JP5525896B2 - Continuous casting mold - Google Patents

Description

The present invention relates to a continuous casting mold used for producing a slab.

Conventionally, in the manufacture of slabs, a continuous casting mold (hereinafter simply referred to as a mold) having a cooling member formed with a space portion penetrating in the vertical direction is used, and molten steel is supplied to the space portion while cooling. It is solidified. Here, since solidification shrinkage occurs in the solidification process of the molten steel, a gap is generated between the cooling member inner surface and the solidified shell formed on the cooling member contact surface side of the molten steel in the drawing direction of the slab, The cooling efficiency of the corner portion of the slab was lowered as compared with other portions, and solidification delay occurred. Therefore, as in Patent Document 1, a mold in which the shape of the cooling member inner surface (molten steel contact surface side) corresponds to the solidification profile of the slab, that is, a multi-taper mold has been proposed.

JP 2008-49385 A

However, in order to make the shape of the inner surface of the cooling member multi-tapered so as to correspond to the solidification profile of the slab, it is necessary to process the inner surface of the cooling member with slightly different dimensions over the entire casting direction. For this reason, there exists a problem that a process is difficult and a manufacturing cost rises. Further, in order to determine the shape of the inner surface of the cooling member, since the shape processing is performed based on the numerical value determined by performing a complicated calculation, the processing becomes complicated and the manufacturing cost increases. Furthermore, even if the shape of the molten steel contact surface side of the cooling member is multi-tapered, the cooling member cannot be cooled uniformly, so the thermal deformation of the cooling member does not occur uniformly, and when the time has elapsed after starting casting, The shape of the multitaper formed on the inner surface of the cooling member gradually changes, and the shape of the inner surface of the cooling member does not correspond to the solidification profile of the slab. As a result, there is a problem that a gap is generated between the inner surface of the cooling member and the solidified shell, and a solidification delay occurs at the corner portion of the slab.

The present invention has been made in view of such circumstances, and is a continuous casting that is easy to process, has a low manufacturing cost, and that can suppress the solidification delay at the corner of the slab and can produce a slab of good quality. An object is to provide a casting mold.

The continuous casting mold according to the present invention that meets the above-mentioned object is formed with a space portion penetrating in the vertical direction on the inside, a cooling member whose outer surface side is cooled by cooling water, and an outer surface side of the cooling member in the vertical direction, respectively. In a continuous casting mold for producing a slab while cooling by supplying molten steel to the space part by a fastening means group composed of a plurality of fastening means arranged side by side and having a support member for mounting the cooling member,
On the inner surface side of the cooling member, there is provided a bulging portion that projects from the upper position to the space portion side with the molten steel surface position as the upper position and 300 mm or more downward from the upper position. The inner line is composed of 3 or more and 8 or less continuous straight portions from the upper position to the lower position, and the angle formed by the adjacent straight portions is within a range of 174 degrees or more and 179.97 degrees or less. And the maximum height h of the bulging part having a straight line connecting the upper position and the lower position as a base is in a range of 0.2 mm or more and 5 mm or less,
Of the many water guide grooves provided on the outer surface side of the cooling member and through which the cooling water flows, the strong cooling water guide groove provided on at least the upper side of the cooling member is a recess provided on the outer surface side of the cooling member. A partition portion in which a proximal end surface is brought into close contact with the support member and protrudes toward a recess portion of the cooling member in a space region formed between the support members, and a distal end portion abuts against a bottom surface of the recess portion of the cooling member Further, the strong cooling water guide groove of the side portion of the fastening means which is formed at least directly below the molten steel surface position of the cooling member among the strong cooling water guide grooves is formed. The inner width of the strong cooling water guide groove between the fastening means adjacent in the vertical direction to be 3 mm or more and 40 mm or less, and the depth of the strong cooling water guide groove in the side portion is The fasteners adjacent to each other in the vertical direction Wherein the strong cooling water guide and deeper than the depth of the groove between are beyond the 20mm or less 3 mm.

In the continuous casting mold according to the present invention, it is preferable that the inner line of the vertical cross section above the upper position of the cooling member is formed by extending the uppermost straight portion constituting the bulging portion.

In the continuous casting mold according to the present invention, the connecting portions of the adjacent straight portions are provided at equal intervals in the vertical direction of the cooling member, and the angles formed by the adjacent straight portions are the same angle. preferable.

In the continuous casting mold according to the present invention, the cooling member includes a pair of short sides arranged to face each other with a gap therebetween, and a pair of long sides arranged to face each other with the short sides sandwiched from both sides in the width direction. It is preferable that the bulging portion be provided on one or both of the pair of short sides and the pair of long sides.

In the continuous casting mold according to the present invention, the cooling member is preferably tube-shaped.

In the continuous casting mold according to the present invention, a coating layer is preferably formed on the molten steel contact surface side of the cooling member.

In the continuous casting mold according to the present invention, the water guide groove includes the strong cooling water guide groove formed on the upper side of the cooling member and a lower side formed on the lower side of the cooling member and communicating with the strong cooling water guide groove. Preferably, the lower water guide groove is formed by disposing a planar second spacer on the cooling member having a plurality of grooves formed on the outer surface side.

In the continuous casting mold according to the present invention, it is preferable that a boundary portion between the strong cooling water guiding groove and the lower water guiding groove is in a range of 200 mm or more and 600 mm or less downward from an upper end of the cooling member.

In the casting mold for continuous casting according to the present invention, at least a horizontal protrusion that increases cooling efficiency is provided at the bottom of the strong cooling water guide groove at a side portion of the fastening means located immediately below the molten steel surface position of the cooling member. It is preferable to provide a fin.

In the casting mold for continuous casting according to the present invention, the molten steel surface position is in a range of 50 mm or more and 150 mm or less downward from the upper end of the cooling member, and the fin is positioned at a position 50 mm above the molten steel surface position. It is preferable to provide within the range to the position of 150 mm below the molten steel surface position.

In the casting mold for continuous casting according to the present invention, a bulging portion is provided on the cooling member inner surface (molten steel contact surface) in a range in which the molten steel surface level is the upper position and the lower position is 300 mm or more downward from the upper position. Thus, since the shape of the inner surface of the cooling member is brought close to the shape corresponding to the solidification profile of the slab, the inner surface of the cooling member can be made simple, and processing can be facilitated to reduce the manufacturing cost. And, the inner width of the strong cooling water guide groove at the side portion of the fastening means located immediately below the molten steel surface position of the cooling member is made narrower than the inner width of the strong cooling water guide groove between the fastening means in the vertical direction , Since the depth of the strong cooling water guide groove on the one side is made deeper than the depth of the strong cooling water guide groove between the fastening means adjacent in the vertical direction, the cooling range of the side part of the fastening means is wider than the other parts. Therefore, it is possible to increase the cooling efficiency of the portion where the conventional temperature is likely to be high, and to cool the cooling member uniformly. As a result, the heat deformation of the cooling member occurs uniformly, and the shape of the inner surface of the cooling member can be maintained in a shape corresponding to the solidification profile of the slab even after a lapse of time from the start of casting. The solidification delay in the corner portion of the steel is suppressed, and a slab of good quality can be manufactured.

In the continuous casting mold according to the present invention, when the inner line of the vertical section above the upper position of the cooling member is formed by extending the uppermost straight line portion constituting the bulging portion, the shape on the inner surface side of the cooling member The manufacturing cost can be further reduced.

In the continuous casting mold according to the present invention, when connecting portions of adjacent straight portions are provided at equal intervals in the vertical direction of the cooling member, and the angles formed by the adjacent straight portions are the same angle, The shape can be further simplified, and the mold can be manufactured more easily.

In the continuous casting mold according to the present invention, the cooling member includes a pair of short sides arranged to face each other with a gap therebetween, and a pair of long sides arranged to face each other with the short sides sandwiched from both sides in the width direction. In the case where the bulging portion is provided on one or both of the pair of short sides and the pair of long sides, a space portion penetrating in the vertical direction can be easily formed.

In the continuous casting mold according to the present invention, when the cooling member has a tube shape, the assembly of the mold becomes easy.

In the continuous casting mold according to the present invention, when a coating layer is formed on the molten steel contact surface side of the cooling member, it is the coating layer portion that is worn by contact with the solidified shell formed on the cooling member contact surface side. Therefore, the cooling member can be easily regenerated by removing the remaining coating layer and forming the coating layer again.

In the continuous casting mold according to the present invention, the lower water guide groove communicating with the strong cooling water guide groove is formed by arranging a planar second spacer on the cooling member having a plurality of grooves formed on the outer surface side. In this case, it is not necessary to make the entire shape of the cooling member into a special shape, and processing becomes easy.

In the casting mold for continuous casting according to the present invention, when the boundary between the strong cooling water guide groove and the lower water guide groove is in the range of 200 mm or more and 600 mm or less downward from the upper end of the cooling member, the molten steel having a particularly large heat load. The restraining strain of the cooling member generated in the vicinity of the surface can be reduced, the generation of cracks in the cooling member can be suppressed, and the life of the mold can be extended.

In the continuous casting mold according to the present invention, in the case where a fin made of a horizontal protrusion that increases cooling efficiency is provided at the bottom of the strong cooling water guide groove at the side portion of the fastening means located immediately below the molten steel surface position of the cooling member. Further, it is possible to suppress an increase in the temperature of the cooling member in the vicinity of the molten metal surface having a large heat load, to suppress generation of cracks in the cooling member, and to extend the life of the mold.
Here, when the fin is provided in a range from a position 50 mm above the molten steel surface position to a position 150 mm below the molten steel surface position, generation of cracks in the cooling member can be further suppressed.

It is a longitudinal cross-sectional view of the long side of the casting mold for continuous casting which concerns on one embodiment of this invention. (A) is a partial plan sectional view in the vicinity of the bolt located immediately below the molten steel surface position of the continuous casting mold, and (B) is a partial plan sectional view between adjacent bolts in the vertical direction of the continuous casting mold. is there. (A) is explanatory drawing of the back side of the long side of the mold for continuous casting, (B) is a sectional view taken along the line aa of (A), and (C) is a sectional view taken along the line bb of (A). It is. (A) is explanatory drawing of the back side of the spacer of the long side of the casting mold for continuous casting, (B) is a side view of the spacer, (C) is a front view of the spacer, and (D) is c of (C). -C arrow sectional drawing, (E) is a dd arrow sectional drawing of (C). (A), (B) is a longitudinal cross-sectional view of the long side of the casting mold for continuous casting which concerns on the 1st, 2nd modification, respectively. It is a fragmentary top sectional view between the volt | bolts adjacent to the up-down direction of the casting mold for continuous casting which concerns on a 3rd modification. (A) is the elements on larger scale of the back side of the long side of the continuous casting mold which concerns on a 3rd modification, (B) is ee arrow sectional drawing of (A).

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIGS. 1 to 4, a continuous casting mold (hereinafter also simply referred to as a mold) 10 according to an embodiment of the present invention forms a space portion 11 penetrating in the vertical direction on the inner side, and the outer surface side. The (rear surface side) includes a cooling member 12 that is cooled by cooling water, and a back plate (also referred to as a cooling box or a water box) 16 that is an example of a support member to which the cooling member 12 is attached. Here, the cooling member 12 includes a pair of short sides (also referred to as short pieces) (not shown) arranged to face each other with a gap therebetween, and a pair of long sides arranged to face each other with the short sides sandwiched from both sides in the width direction. (Also referred to as a long piece) 14. The short side and the long side 14 are backed by a fastening means group composed of a plurality of fastening means arranged in the vertical direction (casting direction) on the back surface (the surface opposite to the surface in contact with the molten steel). Attached to the plate 16. Each fastening means is composed of bolts 15 and 15a.

Thereby, from the water supply part (not shown) provided in the lower part of the back plate 16, the upper part of the back plate 16 is passed through many water guide grooves 17-19 provided in the back side of the short side and the long side 14. A cooling water is made to flow into a drainage part (not shown) provided in the slab, and the molten steel 13 supplied to the space part 11 of the cooling member 12 composed of the short side and the long side 14 is cooled and solidified while being drawn downward. Is to be manufactured.

For example, the short side has a thickness of about 5 mm to 100 mm, a width of about 50 mm to about 300 mm, and a vertical length of about 600 mm to about 1200 mm. Further, the long side 14 has a thickness of about 5 mm or more and 100 mm or less, and the distance between a pair of short sides arranged opposite to each other (width contacting the cast piece) can be changed within a range of 600 mm or more and 3000 mm or less. It has a width that can be made, and the length in the vertical direction is about the same as the short side. The short side and the long side 14 are made of copper or a copper alloy. Thereby, for example, a slab having a width of about 600 mm to about 3000 mm and a thickness of about 50 mm to about 300 mm can be manufactured. Since the short side and the long side 14 are different in only the width and the other configurations are substantially the same, and the pair of long sides 14 are mirror-symmetrical, the long side 14 shown in FIGS. The configuration will be mainly described in detail below.

The position of the molten steel surface of the molten steel 13 across the width direction on the molten steel contact surface 20 side of both the pair of short sides and the pair of long sides 14 constituting the cooling member 12 (that is, the inner surface side of the cooling member 12). A bulging portion 21 that protrudes to the space portion 11 side is provided with a meniscus position (sometimes simply referred to as a hot water surface position) as an upper position P1, and 300 mm or more downward from the upper position P1 as a lower position P2. The molten steel surface position is within a range of 50 mm or more and 150 mm or less (here, about 100 mm) starting from the upper end position of the long side 14 (the same applies to the short side). In addition, although the protrusion amount to the space part 11 side of the bulging part 21 is slight, in FIG. 1, FIG.5 (A) and (B), it has exaggerated and shown for convenience of explanation.

Here, the reason why the upper position P1 of the bulging portion 21 is set as the molten metal surface position is that it is the starting position of the cooling of the molten steel. In addition, the lower position P2 of the bulging portion 21 is set to a position of 300 mm or more downward from the upper position P1 because there is a gap between the solidified shell formed on the mold contact surface side of the molten steel and the inner surface of the cooling member 12. This is because the resulting range is within this range. From the above, the formation position of the bulging portion 21 is the molten steel surface position as the upper position P1 and downward from the upper position P1 to the lower position P2 of 300 mm or more, but the lower position P2 is the upper position P1. It is preferable to set it to the lower end position of the short side and the long side 14 at a position of 500 mm or more downward. In addition, the long side 22 shown in FIG. 5 (A) has the bulging portion 23 forming position with the molten steel surface position as the upper position P1, and downward from the upper position P1 to the lower position P2 of 300 mm or more. In the long side 24 shown in (B), the formation position of the bulging portion 25 is such that the molten steel surface position is the upper position P1 and the lower position P2 is the lower end position of the long side 24.

Contour lines (inner lines) on the molten steel contact surface 20 side of the longitudinal section of the bulging portion 21 are three or more and eight or less (three in this embodiment) straight lines from the upper position P1 to the lower position P2. It is comprised by the parts L1-L3, and the molten steel contact surface 20 of the long side 14 is comprised by the inclined surface of 3 steps or more and 8 steps or less from which inclination angles differ. Here, when the number of straight portions constituting the bulging portion is less than three (two or less), the number of straight portions is too small, and the vertical cross-sectional shape of the bulging portion becomes an extreme shape that partially protrudes. The contact resistance with the slab increases, and wear damage is likely to occur at the bulge portion. On the other hand, when the number of straight portions exceeds eight (9 or more), the number of straight portions is too large, the processing of the bulging portion becomes complicated, and the manufacturing cost increases. From the above, the bulging portion 21 is configured by the three straight portions L1 to L3. However, the lower limit of the number of straight portions is preferably four, and the upper limit is preferably six. In addition, the long side 22 shown to FIG. 5 (A) comprises the bulging part 23 by the three linear parts M1-M3, and the long side 24 shown to FIG. 5 (B) has four bulging parts 25. It comprises straight portions N1 to N4.

Note that the inner line of the longitudinal section on the molten steel contact surface 20 side of the long side 14 (the same applies to the short side) above the upper position P1 of the long side 14 is the uppermost straight line portion L1 constituting the bulging portion 21. It is formed by extending. As shown in FIG. 5A, the longitudinal section above the upper position P1 is the molten steel contact surface side of the long side 22 (the short side is the same), and is a longitudinal section above the upper position P1 of the long side 22. The surface may be in a vertical state (inclination angle 0 degree) parallel to the back side of the long side 22 without forming the uppermost straight line portion M1 constituting the bulging portion 23.

For the straight line portions L1 to L3, the uppermost straight line portion L1, the angle θ1 formed by the second straight line portion L2 adjacent to the straight line portion L1, and the straight line portion L2 and the third straight line portion L3 from the top are formed. The angle θ2 is in the range of 174 degrees or more and 179.97 degrees or less, respectively. Note that the angles θ1 and θ2 are the same angle, but may be different angles. Here, when the angle θ formed by the adjacent straight portions is less than 174 degrees, the shape of the bulging portion in a side cross-sectional view becomes an extreme shape that partially protrudes, and the contact resistance with the slab increases. Wear damage is likely to occur in the bulging portion. On the other hand, when the angle θ formed by the adjacent straight portions exceeds 179.97 degrees, the number of straight portions increases and the processing of the bulging portion becomes complicated, resulting in an increase in manufacturing cost. From the above, the angles θ1 and θ2 formed by the adjacent straight line portions L1 to L3 are set in the range of 174 degrees or more and 179.97 degrees or less, respectively, but the lower limit is 178.0 degrees, and further 179.0 degrees. It is preferable to set the upper limit to 179.90 degrees.

The uppermost straight line portion L1 and the next straight line portion L2 are connected at the connection point X1, the straight line portion L2 and the next straight line portion L3 are connected at the connection point X2, and the lower position P2 is the upper end of the long side 14 (the short side is the same) From the position, the long sides 14 are provided at different intervals S1 to S3 in the vertical direction. The long side 24 shown in FIG. 5B is also connected to the connecting portion Y1 between the straight portion N1 and the straight portion N2, the connecting portion Y2 between the straight portion N2 and the straight portion N3, and the connecting portion between the straight portion N3 and the straight portion N4. Y3 and the lower position P2 are provided at different intervals T1 to T4 in the vertical direction of the long side 24. In addition, you may provide each connection location X1, X2 and the lower position P2 by the equal space | interval S about a part or all of the up-down direction of the long side 14 (a short side is also the same). Here, the uniform interval S includes a case where each interval differs within a range of ± 20% (preferably ± 5%) with respect to an average value of each interval.

As shown in FIG. 1, the maximum height h of the bulging portion 21 whose bottom is a straight line L4 connecting the upper position P1 and the lower position P2 (here, the first straight portion L1 and the second straight portion L2 from the top) The height of the connecting portion X1) is within the range of 0.2 mm to 5 mm. Here, when the maximum height h is less than 0.2 mm, the amount of protrusion of the bulging portion toward the space is too small, and the surface shape of the bulging portion cannot follow the solidification shrinkage of the slab, and the bulging portion A gap is formed between the surface of the steel and the solidified shell formed on the mold contact surface side of the molten steel. On the other hand, when the maximum height h exceeds 5 mm, the longitudinal section of the bulge part becomes an extreme shape that partially protrudes, the contact resistance with the slab increases, and wear damage occurs in the bulge part. It becomes easy. From the above, the maximum height h of the bulging portion 21 is set in the range of 0.2 mm to 5 mm, but the lower limit is preferably 0.5 mm, more preferably 0.55 mm, and the upper limit is 2.5 mm. Furthermore, it is preferable to set it as 2.2 mm.

The formation position of the bulging portion shown above, the number of straight portions constituting the bulging portion, the angle formed by the adjacent straight portions, and the maximum height h of the bulging portion are considered in the following conditions, Further, based on the actual measurement results, it is preferable to make the determination within the above-mentioned range by FEM analysis (analysis using a finite element method) considering solidification shrinkage of the three-dimensional slab and thermal deformation of the mold.
1) Slab shape, slab size, or casting conditions (for example, casting temperature, drawing speed, mold cooling conditions, etc.).
2) Physical quantities derived from components of cast steel (for example, liquid phase temperature, solid phase temperature, transformation temperature, linear expansion coefficient, rigidity value, etc.).
3) Amount of contact heat transfer between the mold and the slab (the amount of shrinkage of the slab is greatly affected by this amount).
Since this contact heat transfer amount is disclosed in Japanese Patent Application Laid-Open No. 2008-49385, the detailed contents thereof are omitted.

On the molten steel contact surface 20 side of the short side and the long side 14, for example, a coating layer is formed by thermal spraying. The coating layer for thermal spraying may be formed over the entire surface of a copper plate (or copper alloy plate, the same shall apply hereinafter) using the same type of components on the short side and the long side 14, and a plurality of types of components May be formed in different regions in the vertical direction of the copper plate according to the function of each component. For the short side and the long side 14 shown above, the copper plate is processed into the above-described shape by performing a conventionally known machining process, and then a coating layer is formed on the surface, and further finishing is performed as necessary. As the coating layer, there are a fusing type that is used by heat treatment after spraying the surfaces of the machined short side and long side 14, and a fusingless type that is used without heat treatment. .

As the fusing type material, a Cr—Si—B based alloy based on Ni or Co can be used, and a cermet added to it can be used as necessary. The fusingless type material includes any one of Co, Ni, or alloys thereof, carbides such as WC (tungsten carbide), nitrides such as TiN, and borides such as CrB. Or what added 2 or more can be used. Note that any of the types of materials described above can be applied to the short side and the long side, but considering the shape change of the copper plate after the heat treatment is finished, a fusing type material is used on the short side, It is preferable to apply a fusingless type material to each of the long sides. The coating layer may be plated. As a material for the plating, for example, a Co alloy such as Co—Ni, a Ni alloy such as Ni—Fe, or Ni can be used.

2 (A), (B), FIGS. 3 (A) to (C), and FIGS. 4 (A) to (E), the water guide grooves 17 to 19 provided on the back side of the long side 14 are It is a strong cooling water guide groove, and is formed by arranging a spacer 27 in a space region 26 formed between a recess provided on the back side of the long side 14 and the back plate 16. The concave portion of the long side 14 is formed by thinning the long side 14 so that the thickness T1 of the long side 14 is 3 mm or more and 30 mm or less, and between the fastening means groups adjacent in the width direction of the long side 14. To form. Here, when the thickness of the long side of the thinned portion is less than 3 mm, the grinding allowance at the time of repeated use of the long side is reduced, and the number of times the mold is used is reduced. On the other hand, when the thickness exceeds 30 mm, the thickness becomes too thick, and the amount of plastic strain increases due to an increase in generated temperature due to an increase in mold temperature and fastening constraints. From the above, the thickness T1 of the thin long side is 3 mm or more and 30 mm or less, but the upper limit is preferably 20 mm, more preferably 12 mm, and the lower limit is preferably 5 mm, further 7 mm.

On the back side of the long side 14, a portion that has not been thinned (that is, a region that connects the bolts 15 and 15 a adjacent to the upper and lower sides of the fastening means group) extends in the vertical direction of the long side 14. It remains as a fixing portion 28 protruding to the back side. In addition, the space | interval U of the fastening means group adjacent to the width direction is about 50 mm or more and 200 mm or less, for example. The bolts 15 and the bolts 15a constituting the fastening means group are different only in shape. Screw holes 29 are formed in the upper and lower portions of the fixing portion 28, the mounting holes 30 formed in the spacer 27 are aligned with the screw holes 29, and screws (not shown) are tightened to attach the spacer 27 to the fixing portion 28. Can be installed. The spacer 27 is made of, for example, copper, copper alloy, aluminum, aluminum alloy, iron, or stainless steel having corrosion resistance, and a plurality of spacers 27 are arranged in the width direction of the long side 14 with the fastening means group as a boundary.

The spacer 27 has a shape in which both sides in the width direction are recessed at the mounting position of the bolt 15, so that the adjacent spacer 27 avoids the bolt 15 and is not installed at the bolt 15. The side part is in contact. The spacer 27 is provided with partition portions 31 and 32 that protrude in the vertical direction of the long side 14 toward the hollow portion of the long side 14, and whose tip ends abut against the bottom surface of the hollow portion of the long side 14. ing. As a result, the space region 26 is partitioned by the partition portions 31 and 32 of the spacer 27 disposed in the space region 26 with the base end face being in close contact with the back plate 16, and a plurality (here) Then, three water guide grooves 17 to 19 are formed. Among the water guide grooves 17 to 19, the water guide grooves 17 and 19 adjacent to the fastening means group are a part in which the cross-sectional shape is located on the side of the bolt 15 in the vertical direction of the long side 14, and other parts. (The portion located on the side of the fixed portion 28). In addition, the cross-sectional shape of the water guide groove 18 positioned between the water guide grooves 17 and 19 is the same in the vertical direction of the long side 14.

The inner width W1 of the water guide groove 17 (the same as the water guide groove 19) of the side portion of the bolt 15 shown in FIG. 2 (A) is the water guide groove located between the adjacent bolts 15 shown in FIG. 2 (B). 17 is narrower than the inner width W2. And the depth D1 of the water guide groove 17 of the side part shown to FIG. 2 (A) is deeper than the depth D2 of the water guide groove 17 located between the volt | bolts 15 adjacent to the up-down direction shown to FIG. 2 (B). It has become. Specifically, W1 is not less than 3 mm and not more than 40 mm, D1 is more than 3 mm and not more than 20 mm, and at this time, D1 / W1 exceeds 0.075 and satisfies the relationship of 5 or less. Further, W2 is 10 mm or more and 80 mm or less, D2 is 3 mm or more and 10 mm or less, and D2 / W2 satisfies the relationship of 0.075 or more and 1 or less. Thereby, the cooling efficiency in the vicinity of the bolt 15 can be increased. Here, the connection part of the part (henceforth area | region A) located in the side of the volt | bolt 15 of the water conveyance groove | channel 17 and the part (henceforth area | region B) located between the volt | bolts 15 adjacent to an up-down direction. In the region B, the inner width is gradually narrowed continuously (curved surface) from the region B to the region A. Further, the connection portion gradually increases in depth from region B to region A.

In addition, the plane cross-sectional area of the water guide groove 17 (region A) on the side portion of the bolt 15 is the same as the plane cross-sectional area of the water guide groove 17 (region B) between the bolts 15 adjacent in the vertical direction, or -50% or more. + 50% or less (preferably, the upper limit is + 20%, further + 5%, the lower limit is −20%, further −5%). Here, by making the plane cross-sectional area of the region A close to the plane cross-sectional area of the region B, the flow rate of the cooling water flowing through the water guide groove 17 can be made substantially uniform from the lower part to the upper part of the long side 14. In addition, in this Embodiment, although shown about the case where the water guide grooves 17-19 were comprised with the strong cooling water guide groove, you may comprise only the upper side of a long side with the above-mentioned strong cooling water guide groove. Further, in the present embodiment, the inner width, depth, and plane cross-sectional area of the water guide grooves at the side portions of all the bolts 15 are set so as to satisfy the predetermined conditions, but are at least directly below the meniscus of the cooling member. The inner width of the strong cooling water guide groove at the side portion of the bolt (fastening means) is set as the above condition. Moreover, you may make it set the said condition with respect to the water guide groove of the side part of the volt | bolt located just under a meniscus, or the water guide groove containing this.

In this case, as shown in FIG. 6, the water guide groove is configured by an upper strong cooling water guide groove and lower water guide grooves 33 to 35 communicating with the strong cooling water guide groove. Each of the lower water guide grooves 33 to 35 may be configured by disposing a planar second spacer 37 on the long side 36 in which a plurality of grooves are formed on the back surface side. The contour shape of the cross section of the lower water guide grooves 33 to 35 is substantially the same as the contour shape of the water guide groove 18, but the inner width thereof may be wider. At this time, a spacer that constitutes the upper strong cooling water guide groove and a planar second spacer 37 that constitutes the lower water guide grooves 33 to 35 are disposed between the fastening means groups adjacent to each other on the long side. It will be. Thereby, processing of each spacer becomes easy. Here, the boundary between the strong cooling water guide groove and the lower water guide grooves 33 to 35 falls within the range of 200 mm to 600 mm (preferably lower limit is 250 mm, upper limit is 450 mm) downward from the upper end of the long side 36. . The meniscus is in the range of 50 mm or more and 150 mm or less downward from the upper end of the long side 36.

Further, as shown in FIGS. 7A and 7B, the space region 26 formed between adjacent fastening means groups of the long side 38 and the spacer 27 having the partition portions 31 and 32 are formed. Of the water guide grooves 39 to 41, the cooling efficiency is increased at the bottom of the portion located on the side of the bolt 15 located immediately below the meniscus of the water guide grooves 39 and 41 (strong cooling water guide grooves) adjacent to both sides of the fastening means group. You may provide the fins 42 and 43 which consist of a horizontal protrusion to make. The long side 38 has the same configuration as the long side 14 except that the fins 42 and 43 are provided. The fins 42 and 43 can be formed by moving, for example, a ball end mill (not shown) in the width direction of the long side 38 with respect to the bottom surface of the region where the water guide grooves 39 and 41 are formed. The fins 42 and 43 are formed in a wave shape when viewed from the side, and the vertical pitch P of the long sides 38 is about 1 mm or more and 5 mm or less, and the depth D3 is a bottom surface before the fins 42 and 43 are formed. On the other hand, it is about 0.5 mm or more and 2 mm or less. The fins may be provided over the entire water guide grooves 39 and 41 or partially, and over the entire range from the position 50 mm above the meniscus to the position 150 mm below the meniscus, Or you may provide partially.

For example, a stainless steel back plate 16 (for example, a thickness of about 50 mm or more and about 500 mm or less) is attached to the back side of the long side 14 described above using a plurality of bolts 15 and 15a. At the time of attachment, grooves (not shown) are formed in the periphery of the back plate 16 so as to surround the water supply portion, the drainage portion, and the water guide grooves 17 to 19 of the long side 14. By disposing (not shown), the adhesion between the long side 14 and the back plate 16 is improved, and leakage of cooling water from the water guide grooves 17 to 19 is prevented. Here, the fastening means has a female screw portion 44 formed on the long side 14 and male screws (not shown) of bolts 15 and 15a that are screwed into the female screw portion 44 to fasten the back plate 16. . Further, in order to attach the male screw, a seal washer that can be waterproofed is disposed in advance in the hole 45 formed in the back plate 16 to prevent leakage of cooling water from the portion to which the male screw is attached.

Next, the operation of the continuous casting mold 10 according to the embodiment of the invention will be described.
In the continuous casting mold 10, on the inner surface (molten steel contact surface side) of the cooling member 12 attached to the back plate 16, the molten steel surface position is the upper position, and 300 mm or more downward from the upper position. The bulging part 21 is provided in the range to be made, and the shape of the inner surface of the cooling member 12 is brought close to the shape corresponding to the solidification profile of the slab. And the inner width of the water guide grooves 17, 18, 19 (strong cooling water guide grooves) at the side portions of the bolts 15, 15a located at least directly below the molten steel surface position of the cooling member 12 is set to the bolts 15, 15a in the vertical direction. The flow rate of the cooling water flowing through the side portions of the bolts 15 and 15a can be made faster than the other portions by making it narrower than the inner width of the water guide grooves 17, 18, and 19 between them.

Further, the depth of the water guide grooves 17, 18, 19 on the side portions of the bolts 15, 15a is made deeper than the depth of the water guide grooves 17, 18, 19 between the bolts 15, 15a adjacent in the vertical direction. The cooling efficiency of the part where the temperature is likely to rise is increased. Furthermore, the flat cross-sectional area of the water guide grooves 17, 18, 19 on the side portions of the bolts 15, 15a is set to -50% of the cross-sectional area of the water guide grooves 17, 18, 19 between the bolts 15, 15a adjacent in the vertical direction. The flow rate of the cooling water is stabilized from the lower part to the upper part of the cooling member 12 by making the range within + 50% or less and widening the cooling range of the side parts of the bolts 15 and 15a more than other parts.

Thereby, the cooling member 12 can be cooled efficiently and uniformly. As a result, the thermal deformation of the cooling member 12 can be made small and uniform, and the inner surface shape of the cooling member 12 is maintained in a shape corresponding to the solidification profile of the slab even after a lapse of time from the start of casting. Thus, solidification delay at the corner of the slab is suppressed, and a slab of good quality can be manufactured. Moreover, since the thermal deformation of the cooling member 12 is small, the lifetime of the cooling member 12 can be extended.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above-described embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included.
For example, you may provide a bulging part in any one of a pair of short side and a pair of long side. In this case, it is necessary to form a space region between the side provided with the bulging portion and the support member to which this side is attached, and to form a strong cooling water guide groove by arranging a spacer in this space region.
Further, the cooling member can be formed in a tube shape.

10: mold for continuous casting, 11: space portion, 12: cooling member, 13: molten steel, 14: long side, 15, 15a: bolt, 16: back plate, 17, 18, 19: water guide groove, 20: molten steel contact Surface, 21: bulging portion, 22: long side, 23: bulging portion, 24: long side, 25: bulging portion, 26: space region, 27: spacer, 28: fixing portion, 29: screw hole, 30 : Mounting hole 31, 32: partition part, 33, 34, 35: lower water guide groove, 36: long side, 37: second spacer, 38: long side, 39, 40, 41: water guide groove, 42, 43: Fin, 44: Female thread, 45: Hole

Claims (10)

By means of a fastening means group comprising a cooling member formed on the inner side with a space portion penetrating in the vertical direction, the outer surface side being cooled by cooling water, and a plurality of fastening means arranged in the vertical direction on the outer surface side of the cooling member. A continuous casting mold having a supporting member for mounting the cooling member, and producing a slab while supplying molten steel to the space and cooling it,
On the inner surface side of the cooling member, there is provided a bulging portion that projects from the upper position to the space portion side with the molten steel surface position as the upper position and 300 mm or more downward from the upper position. The inner line is composed of 3 or more and 8 or less continuous straight portions from the upper position to the lower position, and the angle formed by the adjacent straight portions is within a range of 174 degrees or more and 179.97 degrees or less. And the maximum height h of the bulging part having a straight line connecting the upper position and the lower position as a base is in a range of 0.2 mm or more and 5 mm or less,
Of the many water guide grooves provided on the outer surface side of the cooling member and through which the cooling water flows, the strong cooling water guide groove provided on at least the upper side of the cooling member is a recess provided on the outer surface side of the cooling member. A partition portion in which a proximal end surface is brought into close contact with the support member and protrudes toward a recess portion of the cooling member in a space region formed between the support members, and a distal end portion abuts against a bottom surface of the recess portion of the cooling member Further, the strong cooling water guide groove of the side portion of the fastening means which is formed at least directly below the molten steel surface position of the cooling member among the strong cooling water guide grooves is formed. The inner width of the strong cooling water guide groove between the fastening means adjacent in the vertical direction to be 3 mm or more and 40 mm or less, and the depth of the strong cooling water guide groove in the side portion is The fasteners adjacent to each other in the vertical direction Wherein the strong cooling continuous casting mold, characterized in that the water guide and deeper than the depth of the groove was set to exceed 3 mm 20 mm or less between. 2. The continuous casting mold according to claim 1, wherein an inner line of a longitudinal section above the upper position of the cooling member is formed by extending the uppermost straight portion constituting the bulging portion. Continuous casting mold. The continuous casting mold according to claim 1 or 2, wherein the connecting portions of the adjacent straight portions are provided at equal intervals in the vertical direction of the cooling member, and the angles formed by the adjacent straight portions are the same angle. A mold for continuous casting, characterized in that there is. The continuous casting mold according to any one of claims 1 to 3, wherein the cooling member includes a pair of short sides opposed to each other with a gap therebetween and the short sides sandwiched from both sides in the width direction. And a pair of long sides opposed to each other, wherein the bulging portion is provided on one or both of the pair of short sides and the pair of long sides. The continuous casting mold according to any one of claims 1 to 3, wherein the cooling member has a tube shape. The continuous casting mold according to any one of claims 1 to 5, wherein a coating layer is formed on the molten steel contact surface side of the cooling member. The continuous casting mold according to any one of claims 1 to 6 , wherein the water guide groove is formed on the lower side of the cooling member and the strong cooling water guide groove formed on the upper side of the cooling member. The lower water guide groove is formed by disposing a planar second spacer on the cooling member having a plurality of grooves formed on the outer surface side. The lower water guide groove is connected to the strong cooling water guide groove. A casting mold for continuous casting, characterized by being made. The continuous casting mold according to claim 7 , wherein a boundary portion between the strong cooling water guide groove and the lower water guide groove is in a range of 200 mm or more and 600 mm or less downward from an upper end of the cooling member. Continuous casting mold. The continuous casting mold according to any one of claims 1 to 8 , wherein at least a bottom portion of the strong cooling water guide groove at a side portion of the fastening means located immediately below the molten steel surface position of the cooling member. A continuous casting mold characterized by providing fins made of horizontal protrusions that increase cooling efficiency. The mold for continuous casting according to claim 9 , wherein the molten steel surface position is within a range of 50 mm or more and 150 mm or less downward from the upper end of the cooling member, and the fins are 50 mm above the molten steel surface position. A continuous casting mold characterized by being provided within a range from a position to a position 150 mm below the molten steel surface position.

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