JPH11244998A - Cooling structure of assembled mold for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically reduce the temp. difference of the surface of a cooling copper plate by disposing zigzag a fastening bolt boss parts in a cooling water passage and arranging tapered supporting plates. SOLUTION: In the cooling structure composed of a water cooling type mold wall for feeding the cooling water into the cooling water passage 5 formed between the fastened cooling copper plate 1 and back plate 2, the cooling structure is provided with the fastening bolt boss parts 7 positioned at the interval between the cooling copper plate 1 and the back plate 2 and arranged at the cooling copper plate 1 and the supporting plate 3 disposed at the downstream zone side of the fastening bolt boss part 7, and the cooling copper plate 1 and the back plate 2 are fastened with the fastening bolt 4. In this cooling structure, the fastening bolt boss parts 7 are disposed zigzag in the flow passage of the cooling water. Further, the width of the supporting plate 3 is made not more than the diameter of the fastening bolt boss part 7 at the position adjoined to the fastening bolt boss part 7 and formed as tapered state toward the downstream direction of the cooling water. The length 8 of the supporting plate is made equal to not less than 5 times of the diameter of the fastening bolt boss part 7. The each setting pitch of the fastening bolt boss part 7 is made larger than the diameter of the fastening bolt boss part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for an assembling mold for continuous casting, which can make the surface temperature of a slab uniform during continuous casting and improve the material properties of the slab.

[0002]

2. Description of the Related Art In order to reduce cooling unevenness in a continuous casting mold and to make the cooling uniform, a mold cooling structure for continuous casting includes a mold surface in contact with molten steel and a slab with copper having excellent heat conductivity. Alternatively, there are a water-cooled tubular mold cooling structure and an assembled mold cooling structure formed of a copper alloy.

[0003] The cooling structure of a tubular mold includes an inner copper tube and an outer tube which are in direct contact with a slab and is housed in a housing having a water-cooled groove of a copper or copper alloy mold to fix both ends of the tube. The structure is such that cooling water is supplied to the gap. Since the copper tube can be easily deformed into an arbitrary shape, the production cost is low, and the copper or copper alloy mold wall can be thinned. However, considering the structural strength of the mold, the slab size is 1
The upper limit is about 80 mm square, and it cannot be used as a large mold. Therefore, in this copper tubular mold cooling structure, what is continuously cast is limited to a biletto having a small slab cross-sectional area. Further, the copper tubular mold cooling structure has a housing having a water cooling groove and a copper tube.
Due to the heavy structure, maintenance costs are increased.

Further, as shown in FIGS. 8 (a), 8 (b) and 8 (c), a cooling structure 10 for an assembling mold is provided by processing a cooling water channel 5 in a copper or copper alloy plate. The processed cooling copper plate 1 and the back plate 2 are overlapped, the fastening bolt boss 7 is fastened with the fastening bolts 4 to complete the cooling water flow path 5, and further formed by combining these four stacked plates. The assembled mold having the cooling structure 10 made of copper or a copper alloy is often used for casting blooms and slab slabs because the inner dimensions of the mold can be made accurate. In addition, an assembly mold composed of four copper or copper alloy cooling copper plates can be used as a slab width variable mold by allowing two facing cooling copper plates to slide. The cooling copper plate made of copper or a copper alloy can be easily straightened, so that the maintenance cost can be reduced. However, since the cooling groove, that is, the cooling water flow path 5 is machined in a plurality of paths in the cooling copper plate, the cooling copper plate cannot be thinned, so that the processing cost and the material cost increase. As shown in FIG. 8A, the machining of the cooling copper plate 1 in the vicinity of the fastening bolt boss 7 becomes very complicated. In addition, when the slab width is narrow, there is a problem that the slab has uneven cooling.

[0005] Another cooling structure of the assembled mold has a structure in which cooling water is directly supplied over almost the entire surface between the cooling copper plate and the back plate, and the cooling copper plate and the back plate are fastened with fastening bolts. Have been. The mold using the cooling copper plate having this structure can cool the mold almost entirely except for the vicinity of the fastening bolt, can greatly improve the uniformity of cooling, and can reduce the thickness of the mold.
However, as shown in FIG. 1 (b), the fastening bolts 4 and the bosses 7 present in the cooling water flow path 5 form a stagnation of the cooling water behind them, and as a result, the slab still cannot be cooled. Temperature unevenness on the slab surface due to uniformity is generated.

[0006]

As described above, in the cooling structure of the copper tubular mold in the continuous casting, the strength of the structure is limited and the continuous casting is limited to a small slab having a small slab cross-sectional area. Therefore, this copper tubular mold cannot be used for continuous casting of large slabs. In a cooling structure of an assembled mold in which a water cooling groove or cooling water flow path is formed on a copper or copper alloy plate and combined with a back plate, machining and material costs are required because many cooling water flow paths are directly machined on the copper plate. When the cast slab is continuously cast and the width of the cast slab is narrow, there is a problem that the cooling becomes uneven and the temperature of the slab becomes uneven. Further, in the cooling structure of the assembled mold in which the cooling water is directly fed and circulated over almost the entire surface between the cooling copper plate and the back plate, the cooling water is formed behind the fastening bolt boss existing in the cooling water flow path. As a result, there has been a problem that, as in the above case, the slab has a non-uniform cooling, which causes instability in the material properties due to uneven temperature on the slab surface.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is possible to uniformly cool a large slab to a small slab, and to manufacture a continuous slab having excellent material properties. The cooling structure of the mold is achieved by the continuous casting assembly mold of the present invention described below. The present invention relates to a cooling structure for a continuous casting assembly mold comprising a water-cooled mold wall for supplying and circulating cooling water to a cooling water flow passage formed between a cooling copper plate and a back plate, the cooling copper plate being provided. And a backing plate, and a fastening bolt boss portion provided on the cooling copper plate, and a support plate disposed downstream of the fastening bolt boss portion in the cooling water flow path, and fastening the cooling copper plate and the back plate. This is achieved by a cooling structure for an assembling mold for continuous casting, which is characterized by fastening with bolts.

Further, the present invention is achieved by a cooling structure characterized in that the fastening bolt bosses are arranged in a staggered or staggered manner in the cooling water flow path. further,
The present invention is characterized in that at a position adjacent to the fastening bolt boss portion, the width of the support plate is equal to or less than the diameter of the fastening bolt boss portion, and the width of the support plate is tapered in the downstream direction of the cooling water. Achieved by structure.

Further, the present invention is achieved by a cooling structure characterized in that a length of a support plate parallel to a flow direction of cooling water is set to be not less than the diameter of the fastening bolt boss portion and not more than five times the diameter. . Further, the present invention is achieved by a cooling structure characterized in that the arrangement pitch of the fastening bolt bosses in the direction perpendicular to the flow direction of the cooling water is an arrangement pitch exceeding the diameter of the fastening bolt boss.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, attention has been paid to the arrangement of the fastening bolt bosses for fastening the cooling copper plate and the back plate in the cooling water flow path in order to improve the uneven cooling of the assembly mold. In the cooling structure 10 of the conventional assembly mold, the fastening bolt bosses 7 are arranged in a grid pattern in the cooling water flow path 5 of the cooling copper plate 1 as shown in FIG. In the cooling structure 10 of the assembled mold, the fastening bolt bosses 7 are arranged in a staggered manner in the cooling water flow path 5 as shown in FIG. Thereby, the stagnation of the cooling water generated behind the fastening bolt boss portion in the cooling water channel is improved. Hereinafter, the results of improving the cooling water stagnation of the cooling copper plate 1 in which the fastening bolt bosses 7 of the present invention are arranged in a staggered manner are shown together with comparative examples.

Embodiment 1 As shown in FIG. 2, the flow rate of the cooling water in the assembly mold employing the cooling structure 10 in which the conventional fastening bolt bosses 7 are arranged in a grid pattern as shown in FIG. In the downstream area (for example, about 0.08 m on the horizontal axis in FIG. 2), about 2
m / sec, while the central portion between the respective fastening bolt bosses 7 (for example, about 0.05 in the horizontal axis of FIG. 2).
At position (16), the distribution width of the cooling water flow velocity becomes as high as 14 m / sec. Further, the cycle of the flow velocity distribution of the cooling water velocity in the flow channel width direction was about 6 cm in proportion to the arrangement pitch of the fastening bolt bosses.

Instead, as shown in FIG. 3, the flow rate of the cooling water in the assembly mold employing the cooling structure 10 in which the fastening bolt bosses 7 of the present invention are arranged in a staggered manner is shown in FIG. The downstream area (for example, about 0.
165 m), and about 12 m / s at the center (eg, about 3.5 m on the horizontal axis in FIG. 3) between the fastening bolt bosses 7 closest in the flow channel width direction.
ec, and the distribution width of the cooling water flow velocity is 6 m /
sec. Further, the distribution cycle of the cooling water flow velocity in the flow channel width direction was about 3 cm in proportion to the arrangement pitch of the closest fastening bolt boss portions, and was reduced to half of that in the conventional example. This indicates that the cooling water flow rate is made uniform, thereby significantly reducing the unevenness in the surface temperature of the continuous slab.

Embodiment 2 According to another embodiment of the present invention, in order to further reduce the unevenness of the surface temperature of the continuous slab due to the stagnation of the flow generated on the downstream side of the cooling water flow path of the fastening bolt boss, the fastening bolt boss is required. A support plate can be provided downstream of the cooling water flow path. The support plate may be integrally formed with the fastening bolt boss and provided as a fastening bolt boss with a support plate in the cooling water passage, or the support plate may be separately provided in the cooling passage. The shape and size of the support plate depend on the spacing between the fastening bolt bosses, the flow rate of the cooling water, etc., but the width of the support plate is equal to or smaller than the diameter of the fastening bolt boss, and the height of the support plate is In order to also serve as a support when fastening the copper plate and the back plate with the fastening bolts, the distance between the cooling copper plate and the back plate is made equal. As shown in FIGS. 4A and 4B, the fastening bolt bosses 7 arranged in a staggered manner.
FIG. 1 (a) shows a case of a cooling structure of a cooling copper plate provided with a support plate 3 integrally formed in a square shape on the downstream side of the cooling water.
FIG. 5 shows a comparison of the temperature distribution of the cooling copper plate surface temperature with the case of the cooling copper plate cooling structure of the fastening bolt boss portions 7 which are simply arranged in a staggered manner without providing the support plate. In both examples, the temperature law fixed point of the cooled copper plate was measured at the interval between the fastening bolt boss portions closest to the meniscus of the assembly mold. In FIG. 5, in the case of a chain line in which the arrangement of the fastening bolt boss portions is staggered but the support plate is not arranged,
The surface temperature of the cooling copper plate is about 270 ° C. at the center of the fastening bolt boss on the horizontal axis, that is, at a position of about 0 mm, but is about 235 ° C. at a position about 20 mm away from the center of the fastening bolt boss in the width direction of the cooling water flow path. , The temperature difference is about 35 ° C
Became. On the other hand, when the arrangement of the fastening bolt bosses is staggered and the solid line on which the rectangular support plate is arranged, the surface temperature of the cooling copper plate is about 248 ° C. at the center of the fastening bolt boss on the horizontal axis, that is, at the position of about 0 mm. However, at a position about 20 mm away from the fastening bolt boss in the width direction of the cooling water channel, the temperature is about 230 ° C.
The temperature difference was improved to about 18 ° C. By disposing the support plate on the downstream side of the fastening bolt boss portion, the nonuniformity of the surface temperature of the cooling copper plate in the width direction of the cooling water channel is improved by the heat transfer effect of the support plate.

Embodiment 3 According to another embodiment of the present invention, in order to further reduce the flow stagnation generated on the downstream side of the fastening bolt boss 7, the support plate 3 is moved toward the downstream of the cooling water flow path. This can be achieved by tapering. FIG. 6 shows a partial perspective view and a cross-sectional view of a cooling copper plate provided with a triangular integrally formed support plate 3 on the downstream side of the cooling water of the fastening bolt bosses 7 arranged in a staggered manner. As shown in FIGS. 6A to 6C, a cooling copper plate cooling structure in which a triangular support plate is provided on the cooling water downstream side of each fastening bolt boss portion arranged in a staggered manner, and FIG. FIG. 7 shows a comparison of a cooling copper plate surface temperature with a cooling copper plate provided with a rectangular support plate on the cooling water downstream side of the fastening bolt bosses arranged in a staggered manner as in (a) and (b). . In both examples, the temperature of the cooled copper plate was measured at the position of the fastening bolt boss closest to the meniscus of the assembly mold. In FIG.
In the case where the arrangement of the fastening bolt bosses is staggered but the support plate has a rectangular chain-shaped cooling structure, as described in Embodiment 2, about 20 mm from the center of the fastening bolt boss on the horizontal axis in the width direction of the cooling water flow path. At a remote location, the temperature difference was improved to about 18 ° C. by placing a square support plate. However, when the support plate is further tapered into a triangle, the cooling copper plate surface temperature is about 235 ° C. at the center of the fastening bolt boss on the horizontal axis, but is about 20 mm away from the fastening bolt boss in the cooling water channel width direction. The position was about 230 ° C., and the temperature difference was improved to about 5 ° C. by placing a tapered triangular support plate.
By arranging the tapered triangular support plate on the downstream side of the fastening bolt boss in this manner, stagnation in the width direction of the cooling water flow path is further reduced, and the uniformity of the surface temperature of the cooling copper plate is improved. Material properties are improved.

[0015]

The cooling structure of the continuous casting of the present invention is as follows.
By arranging the fastening bolt bosses in the cooling water flow path in a staggered manner, the cooling water flow velocity distribution width can be reduced, and the distribution cycle in the cooling water flow path width direction can be reduced to about （(FIG. 2).
And FIG. 3). Also, the surface temperature difference of the cooling copper plate can be reduced by arranging the rectangular support plate of the present invention on the cooling copper plate by arranging it in a grid pattern on the fastening bolt boss portion in the conventional cooling water flow path. About 1 /
2 (see FIG. 5).

Further, in the cooling structure for continuous casting of the present invention, the fastening bolt bosses in the cooling water flow passage are arranged in a staggered manner and a tapered support plate is provided, so that the surface temperature difference of the cooling copper plate can be reduced. In comparison with the case where the supporting plate was provided, it was possible to greatly reduce to about 1/7 (see FIGS. 2 and 7).

[Brief description of the drawings]

FIG. 1 (a) shows a cooling structure in which the fastening bolt bosses of the present invention are arranged in a staggered pattern, and FIG. 1 (b) shows a conventional cooling structure in which the fastening bolt bosses are arranged in a grid pattern. It is a perspective view.

FIG. 2 shows the distribution of the average cooling water flow velocity in the width direction of the inside of the cooling water flow path of the cooling mold assembly mold having the conventional fastening bolt bosses arranged in a grid pattern.

FIG. 3 shows the distribution of the average cooling water flow velocity in the width direction of the cooling water flow path of the assembly mold having the cooling structure in which the fastening bolt bosses of the present invention are arranged in a staggered manner.

FIG. 4 is a diagram of a cooling structure in which fastening bolt bosses of the present invention are arranged in a staggered manner and a rectangular support plate is provided;
4A is a partial perspective view of the cooling structure, and FIG. 4B is a cross-sectional view taken along line AA of FIG.

FIG. 5 shows a difference in surface temperature of a cooling copper plate between fastening bolt bosses depending on the presence or absence of a support plate in a cooling copper plate in which fastening bolt bosses for fastening a cooling copper plate and a back plate are staggered.

FIG. 6 is a diagram of a cooling structure in which the fastening bolt bosses 7 of the present invention are arranged in a staggered manner and a triangular support plate is provided, and FIG. 6A is a partial perspective view of the cooling structure; 6
6B is a sectional view taken along line AA of FIG. 6A, and FIG. 6C is a sectional view taken along line BB of FIG. 6A.

FIG. 7 is a graph showing the relationship between the distance from the center of the fastening bolt when a square (chain line) supporting plate and a triangular (solid line) supporting plate are used in the cooling structure of the present invention in which the fastening bolt bosses are arranged in a staggered manner. Shows the surface temperature of the cooled copper plate.

FIG. 8 is a diagram of a conventional cooling structure in which a cooling water channel and a fastening bolt boss are provided directly on a cooling copper plate. FIG. 8A is a partial perspective view of the cooling structure, and FIG. 8) is a sectional view taken along line AA of FIG. 8A, and FIG. 8C is a sectional view taken along line BB of FIG. 8A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cooling copper plate 2 ... Back plate 3 ... Support plate 4 ... Fastening bolt 5 ... Cooling water flow path 6 ... Cooling water flow direction 7 ... Fastening bolt boss part 8 ... Support plate length 9 ... Support plate width 10 ... Cooling structure

Claims (5)

[Claims] 1. A cooling structure for an assembly mold for continuous casting comprising a water-cooled mold wall for feeding cooling water to a cooling water flow passage formed between a cooling copper plate and a back plate, the cooling copper plate being provided. A fastening bolt boss provided on the cooling copper plate, and a support plate disposed downstream of the fastening bolt boss in the cooling water flow path; and A cooling structure for an assembling mold for continuous casting, wherein a copper plate and the back plate are fastened with fastening bolts. 2. The cooling structure according to claim 1, wherein the fastening bolt bosses are arranged in a staggered manner in the cooling water flow path. 3. In a position adjacent to the fastening bolt boss portion, the width of the support plate is set to be equal to or less than the diameter of the fastening bolt boss portion, and the width of the support plate is tapered in a downstream direction of the cooling water. The cooling structure according to claim 1, wherein: 4. The cooling structure according to claim 1, wherein a length of the support plate parallel to a flow direction of the cooling water is set to be equal to or larger than the diameter of the fastening bolt boss and equal to or smaller than five times the diameter. . 5. The arrangement pitch of each of the fastening bolt bosses in a direction perpendicular to the flow direction of the cooling water, the arrangement pitch exceeding the diameter of the fastening bolt boss. Cooling structure.