KR20160078819A - Apparatus for Continuous Casting - Google Patents

Abstract

According to an embodiment of the present invention, a continuous casting apparatus comprises: a mold which includes a pair of long walls and a pair of short walls connecting the pair of long walls; and a mold width variable device which adjusts a taper of the mold by changing a width of an upper side and a lower side of the pair of short walls. The mold width variable device is able to change a taper by continuously operating a first section of reducing the taper, a second section of maintaining the taper, and a third section of increasing the taper in a time series order.

Description

[0001] Apparatus for Continuous Casting [0002]

The present invention relates to a continuous casting apparatus.

Continuous casting is a casting method in which a molten metal is solidified in a mold while continuously extracting a steel ingot or steel ingot. Continuous casting is used to manufacture slabs, blooms and billets, which are primarily rolled materials, and long products of simple cross-section such as square, rectangular, and circular.

In the continuous casting process, the mold width is varied to change the target width value of the slab during casting. In the case of varying the mold width, a method of reducing the taper value of the mold width in one section is used to quickly change the mold width. However, when the taper value of the mold is less than 0.5%, particularly when it falls to a negative value, there is a problem that the possibility of a break out increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a continuous casting apparatus capable of keeping the taper value at or above a threshold value to reduce the possibility of break-out of the mold.

A continuous casting apparatus according to an embodiment of the present invention includes a mold including a pair of barriers and a pair of end walls connecting the pair of barriers; And a mold width varying device for adjusting a taper of the mold by changing a distance between the upper and lower sides of the pair of end walls; Wherein the mold width varying device continuously changes a taper in a first period, a second period in which the taper is maintained, and a third period in which the taper is increased in a time series sequence, .

In addition, the time period of the first section may be shorter than the time period of the third section.

In addition, the moving speed of the upper side of the pair of end walls in the first section may be faster than the moving speed of the lower side of the pair of the end walls.

In addition, the moving speed on the upper side of the pair of end walls and the moving speed on the lower side of the pair of end walls in the second section may be the same.

Further, in the third section, the moving speed of the upper side of the pair of the end walls may be slower than the moving speed of the lower side of the pair of the end walls.

In addition, the values of the taper may be the same at the beginning of the first section and at the end of the third section.

In addition, in the first to third sections, the rate of change in the upward movement speed of the pair of end walls may be the same as the rate of change in the downward movement speed of the pair of end walls.

The moving speeds of the upper and lower ends of the pair of end walls at the start point of the second section may be shifted to the upper and lower moving speeds of the pair of end walls at the end point of the second section, It can be faster than speed.

The continuous casting apparatus according to an embodiment of the present invention can lower the possibility of breaking out even when the taper value of the mold is reduced.

1 is a schematic view of a continuous casting apparatus according to an embodiment of the present invention.
2 is a view illustrating a taper changing method of a mold width varying apparatus according to an embodiment of the present invention.
3 is a graph showing the movement speed and movement path of the end wall of the mold according to the comparative example.
FIG. 4 is a graph showing the moving speed and moving path of the end wall of the mold according to an embodiment of the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

1 is a schematic view of a continuous casting apparatus according to an embodiment of the present invention.

1, a continuous casting apparatus according to an embodiment of the present invention may include a ladle 10, a tundish 20, a mold 30, and a mold width varying device 40, A roll 50 and a spraying means 60 as shown in FIG.

The molten steel M accommodated in the ladle 10 flows into the tundish 20 and moves. The tundish 20 receives molten metal from the ladle 10 and supplies molten metal to the mold 30. The tundish 20 can control the supply rate of the molten metal flowing into the mold 30, distribute the molten metal to the mold 30, store the molten metal, and separate the slag and nonmetallic inclusions.

The mold 30 primarily cools the molten steel. The mold 30 includes a cavity in which molten steel is received as a pair of structurally opposed faces open. The mold 30 includes a pair of end walls 32 connecting a pair of barriers 31 and a pair of barriers 31. Here, the end walls 32 have a smaller area than the barriers 31. The walls 31 are formed in a vertical direction, and the end walls 32 are formed in a vertical direction or a slightly inclined direction. The walls of the mold 30, mainly the end walls 32, may be rotated to be away from or close to each other to have a certain level of taper.

The mold 30 has a function of forming a solidified shell or a solidified shell that maintains the shape of the casting pluck extracted from the mold 30 and a strong solidified shell so that molten metal having less solidification still does not flow out .

The molten steel primarily cooled by the mold 30 is directly cooled by the spraying means 60, while being maintained by the support roll 50 so that the coagulation angle is not deformed. The solidification of the cast steel is mainly cooled by the spraying means (60).

The mold width varying device 40 oscillates the walls of the mold 30 and in particular the end walls 32 according to the target width of the casting to form a taper defined by the end walls 32 of the mold 30, Can be changed. The taper can be varied according to the target width value of the casting, and the taper is determined according to the following equation (1). At this time, D_Top corresponds to an upper distance between the first end wall 32a and the second end wall 32b, and D_Bottom corresponds to a lower distance between the first end wall 32a and the second end wall 32b.

2 is a view showing a taper changing method of the mold width varying device 40 according to an embodiment of the present invention.

The mold width varying device 40 can oscillate the mold 30 according to the target width value of the casting during casting in the continuous casting process, thereby changing the taper. Referring to FIG. 2, the mold width varying device 40 adjusts the moving speed and the moving speed of the first end wall 32a and the second end wall 32b of the mold 30 in three different ways, Can be changed.

The interval ①, interval ② and interval ③ can be continuous in a time series order. The mold width varying device 40 reduces the taper of the mold 30 in the section 1 and maintains the taper of the mold 30 in the section 2. The mold width varying device 40 in the section 3 Increase the taper.

When the taper value of the mold 30 decreases at the end of the interval 1 and falls to less than 0.5%, the possibility of a break out increases. This possibility of break out is due to the fact that the upper distance between the first end wall 32a and the second end wall 32b is shorter than the lower distance between the first end wall 32a and the second end wall 32b, And becomes even higher in the reverse taper section when the taper value has a negative value. For example, when the mold 30 has an inverse taper value, the first end wall 32a and the second end wall 32b may be arranged in a reverse tapered shape as shown by a dotted line in FIG.

However, in order to rapidly change the width of the mold 30 during casting, it is necessary to enter the reverse taper section.

FIG. 3 is a graph showing the moving speed and moving path of the end wall 32 of the mold 30 according to the comparative example, and FIG. 4 is a graph showing the moving speed and moving speed of the end wall 32 of the mold 30 according to an embodiment of the present invention, It is a path graph.

In FIG. 3 and FIG. 4, a section from time t to t0 corresponds to section 1 in FIG. 2, a section from time t0 to time t1 corresponds to section 2 in FIG. 2, and a section from time t1 to time t2 corresponds to section 3 . L_Top represents the upper position of the first end wall 32a and the second end wall 32b, and L_Bottom represents the lower position of the first end wall 32a and the second end wall 32b.

3 and 4, it is assumed that the upper position L_Top and the lower position L_Bottom move in the direction of decreasing the distance between the first end wall 32a and the second end wall 32b and the distance between the first end wall 32a and the second end wall 32b at a positive moving velocity.

3 and 4, the rate of change of the moving speed of the upper side of the pair of the end walls in the section ① to the section ③ may be the same as the rate of change of the moving speed of the lower side of the pair of the end walls.

At the initial time t, both the upper position L_Top and the lower position L_Bottom are located at the position Sl, so that the taper value may be 0%.

The moving speed of the upper position L_Top from the time t to the time t0 is faster than the moving speed of the lower position L_Bottom so that the moving distance of the upper position L_Top is larger than the moving distance of the lower position L_Bottom. As a result, the taper value can be reduced as described above.

The moving speed of the upper position L_Top and the moving speed of the lower position L_Bottom from the time t0 to the time t1 are the same and the distances of the movement paths are the same. Thus, the taper value can be kept constant.

Since the moving speed of the upper position L_Top from the time t1 to the time t2 is slower than the moving speed of the lower position L_Bottom, the moving distance of the upper position L_Top is smaller than the moving distance of the lower position L_Bottom. Therefore, the taper value can increase from time t1 to time t2.

At the end time t2, the upper position L_Top and the lower position L_Bottom are both located at the position Sf, so that the taper value may be 0%.

Although the initial taper value is assumed to be 0 in the above example, in order to prevent the taper value from having an inverse taper value as another example, a taper value of 1% is initially set and a taper value of 0.2% The mold 30 can be oscillated.

3 and FIG. 4, in the comparative example of FIG. 3, the section from time t to time t0 is the same from the section from time t1 to time t2, and the section from time t0 to time t1 is the moving speed 4, the time period from the time t to the time t0 is shorter than the time period from the time t1 to the time t2, and the time period from the time t0 to the time t1 is the end time, Vm. ≪ / RTI > At this time, the speed Vm` may be slower than the speed Vm.

Typically, the amount of decrease of the taper value is determined according to the moving speed and the moving path at time t0 from time t. In order to set the taper value at the end time t2 to be equal to the value of the initial time t0, The interval from time t to time t0 is designed to be the same as the interval from time t1 to time t2.

However, in this case, when the initial taper value is set to 0%, the taper value may have a negative value in the interval from time t0 to time t1, and even if the initial taper value is set to 1% There is a possibility of break-out.

According to the present embodiment, the section from the time t to the time t0 is set shorter than the section from the time t1 to the time t2, while the section between the time t0 and the time t1 is moved to Vm` which is slower than the moving speed Vm.

The interval from the time t to the time t0 is set to be shorter than the interval from the time t1 to the time t2 so that the reduction amount of the taper value in the interval 1 in Fig. 2 can be lowered in comparison with the comparative example.

From the time t0 to the time t1, the traveling speed is maintained at a speed Vm` which is slower than the speed Vm, so that a smaller distance is moved in comparison with the comparative example. However, the lower position L_Bottom during the time period from time t1 to time t2 is compared with the comparative example It can be seen that the present embodiment and the comparative example move at the same distance at the end of the time t2.

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, but, on the contrary, Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Therefore, the spirit of the present invention should not be construed as being limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the following claims, I will say.

10: Ladle
20: Tundish
30: Mold
31: Barriers
31a: the first barrier
31b: the second barrier
32: End walls
32a: first end wall
32b: second end wall
40: mold width variable device
50: support roll
60: Spray means

Claims (8)

A mold including a pair of walls and a pair of end walls connecting the pair of barriers; And
A mold width varying device for adjusting the taper of the mold by changing a distance between the upper and lower sides of the pair of end walls; Lt; / RTI >
Wherein the mold width varying device continuously changes the taper by sequentially performing a first section for reducing the taper, a second section for holding the taper, and a third section for increasing the taper in a time series sequence, .
The method according to claim 1,
Wherein the time period of the first section is shorter than the time period of the third section.
The method according to claim 1,
Wherein the moving speed of the upper side of the pair of end walls in the first section is higher than the moving speed of the lower side of the pair of end walls.

The method according to claim 1,
Wherein a moving speed of the upper side of the pair of end walls in the second section is equal to a moving speed of the lower side of the pair of end walls in the second section.
The method according to claim 1,
And the moving speed of the upper side of the pair of end walls in the third section is lower than the moving speed of the lower side of the pair of end walls.
The method according to claim 1,
Wherein the values of the taper at the start point of the first section and at the end point of the third section are equal to each other.
The method according to claim 1,
Wherein the rate of change of the upward movement speed of the pair of end walls in the first to third sections is equal to the rate of change of the downward movement speed of the pair of end walls.
The method according to claim 1,
Each of the upper and lower moving speeds of the pair of end walls at the start point of the second section is shorter than the moving speed of the upper and lower moving speeds of the pair of end walls at the end point of the second section Fast continuous casting equipment.

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