A short-flow method for rolling thick-walled pipes in a mandrel-restricted continuous rolling mill

Abstract

The invention discloses a short process method for rolling a thick-walled pipe by a retained mandrel continuous rolling unit. The method has the characteristics that front 3 or 4 racks of the continuous rolling unit are utilized to realize a wall thickness control function; the last 1 or 2 racks of the continuous rolling unit are utilized to realize rod falling and sizing functions; pipe falling and sizing procedures are reduced; the production-manufacturing cost is reduced; the length of a mandrel participating in rolling is reduced by more than 50% of the length of the mandrel in the conventional technology, so that the loss of the mandrel is reduced; and the retained mandrel continuous rolling unit has the capability of producing an ultra-thick-walled pipe with the wall thickness above 55mm.

Description

[0001] Technical field: [0002] The invention relates to the technical field of metallurgical machinery, in particular to a short-flow method for rolling thick-walled pipes in a mandrel-limited continuous rolling mill. [0003] Background technique: [0004] The mandrel-limited three-roll continuous rolling unit generally has 5-6 continuous rolling stands, which are used to roll the raw material capillary tube into a barren tube with uniform wall thickness. It mainly plays the role of controlling the wall thickness. In the follow-up, a matching sizing unit is required to control the outer diameter of the product. The working mechanism of the mandrel limiting three-roll rolling mill (take the 5-stand mandrel limiting three-roll rolling mill as an example): 1) After the mandrel is inserted into the inner surface of the steel pipe, the mandrel limiting three-roll rolling mill 5 The first frame and the mandrel jointly participate in the rolling of the wall thickness control; the ...

AI Technical Summary

Problems solved by technology

[0005] At present, limited by the distance between the mandrel-limited three-roll continuous rolling unit and the stripping unit, generally 10-12 meters, in order to ensure the normal bite of the stripping unit, the minimum rolling length of the mandrel-limited three-roll continuous rolling unit is generally 10 More than one meter, which limits the further expansion of thick-walled tubes in mandrel-limited three-roll continuous rolling mills; because according to the principle of constant volume, the thicker the wall thickness, the shorter the length; currently the domestic mandrel-limited three-roll continuous rolling mill Wall thickness generally up to 55mm