SU1061861A1 - Method of strip rolling - Google Patents

Abstract

A BAND ROLLING METHOD consisting in multiple deformation between a pair of rolls with a constant mismatch of their peripheral speeds, characterized in that, in order to improve the quality of the strips and the durability of the rolls by leveling their wear, the speed mismatch is changed by (Inverse, t It is possible to rotate the roller rotating at a greater peripheral speed with a smaller one, and vice versa, while maintaining the scientific research institute of the original value of the error. 05 00 o:

Description

The invention relates to rolling production and can be used in hot roll and cold rolling of sheets, tapes and strips.

A known method of cold rolling strip with tension in rolls having different circumferential speeds, the roll diameter ratio being 1.04-1.1 and the specific tension of the rear end of the strip is 22, 5 times the specific tension of the front end of the ClJ strip.

The disadvantage of this method lies in the uneven wear of the rolls, as a result of which the quality of the rolled strips deteriorates.

There is also known a method of rolling metal, by which the workpiece is defaced by a pair of rolls having different peripheral speeds, and the circumferential speed of one of the rolls is 2-15% less than the circumferential speed of the other 2.

With this method of rolling, the roller, which has a large peripheral speed, wears out more intensively. This degrades the quality of the rolled metal and reduces the productivity of the mill due to downtime associated with the transshipment of worn rolls.

The closest in technical essence and the achieved effect to the invention is a method of rolling strips, consisting in their multiple deformation between a pair of rolls with a constant mismatch of their peripheral speeds NW 3. The magnitude of the mismatch is established according to dependence; V, where V and V2 are the peripheral speeds of the rolls;

/ U. - strip stretching ratio.

The disadvantage of this method is that the drive roller during rolling wears out more intensively than the driven one. This reduces the quality of the rolled strips and the durability of the rolls.

The aim of the invention is to improve the quality of the bands and the durability of the rolls by leveling their wear.

This goal is achieved by the fact that, according to the method of rolling the stripes, which result in multiple deformations between a pair of rolls with a constant mismatch of their peripheral speeds, the speed mismatch is reversed in each subsequent pass, i.e. A roller rotating at a greater peripheral speed is rotated with a smaller one, and vice versa, while maintaining the original magnitude of the error.

FIG. 1 shows a diagram of the deformation zone at rolling in rolls with different peripheral speeds.

in fig. 2 - plots of the length of the slip path versus the angle measured from the plane of the axes of the rolls to the angle of capture i (Compression 32%, mismatch of the speeds of the rolls

5 10%).

Roll 1 and roll 2 have different peripheral speeds. When rolling the next billet 3, roll 1 is the leading one, i.e. he is surrounded

The IV speed is greater than that of the driven roll 2. In this case, the neutral angle J on the drive roll 1 is less than the neutral angle jj of the driven roll 2. The lag zone of the CM on the side of the driving roll 1 is larger than the lag zone of the PR of the driven roll 2. Wear and roll surfaces rolls, when rolling is determined by the work of friction

0 A gt where S is the path of

P „g averaged strength of friction.

On the master roll 1, the length of the slip path in the lag zone is characterized by the branch AB of curve 4, and on the driven roll 2 by the branch ABj of the curve 5. The slip path at the end of the lag zone on the drive roll 1 defined by the ordinate point B,. ,, 0 is longer than on the driven roll 2 (the ordinate of the point B2). This is due to the fact that in the lagging zone the metal flows towards the movement of the roll. The lag zone KM 5 on the drive roll 1 is longer than on the driven roll 2 (OP zone), and the speed of the drive roll 1 is greater than the speed of the driven roll 2.

In the advanced zones (MN and PQ) the metal flows; in the direction of movement of the rolls 1 and 2. The length of the sliding path is characterized by the branches for roll 1 and roll 2.

Although in the advanced zones of the branch and B2C2, curves 4 and 5 decrease due to the fact that the metal flows in the opposite direction, the actual sliding path increases. The total length of the glide path is summed from the absolute values of the 0 glide paths along the lagging and advanced zones, and on the leading roll 1 is 5 and on the driven roll 2 is equal to S ;.

Since S ;, S, the work of the third, on the leading felling 1, is more than the work of firing A to the driven felling 2

(ATP-I CR

To even out the wear of the lugs 1 and 2, after rolling the previous workpiece, the roller 1 at a higher circumferential speed 5 slows down to the peripheral speed of the shelf 2. At the same time, the roller 2 at a lower peripheral speed accelerates the shaft 5 to a peripheral speed

When roller 2 becomes the lead and driven 1, while maintaining the initial level of speed mismatch, the next billet is rolled. In this passage, roll 2, which has become the lead, is more wear. Therefore, the total wear of the rolls 1 and 2 is equalized. The operation of changing the speeds of the rolls is carried out in each subsequent pass. j

The method is carried out as follows.

With a cross section of 200x1400 mm and a weight of 30 tons of steel, FDV is sent in a continuous furnace to 1200 ° C. rolling, which includes a rough group, including a vertical vertical breaker, a duo stand, a universal quarto stand, and three quarto stands combined into a continuous group, a descaler, and a clean continuous group consisting of 7 quarto stands. In the roughing stand group, the slab is crimped to an intermediate thickness of 40 mm. After rolling in the roughing group, the tackle has a temperature of 1050 ° C. In order to obtain higher strength characteristics on the intermediate roller table in front of the finishing group, the rolling is boosted up to. Rolling the hammered metal in the finishing group to a finite thickness of 7 mm leads to an overload of the stands by the rolling force. To reduce the rolling force in the finishing group, misalignment of the peripheral speeds of the rolls, which are created by redistributing the loads of the main drive motors, is carried out. In this case, for example, the upper rollers of the finishing group are leading and have circumferential speeds 12% more than the working

with them in pairs lower vgshki. The mismatch of the circumferential speeds of the rolls causes a zone with oppositely directed friction forces to appear in the deformation zone, due to which rolling forces are reduced by an average of 15%.

Since the contact slip of the metal on the upper rolls is larger than on the lower rolls, the upper rolls in this passage wear out more intensively.

After the end of rolling of the next strip, the relative speeds of the rolls are redistributed; The spinning, rotating at a greater peripheral speed (in our case, the upper one) is rotated with a smaller one, and vice versa. .

The table shows the modes of operation of the 7th (last) stand purely: the howling group and the stability of the rolls.

19.64 12 15100 1300

22.0

19.64 12

22.0 19.64 12

22.0 19.64 12 15100 2000

22.0

22.0 12

19.64

19.64 12

22.0

19.64 1215100 2000

22.0

24.64 1215200

22.0

19.64 1215100

22.0

Known mode

etc.

Proposed Mode 1

etc.

The proposed mode 2, etc.

Table continuation

Claims (1)

METHOD OF LINE ROLLING, consisting in multiple deformation between a pair of rolls with constant mismatch of their peripheral speeds, characterized in that, in order to improve the quality of the strips and the durability of the rolls by equalizing their wear, in each subsequent pass, the speed mismatch is reversed , i.e. a roll rotating with a higher peripheral speed is rotated with a lower, and vice versa, while maintaining ^: the initial value of the mismatch. · Figure 1 g