SU1603625A1 - Method of automatic control of billet cross-cutting in continuous casting machine - Google Patents

Abstract

The invention relates to a foundry, in particular, to the automation of technological processes of machines of non-riveted billets (MILZ) and can be used in systems for automatic control of the ingot cut. The purpose of the invention. is an increase in the yield of a suitable metal due to an increase in the accuracy of determining the mass and length of the cut piece. The invention improves the accuracy of cuts of continuously cast ingot on preforms of a given mass by indirectly taking into account in the casting process the change in the solutions of drawing stands, the size and shape of the ingot section, which is ensured by using the empirical dependence of the weight change of the elementary area on its average velocity. movement. For this, the ingot is preliminarily divided into elementary areas, the time of movement of each elementary area from the beginning of the crystal to the pulling stand is determined, at the exit of which the average speed of each elementary area and its mass as a function of average speed are determined, these masses are summed up to the resultant nelichiny, equal to or greater than the specified mass of the workpiece, calculate the length of the workpiece of a given weight and from the ingot the workpiece of the calculated length. 2 Il. (L

Description

The invention relates to foundry, in particular, to the automation of technological processes of machines for continuous casting of billets (Caster), and can be used in systems for automatic control of the ingot cut.

The aim of the invention is to increase the yield of a suitable metal beyond

Yu

SP

an account of the accuracy of determining the mass and length of the cut piece. Kah FIG. 1 shows the installation scheme that implements the method of automatic control of cutting the ingot; FIG. 2 is a graph showing the dependence of the volume coefficient Kj on the average velocity V; for i-rro tracked section.

Continuous casting matin consists of a crystallizer I, a bearing stand 2, a cutting device 3 Position A denotes an ingot, 5 - a preset of a given mass, 6 - a pulse length sensor, 7 - a control computer,

In the process of continuous casting, molten steel is poured into the mold and using a pulling stand 2, the ingot 4 is pulled from it. The length, ingot L from the beginning of the mold to the pull stand is conventionally divided into grain sections with a length of D1. The signal from the pulse sensor 6 of the length enters the UHF 7, with the help of which the time is fixed; during which the e: g |

1G

distance L, and determine the speed of movement to the tare section V - "L

At the output, the masses of the elementary part of the empirical dependence

ten

M

M

K |

where M J is the mass of the 1st el

plot I

Mts - 15 packs nominal

Kj - volumetric coefficient, hanging from cp of displacement i of tare part

KI

.

distance L, and determine the average speed of movement of each elementary region V- ",

At the exit of the undercarriage stand, the mass of each elementary area is determined using the VWD using the following empirical dependence:

ten

M

M

K |

where M J is the mass of the 1st elementary

plot I

MC is the nominal mass of an elementary segment;

Kj is a volume coefficient depending on the average speed of movement of the i -th elementary segment:

where v, - average speed of first i-ro elementary

25

S

plot; . Y "is the nominal speed of the ingot extrusion; - constant value, set depending on the grade of steel and the design of the tire 30 to continuously cast the workpieces. .

The value of a constant O is determined experimentally for a specific:

a (m, "dm, -hm ,.)

The resultant plots of the resulting link are the resulting or larger. Then workpiece with formulas

P-1

aqr

(n -) & 1 +

M.

where Ijqf is the length of the workpiece with

Noah mass;

L1 is the length of the elementary region; . :

n is the number of elementary areas that have entered, the resulting mass of the workpiece; .

1c MD is the length and mass of the residue from the last elementary segment, partly included in the previous preform of a given mass; .9aA ezdvina mass of the workpiece. . The obtained value for the workpiece is remembered by the UVK, and when the front end of the ingot is moved f fesa to the cutting device from the UVK, the command to cut is given. The cycle is repeated.

25

design and adjustment of the caster, as well as the range of cast steel.

thirty

The obtained values of the masses of the elementary areas as they leave the lower stand are summed up to obtain a resultant value equal to or greater than the specified mass of masses. Then calculate the length of the workpiece with a given mass according to the following formula.

P-1

-Hmm ,.)

+ 1

about

(.}

In the process of cutting an ingot on a continuous casting machine, there are a number of uncontrollable factors, such as temperature change along the length of the ingot and the associated linear expansion coefficient, ingot shape error, change of the haulm stand during casting, etc. the amount has a significant impact on the accuracy of determining the mass of the workpiece.

I. .

Accounting for these factors with the help of additional use of complex and expensive measurement systems for these values seems impractical, since the reliability and reliability of their readings depend on the temperature conditions of operation, the presence of moisture, scale,.

those conditions that are always present in metallurgical workshops.

The most effective consideration of these factors can be done by introducing a generalized indicator of the change in the conditions of ingot formation. an indicator can be the average speed of movement of the elementary section of the ingot,

In the non-stationary casting process, the average speeds of movement of the various elementary sections differ from each other and from the nominal value of the ingot extrusion rate V. A variation in the extrusion rate leads to a change in the length of the liquid phase and temperature fluctuations, which affect the ingot resistance in tons of the cage With increasing resistance, the rolls are moved apart, changing the geometric dimensions of the slit. Thus, the average speed of movement of an ingot indirectly studies all of the indicated factors, De ni1; CLINGING for elementary areas is necessary to more accurately take into account changes in the conditions of its formation along the length,

An empirical dependence of the change in the mass of the elementary region on the average velocity of its movement was obtained. Finding the mass of elementary areas using the obtained empirical dependence of the poems. First, it improves the accuracy of determining the mass of the workpiece by indirectly taking into account a number of uncontrollable factors such as temperature change along the ingot length and the linear expansion coefficient associated with the temperature of the ingot shape error — the change in the rolling stand and t, d Secondly, the rejection of the use of complex and unreliable systems for measuring the shape of the workpiece.

In order to take into account changes in the size and shape of the cross section of a cepreating ingot under non-stationary casting conditions, an empirical relationship (1) was proposed describing the relationship between the volume coefficient Kj and the average velocity Vj for the i-ro hotel-living section. Chart of dependence for bloom radial refinery with adjustment of pull rolls to a size of 285 mm and pulling of an ingot section

ten

15

20

25

thirty

five

0

five

0

five

0.3 g 0.36 m obtained experimentally “ut, is shown in FIG. 2, Curve 8 corresponds to formula (i), and dots 9 are marked: nach-. neither the volume coefficient obtained as a result of measurements and weighings of the cut blanks on an industrial caster

The constant value о, set depending on the design of the continuous casting machine, the settings of the pulling rolls, the section of the cast ingot and the steel grade, characterizes the range of variation of the volume coefficient of the ingot section in the allowable range of variation of the drawing speed from Uts to 2-V. range, we have, as it were, three characteristic zones in which the change in the volume coefficient K follows certain laws, P {) and the speed of insertion of the spit is less than the speed “the volume coefficient K is almost close to e Init, t, e, ingot-sectional shape (its dimensions) differ little from the nominal In the zone A at a speed of V Changes to about 1,3 Vj, Kj change is slow in nature and the absolute value is small.

This is due to the fact that the average velocity of the elementary cross section is still not large and the liquid phase of the ingot does not reach the thrusting stands, and the resistance of the ingot deformation in them is still enough to move the rolls apart.

Zone B is characterized by a significant change in the coefficient K, and, consequently, of the volume of the elementary segment. This is due to the rather high speed of drawing an ingot, its entry into a thin cage with a high temperature and the presence of an unconsolidated middle, which leads to a decrease in the resistance to deformation and an increase in the amount of reduction in the ingot in this zone.

In zone B, at a speed of V ,, 7 Vy, the coefficient Kj is no longer so significantly dependent on the speed Vj, since the tubes in the tunes, adjusted to a certain size, have already moved closer to the limit (in this case 285 mm) even more malleable The deformations, the increase of the latter does not occur because of the injection of a sufficient amount of compression

and existing restrictions on roll rolls ,.

Thus, using the average ingot pull rate For each monitored section, a relatively simple relationship is obtained, taking into account the presence of non-stationary processes during casting, and quantitatively accurately reflecting the change in the ingot volume along its length

In established casting modes, the average velocity Vj will be constant for all elementary sections and equal to the rate of casting, and when the latter is changed, the average creep of sections will change according to hyperbolic dependence, and its value will again be constant for everyone when . a surface element is cast that is poured at a new constant speed.

Substituting the values of average velocity V; in dependence (I), we obtain that, for any disturbances of velocity, the volume coefficient K ;, and with it, the mass MJ will smoothly vary in a dependence that is close to piecewise linear, during the time corresponding to its transition time.

The choice of the U1 value should be determined in the following way: on the one hand, the smaller the value

 splitting the gauge into elementary areas is, the less discrete and, consequently, the mass and length of the cut piece is determined more accurately, on the other hand, reducing the value of M to 4 small values is impossible due to measurement error and tracking by moving elementary areas. Technical means of measuring the length, for example, on a continuous casting machine, this number-pulse sensors of the PDF type, have

, technical specification - 1 or 2 pulses per 1 mm length, if we also add the measurement error associated with ingot slippage; That is, from the experience of operation, it is a half-time that choosing 61 less than 20-30 tm is inexpedient. The optimal value for & 1 can be recommended range from 50 to 200 mm. Choice: 2tl in this range will provide sufficient accuracy in determining the mass and length of the cut workpiece and not

o

five

0

five

will create problems in practical ryo-. systemization.

Example 1. In the process of continuous casting of a metal on a bloom radial caster, a 40X steel is introduced into the mold and using a pulling stand, an ingot with a nominal section of 0.3 ± 0.36 m is pulled out at a speed of 0.6 m / min. at the nominal exhaust speed U „0.4 m / min.

The bar of the ingot from the lower slice of the crystallizer to the pulling stand L 18.6 m is conventionally divided into elementary sections 61 61.1 m long. With the help of a pulsed sensor of the length of the ingot and UVK, the movement of these elementary sections is monitored and for each of them determines the average speed displacement V, as a quotient of dividing the distance L by time; the passage of the elementary section of the distance. In the stationary mode of casting, the average speed of movement of all the elementary sections will be the same and equal to the drawing speed:

thirty

V:

L 18.6 -,.

F s1 m / min.

where

31 min - the time of movement of the 1st elementary of a new section, fixed by the UVK.

The rolls of the rolling stand, adjusted to a size of 0.285 m, compress the ingot with a thickness of 0.3 m with the help of a hydraulic pressure mechanism, while under the action of the resistance of the ingot deformation, the rolls of the walking stand can move apart, changing, ingot, the thickness of the ingot from 0.285 " up to 0.3 m., constant value 5,. determined experimentally as a result of measurements and weighings of cut-off blanks for a given construction and adjustment of a continuous casting machine, as well as for steel grade 40X, equal to 0.04.

At the exit from the bearing stand, for each i-ro elementary section of the ingot, its volumetric coefficient K is determined; depending on the average velocity of the elementary section VJ, -ir

1r 2

KI - I -41 + arctpf§.lYi

 5 + arct8 (v-. 12)

and

1603625 0

sections Mj, "82.62 kg, its length would be 7988 mm, however

0.004 T, the masses of the elementary segments f f / 2 ctg (- 12) j j are from M | ,, then, by summing up their values, we get for n 8 8

 0.98

. .4 for K, determine the mass of each -2 M; "6558,408 kg".

The elementary area of the form

mule

and for n 82

M; M. to; 82.62-0.98 .V

“80.968 kg, h1521M; "6,639.376 kg M d

GD to 82.62 kg - nominal mass

plot size 0 ,,, m.

With the release of the elementary parts Believing that the cut is cut

This means that the bottom stand of their mass is sum-first in this series of heats, i.e. one

are run until a value of 20 ° O M j j O is obtained, then the length of the cut off or greater M jaI is 6600 kg, Prn of nom-billet weighing 6600 kg to the pine weight of all its elementary

L1 (M, dd, - M, -S.M;)

1z "g (p - O-M + g; - + 1.

- (82 - 1) .0.1 .9 ... 1-6558.4. . 8.151 m

- “-.

The resulting value is memorized. , QА1 (M - M -

UVK and with a mixed front torus

Ca from the axis of the cut to this distance UVK

gives the cutting device a signal „i /,“ “

- -i - i | 5 S5y .. ,,

When cutting the following blanks, ". Oo

values of residues 1 are reported and refer to the first cut of the store. So the lynn of the first, cutting cut.

la through the 82nd elementary section. Another part is 1o 41 long and divided into two parts. One part - 1, 0.1 - 0.051 0.049 m and maslda Q soi

M, b ... “JL. .§Р68. 39,674 kg

h

RELATES to the second billet. Sum-m + JM; "6679.05 kg M,".

ru mass of the following elementary45. tgt, "A

the plots with the magnitude of the remainder M, by the length of the second cut-off tally for n "82" kn will be

 . I ..

 zag - + (82 - 1) .0,1 + 2-ii-li P5.I.3b674 - 6558j p8i

and the length and weight of the residue

i; . 0.1 - 2Л..О - 2n ||| 6554082. . ,, „

". . 2.2 ".1 | SY. ".35".

h

Already 81 elementary members will be required for the third blank to be cut.

AND;.

6,637.758 kg

  .098 + (81 - 1). 0.1

Y

When the ingot extrusion speed changes, the amount of its resistance to deformation in pull rolls changes, and consequently, the amount of retraction, which is taken into account by the volume coefficient K ", determined by the average movement speed of the elementary sections, In the case of an unsteady casting process, pull rate, the average cKdipiocTb movement of each elementary segment is not equal to the last value of the pull rate and may differ significantly from it, but will differ from each other and, Independent user speed different elementary lan

6.05 1 -

4- arctg

The mass of each elementary segment is

 . eight . 51M; "6620,88 kg M

9

The length of the cut billet weighing 35 M will be equal to

i ш «А 14 Гч I X 0 ± 1 16600 - О - 83 78.82)} df vB4 - I). O, I "- 8.374 m

Example 3, In the mold p of a ball-bearing steel grade of equal MS, steel grade SH-15 to 0.03 is supplied. Then the volume coefficients

TO; for all elementary parts moving at an average speed V; 0.3 m / min will be equal

45

and extracting an ingot of the same cross section of 0.3 x 0.36 m with a constant minimum permissible speed of 0.3 m / min. Constant value b for

Kj. , - 9-f 2 I - arctg (§5; Oh3., 2) 0.998.

mass of each elementary segment

M

8: g, 62 "0.998" 82.47 kg.

one,. (81 1) .. 0.1. 2L: 16600 .-. D.80.182,471. , 003 m.

Thus, the technical solution provides higher points. The sum of the masses of the elementary parts, JCOB with the remainder will be

0

--GOTGbR -------- -. IKL. To simplify the calculations, below are the printers for the stationary casting process at the boundary values of the ingot extrusion rate.

Example 2. At the same radial caster in the mold serves steel grade 3 tbsp. and extracting from it an ingot with a section of 0,, 36 m with a constant speed of 0.8 m / min (maximum for a given caster), a constant value S for the same design and setting of a continuous caster, but for a grade of steel 3 equal to 0.05 . The average speed of movement of all elementary areas is equal to the sorrow of drawing the ingot 25 from the mold, and the volume coefficients

five

0

(5, p - U,

0.954.

thirty

M; “82.62. 0.954 "78.82 kg. The sum of 84 plots will be a mass

EVIL

With 1.

O and M,

ABOUT,

and the sum of the 81st precinct will amount to us 6,680.07 kg, which is 80.07 kg more than 1 Mzv, d. Then the length of the cut billet with a mass Mzad 6600 kg will be equal to

cut ing length of a continuous ingot to workpieces with a planed weight and lower

The increase in yield due to a reduction in trimming was 0.5X.

Claims (1)

Invention Formula The method of automatic control. Opening the ingot on a continuous casting machine, at which the length of the ingot drawn from the mold is continuously measured by a pulling stand, calculates the length of the blank with a given mass and cutting off the ingot of the calculated length, , in order to increase the yield of a suitable metal by increasing the accuracy of determining the mass and length of the cut piece, the time is taken during which each elementary section of the casting length of fil passes the distance from the beginning of the crista. the average speed of each elementary section and its mass in relation to the exit from the walking stand as a function of the average speed according to the following dependence  M: Mts-K ;, AKM (n - 1) L1 + de one 30 g S (n - i) g length of the workpiece with a given weight; the length of the elementary region; the maximum number of elementary plots, the sum / mass of which does not exceed a given mass of the workpiece; de M {- the mass of the 1st elementary segment nominal mass area corresponding to the nominal ingot extrusion rate; - volume coefficient, depending on the average speed of movement of the i-ro elementary segment. -. M „K; I in It arctg ( 8 -v; - 12) about | th and tij her th 20 25 thirty where v; average speed of movement of the i-th elementary segment} the nominal discharge speed of the ingot gizani; constant value, set depending on the steel grade and construction of the tool-. us continuous casting blanks, and summarize the masses of the elementary areas, and the ingot cut is produced when the length of the billet reaches the value calculated by the mathematical. expression P-1 M.) -M, | "1 t Mp "35 40 + I about loJ MOstylem 90 A length and weight FROM the last part of entered into the previous one preparation of a given maezy; given mass of the workpiece. 1 C, N / NS.