RU2591887C2 - Roughing rolling mill - Google Patents

Abstract

FIELD: metal processing.

SUBSTANCE: invention relates to rolling of profiles with high degree of reduction and can be used for rough rolling of continuously cast billets. Proposed stand comprises foundation, in which driven rolls with four teeth are installed on shafts.

EFFECT: high degree of reduction and improved quality of finished products in combination with high degree of reduction of rolled billet is ensured by fact that teeth on rolls are made with involute profile with rounded tops and rounded cavities, shafts driven rolls on both sides of stand are conjugated by gears for synchronous rotation of rolls, wherein drives of rolls are mounted from both sides of bed of two pairs of electric motors, drive gears located on both sides secured on appropriate shaft of driven gears.

4 cl, 3 dwg

Description

The inventive object relates to the processing of metals by pressure, to rolling profiles with a high degree of compression and can be used for rough rolling of continuously cast billets.

The closest in combination of features to the claimed object is a draft rolling stand selected as a prototype, containing a bed in which drive rolls with four teeth are installed on the shafts (description of the invention “Roughing block of rolling stands” to copyright certificate No. 1830766, MKI B21B 1/12 , B21B 31/08, published on 02/20/1996).

The claimed object and the prototype match the following essential features. Both devices contain a frame in which drive shafts with four teeth are mounted on the shafts.

Analysis of the technical properties of the prototype, due to its features, shows that the following reasons hinder the receipt of the expected technical result when using the prototype. During the rotation of the rolls with teeth of a known shape, the metal between the teeth is deformed unevenly, the upper and lower rolls experience different rolling moments and magnitudes and, accordingly, different rolling forces of the shafts. For a complete revolution of the rolls, the ratio of moments and the amount of twisting of the work rolls relative to each other changes four times. When wavy rolls are installed in a traditional rolling stand with spindles, a gear stand and an electric motor, the spindles experience significant torques, which does not significantly increase the degree of compression of the workpiece in one pass. Twisting the spindles relative to each other leads to the rotation of one work roll relative to another roll and, thereby, the gap in the roll center changes and, as a result, the thickness of the strip emerging from the roll center changes. Given the existing shape of the teeth on the drive rolls and the occurrence of large torsional forces on non-synchronized shafts, it is impossible to transmit large torques to ensure high compression rates of the workpiece, while the quality of the rolled workpiece deteriorates due to the lack of a constant gap between the roll elements during the rolling of the workpiece.

The claimed object is based on the task of creating such a rough rolling stand in which an improvement by introducing new elements would make it possible to increase the degree of compression of the workpiece and improve the quality of the finished product with a high degree of compression of the rolled workpiece when using the proposed object.

The essence of the proposed facility is as follows. The rough rolling mill contains a bed in which drive rolls with four teeth are mounted on the shafts. A distinctive feature of the claimed object is the following. The teeth on the drive rolls are made with an involute profile with rounded peaks and rounded hollows. Shafts of drive rolls on both sides of the frame are interconnected by gears for synchronous rotation of the rolls. In this case, the roll drives are made in the form of two pairs of electric motors located on both sides of the bed, the drive gears of which are located on both sides of the driven gears mounted on the corresponding shaft.

In the particular case of execution of the inventive stand is characterized in that:

- at least one roll is made with teeth of different heights to ensure different degrees of deformation along the length of the rolled workpiece;

- at least on one roll the teeth are made with different heights, differing by 5-50%.

- at least one roll is made with teeth, the height of which is successively reduced by 5-30%.

The boundary values of the change in the height of the teeth on the drive rolls are determined experimentally.

The clearance between the work rolls within 10% of the rolled workpiece thickness can be adjusted using the push screws to move the top roll. If necessary, roll strips of various thicknesses, change the synchronizing gears on the shafts or install rolls with a different rolling diameter and a different tooth size.

When using the inventive rough rolling mill, it is expected to achieve a technical result, which consists in providing an increase in the degree of compression of the workpiece and improving the quality of the finished product with a high degree of compression of the rolled workpiece.

In addition, it is possible to achieve an additional technical effect consisting in expanding the technological capabilities of the rough rolling mill by creating deformation rolls as during forging or as when testing metals for plasticity.

Between the totality of the essential features of the claimed object and the achieved technical result, there is the following causal relationship. The implementation of the teeth on the drive rolls with an involute profile, with rounded tops and rounded hollows, pairing the shafts of the drive rolls on both sides of the frame with gears for synchronous rotation of the rolls, the drive rolls in the form of two pairs of electric motors located on both sides of the frame, the drive gears of which are located on both sides of the driven gears fixed to the corresponding shaft, provides optimal consistent uniform deformation of the metal over the entire surface the operating teeth of the drive rolls during involute engagement through the rolled metal and during the simultaneous rotation of the rolls during the transmission of large torque to each roll individually to ensure high compression of the workpiece and to ensure the constancy of the gap between the roll elements during smooth bending of the workpiece during its rolling and, consequently high quality laminated workpiece. The installation of two pairs of identical gears on the rolls from the outer sides of the stand does not allow the rolls to twist relative to each other. This ensures a constant gap between the teeth of the work rolls during rotation and deformation of the metal and, accordingly, ensures a constant thickness of the strip. The installation of electric motors in pairs on each side of the bed to each roll allows you to divide the total rolling torque into four moments and, thereby, achieve a compact stand. The torque from the electric motors is transmitted directly to the work rolls, bypassing the spindles and gear stands. With this arrangement of the inventive stand, the area is reduced by at least two times. In the inventive stand, each work roll is rotated from two sides, which ensures uniform transmission of torque to the deformable metal. These torques act on both sides of the working part of the roll. A dangerous section is the transitional part from the working part of the roll to the axis of the roll. In the inventive stand, the torque now acts on both sides of the working part of the roll, and two transitional sections are already dangerous sections, and the moment twisting the working part of the roll affects each section with a value twice as small as the total moment acting on the roll . In a dangerous section, half the time acts. The critical cross section on the roll will be less, which also makes it possible to produce a smaller work roll and thereby reduce the dimensions of the stand itself.

The implementation in the particular case of at least one roll with teeth of different heights allows you to expand the technological capabilities of the rolling stand by providing a different degree of deformation along the length of the rolled workpiece.

Performing in a particular case in the inventive stand on at least one tooth roll with different heights differing by 5-50%, allows to provide a different variable degree of deformation along the length of the rolled workpiece and use the forging effect during repeated rolling to improve the quality of the rolled workpiece and during testing samples for ductility.

In addition, the implementation of at least one roll with teeth, the height of which is successively reduced by 5-30%, allows you to create different degrees of deformation along the length of the workpiece, as when testing metals for ductility.

When smelting precision alloys, technological instructions provide for taking metal samples for ductility. Before release, the metal is poured into the probe, then the casting is removed from the probe and forged onto a square or plate. If the probe is forged with cracks, the required additives are added to the melting and only after that the metal is poured into the molds. If the metal is forged without cracks, then the melting is immediately poured into the molds. Forging a probe requires a forging hammer. But at the mini-factories this hammer is not. Therefore, the forging function for the rough rolling stand is appropriate.

The essence of the inventive rough rolling mill is illustrated by illustrative materials, which schematically depict:

- in FIG. 1 is a front view of the crate;

- in FIG. 2 - view of the crate from above;

- in FIG. 3 is a diagram of the start of rolling of a workpiece.

The following notation is used on the illustrated materials.

1 - bed;

2 - shaft;

3 - shaft;

4 - roll;

5 - roll;

6 - gear;

7 - gear;

8 - gear;

9 - gear;

10 - electric motor;

11 - an electric motor;

12 - electric motor;

13 - electric motor;

14 - a leading gear wheel;

15 - a leading gear wheel;

16 - driven gear;

17 - a leading gear wheel;

18 - a leading gear wheel;

19 - driven gear;

20 - tooth on the roll 4;

21 - tooth on the roll 4;

22 - tooth on the roll 4;

23 - tooth on the roll 4;

24 - tooth on the roll 5;

25 - tooth on the roll 5;

26 - tooth on the roll 5;

27 - tooth on the roll 5;

28 - workpiece;

29 - peal.

In a specific exemplary embodiment, the rolling mill stand comprises a frame 1, in which drive rolls 4 and 5 with four teeth are mounted on shafts 2 and 3. The teeth on the rolls 4 and 5 are made with an involute profile with rounded peaks and rounded hollows. Shafts 2 and 3 on both sides of the bed are interconnected by two pairs of gears 6 and 7, 8 and 9 for synchronous rotation of the rolls 4 and 5. In this case, the drives of the rolls 4 and 5 are made in the form of two pairs of electric motors 10 and 11 located on both sides of the bed , 12 and 13. The driving gears 14 and 15 of the electric motors 10 and 11 are located on both sides of the driven gear 16 fixed to the shaft 2, and the driving gears 17 and 18 of the electric motors 12 and 13 are located on both sides of the driven gear 19 of the shaft 3. work rolls 4 and 5 with teeth must be considered, h then the line of involute engagement of the teeth 20-27 is the middle of the rolled workpiece located between the teeth.

In a specific example, the rough rolling mill operates as follows. Electric motors 10-13 through the drive gears 14 and 15, 17 and 18 and the driven gears 16 and 19 of the rolls 4 and 5 are rotated to the position where the tooth 21 of the upper roll 4 occupies a horizontal position (Fig. 3). In this case, the tooth 25 of the lower roll 5, synchronized with the upper roll 4 of gears 6-9, occupies a position at 45 ° to the horizontal axis. Such a solution of rolls is most optimal for gripping the workpiece. In this solution of the rolls, a workpiece 28 is installed, heated to 1000-1200 ° C, and after turning on the electric motors 10-13, the process of intensive deformation of the workpiece 28 between the teeth 20-27 in the rolls 4 and 5 into the roll 29 is implemented. In this case, the rolled metal is consistently uniformly deforms along the entire involute surface of the interacting teeth of 20-27 drive rolls 4 and 5 with involute engagement through the rolled metal and with simultaneous rotation of the rolls 4 and 5 in the process of transmitting large torque to each roll individually, for ensuring high degrees of compression of the workpiece. In the process of rolling the workpiece, the relative position of the rolls 4 and 5 does not change and the gap between the teeth of the rolls remains constant, which leads to high quality rolling. The degree of compression of the workpiece is 50-90% per pass.

If, for example, the upper roll 4 is made with teeth of different heights, for example, the height of tooth 21 is less than the height of the remaining teeth 20, 22 and 23, then when rolling a workpiece in rolls 4 and 5, a different degree of deformation along the length of the rolled workpiece will be provided. This will produce a periodic profile with periodically changing thickness.

If, for example, in the upper roll 4 adjacent teeth are made with different heights, for example, the height of the teeth 21 and 23 is 50% less than the height of the teeth 20 and 22, then when rolling the workpiece in the rolls 4 and 5, a variable degree of deformation along the length of the rolled blanks, which allows you to use the forging effect during repeated rolling to increase the mechanical properties of the roll.

If, for example, the upper roll 4 is made with teeth whose height decreases successively, for example, the height of tooth 21 is 30% less than the height of tooth 20, the height of tooth 22 is 30% less than the height of tooth 21 and the height of tooth 23 is 30% less than the height of tooth 22 , then when rolling the workpiece in rolls 4 and 5, various degrees of deformation along the length of the workpiece will be provided, as when testing metals for ductility.

Claims (4)

1. A rough rolling stand comprising a bed in which drive rolls with four teeth are installed on the shafts and roll drives, characterized in that the teeth on the rolls are made with an involute profile with rounded peaks and rounded hollows, and drive roll shafts on both sides of the bed are interconnected by gears with the possibility of synchronous rotation of the rolls, while the roll drives are made in the form of two pairs of electric motors located on both sides of the bed, the drive gears of which are located on both sides akreplennyh on the respective shaft driven pinion. 2. A cage according to claim 1, characterized in that at least one roll is made with teeth of different heights to provide different degrees of deformation along the length of the rolled workpiece. 3. The stand according to claim 1, characterized in that at least on one roll the adjacent teeth have a height differing by 5-50%. 4. The stand according to claim 1, characterized in that at least one roll is made with teeth, the height of which is successively reduced by 5-30%.

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