JP6817498B1 - Mold for continuous casting - Google Patents

Abstract

It has a mold space portion 13 surrounded by a pair of short sides 11 arranged to face each other at intervals and a pair of long sides 12 sandwiching the short sides 11 from both sides in the width direction, and the pair of short sides 11 And a pair of long sides 13, and a chamfer forming portion 15 that bulges toward the mold space 13 side is provided on the short side 11 of the four corner regions R of the mold wall 14 that forms the mold space 13. , A mold 10 for continuous casting in which molten steel is injected into the mold space 13 and then cooled and pulled out as a slab. The surface of the chamfer forming portion 15 on the mold space 13 side has a horizontal cross section directed toward the mold space 13. It is composed of a plurality of continuous straight portions 16 and 17 formed so as to bulge out, and is formed by a straight portion 17 that abuts or is close to the long side 12 with respect to the surface S1 on the mold space 13 side of the long side 12. The angle θ1 is more than 60 degrees and less than 90 degrees, and a wear-resistant film is formed on the surface of the chamfer forming portion 15 on the mold space 13 side.

Description

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

For the slab, a continuous casting mold (hereinafter, also simply referred to as a mold) having a mold wall in which a mold space portion penetrating in the vertical direction is formed inside is used, and molten steel supplied to the mold space portion is used as a mold wall. It is solidified and cast while cooling with. The cast slab is further conveyed downstream in the casting direction and cut into a slab, and the slab is rolled by a rolling mill.
However, since the slab has a substantially quadrangular cross section, bending or cracking may occur at the widthwise end portion of the slab during rolling of the slab, which may lead to quality defects or a decrease in yield.

Therefore, for example, Patent Document 1 has a mold space portion surrounded by a pair of short sides arranged so as to face each other at intervals and a pair of long sides sandwiching the short sides from both sides in the width direction. A chamfer forming portion having a triangular cross section is provided on the short sides of the four corner regions of the mold wall, which is composed of a pair of short sides and a pair of long sides and forms a mold space portion, and which bulges toward the mold space portion side. Molds are disclosed. The pair of short sides are clamped by a pair of long sides sandwiching the pair of short sides. Further, usually, a wear-resistant film (plating film) is formed on the surface of the chamfer forming portion.

Japanese Patent No. 6085571

As a result of analyzing the thermal deformation state of the mold during continuous casting, the short side expands thermally in the width direction with a maximum of about 80 mm below the meniscus (hot water surface) level, and 300 mm below this (particularly). A relatively large thermal deformation occurred in the range up to about 200 mm). In particular, in the vicinity immediately below the meniscus where the thermal deformation is large, a large stress is generated because the corner edge portion on the short side of the mold space side strongly contacts the surface of the long side on the mold space side.
For this reason, in the above-mentioned chamfer forming portion having a triangular cross section, for example, deformation, damage or chipping of the film, etc. occur at the acute-angled end portion on the side contacting the surface on the mold space side of the long side. It is easy to do, and there is a risk of shortening the life of the mold and causing poor quality of the slab.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a mold for continuous casting, which can prolong the life of a slab and can produce a slab of good quality with a high yield.

The continuous casting mold according to the first invention according to the above object is surrounded by a pair of short sides arranged to face each other at intervals and a pair of long sides sandwiching the short sides from both sides in the width direction. It has a mold space portion, is composed of the pair of short sides and the pair of long sides, and expands toward the mold space portion side on the short sides of the four corner regions of the mold wall forming the mold space portion. In a continuous casting mold, which is provided with a chamfer forming portion to be ejected, molten steel is injected into the mold space, cooled, and drawn as a slab.
The width of the short sides is 500 mm or less, and the distance between the pair of short sides arranged so as to face each other is 3500 mm or less.
The surface of the chamfer forming portion on the mold space side is composed of a plurality of continuous straight portions formed so that the horizontal cross section bulges toward the mold space side, and the mold on the long side is formed. The angle formed by the straight line portion in contact with or close to the long side with respect to the surface on the space side is more than 60 degrees and less than 90 degrees, and the surface of the short side excluding the four corner regions of the mold wall. The angle formed by the straight line portion continuous with the surface is 5 degrees or more and 50 degrees or less.
The width of the chamfer forming portion in the short side direction is 10 mm to 50 mm, which is longer than the width in the long side direction, and the width of the straight portion in contact with or close to the long side is 1 mm to 10 mm. Yes,
A wear-resistant film is formed on the surface of the chamfer forming portion on the mold space side.

The continuous casting mold according to the second invention according to the above object is surrounded by a pair of short sides arranged to face each other at intervals and a pair of long sides sandwiching the short sides from both sides in the width direction. It has a mold space portion, is composed of the pair of short sides and the pair of long sides, and expands toward the mold space portion side on the short sides of the four corner regions of the mold wall forming the mold space portion. In a continuous casting mold, which is provided with a chamfer forming portion to be ejected, molten steel is injected into the mold space, cooled, and drawn as a slab.
The width of the short sides is 500 mm or less, and the distance between the pair of short sides arranged so as to face each other is 3500 mm or less.
The surface of the chamfer forming portion on the mold space side is composed of a plurality of continuous straight lines formed so that the horizontal cross section bulges toward the mold space side, and the plurality of straight lines. Of the connecting portions of the portions, the connecting portion formed on the straight portion that is in contact with or close to the long side is composed of a curved portion that bulges toward the mold space portion side, and further, the mold. The angle formed by the straight line portion continuous with the surface with respect to the surface of the short side excluding the four corner regions of the wall is 5 degrees or more and 50 degrees or less.
The width of the chamfer forming portion in the short side direction is 10 mm to 50 mm, which is longer than the width in the long side direction, and the width of the straight portion in contact with or close to the long side is 1 mm to 5 mm. Yes,
A wear-resistant film is formed on the surface of the chamfer forming portion on the mold space side.

The continuous casting mold according to the third invention according to the above object is surrounded by a pair of short sides arranged to face each other at intervals and a pair of long sides sandwiching the short sides from both sides in the width direction. It has a mold space portion, is composed of the pair of short sides and the pair of long sides, and expands toward the mold space portion side on the short sides of the four corner regions of the mold wall forming the mold space portion. In a continuous casting mold, which is provided with a chamfer forming portion to be ejected, molten steel is injected into the mold space, cooled, and drawn as a slab.
The width of the short sides is 500 mm or less, and the distance between the pair of short sides arranged so as to face each other is 3500 mm or less.
The surface of the chamfer forming portion on the mold space side is composed of a curved portion formed so that the horizontal cross section bulges toward the mold space side, and the surface of the long side of the mold space side. The angle formed by the tangent of the rising portion of the curved portion with respect to the surface is more than 60 degrees and 90 degrees or less, and the tangent of the rising portion of the curved portion to the surface of the short side excluding the four corner regions of the mold wall. The angle between the two is 10 degrees or more and 50 degrees or less.
The width of the chamfer forming portion in the short side direction is 10 mm to 50 mm, which is longer than the width in the long side direction.
A wear-resistant film is formed on the surface of the chamfer forming portion on the mold space side.

In the continuous casting mold according to the first to third inventions, the chamfer forming portion formed on the opposite short side follows the solidification shrinkage amount of the slab shell in the direction in which the slab is pulled out. It is preferable that an inclined portion is formed in which the interval is gradually narrowed.
In the mold for continuous casting according to the first to third inventions, the coating is preferably a thermal spray coating or a plating coating.

The mold for continuous casting according to the present invention is composed of a plurality of continuous straight portions or curved portions so that the surface of the chamfer forming portion on the mold space side bulges toward the mold space side in the horizontal cross section. Therefore, the shape of the end of the chamfer forming portion that contacts the surface of the long side on the mold space side can be made gentler than the conventional sharp angle shape. As a result, the rigidity of the end portion of the chamfer forming portion can be improved as compared with the conventional case. Further, by forming an wear-resistant film on the surface of the chamfer forming portion on the mold space side, damage or chipping of the film can be reduced as compared with the conventional case.
Therefore, the life can be extended as compared with the conventional case, and slabs of good quality can be produced with good yield.

It is a partial plan sectional view of the mold for continuous casting which concerns on 1st Example of this invention. It is a partial plan sectional view of the mold for continuous casting which concerns on 2nd Example of this invention. It is a partial plan sectional view of the mold for continuous casting which concerns on 3rd Example of this invention. (A) and (B) are partial plan sectional views of the chamfer forming portion of the continuous casting mold according to the conventional example, explanatory views of the analysis results of the chamfer forming portion after casting, (C) and (D) are It is a partial plan sectional view of the chamfer forming part of the continuous casting mold which concerns on an experimental example, and is explanatory drawing of the analysis result of the chamfer forming part after casting.

Subsequently, an embodiment embodying the present invention will be described with reference to the attached drawings, and the present invention will be understood.
As shown in FIG. 1, the continuous casting mold (hereinafter, also simply referred to as a mold) 10 according to the first embodiment of the present invention has a pair of short sides 11 arranged to face each other at intervals and the short sides thereof. Molten steel (not shown) is injected into the mold space 13 surrounded by a pair of long sides 12 sandwiching the sides 11 from both sides in the width direction, cooled, and pulled out as a slab, which has a longer life than before. It is a mold that can produce slabs of good quality with good yield. The details will be described below.

Each of the pair of short sides 11 has a thickness of 10 mm or more and 100 mm or less, a width of 50 mm or more and 500 mm or less, and a length in the casting direction of 600 mm or more and 1200 mm or less. The pair of short sides 11 are plane-symmetrical and have the same configuration.
Further, each of the pair of long sides 12 has a thickness of, for example, about 10 mm or more and 100 mm or less, and the distance between the pair of short sides 11 arranged to face each other (width in which the long side 12 contacts the slab) is in the range of 200 mm or more and 3500 mm or less. It has a width that can be changed with, and the length in the casting direction is about the same as the short side 11.
The pair of short sides 11 are clamped by a pair of long sides 12 sandwiching the short sides 11.

The short side 11 and the long side 12 described above are made of copper or a copper alloy, and a wear-resistant film (not shown) is formed on each surface on the mold space 13 side thereof, and the short side 11 and the long side 12 are formed. The back plate (not shown) that abuts and is fixed to each back surface is made of stainless steel or steel.
On the back surface side (back plate side) of the short side 11, a large number of water guide grooves (not shown) are provided in the casting direction (drawing direction of the slab). The large number of water guide grooves are formed in the width direction of the short side 11 at a predetermined pitch (same pitch and / or different pitch) within a range of, for example, about 5 mm or more and 200 mm or less. A large number of the above-mentioned water guide grooves are also provided on the back surface side of the long side 12 in the casting direction at a predetermined pitch in the width direction of the long side 12.

The mold wall 14 forming the mold space 13 is formed by the pair of short sides 11 and the pair of long sides 12 described above.
As shown in FIG. 1, chamfer forming portions 15 that bulge toward the mold space portion 13 side are formed on the short sides 11 of the four corner regions R of the mold wall 14. In this way, the chamfer forming portions 15 are provided at both ends of the short sides 11 in order to make the distance between the pair of short sides 11 adjustable (the width of the slab that can be cast by one mold 10). This is to enable various changes).

The chamfer forming portions 15 formed in the four corner regions R of the mold wall 14 have the same shape, but may have different shapes within the range of the following conditions.
That is, the chamfer forming portion 15 has a substantially triangular shape in a substantially cross-sectional shape, and the width X in the width direction of the short side 11 (hereinafter, also referred to as the short side direction) is the width direction of the long side 12 (hereinafter, also referred to as the short side direction). The width (also described as the long side direction) is longer than the width (protruding width to the mold space portion 13) Y (that is, the chamfer forming portion 15 has a width toward the end position in the width direction of the short side 11). Is gradually spreading).
For example, the width X is about 10 mm to 50 mm (preferably the upper limit is 40 mm and further 30 mm), and the width Y is about 3 mm to 40 mm (preferably the lower limit is 5 mm and further 10 mm, the upper limit is 30 mm and further 25 mm). Degree.

By making the width X in the short side direction longer than the width Y in the long side direction as in the chamfer forming portion 15, for example, when manufacturing the short side, the chamfer forming portion can be easily processed and shortened. Damage (bending and cracking) of the chamfer forming part can be prevented during transportation and installation of the side, and when using the short side (during continuous casting), the chamfer forming part due to the water guide groove formed on the short side It is possible to suppress a decrease in cooling efficiency, suppress deformation and damage thereof, and further prevent it. If the chamfer forming portion is deformed or damaged, chamfering (chamfering) of the desired shape cannot be performed on the corner portion of the slab.

The surface of the chamfer forming portion 15 on the mold space 13 side is composed of a plurality of continuous straight portions 16 and 17 formed so that the horizontal cross section bulges toward the mold space 13 side, and the horizontal cross section is formed. The surface formed by the straight portions 16 and 17 is a contact surface with the molten steel (slab shell) supplied to the mold space portion 15.
Of these two straight portions 16 and 17, it is in contact with or close to the long side 12 (the gap between the long side 12 and the surface S1 on the mold space 13 side is 0 mm, or the gap with the surface S1 exceeds 0 mm. The width x1 in the short side direction of the straight portion 17 (closest to the long side 12) located on the side 1 mm or less (the same applies hereinafter) is, for example, 1 mm to 10 mm (preferably, the lower limit is 2 mm and the upper limit is 7 mm). , Furthermore, it is about 5 mm).

The angle θ1 formed by the straight line portion 17 with respect to the surface S1 on the long side 12 on the mold space portion 13 side is more than 60 degrees and less than 90 degrees (preferably, the lower limit is 70 degrees, further 75 degrees, and the upper limit is 85 degrees).
Here, when the angle θ1 formed by the surface of the long side and the straight portion is 60 degrees or less, the shape of the end portion on the side that abuts or approaches the surface on the mold space side of the long side becomes too acute, for example. Deformation, damage or chipping of the film, etc. (hereinafter, also referred to as deformation) are likely to occur. On the other hand, when the angle θ1 formed by the straight portion is 90 degrees or more, for example, when the width x1 in the short side direction of the straight portion abutting or approaching the long side forming the chamfer forming portion becomes long, for example, rolling. At that time, bending or cracking may occur at the widthwise end of the slab, which may lead to quality defects or a decrease in yield.

Of the two straight portions 16 and 17 described above, the other straight portion 16 (located closest to the short side 11) has a surface S2 (at the four corners of the mold wall 14) on the mold space 13 side of the short side 11. The angle (rising angle) θ2 formed by the straight line portion 16 with respect to the surface (molten steel contact surface) of the short side 11 excluding the region R is, for example, 5 to 50 degrees (preferably, the lower limit is 10 degrees, further 20 degrees. , The upper limit is about 40 degrees, and further about 35 degrees).
Here, when the angle θ2 formed by the straight line portion is less than 5 degrees, the effect of forming the chamfer forming portion becomes small. On the other hand, when the angle θ2 formed by the straight portion exceeds 50 degrees, for example, the angle formed by the two straight portions becomes small, and deformation or the like is likely to occur.

The connecting portion 18 in which the two straight portions 16 and the straight portions 17 are continuous is composed of a curved portion that bulges toward the mold space portion 13 side.
Here, since the radius of curvature of the curved portion is, for example, about 1 mm to 20 mm (preferably, the lower limit is 3 mm, the upper limit is 10 mm, and further is 7 mm), the connecting portion of the two straight portions 16 and 17 during continuous casting. Damage to (the edge) can be suppressed and even prevented.
When the angle formed by the two straight portions approaches 180 degrees (for example, when the angle is 160 degrees or more and 170 degrees or less), the continuous connecting portion becomes gentle, so that the curved portion is not formed. You can also.
Further, the rising portion of the straight line portion 16 with respect to the surface S2 on the mold space portion 13 side of the short side 11 is a curved portion recessed toward the mold space portion 13 side (the radius of curvature is the curved portion of the connecting portion 18 described above. Although it can be set within a range), it is not necessary to provide a curved portion (see, for example, FIGS. 2 and 3 described later).

Further, like the chamfer forming portion 15a of the continuous casting mold 10a according to the second embodiment of the present invention shown in FIG. 2, the straight portion 17a forms with respect to the surface S1 on the mold space portion 13a side of the long side 12. The angle θ1 may be 90 degrees. Since the structure is substantially the same as that of the continuous casting mold 10 shown in FIG. 1 except for the structure of the chamfer forming portion 15a, “a” is added to each reference numeral and detailed description thereof will be omitted here.
In this case, the width x2 in the short side direction of the straight line portion 17a is set to a smaller range within the range of the width x1 described above, for example, about 1 mm to 5 mm. Further, since the angle formed by the two straight portions 16a and 17a is smaller than the angle formed by the two straight portions 16 and 17 shown in FIG. 1, the two straight portions 16a and the straight portion 17a are continuous. The connecting portion 18a is composed of a curved portion that bulges toward the mold space portion 13a side.

In the above-mentioned continuous casting molds 10 and 10a, the case where the surface of the chamfer forming portion on the mold space side is composed of two continuous straight portions having a horizontal cross section has been described, but the surface is directed toward the mold space side. It can also be composed of three or more continuous straight portions (upper limit is, for example, about 10) so as to bulge (approximate to a curved portion).
In this case, the width of the straight portion in contact with or close to the long side in the short side direction is set within the range of the width x1 in the short side direction and further within the range of the width x2.
Further, a part or all of the connecting portion of the plurality of straight portions can be formed by the curved portion described above, but if at least the connecting portion formed in the straight portion in contact with or close to the long side is composed of the curved portion. Good.

Further, as in the chamfer forming portion 15b of the continuous casting mold 10b according to the third embodiment of the present invention shown in FIG. 3, the surface on the mold space portion 13b side is directed toward the mold space portion 13b in the horizontal cross section. It can also be composed of a curved portion 19 formed so as to bulge. Since the structure is substantially the same as that of the continuous casting mold 10 shown in FIG. 1 except for the structure of the chamfer forming portion 15b, “b” is added to each reference numeral and detailed description thereof will be omitted here.

Here, the angle θ3 formed by the tangent of the rising portion of the curved portion 19 with respect to the surface S1 on the mold space portion 13b side of the long side 12 is more than 60 degrees and 90 degrees or less (preferably, the lower limit is 70 degrees and further 75 degrees. , The upper limit is 85 degrees). Further, the angle θ4 formed by the tangent of the rising portion of the curved portion 19 with respect to the surface S2b on the mold space portion 13b side of the short side 11b is the same as the above-mentioned formed angle θ2 (for example, 10 to 50 degrees).
For each of the above-mentioned chamfer forming portions 15a and 15b, the rising portion of the straight portion 16a or the curved portion 19 with respect to the surfaces S2a and S2b on the mold space portions 13a and 13b of the short sides 11a and 11b is shown in FIG. Similar to the chamfer forming portion 15, it can also be formed of a curved line that is recessed toward the mold space portions 13a and 13b.

The chamfer forming portion 15 formed on the opposite short side 11 (hereinafter, the same applies to the chamfer forming portion 15a on the short side 11a and the chamfer forming portion 15b on the short side 11b) is provided with a slab shell (solidification shell) in the casting direction. ), An inclined portion is formed in which the interval gradually narrows according to the amount of solidification contraction. The inner cross-sectional shape of the facing chamfer forming portion 15, that is, the surface shape of the inclined portion can be determined by, for example, the method described in Japanese Patent No. 4659706, and will be briefly described below.
The surface shape of the vertical cross section of the inclined portion has the same shape in the width direction, and the taper rate increases as the distance from the meniscus position increases, that is, it becomes a multi-taper. ing. With this multi-taper, the solidification shrinkage profile of the slab in the mold (from the meniscus position (hot water surface) to the mold outlet) is defined by one or both of a curved line (specified by multiple functions) and a plurality of straight lines. And approximated, and applied it to the surface shape of the inclined part.

Hereinafter, the method for determining the multi-taper will be briefly described.
For the multi-taper, FEM analysis (using the finite element method) considering the conditions shown below and the solidification shrinkage of the three-dimensional slab and the thermal deformation of the mold based on the actual measurement results. It is obtained by analysis (the same applies hereinafter). Specifically, the shape of the slab, the size of the slab, the casting conditions (for example, casting temperature, drawing speed, mold cooling conditions, etc.), and the physical quantities derived from the components of the cast steel type (for example, liquid phase temperature, solid phase temperature). , Transformation temperature, linear expansion rate, rigidity value, etc.), contact heat transfer amount between the mold and the slab (the shrinkage amount of the slab is greatly affected by this amount), etc. are used.
The amount of contact heat transfer described above is greatly affected by, for example, the type of lubricant used during casting and the difference in the surface shape of the slab (depending on the steel type, oscillation conditions, and type of lubricant). Therefore, it is necessary to grasp the actual contact heat transfer amount for each casting condition as accurately as possible in order to determine the multi-taper.

Further, on the opposite short sides 11 excluding the regions R at the four corners of the mold wall 14, short side inclined portions whose intervals are gradually narrowed according to the solidification shrinkage amount of the slab shell in the casting direction can be formed. preferable.
The inner cross-sectional shape of the opposite short side 11, that is, the surface shape of the vertical cross section of the short side inclined portion has the same shape over the width direction, and tapers as the distance from the meniscus position increases. It has a shape in which the rate of increase is small, that is, a multi-taper.
Since the shape of the surface of the inclined portion on the short side can be determined by the method described in Japanese Patent No. 4659706 described above, the description thereof will be omitted.

Further, the opposite long sides 12 excluding the regions R at the four corners of the mold wall 14 also have long side inclined portions, that is, multi-taper, in which the intervals gradually narrow according to the solidification shrinkage amount of the slab shell in the casting direction. However, it is also possible to form a shape that is inclined at the same ratio from the meniscus position to the mold outlet, that is, a single taper. In this case, the end face shape of the short side is a shape along the surface of the long side.
In the case of multi-tapering, the inner cross-sectional shape of the opposite long side, that is, the surface shape of the vertical cross section of the long side inclined portion is made the same shape in the width direction, and as the distance from the meniscus position increases. Therefore, the shape is such that the rate of increase in the taper rate is small. The surface shape of the inclined portion on the long side can be determined by the method described in Japanese Patent No. 4659706 described above.

A wear-resistant film is formed on the surface of the chamfer forming portion 15 shown in FIG. 1 on the mold space 13 side (also on the entire surface of the short side 11 on the mold space 13 side) (FIG. 2, FIG. The same applies to the chamfer forming portions 15a and 15b shown in FIG. 3).
This film includes a thermal spray coating formed by thermal spraying and a plating film formed by electroplating, but from the viewpoint of durability, the thermal spray coating is preferable.
This sprayed coating is applied to the surface of the chamfer forming portion 15 on the mold space 13 side (also on the entire surface of the short side 11 on the mold space 13 side), and a roughened base plating layer (for example, Ni). , Co, Fe, or an alloy based on any one or more of these), which is formed by spraying the sprayed particles with a flame sprayer.
The sprayed coating is not particularly limited as long as it is composed of components that can be used in the mold, but for example, it can be formed by using Ni-based sprayed particles, and Co-based sprayed particles are used. Can also be formed.

For example, sprayed particles formed by mixing a granular cermet material composed of Co, Cr, and the balance WC and a granular Ni—Al alloy containing a predetermined amount of Al can be used. The Ni—Al alloy may contain unavoidable impurities.
Specifically, the cermet material contains Co: 5% by mass or more and 15% by mass or less (preferably, the lower limit is 6% by mass and further 7% by mass, the upper limit is 14% by mass and further 13% by mass), Cr: It is composed of 2% by mass or more and 6% by mass or less (preferably, the lower limit is 3% by mass and the upper limit is 5% by mass) and the balance is WC. The cermet material may contain, for example, Fe or the like as an unavoidable impurity.
Further, the Ni—Al alloy has an Al content of more than 0 and 8% by mass or less.
The thickness of the sprayed coating is preferably formed densely (filling rate is 90% or more, more preferably 95% or more) in the range of 0.05 mm or more and 1 mm or less.

It is preferable to provide cooling water water passage holes (hereinafter, also simply referred to as water passage holes) having a circular cross section at both ends of the short side 11 (the same applies to the short sides 11a and 11b) in the width direction.
The water passage hole is formed on the back surface side of the chamfer forming portion 15. The water passage hole can be formed by forming a hole from one side (in this case, the lower side) of the short side 11 in the casting direction and plugging the opening.
At both ends of the water passage hole in the casting direction, a water flow path that communicates with the water guide groove formed at the width direction end of the short side 11 is formed, whereby the cooling water flowing through the water guide groove is sent to the water flow hole. It can be flowed continuously.

In addition, on the short side, instead of the above-mentioned cooling water passage hole, a cooling water passage groove (hereinafter, also simply referred to as a water passage groove) can be formed. In this case, the water passage groove can be formed on the short side with the configuration shown below.
-The bottom of the water passage groove in the depth direction is branched from the water guide groove formed at the widthwise end of the short side so as to be located on the back surface side of the chamfer forming portion (cross section V-shaped).
-The water guide groove is diagonally formed so that the bottom in the depth direction of the water guide groove formed at both ends in the width direction of the short side is located on the back surface side of the chamfer forming part, and the water guide groove is combined with the water flow groove. To do.

In the use of the continuous casting mold 10 shown above, the short side 11 and the long side 12 are cooled by flowing cooling water from the lower part to the upper part of the mold 10 in each water guide groove. The molten steel supplied to the mold space 13 is cooled (the same applies to the molds 10a and 10b for continuous casting). At this time, a part of the cooling water that has flowed into the water guide grooves located at both ends in the width direction of the short side 11 continuously flows into the cooling water flow hole through the water flow path, so that the chamfer forming portion The cooling efficiency of 15 can also be increased.
As a result, for example, a slab having a width of 200 mm or more and 3500 mm or less and a thickness of 50 mm or more and 500 mm or less and chamfered corners while suppressing or further preventing deformation, damage or chipping of the film, etc. Can be manufactured.

Experimental example

Next, an experimental example conducted for confirming the action and effect of the present invention will be described.
Here, using a mold having a short side provided with the chamfer forming portion shown in FIGS. 4 (A) and 4 (C), damage to the edge portion of the chamfer forming portion was compared and examined. Note that FIG. 4A shows a conventional mold, the chamfer forming portion has a triangular cross section, and the end portion on the side in contact with the long side has an acute angle shape. Further, FIG. 4C shows the mold of this experimental example, and the surface of the chamfer forming portion on the mold space side is composed of two continuous straight portions having a horizontal cross section, and the connecting portion of the two straight portions. Is composed of a curved portion that bulges toward the mold space side (the same configuration as in FIG. 2). In FIGS. 4A and 4C, the unit of the numerical value other than the numerical value indicating the angle is "mm".

As described above, during casting, the edge portion of the side surface of the short side in contact with the long side is in a high stress state due to the thermal expansion of the short piece and the clamping force of the mold. Therefore, the edge portion of the chamfer forming portion after casting is plastically deformed.
Therefore, the plastic deformation of the chamfer forming portion after casting was compared by FEM analysis.
In the conventional mold chamfer forming portion shown in FIG. 4 (A), the end portion on the long side in contact with the surface of the mold space portion has an acute-angled shape, so that the rigidity is low, and FIG. As shown in B), it was found that the amount of deformation after casting was about 1 mm.
On the other hand, in the chamfer forming portion of the mold of the present experimental example shown in FIG. 4 (C), the rigidity of the end portion on the side of the long side in contact with the surface of the mold space portion was improved. ), It was found that the amount of deformation after casting can be reduced to less than 1/2 (0.48 mm) of the conventional mold.

From the above, the continuous casting mold of this experimental example can suppress the occurrence of deformation, film damage, chipping, etc., as compared with the conventional one, so that the life can be extended and the quality is good. Can produce slabs with good yield.

Although the present invention has been described above with reference to Examples, the present invention is not limited to the configuration described in the above-described Examples, but is within the scope of the claims. It also includes other possible examples and modifications. For example, the case where a part or all of the above-mentioned Examples and Modifications are combined to form a mold for continuous casting of the present invention is also included in the scope of rights of the present invention.
The continuous casting mold shown in the above embodiment can be used in a conventionally used vertical bending type continuous casting machine or curved type continuous casting machine.
Further, in the above embodiment, the case where the inclined portion is formed in the chamfer forming portion has been described, but the present invention is not limited to this, and for example, the cross section of the chamfer forming portion has the same shape in the casting direction. It can also be.
Further, in the above-described embodiment, the case where the cooling water passage hole (cooling water passage groove) is formed on the short side has been described, but the cooling water passage hole is provided as necessary (chamber forming portion). It does not have to be formed (depending on the cooling state of).

The mold for continuous casting of the present invention can improve the rigidity of the end portion of the chamfer forming portion as compared with the conventional one, and also causes damage or chipping of the abrasion resistant film formed on the surface thereof as compared with the conventional one. It can be reduced in comparison. As a result, the life can be extended as compared with the conventional one, and slabs of good quality can be produced with good yield.

10, 10a, 10b: Mold for continuous casting, 11, 11a, 11b: Short side, 12: Long side, 13, 13a, 13b: Mold space, 14, 14a, 14b: Mold wall, 15, 15a, 15b: Chamfer forming part, 16, 16a, 17, 17a: straight part, 18, 18a: connecting part, 19: curved part

Claims (5)

It has a mold space portion surrounded by a pair of short sides arranged to face each other with a gap and a pair of long sides sandwiching the short sides from both sides in the width direction, and the pair of short sides and the pair. A chamfer forming portion that is composed of a long side and bulges toward the mold space portion is provided on the short side of the four corner regions of the mold wall that forms the mold space portion, and molten steel is provided in the mold space portion. In a continuous casting mold that injects, cools, and pulls out as a slab.
The width of the short sides is 500 mm or less, and the distance between the pair of short sides arranged so as to face each other is 3500 mm or less.
The surface of the chamfer forming portion on the mold space side is composed of a plurality of continuous straight portions formed so that the horizontal cross section bulges toward the mold space side, and the mold on the long side is formed. The angle formed by the straight line portion in contact with or close to the long side with respect to the surface on the space side is more than 60 degrees and less than 90 degrees, and the surface of the short side excluding the four corner regions of the mold wall. The angle formed by the straight line portion continuous with the surface is 5 degrees or more and 50 degrees or less.
The width of the chamfer forming portion in the short side direction is 10 mm to 50 mm, which is longer than the width in the long side direction, and the width of the straight portion in contact with or close to the long side is 1 mm to 10 mm. Yes,
A mold for continuous casting, characterized in that a wear-resistant film is formed on the surface of the chamfer forming portion on the mold space side. It has a mold space portion surrounded by a pair of short sides arranged to face each other with a gap and a pair of long sides sandwiching the short sides from both sides in the width direction, and the pair of short sides and the pair. A chamfer forming portion that is composed of a long side and bulges toward the mold space portion is provided on the short side of the four corner regions of the mold wall that forms the mold space portion, and molten steel is provided in the mold space portion. In a continuous casting mold that injects, cools, and pulls out as a slab.
The width of the short sides is 500 mm or less, and the distance between the pair of short sides arranged so as to face each other is 3500 mm or less.
The surface of the chamfer forming portion on the mold space side is composed of a plurality of continuous straight lines formed so that the horizontal cross section bulges toward the mold space side, and the plurality of straight lines. Of the connecting portions of the portions, the connecting portion formed on the straight portion that is in contact with or close to the long side is composed of a curved portion that bulges toward the mold space portion side, and further, the mold. The angle formed by the straight line portion continuous with the surface with respect to the surface of the short side excluding the four corner regions of the wall is 5 degrees or more and 50 degrees or less.
The width of the chamfer forming portion in the short side direction is 10 mm to 50 mm, which is longer than the width in the long side direction, and the width of the straight portion in contact with or close to the long side is 1 mm to 5 mm. Yes,
A mold for continuous casting, characterized in that a wear-resistant film is formed on the surface of the chamfer forming portion on the mold space side. It has a mold space portion surrounded by a pair of short sides arranged to face each other with a gap and a pair of long sides sandwiching the short sides from both sides in the width direction, and the pair of short sides and the pair. A chamfer forming portion that is composed of a long side and bulges toward the mold space portion is provided on the short side of the four corner regions of the mold wall that forms the mold space portion, and molten steel is provided in the mold space portion. In a continuous casting mold that injects, cools, and pulls out as a slab.
The width of the short sides is 500 mm or less, and the distance between the pair of short sides arranged so as to face each other is 3500 mm or less.
The surface of the chamfer forming portion on the mold space side is composed of a curved portion formed so that the horizontal cross section bulges toward the mold space side, and the surface of the long side of the mold space side. The angle formed by the tangent of the rising portion of the curved portion with respect to the surface is more than 60 degrees and 90 degrees or less, and the tangent of the rising portion of the curved portion to the surface of the short side excluding the four corner regions of the mold wall. The angle between the two is 10 degrees or more and 50 degrees or less.
The width of the chamfer forming portion in the short side direction is 10 mm to 50 mm, which is longer than the width in the long side direction.
A mold for continuous casting, characterized in that a wear-resistant film is formed on the surface of the chamfer forming portion on the mold space side. In the continuous casting mold according to any one of claims 1 to 3, the amount of solidification shrinkage of the slab shell in the direction in which the slab is pulled out from the chamfer forming portion formed on the opposite short side. A mold for continuous casting, characterized in that an inclined portion is formed in which the interval gradually narrows in accordance with the above. The continuous casting mold according to any one of claims 1 to 4, wherein the film is a thermal spray coating or a plating film.

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