JPS6142461A - Operating method for continuous casting installation for thin billet - Google Patents

Abstract

PURPOSE:To improve the quality and yield of a billet by controlling the opening degree of a sliding nozzle in accordance with the time change value of the weight of the molten metal to be poured into a small tundish then adjusting the drawing speed, etc. of a casting machine. CONSTITUTION:A load cell 14 is disposed to a small tundish 5 and the weight of the molten metal 2 poured from a large tundish 4 into said tundish is measured. The opening degree of the sliding nozzle 6 is controlled in accordance with the time change rate thereof. The approach operation of a belt type caster 12 is started upon calculation of the pouring rate after the control. The drawing speed of the caster 12 is adjusted to the prescribed speed at the point of the time when the integrated charging rate determined fro the pouring rate of the molten metal 2 and the amt. of the molten metal in the tundish 5 and the integrated drawing rate coindice with each other. The drawing speed of the caster 12 and the molten metal level thereof are made coincident with target values with high accuracy by the above-mentioned method, by which the stable casting is made possible. The quality and yield of the billet are thus improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for operating a continuous thin slab casting facility, and specifically, the present invention relates to a method for operating a thin slab continuous casting facility, and specifically, the drawing speed during casting of a held type continuous casting machine and its molten metal surface. The present invention proposes a method of operating a continuous thin slab casting facility that can automatically and quickly set the level to each target value.

[Prior art]

The operating method of conventional continuous thin slab casting equipment was as shown below. That is, from this casting equipment (I), a large tundish installed below the casting equipment, and a small tundish unit installed below the large tundish through a sliding nozzle with a slotted hole on the bottom of the large tundish. If the small tundish is an overflow type as shown in Fig. 3, the F4 molten metal overflows from the small tundish, and a twin-held continuous casting machine (hereinafter referred to as In this equipment, the molten metal in the small tundish overflows and the charging of the molten metal into the casters begins. The operator visually detects this and starts the caster.Then, the pull-out speed of the caster is adjusted to the preset opening degree of the sliding nozzle at the time of charging (at the start of casting) or the opening degree. When the molten metal level monitoring device detects that the molten metal level in the caster has reached the target molten metal level, the caster speed is increased. The speed increase is stopped and the current drawing speed is maintained.Then,
The opening degree of the sliding nozzle or the withdrawal speed of the casters was manually operated in accordance with the subsequent increase or decrease in the level of the molten metal.

[Problem that the invention seeks to solve]

However, in actual operation, the relationship between the molten metal injection flow rate and the opening degree of the sliding nozzle varies due to various factors such as the opening of the sliding nozzle due to metal adhesion. It is difficult to define it unambiguously. Therefore, in the conventional method as mentioned above,
There are cases where the actual molten metal injection flow rate is significantly different from the target charging flow rate, and in such cases, it is not possible to achieve the target caster withdrawal speed or the target molten metal health in the caster.
Also, for this reason, the operations described above need to be performed frequently.
There was a problem in that it took a long time to obtain a stable casting condition. As a result, the yield and quality of continuous slabs are adversely affected, as well as breakouts and f/s from casters.
There was a risk that a major accident could occur that would lead to the suspension of gi@ overflow operations.

(Inventors of the present application, etc.) have solved the above problems (Patent application filed in 1983).
-203250 is proposed. In this method, a load cell is installed under an overflow type small tundish, and this is used to calculate the change in the weight of the molten metal in the small tundish before charging it to the casters, and the opening of the sliding nozzle is adjusted to match this with the target charging flow rate. Then, calculate the injection flow rate after control in the same way as before, and based on this, calculate the run-up speed and steady-state pull-out speed of the casters during the run-up operation and the following steady-state operation, and then start charging. This is a method in which the caster is operated for a predetermined period of time at the run-up and pull-out speed at the same time that the caster is sensed, and then steady operation is performed at the steady-state pull-out speed.

With this method, the relationship between the molten metal injection flow rate and the opening degree of the sliding nozzle can be corrected, so the actual molten metal injection flow rate does not differ greatly from the target charging flow rate, and the above problem can be solved.

However, the amount charged or overflowed from the small tundish to the caster is determined by the molten metal head Δh1 (shown in Figure 3) at the overflow section, and this head is not particularly controlled, so it is difficult to determine the appropriate value for the run-up operation time. This is impossible, and for this reason, control accuracy beyond a certain level cannot be expected.

By the way, in addition to the above-mentioned overflow one-way method, there is a so-called elephant nozzle method as shown in FIG. 4 as a method of charging the small tundish to the casters. This type of small tundish has a sliding nozzle placed horizontally on its side wall, and the charging amount can be adjusted by adjusting the opening of this sliding nozzle.This can be used effectively to achieve high-precision control. The technology to do this has not yet been developed.

Ta.

[Means for solving problems]

The present invention has been made in view of the above circumstances. Before the charging of molten metal into the casters starts, the flow rate of the molten metal poured from the large tundish to the small tundish is actually measured, and based on the actual measurement results, the flow rate of the molten metal is determined. The opening degree of the sliding nozzle is controlled so that the injection flow rate into the tundish matches the target charging flow rate, and when the start of charging is detected, the cumulative injection amount from the small tundish to the caster after the start of charging is adjusted. The above-mentioned problem is solved by performing run-up operation until both values match based on the cumulative amount of drawn-out amount, and then starting steady operation from the moment they match. The purpose is to quickly match.

The method of operating the continuous thin slab casting equipment according to the present invention is to charge the molten metal injected from the large tundish into the small tundish through a sliding nozzle into a belt-type continuous casting machine, and then pull out the solidified slab. In the continuous casting equipment for thin slabs, the weight of the molten metal injected from the large tundish into the small tundish is measured with a load cell attached to the small tundish before the start of charging molten metal to the belt-type continuous casting machine. Calculate the injection flow rate of molten metal based on the time change value and make it match the target charging flow rate (control the opening degree of the sliding nozzle, then calculate the injection flow rate after control in the same way as before, After that, when the start of charging is detected, the run-up operation of the Held type continuous casting machine is started, and the cumulative charge amount determined based on the injection amount after detection and the amount of melt in the small tundish, and the withdrawal during the run-up operation. The method is characterized in that the cumulative amount of withdrawal determined based on the speed is sequentially determined, and the withdrawal speed is set to a predetermined value after the time when the cumulative charging amount and the cumulative amount of withdrawal match.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing examples thereof.

FIG. 1 is a schematic diagram showing the configuration of a thin slab continuous casting facility equipped with a small tundish of the elm fan nozzle type to which the method of the present invention is applied.

The molten steel 1jh (molten steel) in the cider 1 is injected into the large tundish 4 located below the cider 1 through the sliding nozzle 3. Big Tanditshu 4
A small tundish 5 of an elephant nozzle type is provided below, and the molten metal 2 is injected into the small tundish 5 through a stopper nozzle 6b in the large tundish 4 and a sliding nozzle 6 attached to the bottom of the large tundish 4. It is now possible to do so.

The sliding nozzle 6 is for adjusting the flow rate of the melt '1Ij2 injected from the large tundish 4 to the small tundish 5, and the sliding nozzle 6 is for adjusting the opening degree.
By changing the sliding position of a with respect to the sliding nozzle 6, its opening degree is adjusted and the flow rate of the i9 hot water 2 is adjusted. An example of the slide portion 6a includes a double-acting hydraulic cylinder 7.
rods 8 are connected. The hydraulic cylinder 7 has oil chambers for advancing and retracting the rod 8, and the rod 8 is advanced (or retracted) by pressure oil supplied to each oil chamber from the hydraulic control circuit 9, and the slide portion 6a in the closing (or opening) direction. The hydraulic control circuit 9 includes a solenoid valve (not shown), a pressure control circuit, etc.
The rod 8 is configured to be moved forward and backward based on an operation command signal given from the controller. The amount of movement of the rod 8, that is, the opening degree of the slide portion 6a, is detected by a position detector 11 attached to the hydraulic cylinder 7, and the detection result is given to the arithmetic and control unit 10 as a feedback signal.

A sliding nozzle 21 is disposed horizontally at a predetermined height position on the side wall of the small tundish 5 into which the flow rate of the molten metal 2 from the large tundish 4 is regulated and injected in this way, and a gutter 17 is provided at the outlet of the sliding nozzle 21. is installed with the tip side slightly lowered.

A caster 12 is placed at a desired position at the tip of the gutter 17, and the molten metal 2 in the small tundish 5 is charged into the caster I2 via the sliding nozzle 2 and the gutter 17.

The sliding nozzle 21 is for adjusting the flow rate of 'R1n2 charged into the caster 12 from the small tanker 5, and its structure and the mechanism attached to adjust its opening degree are similar to those of the sliding nozzle 6. It is similar to Specifically, the sliding nozzle 21 has a structure in which the opening degree can be adjusted by changing the sliding position of the scoop 1' portion 21a for adjusting the opening degree, and the flow rate of the molten metal 2 can be adjusted accordingly.

In the method of the present invention, the set value can be set as described later, and there is no need to change it during casting.

A rod 23 of a double acting l'111 pressure cylinder 22 is connected to an example of the slide portion 21a. The hydraulic cylinder 22 has oil chambers for advancing and retracting the rod 23, and the rod 23 is advanced (or retracted) by pressure oil supplied to each oil chamber from the hydraulic control circuit 24, and the slide portion 21
Move a in the closing (or opening) direction. Hydraulic control circuit 24
is composed of a solenoid valve, a pressure control circuit, etc. (not shown), and is configured to move the rod 23 forward or backward based on an operation command signal received by the arithmetic and control unit 1o. The amount of advance and retreat of the rod 23, that is, the opening degree of the slide' portion 21a, is determined by a position detector 25 attached to the hydraulic cylinder 22.
The detection result is given to the arithmetic and control unit 10 as a feed bank signal.

In addition, detectors 13 such as I-1 and MD are installed above the tip of the gutter 17, and when the charging of molten metal 2 to the caster I2 starts, this is detected and the arithmetic and control unit Report on 10th.

Further, a load cell 14 is attached to the bottom of the small tundish 5 and detects the weight of the melt field 2 poured into the small tundish 5. This detection result is input to the arithmetic and control device 10.

Upper and lower heald roll mechanisms 120 of casters 12. ]2
Between the inlet and outlet sprockets of 1, there is a heel) 120a, respectively.
.

121a is attached, and both hells l120a,
Molten metal 2 is charged from the small tundish 5 between 12Ia and 12Ia. The molten metal 2 is cooled and solidified by a primary cooling spray zone (not shown).

Upper and lower belt roll mechanisms 120 and 121 inlet side sprockets +20b and 121b have both subrokeso 1120b
, 12] A driving motor 15 is connected, and the rotation of the motor 15 drives the casters 12, and the solidified slab is placed downstream of the casters 12 between both belts 120a and +21a. It is fed to a secondary cooling zone 20 consisting of a plurality of rolls and the like. The motor 15 is connected to an arithmetic and control unit 10 via a motor drive control circuit 16, and its rotational speed is adjusted by a drive signal generated from the arithmetic and control unit 10.

In the operating method of the present invention in such equipment, prior to the start of charging the molten metal 2 to the casters 12, the arithmetic and control device 10
is the actual injection flow M Q a + of the molten metal 2 injected from the large tundish 4 into the small tundish 5 via the sliding nozzle 6, as shown in the following equation (1), in the small tundish 5 detected by the load cell 14. Melt field weight W
Calculated based on the time change value dW/dt.

i However, kl is a conversion factor, and the actual injection flow IQa+ and the opening degree X2 at that time detected by the position detector It determine the opening degree Xl of the sliding nozzle 6 and the injection flow IQa at this point in time of operation.
The relationship with l can be detected.

Next, the opening degree xp of the sliding nozzle 6 is automatically controlled based on the above relationship so that the injection flow rate Qa into the small tundish 5 coincides with the target charging flow 1iQt into the caster 12.

During this control, the injection flow rate Qa2 after controlling the opening degree The pull-out speed during the run-up operation of the caster 12 during the steady-tow operation following the run-up operation) is determined.

V2 = 2 ・Qa2 ”'(2
1 However, k2 is a conversion factor, and then the run-up pull-out speed V+ (
"V2-α)". Note that α is the speed for setting the withdrawal speed that will not cause hot water to run out, and is the speed when increasing the speed from the approach withdrawal speed 1 to the steady withdrawal speed v2. This corresponds to the change in the /g hot water level in the caster 12, which rises by 1, and the pull-out speed of the caster 12,
It is determined in accordance with casting conditions such as the charging flow rate Q of the molten metal 1jA2 into the caster 12, and is set in advance.

During this speed calculation, the molten metal 2 continues to be poured into the small tundish 5, and when the molten metal level reaches the height of the sliding nozzle 21, the molten metal 1jk2 flows out from the tundish and is charged into the caster 12. be done. The sliding nozzle 21 is adjusted in advance to a predetermined opening degree by a hydraulic control circuit 24 and a position detector 25, and the opening degree is set so that the scene inside the small tundish 5 is at a predetermined level. It is determined so that the target charging flow rate can be obtained when the distance from the center to the molten metal surface is Δh2.

When the detector 13 detects the start of loading onto the casters 12, the casters 12 are activated and the upper and lower healds 1
20a and +21a, the dummy bar (not shown), which is in position between 20a and 21a, is started to be pulled downward, and the pulling speed is set to the run-up pulling speed V calculated earlier.

On the other hand, as shown in FIG. 2, which will be described in detail later, the cumulative amount of molten metal 2 charged into the caster 12 and the cumulative amount withdrawn by the caster 12 from the time L6 detected by the detector 13 (the dummy head
The calculation of the chargeable volume of molten metal between the target molten metal surface level in the caster is started.

The cumulative charging amount Vin (1) is the value obtained by subtracting the volume equivalent value of the increase in the weight of the molten metal remaining in the small tundish 5 from the amount of injection into the small tundish 5 after the start of charging, which is obtained by integrating the injection flow rate Qa2. [Actual charging 1iVi in Figure 2 +a+
[indicates the weight equivalent to nftl], and is expressed by the following equation (3).

However, k3: Conversion factor W(1): Calculation of cumulative charging amount Vinftl mM of molten metal in the small tundish at time t W(t,): mM of molten metal in the small tundish at time [6] The withdrawal amount V ou L (11 is 7) It is obtained by adding the volume change amount based on the approach withdrawal speed V to the volume Vd from the dummy bar height at the i position to the target molten metal surface level (the diagonal line in Fig. ] is shown by the following formula (4).

However, k; conversion factor above +31. The cumulative charging amount and cumulative pulling amount are determined from time to time using the f41 formula.

When these become equal, the speed is increased from the run-up drawing speed (1) to the steady drawing speed (2), and the molten metal surface level on the small tundish and the molten metal surface level on the caster 12 are automatically set to each target value (constant). become. That is, as the amount of molten metal 2 in the small tundish 5 rises to that level, the amount of outflow from the sliding nozzle 21 increases, so the amount of increase gradually decreases. On the contrary, the molten metal level on the casters 12 rises. During this period, if you change to ν2 when the calculated charging amount = cumulative withdrawal amount, the injection flow rate Qa2 = target charging flow rate, and v2- is set to 2 ・Qa2, so from now on at this point The level will stabilize.

Next, a method of operating a casting facility to which the present invention is applied will be specifically explained. FIG. 2 is a time chart showing the control procedure of the method of the present invention, where the horizontal axis is time and the vertical axis is the weight W1 of the molten metal 2 in the small tundish 5.
．． The opening degrees XA' and Xs of 21 and the withdrawal speed V of the caster 12 are shown, respectively.

First, adjust the sliding nozzle 3 to inject a constant amount of molten metal into the large tundish 4 up to the bell, and then open the stopper nozzle 6b with the opening degree of the sliding nozzle 6 )l (two-dot chain line) set to the fully open state X7!1. By opening the molten metal 2 from the large tundish 4, the molten metal 2 is poured into the small tundish 5. Note that the opening degree Xβ of the sliding nozzle 6 is fully open 1x7! The purpose of this is to prevent the melt 1Jii2 from adhering to the slide portion 6a and to shorten the operating time.

The arithmetic and control unit 10 determines when the weight W of the molten metal 2 detected by the load cell 14 becomes 1. , a predetermined operation command signal is issued to the hydraulic control circuit 9 to set the opening degree ()l of the sliding nozzle 6 to a preset opening degree x7!2, which is slightly smaller than the opening degree at the time of charging, The rotor 1'8 of the hydraulic cylinder 7 is advanced and the opening xe is controlled to X12. Next, the time difference t3-12 between the time t2 when the molten metal weight W becomes W2 and the time t3 when the molten metal weight W becomes W3.
Based on this, the calculation shown in equation (3) below is executed to calculate the injection flow rate Qa during this period.

3-t2 Then, from this flow rate Qa1 and the opening degree XA of the sliding nozzle 6 reported by the position detector 11, the relationship between the injection flow rate Qa and the opening degree X of the sliding nozzle 6 that will be used in actual operation is determined, and this relationship is Based on this, a command signal is issued to the hydraulic control circuit 9 to cause the injection flow rate Qa2 to match the target charging fkL amount Qt, and the opening degree of the sliding nozzle 6 is changed to X7! is controlled by X7!3.

Next, the injection flow rate after controlling the opening Xβ is actually measured.

That is, based on the time difference between the time t4 when the molten metal superposition W becomes W4 by the load cell 14 and the time t5 when the molten metal weight W becomes W5, the calculation shown in the following formula (6) is executed, and the injection after control is performed. Calculate the flow rate Q a 2.

ts -14 Then, using the injection flow rate Qa2 that is equal to or substantially coincident with this target charging flow rate Qt, the steady drawing speed ■2 is determined based on equation (2), and the approach drawing speed ■1 is determined.

After that, when the detector 13 reports the start of charging (16
time), a predetermined drive signal is issued to the motor drive control circuit 16 to start the caster I2, and the withdrawal speed V
is set to the approach pull-out speed v1.

At the same time (time point 16), the arithmetic and control unit 10 starts calculating the cumulative charging amount and #subtraction amount.

If the control period of the arithmetic and control device 10 is Δtc, the cumulative charging amount Vinftl and the cumulative withdrawing amount VouL (tl is the above (3)).

Based on formula (4), they are given by formulas fil and f81, respectively.

Vin(tl-Q a2-n-Δtc-to 3(w
(1)-w(t6)1...(7) Vout ft1=Vd+4-Vl-n-
Δt c -i81 By calculating the values of equations (7) and (8) above by 81 every moment, [ is determined and compared with the charging amount and the cumulative withdrawal amount, V 1nftl = V out f
At time t7 when tl...(9) is reached, a required drive signal is issued to the motor drive control circuit 16 in order to increase the withdrawal speed V of the caster 12 to the steady withdrawal speed v2,
The withdrawal speed V of the casters 12 is set to the steady withdrawal speed v2.

In the method of the present invention, the weight of the melt injected from the large tundish to the small tundish is actually measured, and the opening degree of the sliding nozzle of the large tundish is controlled based on the actual measurement result. Even if the bore diameter is small, it is possible to compensate for this and obtain the injection flow rate Qa2 corresponding to the target charging flow rate Qt.Furthermore, the run-up withdrawal speed is set based on this flow rate Qa2, and the Calculate the cumulative loading amount of the caster and the cumulative pulling amount of the caster, and when both values match,
That is, since the steady drawing speed is set when the Ntis surface level on the caster reaches the target position, it is possible to make the molten metal surface level and the drawing speed match their respective target values with high accuracy and quickly.

Note that since the present invention performs control based on the cumulative charging amount and the cumulative handling amount, there is no problem even if, for example, the operator changes the pull-out speed of the casters or the opening degree of the sliding nozzle 2I during the implementation of the present invention. Furthermore, even if the opening degree of the sliding nozzle of the large tundish is changed during the operation, the flow rate can be measured again and adjusted to a predetermined flow rate without any problems.

In addition, the present invention calculates the cumulative charging amount based on the above-mentioned formula.

It goes without saying that since the cumulative amount of withdrawal is determined and controlled, it can be carried out in the same way even in the case of a small tundish with one overflow type.

〔effect〕

As described in detail above, according to the present invention, the caster withdrawal speed and the molten metal level can be set to match their respective target values with high precision and quickly, and a stable threaded state can be obtained, so continuous casting is possible. The present invention has excellent effects such as improved yield and quality of pieces, and no occurrence of grake-out or overflow of molten metal from casters.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the implementation state of the present invention, FIG. 2 is a time chart showing the control procedure of the present invention, and FIGS. 3 and 4 are schematic diagrams showing the charging method of a small tundish. 2...? '81Jh4...Great Tanditshu 5.
...Small tandish 6...Sliding nozzle 1o...Arithmetic control device 12...Casters 13
...Detector 14...Load cell patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono L, t2 ta
L ts te tbFigure 2 4 (2) Procedural corrector (spontaneous) 1. Indication of the case 1982 Patent Application No. 166053 2, Title of the invention at Operational efficiency of continuous cast slab casting equipment 3, Person making the amendment Relationship to the case Location of patent applicant 5-15 Kitahama, Higashi-ku, Osaka Name Name (
211) Sumitomo Metal Industries, Ltd. Representative Norifumi Kumagai 4, Agent 543 Address 1-14-22 Shitennoji, Tennoji-ku, Osaka City
Nisshin Building No. 207 No. 5, "Detailed Description of the Invention" and "Brief Description of Drawings" columns of the specification subject to amendment, and Drawing 6, Contents of Amendment 6-I U Detailed Description of the Invention J0) column ( 1) On page 4, line 13 of the specification, the phrase "fg hot water overflow" is corrected to "molten metal overflow, etc." (2) On page 4, line 16 of the specification, 1 (the inventors of the present application, etc.) is corrected to ``the applicant of the present application is''. (3) On page 10, line 15 of the specification, the phrase "during casting" is corrected to "during main control." (4) On page 11, line 19 of the specification [Sub I: J Kenol]
Correct the word "J" to "nip pulley." (5) In the 4th and 5th lines of page 12 of the specification, the words "Sprokeno 1-" are corrected to read "Nip pulley." (6) [Determine] on page 13, line 18 of the specification. '' should be corrected to ``to seek.'' (7) On page 16, line 20 of the specification, [Outflow amount guide 1]
``Increase in disk volume'' should be corrected to ``Increase in flow rate''. (8) In the 5th line of page 18 of the specification, the statement ``slightly less than 1 degree of opening'' is corrected to ``close to the degree of opening.'' (9) Insert the following sentence between lines 9 and 10 on page 21 of the specification. [Figure 5 shows the elapsed time (seconds) after charging on the horizontal axis and the weight (tons) of molten metal on the vertical axis, and shows the graph of the time after charging the molten metal into the caster when operating according to the present invention. This is a graph showing an example of the relationship between the cumulative withdrawal amount (Vout(0)) and the settled charging amount (Vin(t) l. After the start of charging, both Vin(t) and Vout(t) gradually increase. However, since the force at Vin(t) is larger than the amount of change in molten metal weight per unit time at Vout(t), the uncharged volume between the upper end of the slab in the caster and the target melting surface and the bell (fifth (hatched part in the figure)
is gradually decreasing. And Vin(L)-Vout
By increasing the withdrawal speed to ■1-■2 from the time point tl (27 seconds in this case) when it reaches (t), the subsequent V
Since in(t) and Vout(L) are the same regardless of the elapsed time, it is possible to match the drawing speed and the f6m level in the caster to the respective target values, thereby achieving the object of the present invention. ” 6-2 “Brief explanation of drawings” (Kaimei III), page 22, line 14, “This is a schematic diagram. This is a graph that shows.'' 6-3 “Drawings” Figure 5 will be supplemented as shown in the attached sheet. 7. List of attached documents

Claims (1)

[Claims] 1. A thin cast slab in which the molten metal injected from the large tundish into the small tundish via a sliding nozzle is charged into a belt-type continuous casting machine, and the solidified slab is pulled out. In continuous casting equipment, before the start of charging molten metal to the belt-type continuous casting machine, the weight of the molten metal poured from the large tundish to the small tundish is measured using a load cell attached to the small tundish, and the weight of the molten metal poured into the small tundish is measured. Calculate the injection flow rate of the molten metal based on the change value, control the opening degree of the sliding nozzle to make it match the target charging flow rate, then calculate the injection flow rate after the control in the same manner as before, and then, When the start of charging is detected, the run-up operation of the belt type continuous casting machine is started, and the cumulative charging amount is determined based on the injection amount after detection and the amount of molten metal in the small tundish, and the withdrawal speed during the run-up operation. 1. A method for operating a continuous casting equipment for thin slabs, characterized in that the cumulative pulling amount determined by the method is sequentially determined, and the drawing speed is set at a predetermined value after the cumulative charging amount and the cumulative pulling amount match.