Mannesmann Aktiengesellschaft

Vallourec Deutschland Gmbh

V&m Deutschland Gmbh

Mannesmannufer Aktiengesellschaft

Christoph Prasser

Ingo Von Hagen

Rolf Kümmerling

Gerd Homberg

Lothar Parschat

Fritz P Pleschiutschnigg

Robert Koppensteiner

Rupert Wieser

Wilhelm Nickel

Winfried Braun

Frank Hagemann

Enno Wieting

Stefan Wiedenmaier

Pierre Lefebvre

Gabriel Pereira

In a method for producing seamless pipes, a hot hollow block created previously in a piercing mill is stretched by means of a continuous rolling mill on a mandrel bar to form a parent pipe and the parent pipe is fed directly to a stretch reducing mill or sizing mill as a finishing mill, while forgoing an extracting mill and a reheating furnace, and is rolled there to the required final pipe diameter. The hollow block is pre-dimensioned in its length in such a manner that only a single length is produced as the required parent pipe length during the stretching in the continuous rolling mill and the parent pipe is pulled off of the mandrel rod by the finishing rolling during the subsequent finishing rolling, wherein the rolling is performed using rolling mill components that are designed in the dimensions thereof for handling single lengths.

Method for producing seamless hot-rolled pipes in continuous pipe rolling mills

In a method of making a seamless hot-finished steel pipe a billet heated to a shaping temperature is pierced by a first shaping to a thick-walled hollow ingot which subsequently undergoes a radial forging process using an internal tool inserted in the hollow ingot and at least two forging jaws of a forging machine. The forging jaws act on the outer surface area of the hollow ingot, wherein the hollow ingot is turned and axially advanced in a clocked manner in the idle stroke phase of the forging jaws.

Method of making a seamless hot-finished steel pipe, and device for carrying out the method

An economical steel for a reinforcement tube which steel meets the minimum requirements for reinforcement tubes, has a composition as follows: 0.15-0.25 % Carbon, 3.40-6.10 % Manganese, 0-1.0 % Nickel, 0-1.0 % Chromium, 0-1.0 % Molybdenum, 0-0.15 % Vanadium, max. 0.03 % Phosphorous, max. 0.03 % Sulfur, max. 0.6 % Silicon, max. 0.05 % Aluminum, with the remainder being iron and usual impurities, such that the sum total of the content of manganese, nickel, chromium, molybdenum and ten times the content of vanadium equals at least 4.5 wt. %.

Steel reinforcement tube

Method of manufacturing plated hollow blocks

A method of manufacturing high-strength seamless steel tubes by hot-rolling followed by accelerated cooling in which feed ingots of a steel annealed with aluminum and/or silicon of the following composition in weight per cent:

Method of manufacturing of high-strength seamless steel tubes

A method for hardening cylindrical hollows made of steel, includes heating followed by cooling, under utilization of a water bath while the hollow rotates about its longitudinal axis, and is partially immersed in the bath, the axis being parallel to the surface of the cooling bath; this method is improved by providing a particular rotation for the hollow as long as the temperature of the hollow is above the martensitic starting temperature; and drastically increasing the speed of rotation such that a significantly higher speed obtains as the martensitic transition temperature is reached.

Hardening a cylindrical hollow object preferably made of steel

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Essen, Germany

Christoph Prasser