SU1357091A1 - Method of cold rolling of strips - Google Patents

Abstract

The invention relates to rolling production and can be used in the preparation of cold-rolled strips, tapes and tin. The purpose of the invention is to increase the flatness of the strips. In the process of cold rolling of stripes in rotating rollers according to the invention, when the rolling speed changes relatively steady, the misalignment of the circumferential speeds of the rolls is introduced, the value of which is in a certain way related to the rolling speed reduction value and metal drawing during rolling. The flatness of the strips is increased by redistributing the frictional forces in the deformation zone when the degree of mismatch of the circumferential speeds of the rolls varies depending on the magnitude of the change in the rolling speed. 1 tab. i (L cond -vl

Description

The invention relates to rolling production and can be used in the manufacture of cold rolled strips, tapes and tin.

The purpose of the invention is to increase the flatness of the strips.

In the process of cold rolling of the strip in the rotating rolls, when the rolling speed changes relative to the steady state, the mismatch of the peripheral speeds of the rolls according to

(0.12-0.19)

the magnitude of the mismatch of the peripheral speeds of the rolls, the peripheral speeds of the rolls,

having set the rolling speed, the current value of the rolling speed, stretching the strip. The indicated mismatch dependence is recommended for geometrical ratios of the deformation zone 1, 3-42.2NoHo / Csr 0.008-0.02, where 1c is the length of the deformation zone, H and H c is the thickness of the metal at the inlet and the average thickness of the metal at the entrance and exit hot spot; - The average diameter of the rolls.

V, Vu

Vr L When rolling in asymmetrical mode, an additional factor of self-stabilization of the process setting appears - the l region with oppositely directed contact friction forces. The perturbing factors acting on the deformation zone due to the effect of speed (change in the coefficient of friction, resistance to metal of the deformation, instability of its mechanical properties) leads to a change in the length of the zone. In particular, with increasing value

and rolling the metal. Then the front end of the strip is fixed on the coiler and the mill is accelerated to a steady speed of v 23 m / s. Simultaneously with the acceleration, a proportional reduction in the misalignment of the peripheral speeds of the rolls is carried out from 22% to zero.

so that at a steady speed of V 23 m / s, the rolling is carried out in a symmetrical mode with equal peripheral speeds of the rolls. Due to the mismatch of the circumferential speeds of the rolls during the acceleration of the mill, whose magnitude is directly proportional to the cancellation of the current value of the rolling speed and steady, it is ensured by equalizing the deformation conditions along the length of the strip independently

zanat disturbing effects prot - 50 rolling speed. Pozhgaetsya

Zone 1 increases, the flatness of sections of the strip decreases, and the effect of friction forces in flashed at a speed below the setting deformation is stitched, as a result of which the increase in shear is at the filling station and during acceleration. NIN force of rolling and shaft deflections. Before rolling the rear end of the forgings does not occur. In the case of a reduced gglose, the speed of rolling smoothly decreases the values of perturbing parameters from 23 m / s to a charging 0.5 m / s.

the opposite effect occurs: the simultaneous proportional zone reliability decreases with increasing speed mismatch

the impact of friction forces, avals from 0 to 22%, will melt. As a result this

the rolling force retains its value, i.e. does not decrease.

Thus, by changing the length of the 1c zone with the introduction of the asymmetry of the deformation according to the proposed relationship, the rolling force, roll deflection and strip flatness are self-stabilized.

Example. A hot rolled strip with a cross section of 3.8 x 1,800 mm of steel 08u, wound into a roll, is transported to an uncoiler of a single-stand reversing mill 1700, which has an individual drive of the work rolls and a maximum (steady) rolling speed V ,, 23 m / s. The roll is installed on the decoiler, bend

the front end of the strip, set the roll gap for rolling with a stretch of Oi 1,4. After that, the front end of the runway; ayut at the filling speed v 0.5 m / s in rolls. The redistribution of current loads of the main drive motors creates a misalignment of the peripheral speeds of the rolls, equal to 22%, determined by the formula a 0.16 - .1.4 0.220,

23

and rolling the metal. Then the front end of the strip is fixed on the coiler and the mill is accelerated to a steady speed of v 23 m / s. Simultaneously with the acceleration, a proportional reduction in the misalignment of the peripheral speeds of the rolls is carried out from 22% to zero.

so that at a steady speed of V 23 m / s, the rolling is carried out in a symmetrical mode with equal peripheral speeds of the rolls. Due to the mismatch of the circumferential speeds of the rolls during the acceleration of the mill, whose magnitude is directly proportional to the cancellation of the current value of the rolling speed and steady, it is ensured by equalizing the deformation conditions along the length of the strip independently

It improves the flatness of the sections of the strip that are rolled at a speed lower than the established one - at the filling station, during acceleration and deceleration.

Note. The flatness of the bands measured on

Plots rolled at speeds below steady-state.

Embodiments of the proposed method are given in the table, where the flatness of the rolled strips is also given.

51

From the table it follows that when implementing the proposed method within the specified range (options 2-4, 6-17), there is an increase in the flatness of the strips in areas that are rolled at rolling speeds below steady-state. Flatness increase is achieved for the entire speed range of the rolling mill (refueling, during acceleration to working

Woo y, V

and braking):

 0.10-0.98

(versions 3.6-10), as well as for all possible extracts used during cold rolling of the strips: D 1.04 - 1.65 (options 3.11-17). In the case of exorbitant values of the coefficient of proportionality (options 1 and 5), in the sections of the strip rolled at lower speeds, the flatness of the strips deteriorates sharply.

Technical and economic advantages of the proposed method consist in the fact that the implementation of the misalignment of the peripheral speeds of the rolls at rolling speeds below steady-state, the value of which is established by the specified ratio, provides compensation for the speed factor of rolling, changes in the coefficient of friction, resistance to metal deformation Composed B.Pavlenko Editor I.Gorna Tehred L. Serdyukova Proofreader A.Zimokosov

Order 5922/6 Edition 481 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5

Production and printing company, Uzhgorod, st. Project, 4

the thickness of the lubricating film in the bearings and the instability of the mechanical properties of the metal. As a result of this, the flatness of the strips is improved, the mill setting is stabilized.

Claims (1)

Invention Formula The method of cold rolling the strips, including the deformation of the metal by rotating rollers with the introduction of the mismatch of the peripheral speeds of the rolls, characterized in that, in order to increase the flatness of the strips, the mismatch of the peripheral velocities of the rolls is carried out depending on the variation of the rolling speed according to a, (0.12-0.19) V, –v, where a is the value of the mismatch between the peripheral speeds of the rolls; V ,, v - circumferential speed rolls; v - having established the rolling speed; VT - current value rolling speeds; X - stretching poysy.