Method and device for making metal pipe

Abstract

Provided is a method for producing tubes from metallic material and a planetary skew rolling mill for producing tubes from metallic material, wherein conventional problems such as yield deterioration of the planetary skew rolling mill, increase of scrap fraction and oxidation of the tubes are overcome, and output and reliability of the planetary skew rolling mill are increased. In a planetary skew rolling mill for producing tubes from a metallic material comprising a plurality of rolls(4) and an inner tool(5) so that a tube blank(3) is rolled into a tube(1) in a gap between the rolls and the inner tool, the planetary skew rolling mill comprises a means(10) for pulling back the inner tool as far as a predetermined moving distance(x) from a working position(8) of the inner tool to a direction opposite to a transfer direction(R) of the tube blank in such a way that the inner tool is controlled or adjusted according to time and returning the inner tool to the working position thereof in such a way that the inner tool is controlled or adjusted according to time, wherein the means is formed as a linear hydraulic actuator or a linear electrical actuator.

Description

technical field [0001] The present invention relates to a method of manufacturing metal pipes in a planetary cross rolling mill, wherein a tube blank is supplied to the planetary cross rolling mill and rolled into a pipe between rolls and a mandrel-shaped inner tool. The invention also relates to a planetary skew rolling mill for the manufacture of metal pipes. Background technique [0002] To produce seamless tubes, it is known to process the tubes in planetary skew rolling mills. Such a method and a planetary skew rolling mill are described, for example, in DE 10107567 A1. Here, a tube blank is supplied to a planetary skew rolling mill and rolled into a tube in a gap formed between planetary skew rolling rolls and a mandrel-shaped inner tool. [0003] Due to the energy input by the rolls into the material to be rolled, the blank tube or tube is heated strongly, so that the tube must be cooled. Thus, it is known from DE 10107567 A1 that in the deformation zone on the ent...

AI Technical Summary

Problems solved by technology

[0004] Thus, the following problems arise in such a production method, that is, the cooling medium used may flow into the open tube end, which makes subsequent further processing such as mandrel drawing more difficult

For this reason, the open tube ends are usually not sprayed with cooling medium, but this has the disadvantageous consequence of reduced product yields and increased scrap in planetary skew rolling mills

It is also disadvantageous that, due to the interruption of cooling in the end region of the tube or tube blank, the tube comes out of the rolling mill hot and thus prone to oxidation

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