RU1801635C - Method for lengthwise rolling tubes - Google Patents

Abstract

Usage: in the manufacture of pipes by cold or hot rolling. The essence of the invention lies in the fact that the pipe is deformed by driven groove rolls on a fixed conical mandrel with an inclination angle of the generatrix greater than the friction angle between the metal and the mandrel. In this case, the pipe is forcibly moved beyond the front end at a speed equal to the peripheral speed along the ridge of the brook during the entire process. 1 ill.

Description

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The invention relates to pipe production and can be used in the manufacture of pipes by cold or hot rolling.

The aim of the invention is to intensify the process.

The drawing shows a diagram of the implementation of the proposed method.

The proposed method is carried out as follows.

Before starting work, the conical op. equal to 1 with an inclination angle forming more than the friction angle between the metal and the mandrel, they are fixed on the rod 2 in such a way that the diameter of the conical mandrel 1 increases along the rolling line and the contact plane of the conical section with the cylindrical one coincides with the axial plane of the groove rolls 3. Then the pipe 4 prepared for rolling, put on the rod 2 and set in a round gauge formed by stream rolls 3. A pulling device (not shown in the drawing) grabs the pipe by its front end and forcibly pulls it through the stream rolls 3 at a speed equal to the peripheral speed along the ridge of the handle of the forcibly rotated rolls. When pulled, the pipe is deformed by the drive brook rollers on a fixed short conical mandrel with an inclination angle forming more than the friction angle between the metal and the mandrel.

An increase in one-time deformation is achieved due to the fact that with an increase in the taper of the mandrel in the focus, deformation, ceteris paribus, the length decreases

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of the wall compression zone and, accordingly, the gap in this section decreases in the round gauge connector, which causes an increase in the resistance to metal flowing into the gauge connector when it is full. Since the deformation is carried out on a mandrel with an angle of inclination forming more than the friction angle between the metal and the mandrel, the workpiece is forcibly moved beyond the front end, thereby creating a more uniform stress-strain state of the metal and the deformation zone, which is characterized by a lag zone, while along the contact surface the friction forces of different signs act, which reduces the tendency of the metal to flow into the caliber connector and to overflow the caliber with metal.

The proposed method was tested in the manufacture of cold-deformed pipes 40 x 2 mm. When rolling pipes, drive brook rolls with a diameter of 240 mm were used, forming a round gauge with a diameter of 40 mm and a fixed conical mandrel, which, at a friction coefficient between the metal and the mandrel of 0.07-0.08 (friction angle of 4 °), had a generatrix inclination angle of 10 °. The workpiece was forcibly pulled through stream rolls at a speed of 10 m / min. In this case, the brook rolls were forcibly rotated at a peripheral speed along the ridge of the stream equal to 10 m / min. The one-time deformation of the workpiece was 46%. It was not possible to deform the workpiece on a mandrel with an inclination angle of the generatrix of 3 °, which corresponds to the known method, due to process disruption due to overfilling and leakage of metal into the gaps through the gauge connector.

Thus, the proposed method in comparison with the known method provides an increase in one-time deformation in a round brook caliber. This became possible due to the creation of conditions under which the concentration of the wall compression zone and more is achieved in the deformation zone.

homogeneous stress-strain state of the metal when acting on the contact surface. strength training of different signs.

Formula s vi

A method for longitudinal rolling of pipes, including the deformation of a pipe by driven brook rolls on a fixed short conical mandrel, characterized in that. that, in order to intensify the process, the pipe is forcibly moved beyond the front end at a speed equal to the circumferential speed along the ridge of the brook during the whole process, and deformed on a reference with a generatrix inclination angle greater than the friction angle between the metal and the mandrel. .- :;