RU1787060C - Method of rolling rings - Google Patents

Abstract

Usage: when rolling rings on ring rolling mills. SUMMARY OF THE INVENTION: In the process of rolling a ring, dressing forces are applied to its outer surface. The indicated forces are applied along planes that are deployed relative to the major axis of the ellipse obtained during the rolling process, at an angle of not more than 45 °. The forces acting along each of the planes are applied with the same sign. At each rotation of the ring by a fourth part of the revolution, the sign of the forces acting along the corresponding plane is reversed. 2 ill.

Description

ate

WITH

The invention relates to the processing of metals by pressure and can be used in rolling rings on ring rolling mills.,

A known method of rolling rings between the outer and inner rolls with the application of forces from the centering rollers to the contour of the outer surface of the ring asymmetrically relative to the longitudinal axis of the mill.

There is also a known method of rolling rings between the outer and inner rolls, which includes applying forces to the contour of the outer surface of the ring on an arc of less than 160 ° near the radial deformation zone, in which at the stage of rolling the ring, the force is adjusted according to a given law, and at the polishing stage, dressing is applied by fixation

centering rollers in positions corresponding to the finished ring of the correct shape. The dressing period lasts 2-3 turns of the ring.

The closest technical solution to the invention is a method of rolling rings with simultaneous application of dressing forces on the outer surface of the ring through each quarter of its revolution in pairs along planes passing through the rolling axis.

A disadvantage of the known methods is that during the period of the most intensive growth of the diameter of the rings, especially thin-walled, the formation of a significant ellipse of the rings is observed, which leads to a destabilization of the rolling process and, as a consequence, to the need to reduce the intensity of deformation, reduce the point XI

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the geometric dimensions of the rings and, in some cases, the need to stop the rolling process, Known methods at a given stage do not actively correct the ellipse, 5 Due to the fact that simultaneous application of effort is not ensured. to the contrary 7 | m / local sections of the rings located in its large zone when these sections pass through the 10th application zone from the centering rollers, a displacement of the ring relative to the longitudinal axis of the mill and an additional distortion of the shape are observed rings. The continuous application of forces from the centering rollers 15 around the entire perimeter of the outer surface of the ring (including in areas located in the smaller zone; its axis) also contributes to an increase in el. lipse of the ring. .:. 20 An object of the invention is to increase the productivity of the process and the quality of the resulting rings. .:

The task which is necessary in this case: to solve, is to create 25 conditions for the active dressing of the ring during the period of intensive growth of its diameter. V ..

In order to achieve the Goal set in the method of rolling rings with the simultaneous application of dressing forces on the outer 30 surface of the ring through each quarter: its rotation, pairwise along the planes passing through the rolling axis, dressing forces are applied along planes that are deployed relative to the major axis of the ellipse, 35 obtained during the rolling process at an angle of not more than 45 °, while the forces acting along each of the planes are applied with the same sign, and with each turn of the ring to the fourth part of the revolution, the sign is 40 forces, acting along the corresponding plane, they are reversed, A:; :::.; .... .. - :. ..

In FIG. 1 shows the rolling process, rings with simultaneous editing of its ellipse; sleep FIG. 2 is a diagram of the application of dressing forces of a ring for one of its rotation during rolling (the diagram corresponds to the arrangement of centering and pressure rollers shown in FIG. 1) .50

In FIG. 1 and 2 the following notation is accepted:

1 - vertical drive roll; 2 - inner roll; 3 - rolled ellipsoidal ring; 4 - centering 55 rollers; 5-pressure rollers; b-measuring roller; 7 - local sections of the ring in the zone of the major axis of the ellipse; P is the dressing force applied to the local sections 7; dcp. average current diameter of the ring.

The dashed line shows the contour of the ring of regular shape with a diameter of dcp .. The signs (+) and (-) show the positive and negative directions of the action of the dressing forces from the centering and pressure rollers of the ring ellipse in the local sections a and b in the area of the major axis of the ellipse,

The essence of the proposed method is as follows. . A pre-prepared hollow billet is put on the inner roll of the ring rolling mill and compression of the billet is started in the radial deformation zone between the outer and inner rolls. During the rolling of the ring, dressing forces are applied to its outer surface. The indicated forces are applied on the outer surface of the ring every quarter of its revolution in pairs along planes passing through the rolling axis and deployed with respect to the major axis of the ellipse obtained during the rolling, at an angle of not more than 45 °. The forces acting along each of the planes are applied with the same sign, and at each turn of the ring by a quarter of the revolution, the sign of the forces acting along the corresponding plane changes to the opposite. This is achieved, for example, by the fact that several pairs of rollers are arranged to the ring, which are mutually asymmetric with respect to the longitudinal axis of the mill and provide contact with the outer surface of the ring in areas opposite to the larger axis of the ring. These rollers are set in positions corresponding to the average diameter of the ring at the moment and as the diameter increases, they are divorced in proportion to the increase in diameter. .

When the rollers are arranged according to the circuit shown in FIG. 1 with their fixation in positions corresponding to the average diameter of the ring at a given time, the rolling process is as follows. : .-. .

The ring of the correct shape during rotation during the rolling period touches all the rollers at the same time. These rollers maintain the ring on the axis of the mill, and no dressing forces are applied.

When the ring is rotated in the correct (for example, elliptical) shape between the indicated pairs of rollers, when they are in positions corresponding to the average diameter of the ring at the moment, to local sections of the ring located in the zone of its larger axis and having, respectively, a size the actual diameter in excess of the estimated diameter of the ring, apply dressing efforts. The indicated forces are applied simultaneously on both local sections located in the zone of its larger axis, asymmetrically relative to the longitudinal axis of the mill, by the corresponding pairs of rollers. When the irregularly shaped ring rotates, the sign of the direction of application of the dressing force relative to the longitudinal axis of the mill changes every fourth part of its rotation, since the ring is swinging by sections located in the zone of its larger axis already with another pair of rollers and so on. Taking into account that the rollers are fixed in positions corresponding to the average diameter of the ring at a given moment in time, when passing between them local sections of the ring located in the zone of its larger axis, the dressing process takes place. ...-,; .

By correcting the irregular shape of the ring, it touches all four rollers simultaneously. In this case, the dressing process is no longer carried out, the rollers provide support of the ring on the axis of the mill.

The straightening operation at the stage of rolling the ring eliminates the distortion of the shape of the ring immediately after its appearance and eliminates the development of the process of distortion of the shape as the ring is rolled without reducing the intensity of its deformation, which ensures an increase in the productivity of the process.

The requirement that the dressing effort be applied only to local sections of the outer. Surface of the ring along planes unfolded relative to the major axis of the ellipse below the. Angle of not more than 45 ° provides for the exclusion of the application of force to sections of the ring located in the zone of the smaller axis and having an actual diameter of a smaller average diameter of the ring at the moment, contributes to the process of active dressing of the ring and provides improved quality rings.

The application of forces acting along each of the planes with the same sign provides active dressing of the ring without shifting it relative to the longitudinal axis of the mill, which helps to increase the productivity of the rolling process and the quality of the rings,

. Changing every fourth part of the rotation of the sign ring of the direction of the application of the dressing forces acting along the corresponding plane from the opposite allows increasing the length of the active dressing period in

the flow of one revolution of the ring and also helps to increase the productivity of the rolling process and the quality of the rings.

. As can be seen from the essence of the proposed solution 5, the signs of the application of dressing forces along planes unfolded relative to the major axis of the ellipse obtained during rolling / at an angle of not more than 45 °, the application of forces acting along each of the planes with the same sign as well as a change in the sign of the forces opposite for each rotation of the ring by a fourth part of the revolution, distinguish the claimed solution from the proto-5 type and determine whether this solution meets the novelty criterion.

The proposed method provides an increase in productivity and quality of the rings. These new properties distinguish the known solution from the known ones and determine its compliance with the criterion, a significant difference. .

The proposed method has been tested under production conditions. 5 Example. When applying the proposed method in the manufacture of ring. products with a diameter of 700-3000 mm at the ring rolling mill of the Nizhnedneprovsky pipe rolling plant named after K. Liebknecht 0 used two centering rollers (4),

located on the side of the outer roll (1) and two rollers (5) mounted on the carriage of the end rolls (8) on the side, pro. opposite to the center of radial deformation 5. The position of these rollers during the rolling and polishing of the ring corresponded to the average diameter of the ring at a given time. During testing of the proposed method, 0 624 rings were rolled. The achieved increase in productivity was 8% in the absence of marriage of rings by ellipse.

At the same time, it is known that in the manufacture of rings according to method 2, it is accepted. 5 basic object of comparison, the rejection of rings by ellipse is 0.7%:

The economic effect due to the reduction of the reduced costs during the production of the end-product was: 03 (3i-32) xA (65.1 -64.3) x

x 62000 49.6 thousand rubles. Where. 3i and For the reduced costs per unit of output, respectively, before and after implementation, rub;

5 . And - the annual volume of production of rings, t. Formula of the invention The method of rolling rings with the application of dressing forces on the outer surface of the ring through each

a quarter of its revolution in pairs along planes passing through the rolling axis, characterized in that that, in order to increase the productivity and quality of the obtained rings due to; by eliminating the ellipse in the cross section of the finished ring, dressing forces are applied along planes that are relatively

the major axis of the ellipse obtained during the rolling process at an angle of not more than 45 °, while the forces acting along each of the planes are applied with the same sign, and with each rotation of the ring a quarter of the revolution, the sign of the forces acting along the corresponding plane change to the opposite.