KR20140129885A - Continuous casting method - Google Patents

Abstract

Disclosed is a continuous casting method. According to an embodiment of the present invention, the continuous casting method comprises: a step of measuring the rate of forced opening a ladle where molten metal is accommodated; a step of tapping the molten metal accommodated in the ladle to a tundish; a step of manufacturing a steel product by tapping the molten metal accommodated in the tundish to a continuous casting machine; and a step of setting the use of the steel product according to whether the rate of forced opening a ladle satisfies the predetermined value.

Description

Continuous casting method {CONTINUOUS CASTING METHOD}

The present invention relates to a continuous casting method.

Continuous casting method of steel is a method of making solid material by injecting molten material into a mold and cooling it, and it is possible to continuously produce intermediate material such as slab, billet, and bloom. Particularly, in the case of a CSP (Compact Strip Production) method using an electric furnace, it is characterized by a continuous line from the steelmaking process to the rolling process.

Therefore, when the above method is applied, the continuous process is performed in a consistent line, so that even if various factors that adversely affect the quality are generated, it is difficult to select the semi-finished products in the intermediate process, so that a defective product can be produced.

Accordingly, it is necessary to inspect whether the defective product is finished after the completion of the production of the steel product, and it is necessary to select the defective product. However, since the worker inspects the defective product manually, the efficiency of the work may be lowered.

Therefore, there is a need to study a continuous casting method capable of treating defective products more quickly and easily considering the characteristics of continuous processes.

The background art of the present invention is disclosed in Korean Patent Laid-Open Publication No. 10-2012-0074370 (2012.07.06, Continuous Casting Method and Apparatus).

Embodiments of the present invention are intended to provide a continuous casting method capable of treating a defective product more quickly and easily in the production of steel products.

According to an aspect of the present invention, there is provided a method of manufacturing a steel product, comprising the steps of: measuring a forging rate of ladle containing molten steel; pouring the molten steel contained in the ladle into a tundish; And setting the use of the steel product according to whether or not the steel sheet satisfies the predetermined value of the steel sheet forming step and the forging ratio of the steel sheet.

Here, the step of manufacturing the steel product may include a performing step in which molten steel passes through the continuous casting machine and solidifies to form an ingot, and a rolling step in which the ingot is processed through the rolling roll.

In the step of setting the purpose of the steel product, the steel product may be set as a genuine product when the forging ratio is 0.5 or less.

And, the continuous casting method may further include a step of transferring the steel product, which is not set as a genuine use item, to the use switching device after the step of setting the use of the steel product.

According to the embodiments of the present invention, since the use of the steel product can be automatically set according to whether or not the forced opening ratio of the ladle satisfies the predetermined value, the continuous casting method capable of handling the defective product more quickly and easily Can be implemented.

1 is a flowchart showing a continuous casting method according to an embodiment of the present invention;
2 is a schematic representation of a continuous casting apparatus according to an embodiment of the invention;
3 is a view showing an experimental result according to a forced opening ratio in a continuous casting method according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a continuous casting method according to the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or corresponding elements, A description thereof will be omitted.

In the case of a ladle that transports molten steel to turndish, if the molten steel remains in the ladle for a long time due to processing delay or the like, the hole for molten steel may be clogged. In this case, it is necessary to forcibly open the lakes, for example, to manually open the holes through which molten steel is to be introduced.

On the other hand, molten steel is more directly exposed to the atmosphere at the time of forced opening of the ladles, and the molten steel exposed to the atmosphere in this way can be reoxidized by coming into contact with oxygen. In addition, since the molten steel directly penetrates the bath surface of the tundish during the forced opening of the ladle, oxygen in the atmosphere can be introduced into the molten steel in the tundish, which can adversely affect the quality of the steel product.

Therefore, in the embodiment of the present invention, a continuous casting method capable of automatically determining whether or not a steel product is defective according to the forced opening ratio of the ladle, which can adversely affect the quality of the steel product, is proposed.

1 is a flowchart showing a continuous casting method according to an embodiment of the present invention. 2 is a schematic view of a continuous casting apparatus according to an embodiment of the present invention. 3 is a graph showing experimental results according to forced open rate in a continuous casting method according to an embodiment of the present invention.

1 to 3, a continuous casting method according to an embodiment of the present invention starts from step S100 of measuring a forced open rate of a ladle 100 containing molten steel.

2, the ladle 100 is a container used for receiving molten steel introduced from an electric furnace or the like and conveying the molten steel to the tundish 200. The ladle 100 is combined with a separate conveying device to convey molten steel .

The ladle 100 may be formed with a hole for introducing molten steel into the tundish 200 and may guide molten steel to the inside of the tundish 200 while minimizing the contact of the molten steel with the atmosphere such as a nozzle And the like can be combined with each other.

The forced opening ratio of the ladle 100 refers to the rate at which a hole for introducing molten steel is clogged and an operator opens a hole through which molten steel is manually introduced, as described above. The forced opening rate of the continuous casting Can be defined as the number of times.

That is, when the forced opening ratio is relatively high, a large number of forced openings occur in the continuous casting process, and when the forced opening ratio is relatively low, the forced openings may be small in the continuous casting process.

On the other hand, the molten steel in the forced opening of the ladle 100 comes into contact with oxygen in the atmosphere. Accordingly, aluminum (Al) and oxygen (O ₂ ) in the molten steel react with each other to increase the composition ratio of aluminum oxide (Al ₂ O ₃ ), and large inclusions may be generated in the molten steel.

Such a large inclusion is contained in an ingot such as a slab, and can be exposed to the surface through a process such as rolling, resulting in defects of rigid inclusions in steel products.

Accordingly, the forced opening ratio of the ladle 100 may have a certain degree of correlation with the defectiveness of the steel product. Accordingly, the continuous casting method according to the present embodiment can measure the forging rate of the ladle 100 and automatically set the use of the steel product on the basis thereof.

Next, the molten steel accommodated in the ladle 100 may be introduced into the tundish 200 (S200). Here, the tundish 200 is a means for temporarily storing molten steel to continuously supply the molten steel to the mold. As shown in FIG. 2, the tundish 200, which is disposed directly above the mold and is a path for supplying molten steel to the mold, .

If the molten steel is injected directly into the mold from the ladle 100, there is a risk of a safety accident, mass production is impossible, and molten steel may be reoxidized. Therefore, the casting speed can be adjusted, After the molten steel is transferred to the dish 200, molten steel can be introduced into the mold.

Next, the molten steel accommodated in the tundish 200 may be introduced into the continuous casting machine 300 to produce a steel product (S300). In this case, the continuous casting machine 300 may include various molds, strands, and the like as shown in FIG.

Next, the usage of the steel product can be set according to whether or not the pre-set value of the forced opening ratio is satisfied (S400). Here, the pre-set value refers to the forced open rate estimated to be the case where there is no defect in the steel product or only the defect within the tolerance value through experiment or statistical data beforehand, and it can be appropriately selected according to the quality control standard have.

Accordingly, if it is estimated in step S400 that there is no defect due to a lower opening ratio than the preset value, or if only a defect within the allowable value exists, the steel product may be set as a regular product (S500).

On the other hand, if it is estimated in step S400 that the forced opening ratio is higher than the preset value and there is a defect exceeding the allowable value, the steel product can be set to be switched for use or discarded.

As described above, the continuous casting method according to the present embodiment can automatically set the use of the steel product according to whether or not the forced opening ratio of the ladle 100 satisfies a preset value, A continuous casting process can be implemented.

Meanwhile, the continuous casting method according to the present embodiment can be more effective when the steelmaking process, the performance process, and the rolling process are formed as a consistent line.

Specifically, the step S300 includes a performance step S310 in which an ingot is formed through solidification of the molten steel through the continuous casting machine 300, and a rolling step S320 in which the ingot is processed through the rolling roll 400 can do.

That is, as shown in FIG. 2, when the performance process facility and the rolling process facility are formed as a consistent line and the process is continuously performed, it may be more difficult to grasp or control the occurrence of defects in the intermediate stage.

Accordingly, the continuous casting method according to the present embodiment, which can automatically determine the defectiveness of the steel product through the forced opening ratio of the ladle 100, is characterized in that when the steelmaking process, the casting process, . ≪ / RTI >

In the continuous casting method according to the present embodiment, the step S400 may set the steel product to a regular use condition when the forging ratio is 0.5 or less. In this case, the use of genuine products refers to the intended use intended for the production of steel products.

Specifically, as shown in FIG. 3, in cases 2, 3 and 5, it can be understood that the incidence of intervening material defects is 2% or less when the forced opening ratio is 0.5 or less. On the other hand, in cases 1, 4, 6 and 7, when the forced opening ratio exceeds 0.5, it can be seen that the incidence of intervening material defects increases drastically.

From these experimental results, it can be seen that there is not a large correlation between the forced opening ratio and the incidence of intervening material defects when the forced opening ratio is 0.5 or less, and the incidence of the defects is relatively low.

On the other hand, when the forced opening ratio exceeds 0.5, the forced opening ratio and the incidence of intervening material faults have a correlation according to the following equation (1).

- Equation 1 -

Y = 0.0916X ² + 0.1445X + 0.0046

Y: Rate of incidence of intervening material defects (%)

X: Forced open rate

Correlation (R ² ) = 0.94

Meanwhile, the above-mentioned experiment was applied to a steelmaking process through an electric furnace, a slab having a thickness of 50 to 60 mm and a width of 900 to 1600 mm, a ladle 100 having a molten steel amount of 100 to 200 tons, a tundish capacity of 20 to 40 tons, The mold is funnel type, the electromagnetic field is EMBR (Electro Magnetic Brake Ruler), the discharge amount is 1.5 ~ 2.5t / min, the immersion nozzle angle is 45 ~ 60 ° downward, the depth of nozzle deposition is 210 ~ 290mm, Has a basicity of 0.5 to 1.5 and a viscosity of 0.5 to 1.5 poise.

As described above, the continuous casting method according to the present embodiment can be strongly estimated as a case where there is no defect or only a defect within a permissible value when the forced opening ratio is 0.5 or less. Therefore, Can be automatically set for a genuine use.

The continuous casting method according to the present embodiment may further include a step (S600) of transferring the steel product not set for the regular use to the use change equipment (not shown) after step S400.

That is, a steel product whose forced opening ratio exceeds a preset value and is estimated to have a defect of an allowable value or more may be removed from the processing line for the genuine product and automatically transferred to the use switching equipment.

For example, after preparing a line for branching from a processing line for a regular use to a use switching facility, the steel product can be controlled to be automatically moved to the branch line when it is not set for a regular use.

In this case, the use switching equipment can be configured in various ways, including facilities for processing products with a relatively high tolerance for defects, or facilities for reintroduction into electric furnaces for re-melting.

Accordingly, all processes from the determination of the defectiveness of the steel product to the conversion of the use can be automatically performed without any operator's operation, and the efficiency of the work can be maximized.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: ladle
200: Tundish
300: Continuous casting machine
400: rolling roll

Claims (4)

Measuring the forced opening rate of the ladle containing molten steel;
Pouring the molten steel contained in the ladle into a tundish;
A step of pouring the molten steel accommodated in the tundish into a continuous casting machine to produce a steel product; And
Setting an application of the steel product according to whether the forced opening ratio satisfies a predetermined value;
/ RTI >
The method according to claim 1,
The step of fabricating the steel product comprises:
A casting step in which the molten steel passes through a continuous casting machine and solidifies to form an ingot; and
A rolling step in which the ingot is processed through a rolling roll
Wherein the continuous casting method comprises the steps of:
3. The method according to claim 1 or 2,
Wherein setting the use of the steel product comprises:
Wherein the steel product is set to be a regular product when the forced open rate is 0.5 or less.
The method of claim 3,
After the step of setting the use of the steel product,
Transferring the steel product not set for a genuine use to an application switching facility;
Further comprising the steps of:

Images