Vallourec Deutschland Gmbh

Mannesmann Aktiengesellschaft

V&m Deutschland Gmbh

Sumitomo Metal Industries, Inc.

Winfried Braun

Rolf Kümmerling

Peter Thieven

Christoph Prasser

Manfred Bellmann

Gerd Homberg

Frank Hagemann

Rene Baadjou

Gabriel Pereira

Hidenori Kinugasa

Sasaki Kenichi

Christian Klempel

A piercing mandrel for piercing heated round blocks of metal for the production of seamless pipes, having a piercing mandrel nose and a piercing mandrel main body which can be connected to a mandrel bar. The outer diameter of the piercing mandrel nose is formed in a conically tapering manner in the longitudinal direction towards the piercing mandrel main body in order to increase the durability of the piercing mandrel when used for piercing round blocks of metal, in particular higher-alloyed steel materials which are difficult to work, by means of skew rolling providing a qualitative improvement of the inner surface of the pierced round block and reducing tool costs.

Piercing mandrel having an improved service life for producing seamless tubes

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

The invention relates to a method for producing seamless tubes from metal, particularly from steel, wherein a previously produced hot hollow block is stretched by means of a three-roll bar rolling mill on a mandrel to form a parent tube and, before running into the bar rolling mill, the hollow block is provided with a rolling step that makes the diameter more uniform by means of an upstream stand. It is in this case provided that the rolls of the upstream stand are moved apart and together to the same extent as the deforming stands of the bar rolling mill, wherein the calibrating base radius of the rolls of the upstream stand extends over 60&#xb0; and this is followed by a flank radius with a tangential transition which is dimensioned such that even with the maximum setting of the rolls in the region of the flank there is virtually no diameter reduction of the largest hollow block diameter to be expected.

Method for producing seamless tubes by means of a three-roll bar rolling mill

Caliber contour in a rolling mill roller for tubes

Growing community of inventors

Düsseldorf, Germany

Winfried Braun