Method and apparatus to reduce the outer diameter and wall thickness of a hollow tube blank by rolling
AssigneeMannesmann Aktiengesellschaft
InventorsGustav-Adolf Pettersson, Ernst Zimmert, Bengt Jagaeus, Aake Sandberg
Life of this patent
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Abstract
In a process for reducing the outer diameter and wall thickness of an essentially cylindrical hollow tube blank by rolling, the front end of the tube blank is introduced into a rolling mill. To prevent piping defects during rolling and to obviate other disadvantages of conventional processes, the diameter and/or the wall thickness of the trailing end portion of the tube blank is reduced before the trailing end portion is introduced into the reduction zone of the rolling mill.
Claims18
Process for reducing by rolling the outside diameter and wall thickness of a primarily cylindrical hollow tube blank, comprising the steps of:
- introducing a forward end portion of a tube blank into a rolling mill;
- providing a mandrel for supporting at least a portion of the tube blank;
- feeding the tube blank through the rolling mill to reduce the outside diameter of the tube blank;
- reducing the outside diameter of the trailing end portion of the tube blank, while the trailing end portion of the tube blank is being supported by the mandrel, in advance of the rolling mill as the tube blank is fed through the rolling mill;
- and
- the rolling mill being a skew rolling mill.
Apparatus for the production of a pre-reduced end portion of a hollow tube blank to achieve a reduced outside diameter and a reduced wall thickness during rolling in a rolling mill, said apparatus comprising:
- a rolling mill for receiving a hollow tube blank to reduce the outer diameter and wall thickness of the tube blank;
- a mandrel for supporting at least a portion of the tube blank;
- means for continuously feeding the tube blank through said rolling mill from a leading end portion of the tube blank to a trailing end portion of the tube blank;
- pre-reduction means positioned in advance alignment of said rolling mill for reducing the outside diameter of the tube blank trailing end portion, while the tube blank trailing end portion is being supported by the mandrel, prior to introduction of the trailing end portion into said rolling mill as the tube blank passes through the rolling mill;
- and
- the rolling mill being a skew rolling mill.
Pre-reduction roll forming apparatus comprising:
- a frame;
- a pair of arms;
- pivot means for connecting said pair of arms in opposed relation on said frame to move said pair of arms toward and away from each other;
- forming means mounted on said pair of arms for engaging a tube blank to reduce the outside diameter thereof as the tube blank is advanced in a preselected feed path relative to said frame;
- actuator means mounted on said frame and connected to said pair of arms for selectively moving said pair of arms to move said forming means between a first position removed from engagement with the tube blank and a second position in engagement with the tube blank;
- control means connected to said actuator means for sensing the presence of the tube blank in the feed path and actuating said actuator means at a preselected time interval for engagement of said forming means with the tube blank;
- a rolling mill positioned in the feed path of the tube blank after said forming means;
- and
- said rolling mill being a skew rolling mill.
Dependencies are inferred from the claim text.