Mannesmann Aktiengesellschaft

Wilhelm Nickel

Rolf Kuemmerling

Klaus-Peter Schirmag

Ingo Von Hagen

Christoph Prasser

Manfred Bellmann

Horst Biller

Manfred Muller

Engelbert Mailander

Klaus-Peter Schirmagg

Wilhelm Sebastian

Manfred Mueller

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

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

A mandrel rod with or without rolled tubes thereon is held by four guide structures, two arranged above and two below with respect to the axis of rolling, and each being arranged on a lever, these levers are arranged in pairs to both sides of the rolling axis, and they are particularly interconnected and connected to a common drive to permit common radial retraction of the guide structure; these guide structures have basically three different positions, one of full retraction permitting a mandrel rod with rolled tubes thereon to be removed by lifting while simultaneously a fresh mandrel rod is placed into the rolling axis from below; in a second position of the guide structures they engage a mandrel rod in the rolling axis, and in the third position they form-fittingly engage a hollow on the mandrel rod in the rolling axis.

Holding and guiding a mandrel rod in rolled stock in and adjacent to a

An apparatus for delivery and removal of mandrel rods for use with rolling mills. A plurality of rocking levers are arranged one behind the other in the direction of rolling and are pivotable into upper and lower positions. Free ends of the levers are provided receivers for receiving the mandrel rod. The pivot or rocking levers are two-armed angle levers which are slidably mounted in two different positions such that in the first position the receivers on the angle levers are maintained in the vertical projection through the rolling axis and in the other position are offset from such vertical projection.

Growing community of inventors

Muelheim, Germany

Wilhelm Nickel