SU1362518A1 - Method of controlling the mode of rolling in cogging mill - Google Patents

Abstract

The invention relates to rolling production, in particular to the production of blooms, billets, simple varietal profiles, and can be used in rolling shops of metallurgical plants. The purpose of the invention is to increase the productivity of the mill by ensuring trouble-free development of a new profiled casting gauge, shortening the rolling cycle, forced downtime and reducing rejects. For the rolling process, starting with the first pass, the actual deformation resistance of the rolled metal is calculated and the rolling pattern is drawn up taking into account the actual deformation resistance and the limitations imposed by the allowable effort and rolling moment, the ratio of the width to the height of the stock, the width of the subsequent pass and the condition sustainable metal capture rolls. The method includes operations: measurement of rolling force, measurement of the roll gap. A new method consists in the fact that according to the measured in the first (trial) passage, the value of the wedge and the corresponding rolling force will be reshooted. deformation for the next pass, rotations for the second pass are calculated, taking into account all the above limitations, rolling in the second pass is performed at the calculated compression value, while the roll gap and rolling force are predicted, deformation resistance for the next pass is predicted the values of the measured values, then the rolling process in subsequent passes is carried out in the same way as described. i С

Description

1. 13

 The invention relates to the processing of metals by pressure, in particular to the hot rolling of blooms, billets and simple varietal profiles, and can be carried out in rolling mills of metallurgical plants.

The aim of the invention is to increase the productivity of the mill by ensuring trouble-free development of a profiled assortment, shortening of the rolling cycle, forced. downtime and reducing rejects.

The method is carried out as follows.

Before rolling the first ingot from the batch, the dimensions of the ingot cross-section, the required cross-sectional dimensions of the finished rolled products, and the amount of reduction in the first (trial) pass are set.

In the first (trial) pass, the current values of the roll gap and the rolling force corresponding to this gap are measured and predicted from the values of the measured strain resistance values for the second pass using the formula

R

P.

Where

2-5 deformation resistance; coefficient of stress, composition; F, - contact area;

P - rolling force; To do this, determine the dimensions of the cross section of the metal after the pass (h |, b |), the Stress state coefficient (pg,) and the contact area (F). The height of the car after the first pass is determined by the formula

h., S + 2hp,

Where. S is the value of the roll gap;

hp - the depth of the stream gauge. The width of the rolled after each passage is determined by the formula

- L 0.934 L |) ° ()

ho /

. ()

where ho, b o are the initial height and width of rolled products;

.2

D - set for each; t;

caliber roll diameter rolls.

The contact area is determined by the formula

B 3, b o.f23 F, 0.135.b „b,. (). (-)

, h, y2b ,,.

t:

(four)

where hp, bk are, respectively, the depth of the stream and the bottom of the caliber, in which the rolling is carried out in this passage.

Stress ratio

determined by the formula

h h h

  - ()

B f). ().

b (s ;;)

(five)

Calculate the amount of reduction in the next pass, the maximum for the allowable rolling force, substitute the value of the maximum allowable rolling force and the deformation resistance value calculated for the previous pass fi (1). Calculate the rolling moment by the expression:

Mp 2 P- H - f 0.5 D. Db,

(6)

45

where f is the coefficient of shoulder rolling force, can be determined by experimentally established dependence

ik 0.78 + 0.017 (D / 2h /) - 0.163 (l (D / 2h. (7)

Compare the calculated time of the fault with the valid (NQOH.). DI F 55 reduces the calculated amount of reduction, as a result of fragile & The magnitude of the rolling force and the coefficient of the shoulder Y, the rolling force, are calculated. Reduction calculated31

crimping is carried out

g, J.-,

No value

until equality

 0

Using the calculated maximum by the allowable rolling force or moment of compression, the capture angle is calculated ((known from the equation

cos dL 1 - d h / D (8)

The calculated capture angle is compared with the allowable rolling conditions for the rolled metal. When uL is CoL 5. O, the calculated reduction value is reduced until equality is reached.

According to the calculated amount of reductions, the sizes of rolled products after passage are predicted

h ho - а h, (9) where h is the predicted height of rolled after passing; 4h - calculated reduction value.

The width of the car after passage is determined by the formula (3). The rolling is then checked by the stability condition to prevent its rolling in the next pass after turning.

, B / n cb / n,

where Gy / b is the allowable value of the b / n ratio for a given calibration.

If the predicted size of the car does not satisfy the inequality (10), the roll is rolled and the allowable amount of compression is recalculated for the next pass, then the original sizes of rolled steel are changed taking into account the canting.

I ho bo;

Ъ „ho,

j

LD - the initial dimensions of the cross-section of the rolled product after turning.

the predicted width is determined by the non-overflow condition

b - b where

"Al

- the width of the caliber.

0

five

0

five

184

If inequality (11) is not fulfilled, the calculated amount of reduction (uh) is reduced to achieve equality 0.

After determining the amount of reduction satisfying all the restrictions imposed, rolling is carried out in the next pass at the calculated value of reduction, whereby the roll gap is measured and the force corresponding to this gap is determined by the formulas (2.3) after skipping, predict the deformation resistance for the next pass using formula (1), and using the algorithm described, determine the amount of shrinkage for the next pass, taking the dimensions of the cross section of the roll after skipping for initial dnye,

In subsequent passes, the rolling process is carried out similarly.

To obtain the required final dimensions of the workpiece (h, b), the amount of reduction in the penultimate passage is determined by the formula

Ah

thirty

bfc h a + (h - bo) with

c - 1 (12)

)

35

40

45

I where ho, bo - the size of rolled before

the last but one pass; c is the broadening coefficient.

The reduction calculation according to the formula (12) is carried out under the condition h bi, where h is the predicted height of the roll after skipping, which is a sign of the last but one pass.

After rolling in the last but one pass, the rolling of the rolled products is carried out, the dimensions of the rolled steel after the passage are determined by formulas (2, 3), the reduction value is calculated in the last pass by the formula

dh h - h

(13)

50 where h is the height of the car before the last pass. Thus, predicting the strain resistance during the rolling process for each subsequent

The 55 passageway allows you to get a more accurate value of the amount of reduction in the next passage, the maximum for the allowable pressure, rolling moment and angle of grip, and using 3625

The following values of reduction in the subsequent stages of determining the maximum reduction that satisfies all the restrictions imposed by m- ensure that each ingot is rolled with a minimum number of passes, prevents the occurrence of a rolled stock failure or non-performance gauges, equipment breakage caused by exceeding the allowable power parameters, which leads to increased productivity of the mill.

Claims (1)

Invention Formula The method of controlling the rolling mode on a blooming mill, which includes measuring the force of the proka-, mezhvalkovogo gap and the impact on the pressure screws, characterized in that, in order to increase the productivity of the mill by ensuring trouble-free development of a new grading grade, the rolling cycle cuts , forced downtime and reduced scrap, the measured gap in the first pass between the rolls and the rolling force corresponding to that gap is calculated Compiled by A. Sergeev Editor About, Tetested Techred M.Didyk Proofreader M.Demchik Order 6334/6 Circulation 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, 4 186 width and height of the car after the first pass and predict the deformation resistance for the second pass, calculate the amount of reduction for the second pass using the cross-sectional dimensions of the car and deformation resistance, allowable force and moment of rolling and the angle of capture, the width of the next pass, the need to rotate the cross section (turning) by 90 ° is determined according to the allowable value of the ratio of the height of the car to its width; Actually, recalculation of the width and height of the rolled stock after the first pass and the amount of reduction according to the listed parameters and limitations are carried out in the second pass with the calculated amount of reduction, in subsequent passes the process of rolling is carried out similarly to the specified geometric dimensions - go rolled.