Mannesmann Aktiengesellschaft

Vallourec Deutschland Gmbh

V&m Deutschland Gmbh

Rolf Kuemmerling

Wilhelm Nickel

Manfred Bellmann

Horst Biller

Klaus-Peter Schirmag

Christof Delhaes

Heiko Hansen

Manfred Mueller

Gunther Manig

A method for producing a tempered, seamlessly hot-rolled steel pipe includes heating a hollow block to forming temperature and rolling the heated block in a rolling mill to form a pipe with a finished diameter after rolling. Subsequently, the pipe is tempered with appropriate tempering parameters after rolling whereby the diameter of the pipe increases during tempering. The finished diameter of the pipe to be tempered after rolling in the rolling mill is adjusted as a function of a value of the growth in diameter of the pipe during tempering.

Method for producing a tempered seamlessly hot-fabricated steel pipe

Seamless tubing and pipes are made from solid rounds with a diameter not exceeding 0.8 of the diameter of the tubing or pipe to be made; the method includes the steps of piercing the solid with a mandrel such that a conical widening angle at the end of piercing has a particular value; a smoothing step is provided downstream from the piercing also with a particular cone angle; and between the piercing and the smoothing of the now pierced hollow is widened under reduction of the wall thickness at a conical angle of widening that is larger (blunter) than the widening angle of piercing and the particular cone angle.

Making seamless pipes, over 200 mm in diameter

A pierced hollow rolled by obliquely positioned conical or barrel-shaped rolls, is held against excessive ovality by driven guide sheaves or disks acting in combination with guide bars downstream for controlling the rate of radial widening of the hollow. Oblique positions of the axes of the disks permits them to be of larger diameter.

Guide structure for pierced hollows

Growing community of inventors

Duisburg, Germany

Rolf Kuemmerling