KR100388040B1 - A method for manufacturing a thick steel plate - Google Patents

Abstract

The present invention relates to a method for manufacturing a thick steel sheet by rolling a slab of a slab, to determine the optimal rolling method using the measurement results of the slab dimensions and to minimize the dimensional defects of the steel sheet by rolling according to the determined rolling method To provide a method for producing a steel sheet after it, there is a purpose.

The present invention is a method of manufacturing a steel sheet by rolling a slab thick plate, by comparing the measurement results, such as the dimensions and weight of the slab with the indicated (target) weight and dimensions to determine whether the defect occurs when working with the indicated rolling method If the failure is expected, the method of manufacturing the steel sheet after changing the rolling method or canceling the work shall be the main point.

Description

Manufacturing method of steel plate {A METHOD FOR MANUFACTURING A THICK STEEL PLATE}

The present invention relates to a method for manufacturing a thick steel sheet by rolling a slab thick plate, more specifically, to determine the rolling method using the measurement results of the slab (material) dimensions, and to roll according to the determined rolling method after the steel sheet It relates to a method of manufacturing.

Thick plate rolling, unlike other rolling processes, requires that all dimensions, i.e., thickness, width, and length after rolling, be satisfied relative to specifications.

Therefore, in order to satisfy the specified thickness, width and length of the product, the rolling target dimension is determined in consideration of the dimensional control error range in the design of the material (slab).

The rolling target thickness is determined by adding the thickness control error to the product thickness in the rolling target dimension determined at the time of material design, and the rolling target width is the width width of the rolling width, the edge cutting amount and the camber The length of the rolled sheet is determined in consideration of the line, the crop amount which is the uneven deformation part of the end, and the intermediate cut amount in the product length.

Once the rolling target thickness, width and length are determined, the weight of the slab is determined by "weight = rolling target thickness x width x length x specific gravity".

When the slab weight is determined in this way, the thickness, width and length of the slab which can satisfy this weight are designed so that the slab is manufactured by continuous casting or crushing rolling mill, and then rolling to satisfy the product dimensions by the thick plate rolling mill. Is carried out.

In general, in the case of producing a thick plate product using a reversible rolling mill slab manufactured by continuous casting or crushing rolling mill is subjected to the rolling process as shown in Figure 1 (a).

In other words, the slab SL is first rolled in the plate length direction to uniformly select the slab thickness so as to meet the breadth rolling conditions.

The even-rolled finished material SB is obtained by the so-called even-rolled rolling step X.

Next, this is rotated 90 degrees horizontally to roll the even-rolled finished material SB in the width direction to secure a predetermined width dimension.

By the so-called bread-rolling rolling process Y, the bread-rolling completed material SW is obtained.

It is then rotated 90 degrees horizontally to roll the breading-rolled finished material SW in the longitudinal direction so as to obtain a predetermined plate thickness, length and mechanical properties, thereby carrying out a finishing rolling process Z to obtain a target dimension to obtain a rolled material PL.

However, when the width of rolling is large in the rolling process, the phenomenon in which crops of both edges of the plate appear more after rolling is completed, i.e., the width of the center portion is greater than the width of the line and end portions in the plate length direction in the width of the plate after rolling. In order to improve this larger concave, as shown in Fig. 1 (b), the width of the material is reduced by using the material length as the product width, and in order to shorten the material rotation time and increase productivity, When the difference between the length and the rolling width falls within the management range, the system of FIG. 1 (c) is adopted, and when the difference between the width and the rolling width of the material falls within the management range, the system of FIG.

On the other hand, the thickness, width, and length of slabs manufactured by continuous casting or crushing rolling mills are less than the dimensions at the time of design due to dimensional control errors occurring during the manufacturing process and scarring for flaw removal of the slab surface. If the weight of the slab is lower than the weight at the time of designing the material, when rolling is performed on this material, the length of the steel sheet is insufficient after completion of rolling as shown in FIG. do.

In order to prevent the shortage of the steel sheet generated in the thick plate process by the above phenomenon, the slab manufacturing process may guarantee the slag weight shortage by cutting the length of the slab longer than the originally planned length.

When the slab weight is equal to the planned weight by the above method, the slab volume and the rolling target dimension are the same, so the product dimension by the volume is theoretically satisfied, but in the case of the rolling method shown in FIG. As shown in b), the width after the completion of rolling is larger than the planned dimension so that the length is relatively short or the width is insufficient as in the case of (c) to fail.

The present inventors have conducted research and experiments to solve the above problems of the conventional method, and based on the results, the present invention has been proposed, and the present invention determines the optimal rolling method using the measurement results of slab dimensions. By rolling according to the determined rolling method to provide a method for producing a later steel sheet that can minimize the dimensional defects of the later steel sheet, the purpose is.

1 is a schematic diagram showing a process of rolling a rolled material in a reversible rolling mill.

Figure 2 is a schematic diagram showing the relationship between the size of the rolled material after rolling completed and the thick steel sheet product

3 is a block diagram of an apparatus for implementing the present invention.

Explanation of symbols on the main parts of the drawings

One . . . After Steel Plate Products 2. . . Steel plate after rolling

3. . . Rolled Material (Slab) 5. . . Width sensor of material

6. . . Sensor for measuring length of material 8. . . Material weigher

13. . . Furnace

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention relates to a method for manufacturing a thick steel sheet using a thick steel sheet manufacturing apparatus comprising a heating furnace, a rolling mill and a width, length and a weighing device on a charging side of the heating furnace,

Setting a thickness, length, and width of the target rolled steel sheet;

Setting a weight, a length, and a width of a target slab for manufacturing the target rolled steel sheet;

The method for producing the target rolled steel sheet using the target slab, slab → even rolling → 90 ° horizontal rotation → width rolling rolling 90 ° horizontal rotation → finishing rolling consisting of finishing rolling (type A rolling method), slab → width Bending rolling → 90 ° horizontal rotation → rolling method consisting of finishing rolling (B type rolling method), slab → 90 ° horizontal rotation → rolling method consisting of finishing rolling (type C rolling method), and slab → rolling method consisting of finishing rolling Selecting from a rolling method group consisting of (D type rolling method);

Measuring the width, length and weight of the slab before rolling;

Obtaining a difference between the measured weight of the slab and the weight of the target slab, and canceling the rolling operation when the difference is out of the control range;

If the difference between the measured slab weight and the target slab weight (weight difference) is within the control range, the difference between the measured slab width and the target slab width (width difference) and the measured slab length and the target slab Obtaining a difference (length difference) from the length of, and performing rolling according to the rolling method set above if both the width difference and the length difference are within a management range;

When the weight difference is within the management range and at least one of the width difference and the length difference is out of the management range, the thickness CSLth of the slab is obtained using Equation (1) below, and the calculated slab thickness CSLth is obtained. After calculating the steel sheet length (CASln) after rolling by using the following formula (2) and the following formula (2), the rolling plate calculating length (CASln) is compared with the rolling plate target length (TASln) set above, and the rolling plate calculating length (CASln) is Canceling the operation when the rolling plate target length (TASln) is smaller, and performing rolling according to the A-type rolling method regardless of the set rolling method when the rolling plate is smaller than the target length (TASln);

CSLth = Mwt × 10 ⁶ / (MSLwd × MSLln × ρ). . . . . . . (One)

Where Mwt: slab measurement weight (kg)

MSLwd: Slab Measuring Width (mm)

MSLln: Slab Measuring Length (mm)

ρ: specific gravity

CASln = CSLth × MSLwd × MSLln / (TASth × TASwd). . . . . . . (2)

[TASth: rolling target thickness (mm)

TASwd: Rolling Target Width (mm)]

The weight difference is within the management range, the difference between the width of the measuring slab and the target width of the rolling plate is within the management range, the length difference is out of the management range, and the rolling plate calculation length CASln is the rolling plate target length ( If TASln) is greater than or equal to TASln), rolling is performed according to the D-type rolling method regardless of the set rolling method;

The weight difference is within the control range, the difference between the length of the measuring slab and the rolled plate target width is within the control range, the width difference is outside the control range, and the rolled plate calculation length CASln is the rolled plate target length ( If TASln) is greater than or equal to TASln), performing rolling according to the C type rolling method regardless of the set rolling method; And

The weight difference is within the control range, the width difference is out of the control range, the length of the measuring slab is smaller than the rolled sheet target width, and the rolled plate calculating length CASln is equal to or larger than the rolled sheet target length TASln. The case relates to a method of manufacturing a steel sheet after the rolling comprising the step of rolling according to the A type rolling method or the B type rolling method.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is suitably applied to a method for producing a thick steel plate using a thick steel plate manufacturing apparatus comprising a heating furnace, a rolling mill, and a width, length, and a weighing device on a charging side of the heating furnace.

In order to manufacture the thick steel sheet according to the present invention using the thick steel sheet manufacturing apparatus, it is necessary to set the thickness, length and width of the target rolled steel sheet.

The thickness, length and width of the target rolled steel sheet are values set according to the demands of consumers.

Next, the weight, length and width of the target slab for manufacturing the target rolled steel sheet are set.

Next, a method for producing a target rolled steel sheet using the target slab is a rolling method (slab type A rolling method) consisting of slab → even rolling → 90 ° horizontal rotation → breading rolling → 90 ° horizontal rotation → finishing rolling. Slab → breadboard rolling → 90 ° horizontal rotation → rolling method consisting of finishing rolling (B type rolling method), slab → 90 ° horizontal rotation → rolling method consisting of finishing rolling (type C rolling method), and slab → finishing rolling It selects from the rolling method group which consists of a rolling method (D type rolling method) which consists of.

The rolling method is selected in consideration of the shape and productivity of the steel sheet.

Next, the width, length and weight of the slab are measured.

The difference between the measured slab weight and the target slab weight is obtained. If the difference is out of the control range, the set rolling operation is canceled.

On the other hand, if the difference between the measured slab weight and the target slab weight (weight difference) is within the control range, the difference between the measured slab width and the target slab width (width difference) and the measured slab length The difference with the length of the target slab (length difference) is obtained, and if both the width difference and the length difference are within the management range, rolling is performed according to the rolling method set above.

When the weight difference is within the control range, and at least one of the width difference and the length difference is out of the control range, the slab thickness CSLth is obtained using the following equation (1), and the slab calculated thickness CSLth is thus obtained. And after calculating the steel sheet length (CASln) after rolling by using the following formula (2), the rolling plate calculation length (CASln) is rolled by comparing the rolling plate calculation length (CASln) and the set rolling plate target length (TASln) If it is smaller than the plate target length (TASln), the operation is canceled, and if it is the same or larger, the rolling is performed according to the A type rolling method regardless of the set rolling method.

CSLth = Mwt × 10 ⁶ / (MSLwd × MSLln × ρ). . . . . . . (One)

Where Mwt: slab measurement weight (kg)

MSLwd: Slab Measuring Width (mm)

MSLln: Slab Measuring Length (mm)

ρ: specific gravity

CASln = CSLth × MSLwd × MSLln / (TASth × TASwd). . . . . . . (2)

[TASth: rolling target thickness (mm)

TASwd: Rolling target width (mm)

In the case where the set rolling method is the C type rolling method of FIG. 1 (c), the slab length becomes the width after rolling completion, and thus the slab measuring length MSLln is used instead of the target width TASwd of Equation (2). In the case of the D type rolling method of FIG. 1D, the slab width becomes the width after rolling, and thus the slab measurement width MSLwd is used instead of the target width TASwd of Equation (2).

In this case, in order to simplify the equation (2), the width spreading amount generated during the length rolling is not considered.

In addition, the weight difference is within the management range, the difference between the width of the measuring slab and the rolling plate target width is within the management range, the length difference is outside the management range, and the rolling plate calculation length CASln is the rolling plate target. When the length (TASln) is equal to or larger than the length (TASln), rolling is performed according to the D type rolling method regardless of the set rolling method.

In addition, the weight difference is within the management range, the difference between the length of the measuring slab and the rolling plate target width is within the management range, the width difference is outside the management range, and the rolling plate calculation length CASln is the rolling plate target. If the length TASln is equal to or larger than the length TASln, rolling is performed according to the C type rolling method regardless of the set rolling method.

Further, the weight difference is within the management range, the width difference is out of the management range, the length of the measuring slab is smaller than the rolling plate target width, and the rolling plate calculation length CASln is equal to the rolling plate target length TASln. If it is larger or larger, rolling is performed according to the A type rolling method or the B type rolling method.

The thick steel plate is manufactured according to the present invention by performing the thick plate rolling as described above.

The above-mentioned management range depends on the controllability of the plant and the real rate management level, but the weight is 2% or less, and the width and length are preferably 5 mm or less, respectively.

Hereinafter, an example of the present invention will be described in detail with reference to FIG. 3, which shows an example of an apparatus for implementing the present invention.

As shown in FIG. 3, when the work-instructed slab 3 is transferred from the furnace charging side roller table 4 to the arrow direction for charging in the furnace 13, the slabs 3 are installed at both sides of the roller table 4. The width is measured by the width measuring sensor 5.

Subsequently, when the weight measuring device 8 is reached, the material is detected by the material position detector 7, and when the material is stopped by the roller table controller 11, the slab length is measured by the length sensor 6 and the weight sensor 8. And the weight is measured, the width, the length measurement record is the width, the length measurement record processor 9, and the weight is transmitted to the process control computer 11 through the weight record processor 10.

The process control computer 11 collecting the measurement results compares the measured weight with the indicated (target) weight in order to determine and determine the working method based on the slab measurement results. Therefore, the work is canceled and the slab 3 is lifted out of the roller table to cancel the work.

In Fig. 3, reference numeral 12 denotes a roller table controller.

However, if the measured weight is larger than the indicated weight, it is possible to achieve the rolling target value by volume, but if the weight deficiency is compensated for by the length of the slab surface scarfing, the length in the case of (b) and (c) of the rolling method of FIG. In the case of (d), the width may be insufficient. Compare the width and length of the slab with the indicated dimension. If the difference is within the control range, work by the original rolling method. If not, the rolling method is determined according to the method described above, followed by rolling.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example)

According to the conventional method and the method of the present invention, when a slab having a thickness × width × length indicated value of 220 mm × 1900 mm × 300 mm and a indicated weight of 9844 kg is rolled with the measurement results and rolling target dimensions as shown in Table 1, The result of rolling by changing the rolling method is shown in Table 2 below.

However, here, the amount of spreading at the time of length rolling was calculated as 7% of the reduction amount.

Rolling Method Slavic measurements Slab equivalent thickness (mm) Rolled Plate Target Dimensions Width (mm) Length (mm) Weight (kg) Thickness (mm) Width (mm) Weight (kg) Type C 1900 3030 9850 218 20.0 3014 20803 Type D 1880 3030 9850 218 20.0 1914 32759

division Rolling Method Actual rolling method Dimension after rolling Remarks Thickness (mm) Width (mm) Length (mm) Conventional method Type C Type C 20.0 3044 20614 189mm long lack Type D Type D 20.0 1894 33132 20mm wide Invention method Type C Type A 20.0 3014 20820 Both width and length are satisfied Borrowing D Type A 20.0 1914 32785 Both width and length are satisfied

As shown in Table 2, the measured weight is 5kg larger than the indicated weight, but in the conventional method, the length of the steel sheet is 30 mm larger than the target width after rolling in case of Type C. While the width is 20mm smaller than the target width and the shortage of the width occurs, in the case of the method of the present invention, as a result of rolling by changing the rolling method, it can be seen that the steel sheet satisfies both the width and the length so that no defect occurs.

As described above, the present invention can determine the optimal rolling method using the measurement results of the slab dimensions and by rolling in accordance with the determined rolling method to minimize the dimensional defects of the steel plate later to improve the error rate and reduce out of order products It works.

Claims (1)

In the method for manufacturing a thick steel plate using a thick steel sheet manufacturing apparatus comprising a heating furnace, a rolling mill and a width, length and weighing device on the charging side of the furnace, Setting a thickness, length, and width of the target rolled steel sheet; Setting a weight, a length, and a width of a target slab for manufacturing the target rolled steel sheet; The method for producing the target rolled steel sheet using the target slab, slab → even rolling → 90 ° horizontal rotation → width rolling rolling 90 ° horizontal rotation → finishing rolling consisting of finishing rolling (type A rolling method), slab → width Bending rolling → 90 ° horizontal rotation → rolling method consisting of finishing rolling (B type rolling method), slab → 90 ° horizontal rotation → rolling method consisting of finishing rolling (type C rolling method), and slab → rolling method consisting of finishing rolling Selecting from a rolling method group consisting of (D type rolling method); Measuring the width, length and weight of the slab before rolling; Obtaining a difference between the measured weight of the slab and the weight of the target slab, and canceling the rolling operation when the difference is out of the control range; If the difference between the measured slab weight and the target slab weight (weight difference) is within the control range, the difference between the measured slab width and the target slab width (width difference) and the measured slab length and the target slab Obtaining a difference (length difference) from the length of, and performing rolling according to the rolling method set above if both the width difference and the length difference are within a management range; When the weight difference is within the management range and at least one of the width difference and the length difference is out of the management range, the thickness CSLth of the slab is obtained using Equation (1) below, and the calculated slab thickness CSLth is obtained. After calculating the steel sheet length (CASln) after rolling by using the following formula (2) and the following formula (2), the rolling plate calculating length (CASln) is compared with the rolling plate target length (TASln) set above, and the rolling plate calculating length (CASln) is Canceling the operation when the rolling plate target length (TASln) is smaller, and performing rolling according to the A-type rolling method regardless of the set rolling method when the rolling plate is smaller than the target length (TASln); CSLth = Mwt × 10 ⁶ / (MSLwd × MSLln × ρ). . . . . . . (One) Where Mwt: slab measurement weight (kg) MSLwd: Slab Measuring Width (mm) MSLln: Slab Measuring Length (mm) ρ: specific gravity CASln = CSLth × MSLwd × MSLln / (TASth × TASwd). . . . . . . (2) [TASth: rolling target thickness (mm) TASwd: Rolling Target Width (mm)] The weight difference is within the management range, the difference between the width of the measuring slab and the target width of the rolling plate is within the management range, the length difference is out of the management range, and the rolling plate calculation length CASln is the rolling plate target length ( If TASln) is greater than or equal to TASln), rolling is performed according to the D-type rolling method regardless of the set rolling method; The weight difference is within the control range, the difference between the length of the measuring slab and the rolled plate target width is within the control range, the width difference is outside the control range, and the rolled plate calculation length CASln is the rolled plate target length ( If TASln) is greater than or equal to TASln), performing rolling according to the C type rolling method regardless of the set rolling method; And The weight difference is within the control range, the width difference is out of the control range, the length of the measuring slab is smaller than the rolled sheet target width, and the rolled plate calculating length CASln is equal to or larger than the rolled sheet target length TASln. In the case of the steel sheet manufacturing method comprising the step of performing rolling according to the A type rolling method or B type rolling method