SU1636076A1 - Method of rolling strips in six-roll stand with v-shaped arrangement of rolls - Google Patents

Abstract

The invention relates to rolling production, mainly to the production of cold-rolled sheet products with high precision geometric dimensions. The goal is to improve the accuracy of the geometric dimensions of the strips by setting the optimum rigidity of the stand. During the rolling process, the position of the support rollers of the rolls is shifted, shifting them relative to the plane passing through the axes of the work rolls by an amount determined by the established range. 3 ill., 1 tab.

Description

The invention relates to rolling production, mainly to the production of cold-rolled sheet products with high precision geometric dimensions.

The aim of the invention is to improve the accuracy of the geometric dimensions of the strips by creating an optimal rigidity of the stand along the aisles.

FIG. Figure 1 shows the rigidity adjustment control of the roller assembly by changing the mutual position of the work roll and the support rollers, as well as the limiting values of the angle p corresponding to the minimum (position 1, p) and maximum rigidity of the roller stand of the stand (position 2. y); Fig. 2 is a diagram of the variation of the force polygon when adjusting the angle p by displacing the axes of the support rollers in the horizontal plane, as well as changing the value of the roll gap in this case; FIG. 3 is a diagram of the change in the inter-roll forces of the PM.V. when the angle p varies from the minimum value (/ EMIN to the maximum with equal rolling forces P.

The method is implemented as follows.

In the case of displacement of the centers of the axes of the support rollers along a circle trajectory centered on the axis of the work roll and a radius (Fig.) Equal to the sum of the radii of the work roll and the support roller, the strip thickness does not change (without taking into account the change in the elastic deformations of the roll assembly). When the axles of the support rollers are displaced along a path corresponding to a smoother curve, or generally along a straight line in the horizontal plane (Figures 2 and 3), the gap between the work rolls increases. Moreover, with an increase in the difference in the curvature of the trajectory of movement of the centers of the axes of the support rollers and the specified circumference, with the same values of the horizontal component of their displacement, the increment of the strip thickness increases.

fe

ON CJ About About | ABOUT

The simplest from the point of view of the simplicity of the equipment for moving the axes of the support rollers, as well as from the point of view of the possibility of fine adjustment of the strip thickness (a slight change in the angle p near a predetermined value corresponding to the required stiffness of the roller assembly) 2).

Moreover, in this case, with relatively large displacements of the axes of the support rollers, the increment of the strip thickness is insignificant, especially with the minimum values of the angle p, as can be seen from the dependence obtained from the geometric relationships of the HRVS IL SLM (Fig. 2)

D C (Don.p + Ored) (COS / 2 - COSp / 2), (1)

where D To - change the roll gap with a horizontal displacement of the axes of the support rollers (and changing the angle);

p is the starting angle before the adjustment;

p - angle after adjustment.

Purposeful regulation of the angle f with the same ratio Don.p / Dpae, mainly in the rolling process, leads to a redistribution of the inter-roll forces and, respectively.

mutual elastic deformations of the work rolls and support rollers with equal rolling forces, as well as a change in the force of the thrust Rasp (Fig. 2) of the stand of the stand and, consequently, a change in the stiffness of the roll assembly to a bend in a wide range (due to barrel lengths of the work roll).

PRI me R. For a mill 1680 with a work roll diameter of 500 mm, an axis of the support rollers of 400 mm and a diameter of support rollers of 100 mm with a minimum allowable clearance of 1 mm and a maximum reduction of 0.8 mm, the angle p from pass to pass is changed in the range (p 55.723 .... 120 degrees directly proportional to the absolute reduction in each pass from the position corresponding to the maximum stiffness, i.e. p-55.723 degrees in the first pass to the minimum ((p 120 degrees) in the last.

A strip of 1.0x1550 mm was rolled out from a 2.5 151550 mm strip. Based on the compression regimes during the production of this band (table), the distribution of the value of the angle p from the gap to the gap is determined. Also, the magnitude of the necessary approximation of the axes of the upper and lower support rollers DK along

the dependences (1) with respect to the base position at which the angle p has the minimum value paz - UMIN. The results are tabulated.

At the first pass, the maximum stiffness of the roller unit is established, which corresponds to the minimum value of the angle p, i.e. p 55.723 degrees Since this position is basic, the value of the DC is 0 mm. On subsequent strip passes, the angle p is changed in each pass directly proportional to the absolute compression from the thickness range from the initial 1.9 mm (after the first pass) to the thickness after the last pass of 1.06 mm, at which the maximum angle p 120 ° is set,

Thus, the increment of the angle p. proportional to absolute compression, equal to 0.22 mm, in the second pass is determined as follows:

Lo (120 ° -55.723) 0.22 s., A ° 2 (1.90-1.06) 16 807 ФаА

0

five

0 5

0

Therefore, the total angle of the second pass is determined by

p / Ebzz + D | p2 55 ,,, 53 degrees.

In the third and subsequent gaps, the value of the angle p is determined in a similar way, substituting each time the value of the total absolute reduction relative to the base value (relative to the thickness of the strip after the first pass). The results are tabulated.

When using the stand in the training mode set the minimum rigidity of the stand, i.e. angle (p at the same time is equal to 120 degrees, and the corresponding additional mutual approach of the pressure devices D K 576.12 mm.

Such a distribution of angles p over the passes of the strip allows in the first pass, when the rigidity of the stand is the highest and the metal is thicker, to form a stable, predetermined transverse profile of the strip with a high degree of its reduction. And the reduced stiffness of the roll angle in the last passes allows an increase in the leveling capacity of the stand, both with respect to the transverse thickness variation of the strips, and with respect to the longitudinal thickness variation. As a result, the accuracy and flatness of the rolled strips increases due to the enhanced functionality of the stand as the position of the support rollers changes in a wide range.

Claims (1)

Claims method of rolling strips in a six-roll stand with a V-shaped arrangement of rolls, including deformation in work rolls and a symmetrical change in the position of the support rolls relative to the plane passing through the axes of the work rolls, changing the angle between the straight lines connecting the center of the work roll with each of the axes of the supporting rollers in contact with it, characterized in that, in order to increase the accuracy of the geometrical dimensions of the strips by creating an optimal rigidity of the stand along the aisles, changing the position PORN rollers are in the process of rolling with the change of angle of crossing to pass a range defined by the expression of "" "Tt tt I Uon.p + Up86)  2- (90-arcsin 120 Opt.r 4- A Pmaks Rrab Don p + Orab hail, where Don p is the diameter of the support roller; DOCH axis diameter of the support roller; Orab - the diameter of the work roll; And - the minimum allowable gap between the support roller and the axis of the adjacent support roller, Apmax maximum permissible absolute compression of the strip in the cage. Don p Phi2 1. yw Phi 3