials like DIN 1.4401/1.4404 as well as ASTM TP316/TP316L.
Is annealing in an inert gas atmosphere (hydrogen, nitrogen, ...) without atmospheric oxygen, to avoid oxidation, so that no scale and/or oxidation layers can form on the work-piece.
Bulged ends are generated at hollows, which are manufactured by means of stretch reduction. For stretch reduction, each hollow section is stretched between two roll stands respectively, because the speed of the individual stands in the delivery direction increases permanently, except for start and end of the hollow. While at the start of the hollows there can be no tension by the subsequent (faster) stand, the retaining effect of the slower rotating stand is missing at the end of the hollow. The bulged ends are cut off of the hollows and disposed as rejects.
This means that internal pressure of a tube, which makes it burst.