KR101462167B1 - Method for casting - Google Patents

Abstract

A casting method according to the present invention includes the steps of determining whether a remaining amount of a first molten steel contained in a tundish has reached a reference amount and determining whether a remaining amount of the first molten steel has reached a reference amount, And adjusting the supply timing of the second molten steel for subsequent casting.
Therefore, according to the embodiments of the present invention, by controlling the casting speed and the timing of supplying the subsequent molten steel in accordance with the remaining amount of the pre-molten steel, the mixed area area of the pre-molten steel and the succeeding molten steel can be minimized. As a result, it is possible to minimize the occurrence of scrap which is caused by intermixing of the bridges, thereby improving the quality of the product. In addition, it is possible to reduce the production cost incurred for disposal of scrap in a post-process.

Description

{Method for casting}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method, and more particularly, to a casting method capable of easily manufacturing a brass.

Generally, in order to continuously produce different steels of different compositions without interruption, only the ladles accommodating new steels are exchanged and continuously cast continuously. That is, without replacing the tundish and the mold, only the ladle is exchanged and cast.

The conventional casting process of the gusset type is performed by minimizing the casting speed of the existing molten steel in the tundish and supplying the molten steel stored in the subsequent ladle to the tundish while injecting the molten steel stored in the mold into the tundish. In this case, the molten steel mixed with each other in the tundish is mixed with each other, and the mixed molten steel is cast as it is and the scrap is generated in the cast steel, and when the molten steel mixed region is wide, the area where the scrap is generated is widened. Such scrap is cut off in a post-process and discarded, which increases the production cost.

In addition, in the past, a molten steel separation jig was used to reduce scrap. However, the use of the jig had to stop the casting speed and raise the tundish.

In Korean Patent No. 10-0264984, molten steel is injected into a mold through a tundish from a ladle in which molten steel of a certain component is introduced, and then molten steel having a different composition from the molten steel is moved The casting method for casting a cast steel by continuously injecting the cast steel into a mold is characterized in that an electromagnetic generating device is provided outside the upper end of the mold so as to be located at a position of 350 mm or less from the molten steel bath surface in the mold, Of 0.7 m / min or less to generate an electromagnetic force at the upper outer side of the mold.

Korean Patent No. 10-0264984

The present invention provides a casting method capable of easily producing a gypsum.

The present invention provides a casting method that minimizes the occurrence of scrap.

The present invention provides a casting method for continuously producing different brass types, comprising the steps of: determining whether a remaining amount of a first molten steel contained in a tundish has reached a reference amount; And adjusting the casting speed according to whether the remaining amount of the first molten steel has reached the reference amount and adjusting the supply time point of the second molten steel for subsequent casting.

Decelerating the casting speed according to whether or not the remaining amount of the first molten steel has reached the first reference amount; And adjusting a supply time point of the second molten steel by determining whether the remaining amount of the first molten steel has reached a second reference amount equal to or less than the first reference amount.

Determining whether the molten steel stored in the tundish reaches the third reference amount after the second molten steel is supplied to the tundish, and adjusting a casting speed; And determining whether the molten steel stored in the tundish reaches a fourth reference amount that is equal to or greater than the third reference amount and maintaining the casting speed constant.

Wherein the first reference amount is 28% to 32% of the reference molten steel amount accommodated in the tundish, and when the remaining amount of the first molten steel reaches the first reference amount, the casting speed is set to 15% to 50% .

Wherein the second reference amount is 10% to 15% of the reference molten steel accommodated in the tundish, and when the amount of molten steel contained in the tundish reaches the second reference amount, the casting speed is set to 15% to 25% .

Wherein the third reference amount is 28% to 32% of the reference molten steel amount accommodated in the tundish, and when the molten steel amount contained in the tundish reaches the third reference amount, the casting speed is set to 30% to 65% .

Wherein the fourth reference amount is 35% to 40% of the reference molten steel amount received in the tundish, and when the amount of molten steel contained in the tundish reaches the fourth reference amount, And maintaining the casting speed constant at 55% to 65% of the reference casting speed.

After the lapse of the predetermined time, if the amount of molten steel in the tundish reaches the fifth reference amount, the casting speed is increased to the reference casting speed.

And the fifth reference amount is 55% to 65% of the reference molten steel amount accommodated in the tundish.

The casting method according to the embodiment of the present invention can minimize the mixed area area of the pre-cast steel and the subsequent cast steel by controlling the casting speed and the timing of supplying the subsequent cast steel according to the remaining amount of pre-cast steel. As a result, it is possible to minimize the occurrence of scrap which is caused by intermixing of the bridges, thereby improving the quality of the product. Also, it is possible to reduce the production cost incurred for disposal of scrap in a post-process.

1 is a schematic view showing a general casting process
FIG. 2 is a flow chart showing the operation progress of the casting method according to the embodiment of the present invention.
3 is a graph showing a casting method according to an embodiment of the present invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

1 is a schematic view showing a general casting process.

1, a general continuous casting apparatus includes a ladle 10 for transporting molten steel, a tundish 20 for temporarily storing molten steel supplied from the ladle 10, The molten steel is supplied to the tundish 20 through the immersion nozzle 30 and solidified into a predetermined shape. The molten steel is supplied from the ladle 10, and the molten steel is injected into the tundish 20 and stored in a predetermined amount. The molten steel injected from the mold 20 is injected into the mold 40 through the immersion nozzle 30 to produce a solid cast steel.

Particularly, in the casting process for continuously casting the bricks, new molten steel (hereinafter referred to as "molten steel") accommodated in the subsequent ladle 10 (hereinafter referred to as "molten steel") accommodated in the molten steel 'To the tundish 20. That is, when the first molten steel remains in the tundish 20 in a predetermined amount, the second molten steel is supplied. Also, while the second molten steel is being supplied, the first molten steel is injected into the mold 40 and solidified. Thereafter, the first molten steel is drawn to the lower portion of the mold 40 in the form of a casting. The cast steel (hereinafter referred to as 'first cast steel') drawn from the mold 40 and provided by the first molten steel is conveyed by the rollers 50 and cooled by the cooling water injected from the segment during conveyance, Piece.

In the embodiment of the present invention, the supply timing of the second molten steel is adjusted according to the remaining amount of the first molten steel, and the casting speed is controlled to minimize the mixed region of the first molten steel and the second molten steel. Here, the mixed region means a region where two different molten steel components are mixed in the tundish 20, and this mixed region is a region where the remaining amount of the first molten steel in the tundish 20, the supply point of the second molten steel, Lt; / RTI >

FIG. 2 is a process flow chart showing the progress of the operation of the casting method according to the embodiment of the present invention. 3 is a graph showing a casting method according to an embodiment of the present invention for casting a heterogeneous steel.

In the embodiment of the present invention, the first molten steel is supplied from the ladle 10 to the tundish 20 in order to manufacture the first cast steel. The first molten steel injected into the tundish 20 is injected into the mold, The first molten steel injected into the mold 40 is solidified and drawn to the lower portion of the mold 40. The first molten steel amount in the tundish 20 is reduced by the continuous casting process, the supply time point of the second molten steel is determined according to the remaining amount of the first molten steel in the tundish 20, and the casting speed is controlled.

That is, the embodiment of the present invention is a casting method for continuously producing different types of bricks, comprising the steps of discharging the first molten steel contained in the tundish 20 and participating in the pre-casting process (S100) A step S120 of determining whether the remaining amount of the molten steel in the tundish 20 has reached the first reference amount S110, a step S120 of decelerating the casting speed when the remaining amount of the first molten steel reaches the first reference amount, (S130). When the remaining amount of the first molten steel reaches the second reference amount, the second molten steel different from the first molten steel is injected into the tundish 20 In step S140, it is determined whether the amount of molten steel in the tundish 20, that is, the amount of molten steel mixed with the first molten steel and the second molten steel has reached the third reference amount (S150). When the mixed molten steel amount reaches the third reference amount The process of increasing the casting speed (S160) (S180) of determining whether the amount of molten steel in the tundish 20 has reached the fourth reference amount (S170); if the amount of molten steel has reached the fourth reference amount (S180) (S190) of determining whether the amount of molten steel in the tundish 20 has reached the fifth reference amount by the second molten steel (S290), and raising the molten steel amount to the reference casting speed when the amount of molten steel reaches the fifth reference amount , And then a second cast steel different from the first cast steel produced from the first molten steel is cast using the second molten steel. Here, the process of reducing the casting speed while discharging the first molten steel may be performed in a plurality of steps, and the process of increasing the address speed while injecting the second molten steel may be performed in a plurality of steps.

At this time, the reference molten steel amount refers to the amount of molten steel held in the tundish 20 for casting the cast steel, and the reference casting speed usually means a casting speed of the cast steel. The first to fifth reference amounts refer to the reference values of the first and second molten steel, which are predetermined values for controlling the discharge and injection of each molten steel. Specifically, the first reference amount is smaller than the reference steel amount, the second reference amount is smaller than the first reference amount, the third reference amount is larger than the second reference amount, and the fourth reference amount is larger than the third reference amount , And the fifth reference amount is larger than the fourth reference amount. The first reference amount and the second reference amount are values at which the first molten steel amount reaches a reference amount that mainly controls the discharge of the first molten steel. The third to fifth reference amounts are values to which the mixed molten steel in which the first molten steel and the second molten steel are mixed as a reference amount for controlling the injection of the second molten steel is a value. From the third reference amount to the fifth reference amount, The amount of the molten steel becomes larger than that of the first molten steel, and from the fifth reference amount, the second molten steel occupies the majority of the total molten steel. For example, when the reference steel amount is 50 tons, the first reference amount is 15 tons, the second reference amount is 6 tons, the third reference amount is 15 tons, the fourth reference amount is 18 tons, the fifth reference amount is 30 tons Can be set. Of course, each reference quantity can be changed depending on operating conditions and environment.

By this process, it is possible to replace the first molten steel and the second molten steel without difficulty, while reducing the amount of mixed molten steel, so that the occurrence of scrap generated by mixing the first cast steel and the second cast steel can be suppressed. Further, the first cast steel making step and the second cast steel making step can be easily connected to each other.

In the following, each step will be described in more detail with reference to FIG. 2 and FIG.

First, during the casting operation of the first casting continuously, the first molten steel in the tundish 20 is discharged (S100), and the remaining amount of the first molten steel in the tundish 20 is detected and sensed in real time, It is determined whether or not the first reference amount has been reached (S110). Here, the first reference amount is 28% to 32% of the reference molten steel amount accommodated in the tundish 20. The reference amount of molten steel generally refers to an amount of molten steel that can be accommodated in the tundish 20, for example, 50 tons. If the first molten steel amount reaches the first reference amount, the casting speed is decreased (S120). More specifically, as shown in FIG. 3, when the first molten steel amount in the tundish 20 reaches a first reference amount, that is, 28% to 32% of the reference molten steel amount during the casting process, The casting speed is reduced to 15% to 50% of the reference casting speed until the reference amount is reached. The reference casting speed is, for example, 0.5 m / min. Preferably, when the first molten steel amount is 15 tons, the speed is reduced to 20% of the reference casting speed, for example, 0.1 m / min. At this time, in the process of decelerating the casting speed until the second reference amount is reached in the first reference amount, the casting speed may be continuously decelerated from the first reference amount to the second reference amount at one time or may be decelerated stepwise . For example, when the first molten steel amount is gradually decreased from the first reference amount to the second reference amount, when the first molten amount reaches 28% to 32% of the first reference amount, that is, the reference molten amount, the first molten amount reaches the first auxiliary reference amount The casting speed is reduced to 35% to 50% of the reference casting speed and maintained for a predetermined time, and then decelerated to 15% to 25% of the reference casting speed up to the second reference amount. The first auxiliary reference amount is 15% to 20% of the reference molten steel amount, and preferably, when the first molten amount reaches 15 tons, the casting speed is increased to 40 %, For example, 0.2 m / min, and is decelerated step by step to 20% of the reference casting speed, for example, 0.1 m / min, until the second reference amount is maintained for a predetermined time.

On the other hand, when the amount of the first molten steel accommodated in the tundish 20 is less than 28% of the reference molten steel amount, there is no time margin during the transition to the next step of the casting operation, thereby hindering the casting operation. If the amount of the first molten steel accommodated in the tundish 20 exceeds 32% of the reference molten steel amount, the casting speed is slowed down in a state where the molten steel is too much. Therefore, the casting speed is frequently changed to match the amount of molten steel in the step. As a result, the quality of the cast steel is deteriorated. In addition, if the casting speed is less than 15% of the reference casting speed, casting may be delayed and the operation may be delayed. If the casting speed exceeds 50% of the reference casting speed, a problem may occur in the tundish 20 due to a rapid casting speed. Accordingly, when the first molten steel amount reaches 28% to 32% of the first reference amount, that is, the reference molten steel amount, the casting speed is reduced to 15% to 50% of the reference casting speed to the second reference amount. In the above description, the process of decelerating the casting speed from the first reference amount to the second reference amount through the first auxiliary reference amount in two steps has been described as an example. However, the present invention is not limited to this, but may be decelerated by a plurality of steps.

Then, the remaining amount of the first molten steel in the tundish 20 is detected or sensed to determine whether the first molten steel has reached the second reference amount (S130). Here, the second reference amount is 10% to 15%, for example, 6 tons of the reference molten steel amount contained in the tundish 20. If the first molten steel amount in the tundish 20 reaches the second reference amount, the second molten steel is injected into the tundish 20 for subsequent casting (S140). More specifically, the supply timing of the second molten steel is adjusted depending on whether the first molten steel amount has reached the second reference amount. 3, when the first amount of molten steel in the tundish 20 reaches the second reference amount, that is, 10% to 15%, the following ladle 10 is opened for subsequent casting and the tundish 20 (S140), and the casting speed is maintained at 15% to 25% of the reference casting speed for a certain period of time. Preferably, when the first molten steel amount is 6 tons, the second molten steel is injected and maintained at 20% of the reference casting speed, for example, 0.1 m / min.

On the other hand, when the first molten steel amount stored in the tundish 20 is less than 10% of the reference molten steel amount, the slag of the tundish 20 may flow into the mold 40, resulting in an operation accident. Also, if the casting speed is not maintained at 15% to 25% of the reference casting speed for a predetermined time, the second molten steel flows into the tundish 20 into which the first molten steel flows, so that the first molten steel and the second molten steel The area of the mixed region is widened. Therefore, when the first molten steel amount reaches the second reference amount, that is, 10% to 15% of the reference molten steel amount, the second molten steel is injected and the casting speed is maintained at 15% to 25% of the reference casting speed.

Then, it is determined whether the amount of molten steel in the tundish 20 has reached the third reference amount (S150). Here, the third reference amount is 28% to 32% of the reference molten steel amount accommodated in the tundish 20. If the amount of molten steel in the tundish 20 reaches the third reference amount, the casting speed is increased up to the fourth reference amount (S160). 3, when the amount of the molten steel in the tundish 20 reaches the third reference amount, that is, 28% to 32% of the amount of the reference molten steel, the amount of molten steel in the tundish 20 becomes the fourth The casting speed is increased from 30% to 65% of the reference casting speed until the reference amount is reached. Preferably, when the amount of the molten steel in the tundish 20 reaches 15 tons, it is increased to 60% of the reference casting speed, for example, 0.3 m / min. At this time, in the process of increasing the casting speed until the fourth reference amount is reached from the third reference amount, the casting speed may be continuously increased from the third reference amount to the fourth reference amount at one time or may be increased stepwise . For example, when the casting speed is gradually increased from the third reference amount to the fourth reference amount, when the amount of the molten steel in the tundish 20 reaches the third reference amount, that is, 28% to 32% ) The casting speed is increased from 30% to 45% of the reference casting speed until the amount of molten steel reaches the second auxiliary reference amount, and is increased to 50% to 65% of the reference casting speed up to the fourth reference amount . The second auxiliary reference amount is 35% to 40% of the reference molten steel amount. Preferably, when the third molten steel amount reaches 15 tons, the casting speed is increased to 40 %, For example, 0.2 m / min, and is increased stepwise up to the fourth reference amount up to 60% of the standard casting speed, for example, 0.3 m / min.

On the other hand, when the amount of molten steel stored in the tundish 20 is less than 28% of the reference molten steel amount, the amount of molten steel can not be smaller than the amount of molten steel necessary for casting the cast steel, thereby hindering the casting operation. If the amount of molten steel stored in the tundish 20 exceeds 32% of the reference molten steel amount, the region where the first molten steel and the second molten steel are mixed is increased. Also, if the casting speed is less than 30% of the reference casting speed, the casting operation may be delayed and the process may be delayed. If the casting speed exceeds 65% of the reference casting speed, the area of the area where the first molten steel and the second molten steel are mixed due to the rapid casting speed is increased. Therefore, when the amount of molten steel in the tundish 20 reaches the third reference amount, that is, 28% to 32% of the reference molten amount, the casting speed is increased from 30% to 65% of the reference casting speed to the fourth reference amount. In the above description, the process of increasing the casting speed from the third reference amount to the fourth reference amount and increasing the casting speed in two steps through the second auxiliary reference amount has been described as an example. However, the present invention is not limited thereto, and the casting speed can be increased by a plurality of steps.

Thereafter, it is determined whether or not the amount of molten steel in the tundish 20 has reached the fourth reference amount (S170). Here, the fourth reference amount is 35% to 40% of the reference molten steel amount accommodated in the tundish 20. When the amount of molten steel in the tundish 20 reaches the fourth reference amount, the casting speed is maintained for a predetermined period of time (S180). 3, when the amount of molten steel in the tundish 20 reaches 35% to 40%, for example, 18 tons of the reference molten steel amount, the casting speed is set to 55% to 60% of the reference casting speed 65%, and the amount of molten steel in the tundish 20 is maintained at 35% to 40% for a certain period of time. Preferably, when the amount of the molten steel in the tundish 20 is 18 tons, 18 tons is maintained at 60% of the reference casting speed, for example, 0.3 m / min for 4 minutes.

On the other hand, when the amount of the molten steel contained in the tundish 20 is less than 35% of the reference molten steel amount, the amount of molten steel required in the tundish 20 necessary for casting is too small, and the temperature in the tundish 20 rapidly drops. This may interfere with casting. If the amount of molten steel stored in the tundish 20 exceeds 40% of the reference molten steel amount, the amount of molten steel in the tundish 20 increases, and the area where the first molten steel and the second molten steel are mixed increases. Also, if the casting speed is less than 30% of the reference casting speed, the casting operation may be delayed and the process may be delayed. If the casting speed exceeds 65% of the reference casting speed, the region where the first molten steel and the second molten steel are mixed due to the rapid casting speed is increased. Here, the reason why the amount of molten steel in the tundish 20 is maintained at 35% to 40% of the reference molten steel amount for a predetermined time when the molten steel reaches the fourth reference amount is that the newly introduced molten steel, that is, This is because when the molten steel is injected into the dish 20, the mixing area of the molten steel is widened due to an abrupt increase in the casting speed. Accordingly, the casting speed is controlled so that the molten steel inflow amount into the tundish 20 is kept constant, and then the molten steel mixed portion is discharged. In order to maintain the amount of molten steel in the tundish 20 at 35% to 40% of the reference molten steel amount as described above, the amount of molten steel injected into the tundish 20 and the amount discharged into the mold 40 It is preferable to control it to be constant. Therefore, when the amount of the molten steel in the tundish 20 reaches the fourth reference amount, that is, 35% to 40%, the amount of molten steel in the tundish 20 is maintained at 35% to 40% And maintained at 55% to 65% of the casting speed for a certain period of time. For example, for 4 minutes.

Thereafter, it is determined whether the amount of molten steel in the tundish 20 has reached the fifth reference amount (S190). Here, the fifth reference amount is 55% to 65% of the reference molten steel amount accommodated in the tundish 20. if. When the amount of molten steel in the tundish 20 reaches the fifth reference amount, the casting speed is increased to the reference casting speed (S200). 3, when the amount of molten steel in the tundish 20 reaches 55 to 65%, for example, 30 tons of the reference molten steel amount, the casting speed is set to a reference casting speed, for example, 0.5 m / min .

On the other hand, if the amount of molten steel contained in the tundish 20 is less than 55% of the reference molten steel amount, the amount of molten steel discharged into the mold 40 is greater than the amount of molten steel injected into the tundish 20 And the level of molten steel is reduced. If the amount of molten steel stored in the tundish 20 exceeds 65% of the reference molten steel amount, the molten steel remains in the tundish 20 for a long time until the molten steel is discharged, thereby deteriorating the quality of the casting. Therefore, when the amount of molten steel in the tundish 20 reaches 55% to 65% of the reference molten steel amount, the casting speed is increased to the reference casting speed.

As described above, in the present invention, it is possible to minimize the mixing ratio of the gaseous components through the casting speed and the molten steel amount control of the tundish 20. As a result, the occurrence of scrap that is caused by mutual mixing of bricks can be minimized. In addition, the quality of the product can be improved by minimizing the mixing of the bridges, and the production cost incurred for disposal of scrap in a post-process can be reduced.

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 exemplary embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the following claims.

10: Ladle 20: Tundish
30: immersion nozzle 40: mold
50: Roller

Claims (9)

A casting method for continuously producing different kinds of bricks,
And judges whether or not the remaining amount of the first molten steel which has been accommodated in the tundish has reached the first reference amount which is 28% to 32% of the reference molten steel amount which is the amount of molten steel accommodated in the tundish for casting the cast steel Process;
Decelerating the casting speed according to whether or not the remaining amount of the first molten steel reaches the first reference amount;
The second molten steel for subsequent casting is injected according to whether or not the remaining amount of the first molten steel has reached the second reference amount which is 10% to 15% of the reference molten steel and the casting speed is set to a constant Time keeping process;
Determining whether or not the molten steel stored in the tundish reaches a third reference amount that is 28% to 32% of the reference molten steel amount after the second molten steel is supplied to the tundish, thereby increasing the casting speed; And
When the amount of molten steel received in the tundish reaches the fourth reference amount, whether the molten steel stored in the tundish reaches a fourth reference amount, which is 35% to 40% of the reference molten steel amount received in the tundish, And maintaining a molten steel amount in the tundish as a fourth reference amount at a casting speed of 55% to 65% of a reference casting speed for a predetermined time. The method according to claim 1,
When the amount of molten steel in the tundish reaches the third reference amount,
The casting speed is increased from 30% to 45% of the reference casting speed until the molten steel amount in the tundish reaches the second auxiliary reference amount which is 35% to 40% of the reference molten steel amount, Wherein the casting speed is increased from 50% to 65% of the reference casting speed up to the fourth reference amount. delete The method according to claim 1,
And when the remaining amount of the first molten steel reaches the first reference amount, the casting speed is reduced to 15% to 50% of the reference casting speed. delete The method according to claim 1,
Wherein the casting speed is increased from 30% to 65% of the reference casting speed when the amount of molten steel contained in the tundish reaches the third reference amount. delete The method according to claim 1,
Wherein the casting speed is increased to a reference casting speed when the amount of molten steel in the tundish reaches the fifth reference amount which is 55% to 65% of the reference molten steel amount after the predetermined time. delete

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