Method for online controlling uneven thickening of seamless steel pipe wall in reducing sizing production

Abstract

The invention discloses a method for online controlling uneven thickening of a seamless steel pipe wall in reducing sizing production. The method comprises the steps as follows: firstly, online adjustment of the roller speed is performed on each rack, piling up of steel in reducing sizing in the pipe is eliminated, reducing sizing is performed under tensile force, the evenness of the pipe wall in the pipe is improved, and the probability of an internal hexagon quality defect is reduced under the condition that the total reducing rate for reducing sizing is increased; secondly, missing tension of the head and tail parts are supplemented by increasing additional tension at the head and tail parts, reducing sizing tension borne by the free head and tail parts of a hot pierced billet is consistent with the tension borne during reducing sizing in the pipe, so that pipe wall thickening at the head and tail parts is basically consistent with the pipe wall thickening in the pipe, the axial wall thickness evenness of the steel pipe after reducing sizing is improved, end cutting loss is reduced, and the yield of the steel pipe is increased.

Description

technical field [0001] The invention belongs to the technical field of production of hot-rolled seamless steel pipes, and more specifically relates to a method for on-line control of uneven wall thickness of seamless steel pipes in the production process of tension reduction and sizing. Background technique [0002] At present, the last deformation process of the hot-rolled seamless steel pipe production line is the reduction and sizing process, such as figure 1 As shown, the principle is as follows: n (the number of racks n is 3 to 32) racks are arranged in series, the roll pass of each rack is composed of three rolls at 120° to each other, and adjacent racks are staggered Arrangement, the throat diameters of any i-th and i+1 racks are separated by a rack spacing L, and the hot waste pipes sent by the rolling process enter any i-th racks, and the steel-clamping (that is, the head end of the hot waste pipes) is automatically completed. Go through the pass pattern of the i-t...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to solve the following technical problems: 1) During the production process of hot-rolled seamless steel pipes, the motor speed of each frame is constant, and the speed of the rollers cannot be adjusted online according to the changes in the production process, so that there is piled steel production between the frames. As a result, the pipe wall on the broken surface of the pipe is unevenly thickened and exceeds the standard requirements of the steel pipe. Lack of front tension at the top and lack of back tension at the free tail, so that the thickness of the pipe wall at the head and tail exceeds that of the middle of the pipe, resulting in serious uneven wall thickness in the axial direction of the steel pipe and increasing the waste cutting loss at the head and tail

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