SU1435620A1 - Method of controlling cooling of rolled shapes in continuous rolling-mill - Google Patents

Abstract

The invention relates to heat treatment of rolled products and is intended for use in the stream of continuous section rolling mills. The purpose of the invention is to increase the productivity of a mill by eliminating the emergency jamming of rolled products in the subsequent stand and rolling resistance of waps. Water is supplied to the rolling surface by means of a cooling device placed in the interstand gap of the mill after the initial section of the rolling section leaves the cooling unit, 1.5-2.5 times the length of the deformation zone in the cage, and the moments of switching on and off of the cooling unit are set to for dependencies 1 il. one

Description

11435620

The invention relates to heat treatment of rolled products and is intended for use in the stream of continuous rolling mills.

The purpose of the invention is to increase the productivity of the mill by eliminating the emergency jamming of rolled steel and the resistance of rolls.

The drawing shows the functional scheme of the cooling device with which the predicted method is carried out.

A device for cooling a casting 1 comprises a 4 o shay unit installed between rolling stands 2 and 3; a drive with 5 actuators; a sensor 7 measuring the speed of rolling; 7 which is kinematically connected to the roll of a stand 2, arithmetic

sp for on by eq de you

ten

15

20

Olok A from exit w: 9 and Uri elements

I1 and 2 times, elements 13 and 14 of comparison, trigger 15 and sensor 16 for the presence of rolled products with direct 17 and nivers — 1-1 to 18 outputs, 25

The device works as follows.

In the initial position ui) okat 1 in the mill line is absent, the drive 5 is turned off, and water does not flow into the installation 4. The arithmetic unit 8 is set up with codes of numbers equivalent to the predetermined value 1 ,,, In, , one.,

to

 6

and with,

When rolling in 1sheet 2 arrives, sensor 7 starts measuring the rolling speed and unit 6 converts the E: PG value to an equivalent code that arrives at one of the inputs of the arithmetic unit 8o. The arithmetic unit calculates the time values of 9d and Outputs 9 and 10, codes of numbers g equivalent to these delays appear.

not with

in about

with ti in e l n l y

35 hours

40 and

45 n

When the hire appears in the era field, the dashboard 16 at its direct output 17 appears a signal that triggers the time element 11, the output code of which begins to increase. When the codes of the time element 11 and the output 9 of the arithmetic unit 8 are equal, the comparison element 13 and the trigger 15c are successively triggered by the output signal, the drive of which turns on, 5. By the time the installation of the rental section of a given length 1d starts, water begins to flow into the rig and cool the rolling.

When the rental disappears from the field of view of the sensor 16, a signal appears at its inverse output 18, which starts the time element 12. When this element counts the duration, equivalent to the value of dd, the output 14 of the comparison is triggered at the output 10 of the arithmetic unit 8. Trigger

15 and the drive 5 is turned off, and the water supply to the installation is stopped. At this point, the end of the roll is behind the installation.

Example. The temperature of rolled products in the finishing group of the high-quality mill is 1000-1050 С; rolled temperature (mass-average) after accelerated cooling in the inter-woven gap (by a known method) 750-840 Cj

the rolling speed in the last icneti of the section mill, depending on the size of the section, the rolling is set within 10-18 m / s; Capacity of the mill, depending on its type and rolled product range, is 35-150 t / h | depending on the assortment, the resistance of the strips of glass between replacements in the nano range is 2700-5400 tons of rolled metal; the distance between the legs of the mill MJ of the cooling device is 2.5-3 m; cooling water pressure MPa,

The proposed method allows to maintain the high temperature of the initial section of the rolling stock, to avoid an increase in the resistance of the deformation and, thereby, shock loads during the capture. This eliminates the sticking of the rolled stock and ensures trouble-free rolling.

and the preservation of the roll size of the rolls, which leads to an increase in mill productivity.

The deterioration of the conditions for capturing the cooled initial section of the car can only be confirmed by calculation, since direct experiments leading to emergency situations are irrational.

Theoretical cooling calculations

round rod with a diameter of 20 mm for conditions close to production, show the following.

After exposure to cooling water for 5 s (approximately the time it takes for the rolling section to pass through the cooling system), in the surface layer of rolled steel up to 5 mm thick, a temperature drop from initial (1000 ° C) to 311435620 is formed.

Atura cooling medium (not above)

). During the movement of the rolling section from the cooling device to the stand (less than 0.2 s), the temperature of its surface increases only to 200-300 ° C.,

The temporal resistance of structural steel at 1000 ° C is about 50 N / mm, and at 200 s it increases up to 500 N / mm, i.e. for the time being doc. Taking into account the fact that the core of the rod remains hot (about 1000 ° C), the rolling force increases to a lesser extent, approximately 4-5 times. The initial section of the rolling is not only deposited from the surface, but also additionally from the end, so it acquires an even lower temperature, and, due to its deformation, it is aggravated during the capture.

In addition, the effect of reducing the coefficient of friction in the deformation zone during gripping appears. So,

The coefficient of cvT of varieties is not, including the eerie wa, about with the aim of the camp and the supply of 15 coolas and lengths of deforms including

20

mom

25

thirty

35

for row steels, at 1000 ° C is about 0.35-0.4, and when reduced to .0.2. By the capture condition, the friction coefficient fu must be at least the tangent of the capture angle oL (fUitgoi.). the departure from this relationship determines the angle of capture and compression of the metal in the cage, i.e. mill calibration. With a decrease (wile twice also decreases by approximately two times. At the same time, the capture of metal by rolls in the known method: becomes unlikely, if not possible.

The limits of the uncooled rental area are determined by the actual statistical variation of the values included in the calculation formulas. With a shorter length of section, the likelihood of non-grip hire is increased. At longer lengths, the positive effect of the proposed method is often maintained. However, it does not make sense to magnify it, since the length of a non-refrigerated rolled stock grows beyond the required.

Where

bo

one,

one,

,

moulaiz o.breteni-

The method of controlling the cold rolling in a continuous mill, including the supply of water to the surface of the rolling in the interfloor gap using a cooling device, characterized in that, in order to increase the mill's productivity by eliminating emergency jamming of the rolled metal in the subsequent stand and increasing the durability of the rolls, the water supply starts after the exit from the cooling device, the start of a roll of the length equal to 1.5-2.5 lengths of the deformation zone in the cage, depending on:

.

V,

6)

and the moment of disconnection is due to

five

0

five

0 5

Where

bo

e.

cool

Vn

in the time interval between the moments of the passage of the start of the hire of the control section and the giving of the command to turn on the device; the time interval between the moments of the passage of the end of the rental of the control section and the giving of a command to turn off the device; distance from the control section to the cooling device;

cooling device lengths;

1, is the specified length of the uncooled initial section of the car;

rolling speed; the time delays of the operation of the cooling device when switching on and off, respectively.

1, OHA

,

iK

toK / t

Claims (1)

Claim A method of controlling the cooling of long products in a continuous mill, comprising supplying water to the surface of the car in the inter-stand space using a cooling device, characterized in that, in order to increase the productivity of the mill by eliminating emergency jamming of the car in the subsequent stand and increasing the resistance of the rolls, the water supply starts after exit from the cooling device, the beginning of the rolling length equal to 1.5-2.5 of the length of the deformation zone in the stand, and the moment of turning on the cooling device is set from zav values: a - ^{+ +} ~ ν - ^c 'b? a point off - depending from where Θ _& K 1 ⁺ γ _η 1skhl time interval between the instants of passage the control section beginning rolling and feeding commands to the switch device; θ ₀ is the time interval between the moments when the end of the rental passes the control section and the command to turn off the device; 1 - distance from the control section to the cooling device; 1 _0hd - cpind, cooling device; 1 _N is the specified length of the uncooled initial section of the rolling stock; ν _η is the rolling speed; time delays of operation of the cooling device as the length of uncooled steel increases beyond the necessary. when turning on and off, respectively.