Mannesmann Aktiengesellschaft

Alfred Lampe

Manfred Bellmann

Gerd Pfeiffer

Horst Biller

Hermann Josef Frentzen

Hermann-Josef Frentzen

Gheorghe Arnatu

Karl Oberem

Seamless tubes are manufactured from a hollow ingot introduced into a continuous-tube rolling mill. The hollow ingot is deformed, directly before introduction into a first stand of the rolling mill, so that without reduction in wall thickness the clearance between a mandrel and an inner surface of the hollow ingot in the region of a base of the groove of the rolls of the first stand is greater than the clearance in the region of roll flanks of the first stand. This advantageously increases the stretch in the first roll groove so that, on one hand, the total stretch limit can be increased and, on the other hand, the central roll groove can be relieved.

Method and apparatus for manufacturing seamless tubes

It was discovered that a rolling mandrel holding a hollow which is rolled in a multistrand mill should be advanced in a particular manner that relates to the stretching the hollow undergoes in the first and second stand, as well as to the speed of the unrolled hollow. A velocity profile has been developed accordingly.

Operating a rolling mill working on seamless tubing

Growing community of inventors

Willich, Germany

Alfred Lampe