KR102156714B1 - dummy and casting method using the same - Google Patents

Abstract

The present invention is a dummy bar that pulls the cast steel from the mold and moves the cast steel in the casting direction, which can be inserted into the mold and partially moves in the thickness direction of the cast steel by a pressing force applied from the outside to enable compression And a body portion extending from the portion and the head portion.
Accordingly, according to the embodiments of the present invention, when the head portion of the dummy bar enters the light pressure lowering section, the upper pressurizing roll is lowered to start the light pressure lowering operation. Accordingly, it is possible to sufficiently lightly lower the initial cast piece connected to the head, thereby suppressing or preventing center segregation and generation of pores. Due to this, the quality of the initial cast part can be improved compared to the conventional one. In addition, there is an effect of reducing the length of the initial cast piece to be cut.

Description

Dummy bar and casting method using the same {dummy and casting method using the same}

The present invention relates to a dummy bar and a casting method using the same, and more particularly, to a dummy bar capable of preventing quality degradation and a casting method using the same.

Casting facilities are facilities that receive refined molten steel from steelmaking facilities and cast them into cast irons of various shapes. Such a casting facility receives the molten steel refined from Tundish and solidifies it into a cast shape, a cooling bed that performs a series of molding operations while secondary cooling the cast steel continuously drawn from the mold, and inserts it into the mold before starting the casting. The lower opening of the mold is closed, and when casting begins, a dummy bar that is drawn to the lower side of the mold while the initial cast piece portion solidified at the initial stage of casting is connected and moves along the cooling table is included.

On the other hand, while the cast steel is solidified and cooled while passing through the cooling zone, the concentrated molten steel remains in the center of the cast steel and is generated as central segregation, and the liquid molten steel solidifies into a solid solidification shell and the volume changes to form pores. . The segregation and pores in the center of the cast steel formed in this way are major defect factors that deteriorate the internal quality of the cast steel.

Therefore, at the end of solidification of the cast steel, soft reduction of the cast steel in the thickness direction is performed to remove the central segregation and pores of the cast steel. A plurality of pressing rolls arranged in one direction so as to face the upper surface of the cast slab at the end of solidification of the cast slab are lowered toward the cast slab, and the slab is pressed down in the thickness direction. At this time, the cast slab is pressed down by the solidification shrinkage rate at the end of solidification, and the concentrated molten steel existing between the columnar crystals by solidification shrinkage suppresses the flow of flowing into the center of the cast steel, and suppresses the occurrence of central segregation of the cast steel by compressing the residual voids .

On the other hand, in the related art, when the head of the dummy bar connected to the initial cast part completely deviated from the light-pressing section in which the push-down roll is installed, the push-down roll is lowered to have a desired reduction force. This is because, when the head portion is in the light pressure reduction section, when the push-down roll is lowered, the push-down force applied to the head portion is reversely applied back to the push-down roll or the casting facility, resulting in a failure or load, and there is a risk of a safety accident.

However, in this case, the light pressure lowering of the initial cast piece connected to the head portion is made only when reaching the second half or the end point of the light pressure lower section, so that the light pressure drop on the initial cast piece portion is not sufficient. In this case, quality deterioration occurs due to central segregation and pores in the initial cast part. In addition, the length of the initial cast part of poor quality becomes long, causing a problem in that a large amount of the initial cast part must be cut.

Korean Patent Registration KR1252647

The present invention provides a dummy bar capable of sufficiently performing light pressure under the initial cast part and a casting method using the same.

The present invention provides a dummy bar capable of improving the quality of an initial cast part to be cast by contacting and connecting with a dummy bar head, and a casting method using the same.

The present invention is a dummy bar that draws a cast piece from a mold and moves the cast piece in the casting direction, and can be inserted into the mold, and a part of the cast piece moves in the thickness direction by a pressing force applied from the outside to prevent compression. Possible head portion; And a body portion extending from the head portion.

The head portion is arranged in a thickness direction of the cast piece and includes a first body and a second body connected to each other, and the first body is directed toward the second body by a force applied from the outside of the first body. Can be moved to.

The second body is provided with a moving space in which at least a part of the first body is accommodated and the direction in which the first body is located is opened,

At least a part of the first body can be inserted into the moving space.

It is installed so as to pass through a sidewall of the second body surrounding the moving space, and an end inserted into the second body is connected to the first body, and includes a moving part movable together with the first body.

A movable groove formed from an outside to an inward direction of the sidewall is provided in the sidewall of the second body so that the movable part may pass therethrough, and the movable groove extends on the sidewall in a movement direction of the first body.

The moving part may include a moving member installed to pass through the moving groove of the second body and having an end inserted into the second body connected to the first body; And a fastening member positioned inside the second body, a hollow type provided to pass through the moving member, and capable of adjusting an adhesion force with the inner surface of the second body.

The moving part is installed so as to pass through the moving groove of the second body, the end inserted into the second body includes a moving member connected to the first body, and the moving groove is positioned under the moving member. It is installed inside and includes an elastic member having an elastic force.

And an elastic member installed to connect the first body and the second body inside the second body and capable of extending and contracting with the movement of the first body.

The casting method according to the present invention includes the process of drawing a head portion of a dummy bar and a cast piece connected to the head portion from a mold; A step of continuously moving the dummy bar from the lower side of the mold to solidify the cast piece drawn from the mold; And light pressure lowering the cast iron entering the light pressure lower section provided on the lower side of the mold; including, in the light pressure lowering the cast steel, when the head portion enters the light pressure lower section, the plurality of upper pressure lowering rolls In the middle, an upper push-down roll positioned at an upper side of the head portion and an upper push-down roll positioned at the rear of the head portion in the light pressure lowering section are lowered.

In lowering the upper push-down roll located at the upper side of the head part and the upper push-down roll located at the rear of the head part in the light pressure lower section, only the head that has entered the light pressure lower section is lightly pressed, or the light pressure is lowered. The head part entered into the section and the cast piece which is located at the rear of the head part by entering the light pressure section are pressed down together.

The light pressure reduction section is from a point at which the first upper push down roll is located to a point at which the last upper push down roll is located among the plurality of upper push down rolls, and the position of the first upper push down roll is a light pressure start point, When the rear end of the head part connected to the cast piece reaches the starting point under the light pressure, lowering the upper push-down roll positioned at the upper side of the head part.

The light pressure reduction section is from a point at which the first upper push down roll is located to a point at which the last upper push down roll is located among the plurality of upper push down rolls, and the position of the first upper push down roll is a light pressure start point, When the position of the last upper rolling-down roll is the end point under light pressure, and the rear end of the head part passes through the start point under light pressure and is located between the start point under light pressure and the end point under light pressure, the position corresponding to the upper side of the head part It includes a process of lowering the upper rolling roll.

During the light pressure reduction section, the head portion passes, and the upper push-down roll positioned at the rear of the current position of the head portion maintains a lowered state at the previous point in time.

In lowering the upper push-down roll corresponding to the upper side of the head part, a part of the head part is moved and compressed in the thickness direction of the cast piece by a pressing force applied from the upper push-down roll.

The head portion is provided with a first body movable by a pressing force applied from the upper push-down roll and a moving space in which at least a part of the first body can be accommodated, and the direction in which the first body is located is opened. It includes a second body, and compresses the first body to reduce a moving space of the second body by a pressing force applied from the upper push-down roll.

Before starting the casting, fastening the moving part so that the end is connected to the first body through the sidewall of the second body surrounding the moving space; And adjusting the adhesion force between the moving part and the second body to adjust the movement resistance of the first body.

After the casting is completed, the process of returning the first body moved in the direction of the second body by the pressing force applied from the upper rolling roll to a state before rolling.

According to the embodiments of the present invention, when the head portion of the dummy bar enters the light pressure lowering section, the upper pressurizing roll is lowered to start the light pressure lowering operation. Accordingly, it is possible to sufficiently lightly lower the initial cast piece connected to the head, thereby suppressing or preventing center segregation and generation of pores. Due to this, the quality of the initial cast part can be improved compared to the conventional one. In addition, there is an effect of reducing the length of the initial cast piece to be cut.

1 is a view showing a casting equipment according to an embodiment of the present invention
2 is a view showing a dummy bar according to an embodiment of the present invention
3 is a three-dimensional view showing a head of a dummy bar and a cast iron connected thereto according to an embodiment of the present invention
4 is a three-dimensional view showing the head of the dummy bar according to an embodiment of the present invention
Fig. 5(a) is a view taken along line A-A' of Fig. 4(a), showing a state before the first body of the head is lowered
FIG. 5(b) is a view taken along line A-A' of FIG. 4(b), showing a state in which the first body of the head is lowered.
FIG. 6(a) is a view taken along line B-B' of FIG. 4(a), showing a state before the first body of the head descends
6(b) is a view taken along line B-B' of FIG. 4(b), showing a state in which the first body of the head is lowered.
7 is a view showing a head according to a first modified example of the embodiment
8 is a view showing a head according to a second modified example of the embodiment
9(a) to 9(d) are views for explaining the operation of the light pressure lower part according to the movement of the head part of the dummy bar according to an embodiment of the present invention
10(a) to 10(d) are diagrams for explaining the operation of the light pressure lower part according to the third modified example of the embodiment
11(a) to 11(b) are views for explaining the operation of the conventional light pressure lower part

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms. It is provided to inform you. In the drawings, the same reference numerals refer to the same elements.

The present invention relates to a dummy bar and a casting method using the same, which can prevent degradation of the quality of cast steel. In addition, the present invention relates to a dummy bar capable of improving the quality of an initial cast part to be cast in contact with or connected to a dummy bar head, and a casting method using the same.

1 is a view showing a casting equipment according to an embodiment of the present invention. 2 is a view showing a dummy bar according to an embodiment of the present invention. 3 is a three-dimensional view showing a head of a dummy bar and a cast iron connected thereto according to an embodiment of the present invention.

4 is a three-dimensional view showing a head of a dummy bar according to an embodiment of the present invention. Here, FIG. 4 (a) is a state before the first body of the head portion is lowered, and FIG. 4 (b) is a state in which the first body is lowered.

FIG. 5(a) is a view taken along line A-A' of FIG. 4(a) and shows a state before the first body of the head is lowered. 5(b) is a view taken along line A-A' of FIG. 4(b) and shows a state in which the first body of the head is lowered. 6(a) is a view taken along line B-B' of FIG. 4(a) and shows a state before the first body of the head is lowered. 6(b) is a view taken along line B-B' of FIG. 4(b), and shows a state in which the first body of the head is lowered.

Hereinafter, a casting facility according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

Referring to FIG. 1, the casting facility receives molten steel and temporarily stores the molten steel in a tundish 10, the upper and lower portions are opened, and the molten steel stored in the tundish 10 is received and initially solidified in a certain shape ( A plurality of rolls 5110 and 5210 that are arranged in the casting direction from the lower side of the mold 20 for primary solidification) and move or guide the drawn cast pieces S in one direction. ), a cooling zone 5000 for secondary solidification while moving the cast steel S, inserted to close the lower opening of the mold 20 before the start of casting, and when the casting starts, the cast steel solidified at the beginning of the casting (S ) Is drawn to the lower side of the mold 20 in a connected state and includes a dummy bar 6000 that moves along the cooling table 5000.

In addition, the casting facility includes a position detection unit 4000 capable of detecting the position of the dummy bar 6000 in real time during casting. In addition, the casting equipment is located in front of the immersion nozzle 30 to supply the molten steel of the tundish 10 to the mold 20, the cooling table 5000, and a cutter (not shown) to cut the solidified cast steel. Include.

Hereinafter, the solidified cast area on the dummy bar 6000 or in contact with the dummy bar 6000 is referred to as an initial cast part.

The tundish 10 is a means for supplying molten steel to the mold 20, and is a shape of a container having an inner space for receiving molten steel, the outermost outer wall is formed of iron skin, and the inner wall of the iron skin is protected with refractory material.

The immersion nozzle 30 is used to supply the molten steel of the tundish 10 to the mold 20 and is installed to connect the tundish 10 and the mold 20.

The mold 20 has an upper side and a lower side open, and a hollow shape having an inner space. In addition, the mold 20 is in a form where the lower side is open as described above for the continuous drawing of the first solidified cast piece S, and the lower opening is closed by the dummy bar 6000 before the start of casting. . That is, before the molten steel is injected into the mold 20, the dummy bar 6000 is inserted through the upper opening of the mold 20, and the lower opening of the mold 20 is closed or sealed with the dummy bar 6000, After that, molten steel is injected into the mold 20.

The cooling table 5000 is provided with a plurality of rolls (hereinafter referred to as guide rolls 5110) arranged in one direction from the lower side of the mold 20, so that the cast pieces S drawn from the mold 20 are moved in one direction. While providing a driving force to move, a plurality of rolls arranged in one direction from the front of the guide portion 5100 and the guide portion 5100 to guide the movement thereof, and press down the cast piece S (hereinafter referred to as the push-down roll 5210 )) and includes a light pressure lower portion 5200.

The guide part 5100 is located between the plurality of guide rolls 5110 and the plurality of guide rolls 5110 arranged in a row from the lower side of the mold 20 to the front end of the light pressure lower part 5200 to face the cast piece S. It includes a nozzle (not shown) for spraying cooling water.

The guide roll 5110 is installed to face each of the upper and lower surfaces of the cast piece (S). Hereinafter, a guide roll disposed to face the upper surface of the cast piece S is referred to as an upper guide roll 5111a, and a guide roll disposed to face the lower surface of the cast piece S is referred to as a lower guide roll 5111b.

In addition, nozzles are provided between the plurality of upper guide rolls 5111a and between the plurality of lower guide rolls 5111b to spray coolant toward the cast piece S.

Meanwhile, the cast piece S drawn from the mold 20 is solidified by the sprayed cooling water while moving so as to pass between the plurality of upper guide rolls 5111a and the lower guide rolls 5111b.

By the way, while the cast piece S is solidified and cooled while passing through the cooling zone 5000, unsolidified molten steel may remain in the center of the cast piece S in the thickness direction, which causes central segregation. In order to prevent this, the cast piece (S) is usually lightly pressed in the thickness direction at the end of solidification of the cast piece (S). To this end, a light pressure lower part 5200 is installed in the end of solidification section of the cooling table 5000.

Hereinafter, a description will be given of a position where the light pressure lower section (SRS) or the light pressure lower portion 5200 is installed.

As the cast (S) is solidified and cooled while passing through the cooling zone (5000), as described above, the amount of liquid in the center of the cast (S) decreases from the lower side of the mold (20) to the direction in which the cutter (not shown) is located. , The solid phase increases. That is, from the lower side of the mold 20 to the direction in which the cutter is located, the solidification rate increases.

Accordingly, the cooling zone 5000 can be divided into a plurality of sections according to the solidification rate of the central part of the cast steel. For example, the cooling zone 5000 may be divided into an initial solidification period, an intermediate solidification period, and an end solidification period in the extension direction from the lower side of the mold 20 according to the solidification rate of the cast steel.

In the cooling zone 5000, when the position where the solidification of the cast slab S is completed without a liquid phase, that is, the solidification rate at the solidification completion point is '1.0', for example, a section in which the solidification rate is 0.3 or more is called the end of solidification period .

The light pressure lower part 5200 may be installed in a section with a solidification rate of 0.3 or more, for example, installed in a section with a solidification rate of 0.3 to 1.0, a section with a solidus rate of 0.3 to 0.7, or may be installed in a section with a solidity rate of 0.6 to 0.9. have. In the end of the solidification period, the position where the light pressure lower part 5200 is installed may be variously adjusted according to the steel type to be cast and the specifications of the casting facility.

The end of solidification period of the cooling zone 5000 is a value preset according to the specifications of the casting equipment, the amount of cooling water sprayed, and the casting speed. In addition, the position where the light pressure lower part 5200 is installed in the end of solidification period is determined according to the type of steel to be cast.

The light pressure lower part 5200 is located in front of the guide roll 5110 and includes a rolling-down roll 5210 for light-pressing the cast piece, and a driving unit 5220 providing a driving force for raising and lowering the rolling-down roll 5210.

The push-down roll 5210 is a plurality of upper push-down rolls 5211a arranged in one direction so that each faces the upper surface of the cast piece S from the rear of the upper guide roll 5111a, each of which is a plurality of upper push-down rolls ( It is located under the upper push-down roll (5211a) so as to face the 5211a, and includes a plurality of lower push-down rolls (5211b) arranged in an array direction of the plurality of upper push-down rolls (5211a).

In addition, the driving unit 5220 is connected to the plurality of upper push-down rolls 5211a to lift and lower the plurality of upper push-down rolls 5211a to adjust the distance between the upper push-down rolls 5211a and the lower push-down rolls 5211b. do.

Hereinafter, of the cooling table 5000, of the plurality of upper push-down rolls 5211a and the plurality of lower push-down rolls 5211b, the last from the position of the first upper push-down roll 5211a and the first lower push-down roll 5211b. The section up to the position of the upper down roll 5211a and the last lower down roll 5211b is referred to as a light pressure down section SRS (see FIG. 9).

And, for convenience of explanation, the reference numeral of the first upper push-down roll, which is one of the plurality of upper push-down rolls 5211a, is HR ₁ , and the reference numeral of the first lower push-down roll of the plurality of lower push-down rolls 5211b is LR Explained as ₁ .

However, the first upper push-down roll (HR ₁ ) is _one of the plurality of upper push-down rolls (5211a), and the first lower push-down roll (LR ₁ ) is _one of the plurality of upper push-down rolls (5211a).

In addition, the location where the first upper rolling-down roll (HR ₁ ) and the first lower rolling-down roll (LR ₁ ) of the cooling table 5000 are installed is named as the light pressure starting point (P ₁ ), and the last of the cooling table 5000 The installed position of the upper push-down roll 5211a and the last lower push-down roll 5211b is referred to as a light-pressing end point P ₂ (see FIG. 9 ).

The driving unit 5220 is connected so that the plurality of upper push-down rolls 5211a are individually or independently driven. The driving unit 5220 individually drives the plurality of upper push-down rolls 5211a according to the position of the dummy bar 6100 of the dummy bar 6000 and the head unit 6100 detected by the position detection unit 4000.

The driving unit 5220 according to the embodiment is of a hydraulic cylinder type, but is not limited thereto, and any means may be used as long as it is a means capable of raising and lowering the upper push-down roll 5211a.

The light pressure lower part 5200 is a means for light pressure lowering the cast steel S in order to compensate for the solidification shrinkage at the end of solidification, and the rolling force applied to the cast steel S is an upper reduction roll 5211a and a lower reduction roll 5211b. It is determined by the separation distance, that is, the gap. In addition, the gap between the upper push-down roll 5211a and the lower push-down roll 5211b is adjusted by the movement of the upper push-down roll 5211a.

At this time, the gap between the upper and lower push-down rolls 5111a and 5111b lowered for light pressure is smaller than the gap between the upper and lower guide rolls 5111a and 5111b. And, in adjusting the gap between the plurality of upper rollers (5211a) and the plurality of lower rollers (5211b) for light pressure reduction of the cast piece (S), from the light pressure start point (P ₁ ) to the light pressure end point (P It is desirable to adjust the gap to decrease as it goes to ₂ ).

The dummy bar 6000 closes the lower opening of the mold 20 before the start of casting, and after the start of casting, the cast piece S is drawn in a connected state and moves along the cooling table 5000. That is, when the dummy bar 6000 closes the lower opening of the mold 20, molten steel is injected into the mold 20. At this time, the molten steel injected into the mold 20 at the beginning of casting is solidified on the dummy bar 6000 or to be connected to the dummy bar 6000. In addition, after the dummy bar 6000 is drawn from the mold 20, it moves along the cooling table 5000, and the initial cast piece part is drawn and moved in contact with or connected to the dummy bar 6000.

2, the dummy bar 6000 is inserted into the mold 20 to close the mold 20 before the start of casting, and when passing through the light pressure lower section SRS, from the light pressure lower part 5200 It includes a head portion 6100 capable of contracting or compressing in the thickness direction of the cast piece S by the applied pressing force and a body portion 6200 extending in one direction from the head portion 6100.

Here, the body portion 6200 includes a main body 6210 extending from the front end 6100a of the head portion 6100 and a tail portion 6220 extending from the main body.

The head portion 6100, the main body 6210, and the tail portion 6220 may be connected in a link manner so as to be freely flowable while being connected to each other. In addition, an extension length of the head portion 6100 and the tail portion 6220 in the moving direction of the dummy bar 6000 or the cast piece S may be 10% or less of the main body 6200.

The main body 6210 includes a plurality of blocks arranged in series in the casting direction. The plurality of blocks may have a pin-coupled link structure so as to be individually flowable.

The tail portion 6220 has a plate shape connected to the other end of the main body 6210, and is provided with a fastening groove 6300h capable of fastening a traction device (not shown).

The head part 6100 has a structure capable of contracting or compressing in the thickness direction of the cast piece S by the pressure applied from the light pressure lower part 5200. More specifically, the head portion 6100, as shown in FIGS. 3 to 6, when passing through the light pressure lower section (SRS), by the pressing force applied from the upper rolling down roll (5211a) of the light pressure lower portion 5200 The first body 6110 movable in the direction of the lower push-down roll 5211b, the second body 6120 separated from the first body 6110, and the first body according to the pressing force applied to the first body 6110 The first body 6110 and the second body 6120 are connected to enable movement of the 6110, and can be moved together with the first body 6110, and applied from the light pressure lower part 5200 according to the coupling state. It includes a moving part 6130 that can adjust the movement resistance of the first body 6110 according to the pressing force.

Here, since the first body 6110 moves in the direction of the lower surface of the lower push-down roll 5211b or the cast piece S by the pressing force applied from the upper push-down roll 5211a, for convenience of description, 1 The movement of the body 6110 in the direction of the lower surface of the lower push-down roll 5211b or the cast piece S by the push-down force applied from the upper push-down roll 5211a is referred to as'downward movement'.

First, the second body 6120 will be described.

Referring to FIG. 5, the second body 6120 has an upper side open so that at least a part of the first body 6110 can be inserted or lowered, and has an inner space of a shape recessed from the top to the bottom. Here, the internal space provided in the second body 6120 is a space in which the lower portion of the first body 6110 is inserted and is hereinafter referred to as a moving space. And, hereinafter, among the walls surrounding the moving space of the second body 6120, the wall located at the lower side of the moving space is referred to as the lower wall 6121, and the wall positioned in the lateral direction of the moving space is referred to as the side wall 6122. do.

Of the second body 6120, a groove 6122 that penetrates from the outside in the direction of the movement space and extends in the vertical direction (hereinafter, referred to as movable groove 6122h) is provided in the side wall 6122 surrounding the movement space. The moving groove 6122h is a groove in which a moving part 6130 described later is installed.

The first body 6110 is located above the second body 6120 and can move downward toward the moving space of the second body 6120 by a pressing force applied from the upper push-down roll 5211a.

The first body 6110 according to the embodiment has a first body 6111 and a first body 6110 extending to have a longer width W ₂ than the width W ₁ of the moving space of the second body 6120. 6111 is formed to extend downwardly, and is smaller than the width (W ₂ ) of the first body 6111 and the width (W ₁ ) of the moving space (W ₁ ) so as to be inserted or accommodated in the moving space of the second body 6120 It may include a second body 6112 having W ₃ ).

The shape of the first body 6110 is not limited to the above-described example, and at least a portion of the first body 6120 may be inserted into the moving space of the second body 6120 and may be changed into various shapes capable of descending.

The moving part 6130 includes the first body 6110 and the second body 6120 so that the first body 6120 from the first body 6120 or the first body 6110 from the second body 6120 is not separated. While connecting the 6120 to each other, it is configured to be lowered together with the first body 6110 by a pressing force applied to the first body 6110.

The moving part 6130 according to the embodiment is installed to pass through the moving groove 6122h provided in the second body 6120 so as to penetrate the side wall 6122 of the second body 6120 from the outside to the inside, As a means for fixing the moving member 6131 and the moving member 6131 connected to the first body 6110, the end inserted into the second body 6120 is inserted into the inside of the second body 6120 The moving member 6131 is fastened to pass therethrough, and one surface facing the inner surface of the second body 6120 includes a fastening member 6132 capable of being in close contact with the inner surface of the second body 6120.

The moving part 6130 as described above may adjust the movement resistance of the first body 6110 according to the pressing force applied from the light pressure lower part 5200 according to the degree of fastening using the fastening member 6132. For example, the moving member 6131 may be a bolt having a thread on the outer circumferential surface, and the fastening member 6132 may be a nut having a thread on the inner circumferential surface.

At this time, the adhesion force and friction force between the fastening member 6132 and the inner surface of the second body 6120 vary according to the degree of tightening of the fastening member 6132 as a nut. That is, as the adhesion between the fastening member 6132 and the inner surface of the second body 6120 increases, the frictional force increases. Accordingly, when a pressing force is applied to the head portion 6100 from the upper push-down roll 5211a, the first body 6110 has strong resistance to the downward movement force. Conversely, as the adhesion between the fastening member 6132 and the inner surface of the second body 6120 is weaker, the frictional force decreases. Accordingly, when a pressing force is applied to the head portion from the upper push-down roll 5211a, resistance to the force of the first body 6110 to move downward is weakened.

Therefore, by adjusting the adhesion force between the fastening member 6132 and the inner surface of the second body 6120, it is possible to adjust the downward movement resistance of the first body 6110 according to the pressing force applied to the first body 6110. . In other words, even if a pressing force is applied to the first body 6110, the first body 6110 does not descend, or a small reduction force is applied compared to the pressing force for light pressure reduction of the cast piece S, or from the outside. When a small impact is applied, a problem that the first body 6110 descends can be prevented.

A plurality of moving parts as described above may be provided, and may be arranged in a longitudinal direction of the cast piece S on the sidewall of the second body.

As described above, the head portion 6100 according to the embodiment can be compressed by the pressure applied from the light pressure lower portion 5200. To this end, the first body 6110 and the second body 6120 are spaced apart by a predetermined interval before the pressing force is applied to the head portion 6100. More specifically, the lower surface of the first body 6110 and the lower surface of the second body 6120 are kept spaced apart from each other.

Hereinafter, when the first body 6110 and the second body 6120 are spaced apart from each other, the space between them is referred to as a public part 6110h. Here, the public part 6110h is a part of the moving space provided in the second body 6120.

The reason that the hollow portion 6110h maintains a certain height before the pressing force is applied to the head portion 6100 is because the first body 6110 has movement resistance by the moving portion 6130.

Here, before the pressing force is applied to the head portion 6100 or before the first body 6110 is lowered, the separation distance between the first body 6110 and the second body 6120, that is, the height of the public portion 6110h It is preferable that it is 4 to 12% of the total height of the head portion 6100.

In addition, when a pressing force is applied to the first body 6110 by the lowering of the upper pressing roll 5211a, the second body 6120 is fixed and the first body 6110 moves downward, so that the head portion (6100) is compressed overall. That is, the separation distance between the first body 6110 and the second body 6120, that is, the height of the public portion 6110h decreases, or the lower surface of the first body 6110 and the upper portion of the second body 6120 Since the surfaces are in contact with each other, the void portions 6110h disappear (see Figs. 5(b) and 6(b)).

On the other hand, if the height of the hollow portion 6110h is less than 4% before the pressing force is applied to the head 6100 or before the first body 6110 is lowered, the reduction force applied from the light pressure lower portion 5200 is reduced. 1 Since the distance at which the body 6110 can descend is small, a load may be generated on the light pressure lower part 5200 or the casting facility.

Conversely, before the pressing force is applied to the head portion 6100 or before the first body 6110 is lowered, the height of the hollow portion 6110h exceeds 12%, the reduction applied from the light pressure lower portion 5200 It may be to make it larger than necessary or unnecessarily compared to the power.

Therefore, before the pressing force is applied to the head portion 6100 or before the first body 6110 is lowered, the height of the hollow portion 6110h is made to be 4 to 12% of the total height of the head portion 6100 . This can be controlled by adjusting the adhesion between the fastening member 6132 of the moving part 6130 and the second body 6120 when the lower part of the first body 6110 is installed to be inserted into the second body 6120 .

In the above, it has been described that the fastening member 6132 is positioned inside the second body 6120 and is installed so that one surface is in close contact with the one surface of the second body 6120.

However, the present invention is not limited thereto, and the fastening member 6132 may be adjusted in any position capable of adjusting the adhesion with the second body 6120, for example, the fastening member 6132 is located outside the second body 6120 Can be installed to

In this way, when a pressing force is applied, the head portion 6100 can be compressed in response to the pressing force. That is, the pressing force applied from the light pressure lower part 5200 to the head part 6100 is consumed to compress the head part 6100, and does not return to the light pressure lower part 5200 or the casting facility again as in the prior art. Accordingly, even if the pressing force of the light pressure lower portion 5200 is applied to the head portion 6100 itself, failure or load of the light pressure lower portion 5200 or the casting facility may be prevented. Accordingly, when the head portion 6100 is located in the light pressure lower section SRS, the light pressure lower portion 5200 can be reduced by a light pressure lowering force for light pressure lowering of the cast piece S.

In other words, when the head part 6100 and the initial cast part connected thereto enter the light pressure reduction section, the upper push-down roll 5211a corresponding to the initial cast part connected to the head part 6100 is lowered, and the initial The cast part can be made light pressure.

Accordingly, the initial cast part connected to the head part 6100 can be sufficiently lightly reduced, so that central segregation and pores of the initial cast part can be suppressed.

When casting is completed, the head portion 6100 of the dummy bar 6000 is separated to return the first body 6110 to its original state, that is, to a state before compression.

7 is a view showing a head according to a first modified example of the embodiment

In the above, it has been described that the head part 6100 is composed of the first body 6110, the second body 6120, and the moving part 6130.

However, the present invention is not limited thereto, and as in the first modified example according to the embodiment shown in FIG. 7, the head 6100 is an elastic member inserted into the moving groove 6122h so as to be located under the moving part 6130 (6140) may be included. More specifically, the elastic member 6140 is installed inside the moving groove 6122h so as to be located under the moving member 6131.

At this time, the elastic member 6140 is provided so that the movement resistance of the first body 6110 according to the pressing force applied from the upper push-down roll 5211a becomes a target level. That is, by changing the type, material, structure, etc. of the elastic member 6140, an elastic member 6140 having a desired elastic force is provided, and it is installed in the moving groove 6122h.

In addition, the elastic member 6140 makes it possible to support the moving member when its upper surface is in contact with the moving member 6131 when a pressing force is not applied to the first body 6110, that is, not compressed. Have a height

Accordingly, the elastic member 6140 serves as a stopper for supporting the moving member 6131 so that it does not move downward when a pressing force is not applied to the first body 6110, while the moving part and the first It serves to adjust the movement resistance of the body 6110.

In this case, the moving part 6130 may include only the moving member 6131 connecting the first body 6110 and the second body 6120 without the fastening member 6132. Here, the moving member 6131 moves downward along with the downward movement of the first body 6110 while having a function of connecting the first body 6110 and the second body 6120 as described above. And, as described above, the movement resistance of the first body 6110 is adjusted by the elastic force of the elastic member 6140.

In this case, the first body 6110 may be raised to its original position by the restoring force of the elastic member 6140 when the head 6100 exits the light pressure section.

8 is a view showing a head according to a second modified example of the embodiment.

In the above-described first modified example, it has been described that the elastic member 6140 is provided under the moving groove 6122h so as to be positioned under the moving member 6131.

However, the present invention is not limited thereto, and the elastic member 6140 may be installed in the moving space of the second body 6120 so as to be located under the first body 6110 as in the second modified example illustrated in FIG. 8. . At this time, one end of the elastic member 6140 is fixed to the first body 6110, and the other end of the elastic member 6140 is fixed to the second body 6120.

Here, the elastic member 6140 serves as a stopper to support the first body 6110 from moving downward when a pressing force is not applied to the first body 6110, while the moving part 6130 ) And the movement resistance of the first body 6110.

In this case, the first body 6110 may be raised to its original position by the restoring force of the elastic member 6140 when the head 6100 exits the light pressure section.

The elastic member 6140 according to the first and second modifications may be a block made of a material having elastic force, such as rubber or a spring.

Hereinafter, an operation of a light pressure lower part and a light pressure lowering method will be described with reference to FIGS. 1 to 6 and FIG. 9 when applying a dummy bar according to an embodiment of the present invention.

9(a) to 9(d) are views for explaining an operation of a light pressure lower part according to a movement of a head part of a dummy bar according to an embodiment of the present invention.

Before starting the casting, the dummy bar 6000 is inserted into the mold 20 through the upper opening of the mold 20, and the lower opening of the mold 20 is closed using the head portion 6100. In this case, the main body 6210 and the tail portion 6220 of the dummy bar 6000 may be located under the mold 20.

Thereafter, molten steel is injected into the mold 20 to first solidify the molten steel in the mold 20. At this time, the molten steel injected into the mold 20 at the beginning of casting is solidified on the head 6100 of the dummy bar 6000, and thus the initial cast part is contacted and connected to the head 6100.

Next, by moving the dummy bar 6000 in the extending direction of the cooling table 5000, the head portion 6100 to which the initial cast piece portion is connected is drawn out from the mold 20. The cast piece S drawn from the mold 20 by the movement of the dummy bar 6000 is solidified while moving along the plurality of guide rolls 5110.

Thereafter, when the head portion 6100 of the dummy bar 6000 enters the light pressure reduction section SRS, the driving unit 5220 lowers the upper push-down roll 5211a to become a gap for light pressure reduction of the cast piece S. .

That is, as shown in FIG. 9(a), when the head portion 6100 has not yet reached the light pressure lowering section SRS, and is at a point before that, the upper lowering roll 5211a is not lowered. Thereafter, as shown in FIG. 9(b), when the head portion 6100 enters the light pressure lower section, the light pressure lower portion 5200 is operated. More specifically, when the rear end 6100b of the head part 6100, which is in direct contact with or connected to the initial cast part part, reaches the starting point P _{1 under} light pressure, the upper rolling down roll 5211a To descend.

The area in the direction in which the dummy bar 6000 moves is referred to as the front, and the area that has already been moved and passed is referred to as the rear. Accordingly, among both ends of the head portion 6100 in the moving direction of the dummy bar 6000, the front end 6100a is referred to as the front end 6100a, and the rear end 6100b is the rear end.

At this time, of the plurality of upper push-down rolls 5211a, the upper push-down roll 5211a positioned corresponding to the upper side of the head portion 6100 is lowered. That is, when the rear end 6100b of the head portion 6100 reaches the starting point under light pressure, at least the first upper pressure lowering roll HR ₁ is lowered. When the rear end 6100b of the head part 6100 reaches the starting point P _{1 under} light pressure, a plurality of upper push-down rolls 5211a including the first upper push-down roll HR ₁ on the upper side of the head part 6100 ) Are located, lower them all.

Here, lowering the upper push-down roll 5211a positioned corresponding to the upper side of the head part 6100 means that among the plurality of upper push-down rolls 5211a, the upper push-down roll 5211a located directly above the head part 6100. ) Means to descend.

Thereafter, when the dummy bar 6000 further moves, as shown in FIGS. 9(c) and 9(d), the cast piece S enters the light pressure section SRS. Further, the position of the head portion 6100 is changed in real time by the continuous movement of the dummy bar 6000.

At this time, according to the position change of the head part 6100, the upper push-down roll 5211a corresponding to the upper side of the head part 6100 is lowered. In addition, the upper push-down roll 5211a in which the head portion 6100 has passed or is in the past position does not rise again even if the head portion 6100 passes, but maintains the lowered state.

In other words, it is in a state of descending from the upper push-down roll 5211a located at the light pressure starting point P ₁ to the upper push-down roll 5211a located above the head 6100 at the present time. In addition, the upper push-down roll 5211a positioned in front of the head portion 6100 is still before being lowered.

By this operation, the plurality of upper push-down rolls 5211a located in the light-pressing section SRS are sequentially pushed down. Thus, as shown in Figure 9 (d), when the head part 6100 is out of the light pressure end point (P ₂ ), all of the plurality of upper pressure lower rolls 5211a located in the light pressure lower section (SRS) are lowered. State.

And, even if the head portion 6100 is out of the light pressure end point (P ₂ ), the plurality of upper pressure lowering rolls 5211a maintain a lowered state, and the cast iron S is continuously in the light pressure lower section (SRS). It enters and becomes light pressure.

10(a) to 10(c) are diagrams for explaining the operation of the light pressure lower part according to the third modified example of the embodiment.

In the above, when the rear end of the head part 6100 reaches the light pressure starting point P ₁ , the upper push-down roll 5211a corresponding to the head part 6100 is lowered.

However, this is not limited, as in the third modified example shown in Figure 10, the head portion 6100 is the soft reduction starting point through the (P _1), the soft reduction starting point (P ₁₎ and the soft reduction end When located between the points (P ₂ ) (refer to FIG. 10(c)), the upper push-down roll 5211a located corresponding to the upper side of the head part 6100 and the upper push-down roll located behind the head part 6100 You can start light pressure by lowering (5211a).

In this way, even when lowering the upper rolling roll to pass through the soft reduction starting point (P _1), the soft reduction starting point when the head portion 6100 located between the (P ₁₎ and the soft reduction end point (P _2), Since the upper push-down roll (5211a) is lowered, when the head part 6100 is out of the light-pressing end point (P ₂ ), the upper push-down roll (5211a) is lowered. I can.

On the other hand, conventionally, as shown in FIG. 11, even if the head portion 610 enters the light pressure reduction section SRS (FIG. 11(a)), the upper pressure reduction roll 5211a was not lowered. More specifically, even if the head part 610 and the initial cast part connected to the head part 610 enters the light pressure reduction section (SRS), the upper push-down roll 5211a is not lowered, or the upper push-down roll 5211a and The upper push-down roll 5211a was not lowered so that the gap between the lower push-down rolls 5211b becomes a gap for light pressure reduction of the cast piece S.

And, as shown in Fig. 11 (b), when the head portion 610 completely out of the light pressure reduction section (SRS), by lowering the plurality of upper rolling down rolls (5211a), the gap for light pressure reduction of the cast piece (S) is It was adjusted to be. In other words, when the rear end (610b) of the head portion 610 is out of the light pressure end point (P ₂ ), the light pressure lowering is started by lowering the plurality of upper pressure lowering rolls (5211a) of the light pressure lowering section (SRS). I did.

This is because, when the dummy bar 600 is passing through the light pressure section, when the pressing force of the light pressure lower part 5200 is applied to the dummy bar 600, the dummy bar 600 cannot absorb it, conversely This is because a load may occur in the light pressure lower part 5200 or the casting facility, and a safety accident may occur. Therefore, in the prior art, as described above, when the light pressure reduction section SRS completely exits to the head portion 610 of the dummy bar 600, the cast iron S is lightly pressured.

However, in this case, there is a problem in that the reduction of the initial cast piece connected to the head portion 610 is insufficient. This is because the head portion 610 is subjected to light pressure lowering only when it leaves the light pressure lower section (SRS), even if the initial cast piece connected to the head portion 610 passes through the light pressure lower section (SRS), the head portion ( If 610) does not pass through the light pressure section (SRS), it is because light pressure is not performed. Accordingly, there is a problem in that the light pressure of the initial cast part connected to the head part 610 is insufficient, and the central segregation and pores are not removed or insufficient, and thus the quality of the initial cast part is deteriorated.

However, in the embodiments of the present invention, as described above, when the head portion 6100 of the dummy bar 6000 enters the light pressure section SRS, the pressure to lower the light pressure of the cast piece S is the head portion 6100 ) To be applied to the head portion 6100 and the upper push-down roll 5211a corresponding to the lower portion. And, according to the movement of the head part 6100, the upper push-down roll 5211a located corresponding to the upper side of the head part 6100 at the present time, and the upper part located corresponding to the previous area of the head part 6100 at the present time. The push-down roll 5211a is in a lowered state. Thus, while passing through the light pressure section (SRS), the light pressure load force of the cast piece (S) is applied to the head portion 6100, and the initial cast piece portion connected to the head portion 6100 is light pressure starting point (P ₁ ) The light pressure load is continuously applied from the light pressure to the end point (P ₂ ).

Accordingly, it is possible to sufficiently lightly lower the initial cast part, thereby suppressing or preventing the occurrence of central segregation and pores, thereby improving the quality of the initial cast part compared to the prior art. In addition, there is an effect of reducing the length of the initial cast piece to be cut.

5200: light pressure lower part 5210: abha roll
5211a: upper push-down roll 5211b: lower push-down roll
6100: head portion 6100: first body
6120: second body 6100a, 610a: shear
6100b, 610b: rear end 6130: moving part
6131: moving member 6122h: moving groove
6140: elastic member 6200, 620: body portion
6210, 621: main body 6220, 622: tail part

Claims (17)

As a dummy bar for drawing the cast steel from the mold and moving the cast steel in the casting direction,
A head part that can be inserted into the mold and is partially moved in the thickness direction of the cast piece by a pressing force applied from the outside to be compressed; And
A body portion extending from the head portion;
Including,
The head portion is arranged in a thickness direction of the cast piece and includes a first body and a second body connected to each other,
The first body is a dummy bar that is movable in a direction of the second body by a force applied from an outside of the first body. delete The method according to claim 1,
The second body is provided with a moving space in which at least a part of the first body is accommodated and the direction in which the first body is located is opened,
At least a portion of the first body is a dummy bar that can be inserted into the moving space. The method of claim 3,
A dummy bar installed to pass through a sidewall of the second body surrounding the moving space, the end inserted into the second body is connected to the first body, and includes a moving part movable together with the first body . The method of claim 4,
A moving groove formed from an outside to an inward direction of the side wall is provided in the side wall of the second body so that the moving part can pass therethrough,
The moving groove is a dummy bar extending on the sidewall in a moving direction of the first body. The method of claim 5,
The moving part,
A moving member installed to pass through the moving groove of the second body and having an end inserted into the second body connected to the first body; And
A fastening member that is located inside the second body and is a hollow type provided to pass through the moving member, and is capable of adjusting an adhesion force with the inner surface of the second body;
A dummy bar comprising a. The method of claim 5,
The moving part is installed to pass through the moving groove of the second body, and the end inserted into the second body includes a moving member connected to the first body,
A dummy bar installed inside the movable groove so as to be located under the movable member and including an elastic member having an elastic force. The method according to claim 1,
A dummy bar including an elastic member installed to connect between the first body and the second body inside the second body and capable of extending and contracting with the movement of the first body. Drawing the head portion of the dummy bar and the cast piece connected to the head portion from the mold;
A step of continuously moving the dummy bar from the lower side of the mold to solidify the cast piece drawn from the mold; And
Light pressure lowering the cast piece entering the light pressure lower section provided on the lower side of the mold;
Including,
In the process of light pressure lowering the cast steel,
When the head portion enters the light pressure section, a process of lowering an upper pressure reduction roll positioned at the upper side of the head from among a plurality of upper pressure reduction rolls and an upper pressure reduction roll located at the rear of the head portion in the light pressure reduction section. Includes,
The head portion is provided with a first body movable by a pressing force applied from the upper push-down roll and a moving space in which at least a part of the first body can be accommodated, and the direction in which the first body is located is opened. Comprising a second body,
Casting method of compressing the first body to reduce the moving space of the second body by a pressing force applied from the upper rolling roll. The method of claim 9,
In lowering the upper push-down roll located at the upper side of the head part and the upper push-down roll located at the rear of the head part in the light pressure reduction section,
Casting method of lowering only the head portion entering the light pressure section, or pressing the head portion entering the light pressure section and the cast piece located at the rear of the head section when entering the light pressure section. The method of claim 10,
The light pressure reduction section is from a point at which the first upper push down roll is located among the plurality of upper push down rolls to a point at which the last upper push down roll is located,
The position of the first upper rolling roll is the starting point under light pressure,
When the rear end of the head portion connected to the cast piece reaches the starting point under the light pressure, lowering the upper rolling-down roll positioned on the upper side of the head portion. The method of claim 10,
The light pressure reduction section is from a point at which the first upper push down roll is located among the plurality of upper push down rolls to a point at which the last upper push down roll is located,
The position of the first upper rolling roll is the starting point under light pressure,
The position of the last upper rolling roll is the end point under light pressure,
When the rear end of the head portion passes through the light pressure start point and is located between the light pressure start point and the light pressure end point, lowering the upper rolling-down roll positioned at the upper side of the head portion. The method of claim 9,
The casting method in which the head portion passes through the light pressure section, and the upper push-down roll located at the rear of the position of the head portion at the present time maintains a lowered state at the previous point in time. The method according to any one of claims 9 to 13,
In lowering the upper push-down roll corresponding to the upper side of the head,
Casting method in which a part of the head part is moved in the thickness direction of the cast iron and compressed by a pressing force applied from the upper pressing roll. delete The method of claim 14,
Before starting the casting, fastening the moving part so that the end is connected to the first body through the sidewall of the second body surrounding the moving space; And
Adjusting the movement resistance of the first body by adjusting the adhesion force between the moving part and the second body;
Casting method comprising a. The method of claim 14,
After the casting is finished, the casting method comprising the step of returning the first body moved in the direction of the second body by the rolling force applied from the upper rolling-down roll to a state before rolling.

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