SU1452631A1 - Method of continuous rolling of sheets - Google Patents

Abstract

The invention relates to rolling production, namely to rolling on a continuous mill, and can be used in the finishing group of a continuous broadband mill. The purpose of the invention is to increase the geometric accuracy of the sheet. The method consists in that the working and supporting rolls of the stands of the finishing group of the mill, with the exception of the first stand, are rolled in the transverse direction relative to the axis of the rolling during rolling. Moreover, the rolls of adjacent stands during rolling combine reciprocating movement, shifting to opposite sides. The time of work in one position is determined depending on the operating modes and characteristics of the rolls by dependencies. The method improves the accuracy of the finished strips, extends the life of the roll system and increases the mill productivity by reducing downtime for additional handling. 1 tab. (L

Description

ate to

OS

oo

 one

The invention relates to rolling production, namely to rolling on a continuous mill, and can be used in the finishing group of a continuous broadband mill.

The purpose of the invention is to increase the geometric accuracy of the sheet.

The method consists in that the rolls of the stands of the finishing continuous group of the mill, with the exception of the first stand, are periodically moved in the transverse direction relative to the axis of the rolling during rolling. Moreover, the rolls of adjacent stands during rolling perform a reciprocating motion, shifting to opposite sides. Working time in one position is determined by the dependence

.five.

fUP

е о - allowable working time

rolls in one position, with;

allowable value of the worn-out volume of the working shaft, 3.

UV - R -

ak, m

working speed

rolls, m / s;

width of rolled sheet, m;

radius of work rolls, m;

working strength

rolls, kgf / mm; - coefficient of friction; P - specific pressure, kgf / mm; c is a constant constant for

of all mills, equal to 2.210, the magnitude of the rolls displacement in the direction of obtaining symmetric wear, which is cut-off to the rolling axis, is determined by

.B;

45

2

de

S - roll shift in the transverse direction, m; the maximum permissible width of rolled sheets in the campaign of work rolls, m; the width of the rolled sheet, m,

bt When moving during the rolling of sheets of working and support rolls of the finishing mill continuous mill stands, the local wear is redistributed over a much wider portion of the roll barrel length.

five

0

five

0

five

which prevents the formation of local depressions on the surface of the work rolls, eliminates the causes of the defect of the cold rolled sheet bubble, thereby eliminating the need for additional transshipment or additional recovery treatment of the rolls of the second and third stands of the mill before rolling the rolled stock for cold rolling mills. Eliminating unproductive mill downtime for additional transshipment or refurbishing significantly increases the mill's productivity.

The magnitude of the rolls displacement is determined by the condition of ensuring symmetric wear, maximum use of the length of the roll barrel, and therefore is determined by the dependence

l b o - b,

th

At such an offset, wear is distributed along the length of the roll barrel, equal to the maximum allowable width of the rolled sheet in the roll work campaign.

In the chains of preventing local development of the BMiae rolls, the limiting value due to the requirements of dimensional and geometric accuracy of rolled sheets, the permissible operating time of the rolls in one position is determined taking into account the flow conditions and the parameters of the working rolls

0

five

five

AV

V. B-2 u-R

ABOUT

G-8

Jari maintains a non-program flow through the hot run constantly and fie3CHCTeMHO changes the width of the rolled strips. When the offset rolls

| B o - b; stands on the size and edge of the rolled strip correspond to the point of maximum use of the length of the roll barrel for any width of rolled strip. Changing the direction of the axial displacement of the rolls to the opposite after a certain rolling time eliminates the conditions for the formation of local wear of the surface of the rolls. Thus, the rolling of a batch of broader rolling strips of a batch of narrow strips does not lead to a violation of the accuracy of the finished sheet. That is, an increase in

3U

dimensional and geometrical accuracy of the finished sheet when conducting beeprogramm rolling.

The movement of the rolls of the stands of the finishing continuous group of the mill is carried out in all the cells of the group with the exception of the first stand. The stationary, for lateral movement of the rolls to the stand of the finishing group of the continuous mill, is determined by the conditions of the grip tackle and the stability of the rolled sheets on the feeding roller table. The invariance of the rolling axis of the strips is ensured by the opposite movement of the rolls of the cage stands, since the movement of the rolls of adjacent stands in one direction, even with a constant position of the core reinforcement, cannot ensure the stability of the strip relative to the axis of rolling.

The permissible time of work of the rolls in one position due to the prevention of local wear is recorded:

Where

LTP is the allowable friction path, m V is the linear speed of the rolls, m / s;

. UV

de iji - wear rate; And - the surface area of the third 21R

NIN, m; uV - the amount of worn material

on the way of training, m. For work rolls

BUT ,

de B - the width of the rolled strip, m; R is the radius of the work rolls, m

&

H fr

de 0g - ultimate strength of workers

rolls, kgf / mm; (U is the coefficient of friction; P is the specific pressure, kgf / mm

с - coefficient taking into account the circuit.

Based on the data, it was determined that for the longitudinal rolling scheme in continuous groups of stands, the coefficient of friction scheme is from 2.210.

The dependence dp for determining the permissible operating time of the rolls in one position is as follows:

thirty

50

55

Lv ..

fjp

five

Example. In a two-batch continuous group, two control batches of stripes are rolled under conditions of unprogrammed rolling with a thickness of 2 mm and a width varying from 1-20 to 200 mm from steel Art. 3 ps A lightly worn film is applied to the work rolls of the second stand.

When rolling the strips, the temperature-speed and deformation conditions of the rolling remain unchanged.

The first batch of strips rolled through a fixed set of rolls. The second batch of strips is rolled in the conditions of movement of the rolls of the second stand of the continuous installation group, in a direction transverse to the axis, depending on the width of the rolled strips. After each batch, control strips are rolled, followed by measuring the parameters of dimensional and geometric accuracy.

The results obtained are presented in the table.

30 The maximum amount of movement of the second stand of the continuous group from the axial position during the non-program rolling of the second batch of strips is

0

About 2

30 mm.

200-j 2g 2

Work time in one position is equal to

7 1SG - 4,

2.2-10 --o; TTo72 2 O708 -0.087 -45.6

 220 s

Thus, the proposed method of continuous rolling of sheets reduces the raznotolrdannost by 0.03 mm, and flatness by 3.4 mm / m.

Formulas

the invention

The method of continuous rolling of sheets, including the deformation of the workpiece in rolls with a smooth barrel with periodic movement in the transverse direction of the set of rolls relative to the axis of rolling during pauses, in order to improve the geometric accuracy of the sheet of the set of lash rolls.

with the exception of the first one, the displacement is determined by the value

B o - b; 2

Where

S

S roll shift in the transverse direction, m; the maximum allowable width of the rolled sheets in the campaign of work rolls, m;

width of the rolled sheet, m,

at the same time, the set of rolls of adjacent lashes is moved in opposite directions, and the time of work in one half is determined by the formula

iv d-in

 V

g

A52631 where

ten

15

20

g

4V.

in R - in (U - P with

permissible time of work of the rolls in one position, with; allowable amount of worn-out work rolls, m;

circumferential speed of the work rolls, m / s;

width of rolled sheet, m;

radius of work rolls, m; tensile strength of work rolls, kgf / mm;

friction coefficient;

unit pressure

kg.s / mm;

constant coefficient for

all mills equal

2 2 10

Claims (1)

The claims 50 A method of continuous rolling of sheets, including deformation of the workpiece in rolls with a smooth barrel with periodic movement in the transverse direction of the set of rolls relative to the axis of rolling during pauses, characterized in that, in order to increase the geometric accuracy of the sheet of the set of rolls of lashes, 1452631 6 ea with the exception of the first, move by the value determined by the dependence s. -be-pL-. ₅ where (Y is the displacement of the rolls in the transverse direction, m; B _about - the value of the maximum permissible width of the rolled sheets in the campaign of the work rolls, m; bj is the width of the rolled sheet, m, while the set of rolls of adjacent _1g lashes is moved in opposite directions, and the working time in one position is determined by the formula ₌ du σ _β ^C - ^C v2rRB ”” _9P where c is the permissible time for the rolls to work in one position ,from; ДУ - permissible value of the wear volume of working rolls, m ^e ; I ’* Vg is the peripheral speed of the work rolls, m / s; In - the width of the rolled sheet, m; R is the radius of the work rolls, m; <3θ is the tensile strength of the work rolls, kgf / mm ² ; (U is the coefficient of friction; P - specific pressure, kg.s / mm ² ; C is a constant coefficient for all mills, equal to 2'2 * 10 ⁷ , DN, m ⁵ m / s M 1 ----------------------- 1 1 i 1 eleven 1 x 1 eleven eleven kgf / mm I ^st s P, kgf / mm 1 1 1 o 1 A 1 1 0.1 0.2 0.08 4 0,087 45.6.