KR20130075275A - Guide roller assembly of continuous casting apparatus - Google Patents

Abstract

The present invention is a guide roller assembly for guiding and compressing a cast in a continuous casting device, the first split roll, the second split roll having a relatively longer roll length than the first split roll and the roll than the second split roll A first guide roller having a long length of the third dividing roll connected sequentially in the width direction of the cast steel, and having a bearing between the dividing rolls; Arranged in parallel with the first guide roller, the third split roll, the first split roll and the second split roll are sequentially connected in the width direction of the cast steel, and the bearing is installed between the split rolls. A second guide roller; And the second dividing roll, the third dividing roll, and the first dividing roll are sequentially connected in the width direction of the cast piece, and the bearing is disposed between the dividing rolls. Disclosed is a guide roller assembly of a continuous casting apparatus including at least one guide roller unit unit including a third guide roller provided in the traveling direction of the cast steel. The guide roller assembly of the continuous casting device as described above can prevent non-uniform solidification in the width direction of the cast.

Description

Guide roller assembly of continuous casting device {GUIDE ROLLER ASSEMBLY OF CONTINUOUS CASTING APPARATUS}

The present invention relates to a guide roller of a continuous casting apparatus, and more particularly, to a guide roller assembly of a continuous casting apparatus which is installed in the upper and lower segments of the segment in the continuous casting apparatus to guide and press the cast.

In general, a continuous casting process is a process of continuously solidifying molten steel in a solid phase of a certain shape. In the continuous casting process, due to the characteristics of the process, the central segregation necessarily occurs inside the slab of the continuous casting. The cause of the central segregation is to discharge the solute concentrated in the molten steel liquid during the solidification process. The concentrated solute liquid flows due to the difference in temperature and solute concentration in the liquid phase, the flow due to the gravity of the crystals formed in the molten steel and the final stage of solidification. The central segregation is formed by the flow due to the solidification shrinkage and the like formed in the. That is, the central segregation is caused by the flow of the concentrated solute liquid. The main cause of this flow is largely affected by the solidification shrinkage and slab bulging of the residual molten steel. It is most affected by the flow of residual molten steel by solidification shrinkage near the point. A representative technique for reducing the occurrence of such central segregation is soft reduction.

1 is a schematic diagram of a typical continuous casting apparatus strand. As shown in FIG. 1, molten steel is injected into a tundish 13 through a long nozzle from a ladle 11 in which molten steel after the refining process is contained, and a tundish ( The molten steel temporarily stored in 13 is injected into the mold 15 through a molten steel transmission device (not shown) located between the tundish 13 and the mold 15, and the primary cooling in the mold 15 is performed. As a result of solidification through secondary cooling at the bottom of the mold 15, a series of processes for producing the cast 3 such as billet, bloom, slab, and the like are performed.

FIG. 2 is a perspective view of the segment shown in FIG. 1. FIG. As shown in FIG. 2, the molten steel discharged through the mold 15 passes through the primary cooling in the mold 15 to the segment 17 of the continuous casting apparatus 1 in a state in which the surface solidifies somewhat. It is drawn between the upper and lower guide rollers 20 provided, and at this time, the cooling water is sprayed for rapid solidification of the molten steel and is continuously changed into the shape of the cast steel 3.

Here, the pressing force is applied to the slab 3 by the guide roller 20 attached to the lightly-loaded segment 17 during the process of the continuous casting machine 1. More specifically, at the end of solidification, the slab (3) is pressed down as much as the solidification shrinkage, and the concentrated molten steel existing between the columnar tops due to the solidification shrinkage suppresses the flow of the molten steel into the center of the slab, and compresses the remaining voids to compress the center segregation of the slab. Will improve.

On the other hand, the low pressure technology for controlling the central segregation of cast steel was introduced in the mid-1980s, and most of the advanced steels are currently used in advanced steel mills for billets, blooms, slabs, etc. Related patents related to the technology under low pressure include Japanese Patent Publication Nos. 1996-257715, 1995-060424, 1994-126405, 1993-069099, etc., and most of the contents under low pressure range from 0.1 to 0.3 The general content of performing under reduced pressure and ending under reduced pressure in the 0.7-0.8 section is disclosed. A major concern in this patent is that of slab width non-uniform coagulation delays that typically occur during slab playing.

3 is a view showing uneven solidification in the width direction of the cast steel. As shown in FIG. 3, the distance from the mold according to the slab width between the liquid phase 4 and the solid phase 5 region near the solidification completion point of the slab indicates that the solidification complete line does not appear in a straight line and both ends of the slab are solidified. The phenomenon that the solidification delay portion is delayed compared to the width center portion appears. This cause is known as the flow according to the shape of the immersion nozzle in the mold, the roll shape and deformation of the continuous casting device, the secondary cooling unevenness and the like. Therefore, many researchers have been making efforts to control the nonuniformity of solidification in the slab width direction, but it is still common in continuous casting apparatus. Such uneven solidification in the slab width direction generally occurs in the continuous casting process. When applying low pressure considering only the center of the width without improving the solidification delay, the solidification delay part is out of the appropriate low pressure section and deteriorates in quality. .

4 is a view for explaining the causes of nonuniform solidification in the width direction of the cast steel. As shown in Figure 4, when the application of light pressure under the slab slabs in 200mm intervals in the casting direction by processing the specimens in the cast slab showed the grade by the AP method, showing the non-uniform coagulation delay in the slab width direction (See FIG. 4A). In addition, as a result of measuring the slab width direction temperature, it can be confirmed that the temperature difference occurs at the same position (see Fig. 4 (b)). As a result of finding the defect in the center of the cast piece by ultrasonically casting the cast thus obtained (see Fig. 4 (c)) and the result of finding the defect in the center of the product obtained through post-process rolling (see Fig. 4 (d)) the same position You can see that In addition, when casting under the same steel grade and casting conditions, it can be seen that there is a large difference in slab width between cast slab widths due to non-uniform solidification delays in the slab width. This shows a tendency to deteriorate. In other words, the center segregation index is about 2 to 3 times larger than the center width and the coagulation delay.

The present invention has been made in order to solve the above problems, the guide of the continuous casting device that can prevent uneven solidification in the width direction of the slab by uniformizing the amount of heat escaped by the contact of the guide roller and the slab during the continuous casting process It is intended to provide a roller assembly.

The present invention is a guide roller assembly for guiding and compressing a cast in a continuous casting device, the first split roll, the second split roll having a relatively longer roll length than the first split roll and the roll than the second split roll A first guide roller having a long length of the third dividing roll connected sequentially in the width direction of the cast steel, and having a bearing between the dividing rolls; Arranged in parallel with the first guide roller, the third split roll, the first split roll and the second split roll are sequentially connected in the width direction of the cast steel, and the bearing is installed between the split rolls. A second guide roller; And the second dividing roll, the third dividing roll, and the first dividing roll are sequentially connected in the width direction of the cast piece, and the bearing is disposed between the dividing rolls. Disclosed is a guide roller assembly of a continuous casting apparatus including at least one guide roller unit unit including a third guide roller to be installed in a traveling direction (casting direction) of the cast.

In addition, the length ratio of the bearing, the first divided roll, the second divided roll, the third divided roll is 1: 2.5 ~ 3.5: 4.5 ~ 5.5: 6.5 ~ 7.5 discloses a guide roller assembly of the continuous casting device do.

In addition, the length ratio of the bearing, the first divided roll, the second divided roll, the third divided roll is 1: 3: 5: 7: guide roller assembly of a continuous casting device, characterized in that.

In addition, the length ratio of the bearing, the first split roll, the second split roll, the third split roll is a guide roller assembly of the continuous casting device, characterized in that 1: 4.5 to 5.5: 7.5 to 8.5: 10.5 to 11.5 do.

In addition, the length ratio of the bearing, the first divided roll, the second divided roll, the third divided roll is a guide roller assembly of the continuous casting device, characterized in that 1: 5: 8: 11.

The guide roller assembly of the continuous casting apparatus according to the present invention controls the contact portion (split roll) and the non-contact portion (bearing) of the guide roller to the cast steel during the continuous casting process evenly in the slab width direction, the contact between the guide roller and the cast steel It is possible to prevent the non-uniform solidification in the width direction of the slab by making the amount of heat escaped by the uniform, and it is possible to ensure excellent internal quality of the cast using this.

1 is a schematic diagram of a general continuous casting apparatus.
FIG. 2 is a perspective view of the segment shown in FIG. 1. FIG.
3 is a view showing uneven solidification in the width direction of the cast steel.
4 and 5 are diagrams for explaining the cause of the nonuniform coagulation in the width direction of the cast steel.
Figure 6 is a diagram illustrating a split roll design of the guide roller assembly of the continuous casting device according to a preferred embodiment of the present invention.
Figure 7 is a graph showing the measurement results of the width direction of the slab by the split roll design of the guide roller assembly of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Prior to the description of the present invention, as shown in Figure 5, the non-uniform solidification position is secondary cooling that is injected into the bearing (roll pocket) and the secondary cooling nozzle of the guide roller composed of split rolls in two or more constituting the segment It can be seen that it is closely related to the injection quantity.

FIG. 5A shows a secondary cooling nozzle arrangement installed in a segment of a general continuous casting apparatus. In general, two to six secondary cooling nozzles are arranged between the rolls, and the amount of ejected water from each nozzle is equal. Therefore, the injection volume from the secondary cooling nozzle at the edge is 1/2 times less than the quantity injected from the inner nozzle, so that the slab width edge portion 6 due to the lack of secondary cooling quantity (6), more precisely, the short side Nonuniformity will occur at 200 to 300 mm from the part. In order to solve this problem, Korean Patent Publication No. 10-2005-0060818 proposed a low-pressure condition to compensate for the uneven solidification delay length of the slab in the width direction. Meanwhile, Korean Patent Publication No. 10-2003-0054599 discloses a method of equalizing the surface coagulation rate of a slab during continuous casting by compensating the spray water of the cooling nozzle installed in the slab width direction to minimize the unevenness in the slab width direction by the difference in the solidification speed. Presented. However, it is possible to reduce the center segregation due to the underpressure condition for compensating the solidification retardation length in the slab width direction edge portion 6 or the increase in the amount of secondary cooling nozzles located at both edges, but the underpressure portion in the width center portion is possible. May be set as a surplus so that the central segregation in the center portion of the cast may deteriorate. As shown in (b) of FIG. 5, the surface solidification rate compensation using the coolant is difficult at the point where the slab surface temperature near the center of the slab width is high. This is because the non-uniform solidification position generated at both sides 7 around the center of the slab is generated at the bearing (roll pocket) position of the guide roller composed of the split rolls constituting the segment. Therefore, it is known that the solidification process of the cast steel is generally larger than the secondary cooling process, and the amount of heat released by the contact between the roll and the cast steel is generally higher. This position is, for example, that there are 100 guide rollers in the segment of the continuous casting apparatus. Suppose that only 50 are in contact and the calories are drawn out, which leads to a delay in coagulation. Therefore, in order to fundamentally prevent cast nonuniform solidification occurring at the bearing (roll pocket) position of the guide roller composed of the split rolls constituting the segment, the present invention will be described in detail according to the split roll design concept of the guide roller assembly. .

The guide roller assembly 100 of the continuous casting apparatus 1 according to the preferred embodiment of the present invention can be applied variously regardless of the number of the number of division rolls, whether three or five, but the following three mainly It will be described by applying to the guide roller assembly 100 is produced in the form of a split roll.

Figure 6 is a diagram illustrating a split roll design of the guide roller assembly of the continuous casting device according to a preferred embodiment of the present invention.

As shown in Figure 6, the guide roller assembly 100 of the continuous casting device 1 according to a preferred embodiment of the present invention is the first guide roller 110, the second guide roller 120 and the third guide roller At least one guide roller unit unit 140 including the 130 in the driving direction (casting direction) of the cast (3, see Fig. 1). In this embodiment, the configuration is provided with three guide roller unit unit 140, but the number of the guide roller unit unit 140 is two, four or five, regardless of the number of various Applicable

The first guide roller 110 has a roll length relatively greater than the first split roll 111 and the second split roll 112 and the second split roll 112 having a longer roll length than the first split roll 111. The long third split rolls 113 are sequentially connected in the width direction of the cast steel. In addition, a bearing 115 is provided between the dividing rolls. Here, the first, second and third split rolls 111, 112 and 113 are in contact with the cast steel and the bearing 115 is in non-contact with the cast 3.

The second guide roller 120 is arranged in parallel with the first guide roller 110. In addition, in the second guide roller 120, the third split roll 113, the first split roll 111, and the second split roll 112 are sequentially connected in the width direction of the cast piece 3. In addition, a bearing 115 is provided between the dividing rolls.

The third guide roller 130 is arranged in parallel with the second guide roller 120. In addition, in the third guide roller 130, the second split roll 112, the third split roll 113, and the first split roll 111 are sequentially connected in the width direction of the cast piece 3. In addition, a bearing 115 is provided between the dividing rolls.

That is, the guide roller assembly 100 of the continuous casting apparatus 1 according to the preferred embodiment of the present invention is the contact (parting rolls (111, 112, 113) and the non-contacting part (bearing 115) to the cast (3) cast ( 3) Evenly adjusted in the width direction, the amount of heat escaped by the contact between the guide roller and the slab is uniform to prevent uneven solidification in the slab width direction.

In addition, since the size of the bearing 115 generally has a width of 90 to 150 mm, in this embodiment, the length of the split rolls constituting one guide roller in three forms can be designed in the following ratio.

1) Length of bearing 115: First split roll (shortest roll) 111 Length: Second split roll (middle roll) 112 Length: Third split roll (longest roll) 113 Length = 1: 3: 5: 7

2) Bearing 115 Length: 1st split roll (shortest roll) 111 Length: 2nd split roll (middle roll) 112 Length: 3rd split roll (longest roll) 113 Length = 1: 5: 8: 11

On the other hand, the configuration of the segment can vary depending on the cast steel thickness, cast steel width and the circumferential design, the bearing 115 specifications between the split rolls (111, 112, 113) for transmitting the pressing force can be varied. This variation is closely related to the size of the bearing 115, and in particular, since the length of the bearing 115 may be different, Equations 1) and 2) are represented by the following modified equations 3) and 4). Can be.

3) Length of bearing 115: First split roll (shortest roll) 111 Length: Second split roll (middle roll) 112 Length: Third split roll (longest roll) 113 Length = 1: 2.5 ~ 3.5: 4.5 ~ 5.5: 6.5 ~ 7.5

Equation 4) Bearing 115 length: First split roll (shortest roll) 111 Length: Second split roll (middle roll) 112 Length: Third split roll (longest roll) 113 Length = 1: 4.5 ~ 5.5: 7.5 ~ 8.5: 10.5 ~ 11.5

For example, in the case of a facility that produces a maximum casting width of 2,400 mm in a segment consisting of nine guide rollers using the above equation, the design of the split roll is as follows. When the length of the bearing 115 is designed to be 132 mm, the length of the first split roll (shortest roll) 111 is 462 mm, the length of the second split roll (middle roll) 112 is 726 mm, and the third split roll is The longest roll 113 is designed to have a length of 990 mm, and the length of the guide rollers 110, 120, and 130 is 2,442 mm. Is determined by.

On the other hand, in the case of a facility that will produce a maximum casting width of 2200 mm, the design of the split roll is as follows. When the length of the bearing 115 is designed to be 85 mm, the length of the first split roll (shortest roll) 111 is 425 mm, the length of the second split roll (middle roll) 112 is 680 mm, and the third split roll is The longest roll 113 is designed to have a length of 935 mm, and the length of the guide rollers 110, 120, and 130 is 2,210 mm (calculated as two because the bearing rolls are between the split rolls). In design, it is determined by Equation 2) or Equation 4).

A design example of the guide roller assembly 100 was derived from the above equation, and the non-coagulated delayed part was uniformly arranged by temporally and spatially arranging the contact portions (split rolls 111, 112, 113) and the non-contact portions (bearing 115) with the slab 3. It can prevent. This is because the guide roller design is possible by inducing equal heat distribution of the contact portion and the non-contact portion between the guide roller and the cast steel. That is, the amount of heat that escapes due to the contact between the guide roller and the slab is equally adjusted by adjusting the contact portions (split rolls 111, 112, 113) and the non-contact portions (bearing 115) with respect to the slab 3 in the width direction of the slab 3. By making it uniform, uneven solidification of the slab 3 width direction can be prevented.

On the other hand, when designing the guide roller in the range beyond the length ratio of the bearings and the split rolls presented in the above formulas 1) to 4), the contact portion (the split rolls 111, 112 and 113) and the non-contacting portion ( Part of bearing 115) is unevenly temporally and spatially, resulting in a large difference in slab width between cast slab width and slab width in the same steel grade and casting conditions. Since there is a problem that the quality deteriorates in the delay portion, the same effect as in the present invention cannot be expected at all.

Figure 7 is a graph showing the measurement results of the width direction of the slab by improving the split roll design of the guide roller assembly of the present invention.

As shown in FIG. 7, the result of casting production by optimizing the design of the split rolls 111, 112 and 113 of the segment guide roller assembly 100 is shown. 4 and 5 described above, the slab width direction temperature distribution by the existing split roll arrangement shows a non-uniform temperature difference of up to about 70 degrees, but the slab width direction with the optimized split roll (111, 112, 113) arrangement arrangement shown in FIG. It can be seen that the deviation of the temperature is greatly improved within 15 degrees. The internal quality of the cast can be obtained uniformly in the width direction of the cast, and the defect of the customer can be minimized by the production of steel with excellent internal quality.

While the present invention has been described in connection with certain exemplary embodiments, it will be understood by those skilled in the art that various changes may be made without departing from the scope of the present invention. In addition, the description in parentheses among the description of the claims is intended to prevent the ambiguity of the description, and the scope of the claims should be interpreted including all the descriptions in the parentheses.

1: continuous casting apparatus 100: guide roller assembly
110: first guide roller 111: first split roll
112: second split roll 113: third split roll
115: bearing 120: second guide roller
130: third guide roller 140: guide roller unit

Claims (5)

In the guide roller assembly for guiding and pressing the cast in a continuous casting device,
A first split roll, a second split roll having a longer roll length than the first split roll, and a third split roll having a longer roll length than the second split roll are sequentially connected in the width direction of the cast steel, A first guide roller having a bearing installed between the split rolls;
Arranged in parallel with the first guide roller, the third split roll, the first split roll and the second split roll are sequentially connected in the width direction of the cast steel, and the bearing is installed between the split rolls. A second guide roller; And
Arranged in parallel with the second guide roller, the second split roll, the third split roll and the first split roll are sequentially connected in the width direction of the cast steel, and the bearing is installed between the split rolls. Guide roller assembly of a continuous casting device comprising at least one guide roller unit unit comprising a third guide roller which is to be in the running direction (casting direction) of the cast. The guide of the continuous casting apparatus according to claim 1, wherein the length ratio of the bearing, the first split roll, the second split roll, and the third split roll is 1: 2.5 to 3.5: 4.5 to 5.5: 6.5 to 7.5. Roller assembly. The guide roller assembly of claim 2, wherein the length ratio of the bearing, the first split roll, the second split roll, and the third split roll is 1: 3: 5: 7. The guide of the continuous casting apparatus according to claim 1, wherein the length ratio of the bearing, the first split roll, the second split roll, and the third split roll is 1: 4.5 to 5.5: 7.5 to 8.5: 10.5 to 11.5. Roller assembly. The guide roller assembly of claim 4, wherein a length ratio of the bearing, the first split roll, the second split roll, and the third split roll is 1: 5: 8: 11.

Images