JP2014188521A - Mold for continuous casting and manufacturing method of mold for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for continuous casting in which a recess is provided on a mold inner wall surface of the mold for continuous casting, and when the recess is filled with a low heat-conductive metal, the recess is filled closely with the low heat-conductive metal, and to provide a manufacturing method of the mold for continuous casting.SOLUTION: A mold for continuous casting is provided with a recess 2 formed sectionally by a bottom wall 2a and a side wall 2b linked to the edge of the bottom wall 2a on a mold wall part forming a casting space, and having an open end 2c opened on the outer surface of the mold wall part, and includes a metal filled layer 3 formed by plating treatment or spray coating in the recess 2. The mold for continuous casting is further provided with a rounding part 2d on a portion where the bottom wall 2a and the side wall 2b of the recess 2 are intersected together.

Description

  The present invention is for continuous casting in which a recess such as a circle, a pseudo circle, a longitudinal groove, a lateral groove or a lattice groove is provided on the surface of the mold wall portion forming the casting space, and a metal filling layer is provided in the recess. The present invention relates to a mold and a method for producing the mold.

  Conventionally, a continuous cast slab is surrounded by a water-cooled copper mold, and a continuous casting mold having a space portion penetrating in the vertical direction is used. The molten steel supplied to this space is solidified while being cooled by the water-cooled copper mold. It is manufactured by.

  In Patent Documents 1 and 2, there is a mold in which the inner wall surface of this continuous casting mold is processed to have a V-shaped, U-shaped, and square cross-sectional groove, and the groove is filled with a low thermal conductive material (metal, ceramics). Proposed.

  In forming a filling layer by filling a concave groove (circular, pseudo-circular, vertical groove, horizontal groove, lattice groove, etc.) provided on the surface of such a continuous casting mold with a low thermal conductive material, a plating process or a thermal spraying method is used. When applied, there were the following problems.

  That is, when the width or depth of the groove is deep, a gap (gap) may be generated between the filling layer and the side wall of the groove, and the adhesion strength of the filling layer to the mold is not sufficient, compared with the conventional mold. Mold life is shortened. There is also a concern that the presence of voids inside the mold causes uneven heat transfer in the mold, resulting in uneven solidification of the slab and operational problems such as breakout. The

  In addition, for example, in the case of electroplating, such a phenomenon is that current tends to flow on the surface layer of the mold, but it is difficult for current to flow at the inner side, particularly at the portion where the bottom wall and side wall of the groove intersect, In the thermal spraying method, it is considered that the thermal spray material is likely to adhere to the surface of the mold as compared with the inside of the groove portion, and the prior art mentioned in this regard is not known at present.

JP-A-1-289542 Japanese Patent Laid-Open No. 2-6037

  An object of the present invention is to provide a continuous casting mold capable of solving a conventional problem that has occurred when a recess is provided in a mold wall surface of a continuous casting mold and the recess is filled with a low thermal conductive material, and the manufacture of the mold. Proposed method.

  The present invention has an open end that is defined by a bottom wall and a side wall connected to an edge of the bottom wall on the surface of the mold wall forming the casting space, and is open at the outer surface of the mold wall. A continuous casting mold provided with a recess, and a metal filling layer formed by plating or thermal spraying in the recess, wherein the recess is located at a portion where the bottom wall and the side wall intersect. A continuous casting mold characterized by having a rounded portion.

In the continuous casting mold having the above-described configuration, when the radius of curvature of the rounded portion is R (mm) and the gap width of the recess is d (mm), the following equation (1):
0.2 ≦ R ≦ d / 2 (1)
And the recess has a chamfered portion at the open end, and the chamfered portion has a chamfer thickness of a (mm), a chamfer width of L (mm), and When the depth is H (mm) and the opening width of the recess is d (mm),
0.5 ≦ a ≦ H / 2 (2)
0.5 ≦ L ≦ d / 2 (3)
Is preferable as a specific means for solving the problems of the present invention.

  Further, the present invention provides an open end that is defined by a bottom wall and a side wall connected to an edge of the bottom wall on the surface of the mold wall that forms the casting space, and is open at the outer surface of the casting wall. A continuous casting mold provided with a metal filling layer formed by plating or thermal spraying, wherein a tapered cross section is formed on a side wall of the recess toward the bottom wall. A continuous casting mold characterized by having a taper formed into a shape.

In the continuous casting mold having the above-described configuration, the recess has a taper machining allowance of b (mm), and the opening width of the recess is d (mm).
0.5 ≦ b ≦ d / 2 (4)
It is preferable as a specific means for solving the problems of the present invention to satisfy the above.

  Further, in the present invention, in manufacturing a continuous casting mold having the above-described configuration, a rounded portion is formed at a portion where the bottom wall and the side wall of the recess intersect, and then the recess is formed by plating or spraying. A method for producing a casting mold for continuous casting, characterized in that a metal filling layer is formed on the surface.

  In the method for producing a continuous casting mold having the above-described configuration, when the radius of curvature of the rounded portion is R (mm) and the opening width of the recess is d (mm), the rounded portion is the above (1). It is preferable to form it under conditions that satisfy the formula.

  In addition, the present invention provides a chamfering process after forming a metal filling layer by chamfering the opening end of the recess prior to forming the metal filling layer in the recess by plating or spraying. The method for producing a continuous casting mold is characterized in that at least the thickness of the part subjected to the above is removed over the entire surface of the mold wall.

  Furthermore, the present invention is a method for producing a casting mold for continuous casting, characterized in that, prior to forming a metal filling layer by plating or spraying in a recess, the side wall of the recess is tapered.

  According to the continuous casting mold of the present invention having the above-described configuration, a rounded portion having an arc shape is provided at a portion where the bottom wall and the side wall of the recess intersect, so that a metal filling layer is formed by plating. In this case, the metal filling layer can be efficiently formed by the smooth flow of the current at the site. Further, even when the metal filling layer is formed by thermal spraying, the filler can be directly collided, adhered, and deposited on the portion, and voids that reduce the adhesion strength are not formed.

  By providing the rounded part so as to satisfy the conditions of 0.2 ≦ R ≦ d / 2 (R: radius of curvature of the rounded part (mm), d: frontage dimension of the recess (mm)), plating treatment, Regardless of the spraying method, the filler can be deposited and deposited evenly in the recess.

  By providing the chamfered portion at the opening end of the recess, the size of the frontage at that portion is enlarged, so that the interior of the recess can be filled with the filler during the plating process or thermal spraying. In addition, the filler does not adhere around the open end of the recess, and the size of the frontage is not narrowed early.

  0.5 ≦ a ≦ H / 2, 0.5 ≦ L ≦ d / 2 (a: chamfer height (mm), L: chamfer width (mm), H: depth of recess (filling) By providing the layer thickness) (mm) and d: the frontage dimension of the recess is d (mm)), it is possible to form a filling layer without generating voids.

  By forming a taper on the side wall of the recess with a tapered cross-section toward the bottom wall, the frontage dimension at the open end of the recess is enlarged, and the frontage dimension can be easily narrowed even if a filler is attached. In addition, the filler can be efficiently attached even at the portion where the bottom wall and the side wall intersect.

By forming the taper under the conditions of 0.5 ≦ b ≦ d / 2 (b: taper machining allowance (mm), d: opening size of the recess (mm)), the bottom wall and the side wall of the recess are formed. The filler can be reliably attached to the intersecting portion (corner portion).

  According to the method for producing a continuous casting mold of the present invention, a rounded portion having an arc shape is formed at a portion where the bottom wall and the side wall of the recess intersect, and then a metal is formed in the recess by plating or spraying. Since the filling layer is formed, the filling material adheres and accumulates over the entire area of the recess.

  In the production of continuous casting, prior to forming a metal filling layer in the recess by plating or spraying, chamfering is performed at the open end of the recess, or the side wall of the recess is tapered. By this, the frontage dimension in the opening end of a recess is expanded, and the whole area of a recess can be filled with a filler.

It is the figure which showed typically a part of wall part of the casting_mold | template for continuous casting according to this invention. It is the figure which showed the AA cross section of FIG. It is the figure which showed the cross section of the conventional continuous casting mold about the principal part. It is the figure which showed the other example of the casting mold for continuous casting according to this invention. It is the figure which showed the further another example of the casting mold for continuous casting according to this invention.

Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 is a view schematically showing a part of the outer surface of a wall portion of a continuous casting mold according to the present invention, and FIG. 2 is a view showing a cross section AA of FIG.

  Reference numeral 1 in the figure denotes a mold copper plate that forms the mold wall, and 2 denotes a recess formed on the surface of the mold copper plate 1. The recess 2 includes a bottom wall 2a and a side wall 2b connected to the bottom wall 2a. The recess 2 has an open end 2c opened at the surface of the mold wall, and the bottom wall 2a and the side wall 2b intersect with each other. Is formed with a rounded portion 2d having a radius of curvature of R (mm).

The recess 2 is shown here as an example in which the planar shape is circular. However, the recess 2 is a pseudo-circular shape, a horizontal groove extending along the width direction of the mold, or a vertical groove extending in a direction intersecting the horizontal groove (in the casting direction). Parallel grooves) or lattice grooves in which horizontal grooves and vertical grooves are combined can also be applied. In addition, a pseudo-circle refers to a shape having a circle-equivalent diameter calculated by circle-equivalent diameter = (4 × S / π) ^1/2 (S: opening area of recess 2 (mm ² )). And

  Reference numeral 3 denotes a metal filling layer formed in the recess 2 by plating or spraying. As a material for forming the metal filling layer 3, Ni is used as a material having a large difference in thermal conductivity from the mold copper plate in order to give a heat transfer distribution. In addition, a metal that can be plated or sprayed may be used. it can.

  A recess (groove) provided in this type of conventional continuous casting mold has a corner portion 4c at a portion where the bottom wall 4a and the side wall 4b of the recess 4 intersect, as shown in FIG. have.

  In the recess 4, when the metal filling layer 3 is formed in the recess 4 by plating (electroplating or the like) or thermal spraying, in particular, the filler S is difficult to adhere and deposit at the corner 4 c, Further, at the opening end 4d of the groove portion 4, the filler S adheres and the frontage width (corresponding to the diameter when the recess 4 is circular) d is narrowed, so that a filling layer is formed in the groove portion 4. Even in such a case, there is a case where a gap is left between the side wall 4b and the filling layer, and there is a concern that the formed filling layer 3 cannot secure sufficient adhesion strength to the mold.

  However, in the present invention, since the rounded portion 2d is provided at the portion where the bottom wall 2a and the side wall 2b intersect, the filler can be reliably attached at that portion, thereby Adhesion to the mold is improved.

In the present invention, the radius of curvature R of the rounded portion 2d is
0.2 ≦ R ≦ d / 2 (1)
Although the reason for this varies depending on the shape of the recess 2, if the radius of curvature R of the rounded portion 2 d is at least 0.2 mm, the filler is reliably attached and deposited on that portion. Because it can. On the other hand, when the radius of curvature R of the rounded portion 2d exceeds d / 2, the volume of the recess 2 is remarkably reduced, so that a sufficient heat transfer distribution cannot be obtained, and the effect of reducing the surface crack of the cast slab is obtained. Decrease. For this reason, in providing the rounding part 2d, the curvature radius R was made into 0.2 <= R <= d / 2.

  FIG. 4 is a diagram showing another embodiment of a continuous casting mold according to the present invention with respect to the main part thereof. In this example, a chamfered portion 5 is provided at the open end 2c of the recess 2 (a portion where the side wall 2b of the recess 2 intersects the wall surface of the mold).

  Even when the rounded portion 2d is provided in the concave portion 2, when the depth H of the concave portion 2 becomes deeper than a certain level, the gap width d is narrowed by the filler adhering around the opening end 2c. Therefore, there is a concern that the metal filling layer 3 cannot be efficiently formed in the entire area of the recess 2.

  By providing the chamfered portion 5, it is possible to suppress the opening width d of the opening end 2 c from being narrowed, and to reliably attach the filler to the rounded portion 2 d of the recess 2.

In the present invention, the chamfered portion 5 is
0.5 ≦ a ≦ H / 2 (2)
0.5 ≦ L ≦ d / 2 (3)
The reason is that if the chamfering thickness a and the chamfering width L are both less than 0.5 mm, the filling material adheres around the open end 2c and the dimension of the frontage of that part is early. This is because d is narrowed. On the other hand, when the chamfering thickness a exceeds H / 2 and the chamfering width L exceeds d / 2, a metal filling layer 3 having a desired size (area and thickness) can be obtained. Can not. Therefore, in the present invention, when the chamfered portion 5 is provided, 5 ≦ a ≦ H / 2 and 0.5 ≦ L ≦ d / 2.

  When the chamfered portion 5 is provided at the open end 2c of the recess 2 to form the metal filling layer 3, at least the thickness of the chamfered portion after the metal filling layer 3 is formed (the chamfer thickness a). The portion can be removed over the entire surface of the mold wall portion to obtain a cross-section as shown in FIG. 1, thereby obtaining a metal filling layer 3 having a desired size.

  In FIG. 4, the chamfered surface 5a formed in the chamfered portion 5 is shown as a flat (straight) shape as an example. However, if the chamfered surface 5a satisfies the conditions of the above expressions (2) and (3). For example, the chamfered surface 5a may have a concave or convex curved surface, and even in this case, the same effect can be obtained.

  FIG. 5 is a view showing still another embodiment of a continuous casting mold according to the present invention with respect to the main part thereof. In this example, the side wall 2b of the recess 2 is provided with a taper 6 having a tapered cross-sectional shape toward the bottom wall 2a.

  By providing the taper 6 on the side wall 2b of the recess 2, the opening end 2c of the recess 2 is expanded, and the filler can be efficiently supplied to the recess 2. Even when the taper 6 is provided, the filling layer 3 may be formed after performing processing that satisfies the expressions (2) and (3). Further, since the area at the interface between the mold and the filling layer 3 can be increased, the adhesion of the filling layer 3 to the mold is improved, and even if a crack occurs in the filling layer 3 on the mold surface, As a result, the life of the mold can be extended.

In the present invention, in providing the taper 6 on the side wall 2b of the recess 2,
0.5 ≦ b ≦ d / 2 (4)
However, if the taper machining allowance b is smaller than 0.5 mm, the opening end 2c narrows early due to the filler adhering around the opening end 2c of the recess 2. This is because it becomes difficult to adhere and deposit the filler at the portion where the bottom wall 2a and the side wall 2b intersect. On the other hand, if it is larger than d / 2, the volume of the recess 2 is reduced, so that a sufficient heat transfer distribution cannot be obtained, and the effect of reducing the surface cracks of the cast slab is reduced. For this reason, in this invention, when providing the taper 6 in the side wall 2b of the recess 2, it was made to satisfy said conditions.

  Particularly, in the case where the side wall 2b of the recess 2 is provided with the taper 6, there is an advantage that the filler can be attached without providing the rounded portion 2c at the portion where the bottom wall 2a and the side wall 2b intersect.

In the above equation (2), the depth (the thickness of the metal filling layer 3) H of the recess 2 is more effective for providing the effect of providing the metal filling layer 3, that is, the non-solidified shell. From the viewpoint of preventing uniform solidification,
H ≧ d / 3 (5)
It is good to do.

  The preferred conditions for forming the filling layer 3 by electroplating treatment vary depending on the shape of the recess 2 and the type of filling metal, but at a liquid temperature of 40 to 60 ° C., a voltage of 1.5 to 3.0 V, a current It is desirable to set it as 1.0-2.0A.

  In addition, since a metal will adhere also to parts other than the recess 2 when plating is performed, after performing the plating process for several hours to several tens of hours, the metal attached to other than the recess 2 is removed by cutting, and further It is preferable to form the filling layer 3 by repeating the step of performing the plating process a plurality of times.

  The preferred conditions for forming the filling layer 3 by thermal spraying vary depending on the shape of the recess 2 and the type of filling metal, but the metal is melted using a kerosene and oxygen gas flame as a heat source, and the melting point to the melting point + 200 ° C. After heating to a temperature up to about, a metal is sprayed onto the mold copper plate 1 with nitrogen gas to fill the recess 2 with the metal.

  Also in this case, as with the plating process, it is inevitable that metal adheres to other than the recess 2, so after spraying for a predetermined time, the metal adhering to other than the recess 2 is removed by cutting and sprayed again. It is preferable to form the filling layer 3 by repeating the process performed a plurality of times.

  For a continuous casting mold as shown in FIG. 1 provided with a circular recess 2 having a diameter of 4 to 10 mm and a depth of 1 to 4 mm, the radius of curvature R of the rounded portion of the recess 2 and the chamfer thickness a Electroplating treatment with various changes in chamfer width L and taper machining allowance b (liquid temperature 40 to 60 ° C., voltage 1.5 to 3.0 V, current 1.0 to 2.0 A, recess diameter d or thickness The plating process was repeated 2 to 4 times depending on the length h), and the recess 2 was filled with Ni to form a metal filling layer 3, and the filling state of the obtained filling layer 3 was investigated.

The results are shown in Table 1.

  From Table 1, in the continuous casting mold having the recess 2 having the corner 4 at the intersection where the bottom wall 2a and the side wall 2b intersect, it is inevitable that voids are generated in the packed bed 3. In the continuous casting mold according to the present invention, it was confirmed that only a part of the voids were generated when H / d exceeded 1/3.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture the casting mold for continuous casting which filled the recessed part provided in the casting mold inner wall surface of the casting mold for continuous casting with the low heat conductive metal without gap.

DESCRIPTION OF SYMBOLS 1 Mold copper plate 2 Recess 2a Bottom wall 2b Side wall 2c Open end 2d Rounding part 3 Metal filling layer 4 Recess 4a Bottom wall 4b Side wall 4c Corner | angular part 4d Corner | angular part 5a chamfered part 5a Chamfered surface 6 Taper process part of an opening end side S filler

In the production of a continuous casting mold , prior to forming a metal filling layer in the recess by plating or spraying , chamfering is performed at the open end of the recess or taper is applied to the side wall of the recess. By this, the frontage dimension in the opening end of a recess is expanded, and the whole area of a recess can be filled with a filler.

In the present invention, the chamfered portion 5 is
0.5 ≦ a ≦ H / 2 (2)
0.5 ≦ L ≦ d / 2 (3)
The reason is that when the chamfering thickness a and the chamfering width L are both less than 0.5 mm, the filling material adheres around the opening end 2c and the dimension of the frontage of that part is early. This is because d is narrowed. On the other hand, when the chamfering thickness a exceeds H / 2 and the chamfering width L exceeds d / 2, a metal filling layer 3 having a desired size (area and thickness) can be obtained. Can not. For this reason, in the present invention, when the chamfered portion 5 is provided, 0.5 ≦ a ≦ H / 2 and 0.5 ≦ L ≦ d / 2.

Claims (9)

A mold wall that forms a casting space is partitioned by a bottom wall and a side wall connected to an edge of the bottom wall, and a recess having an open end that is open at the outer surface of the mold wall is provided. A mold for continuous casting provided with a metal filling layer formed by plating or spraying in a recess,
The continuous casting mold according to claim 1, wherein the recess has a rounded portion at a portion where the bottom wall and the side wall intersect. When the radius of curvature is R (mm) and the gap width of the recess is d (mm), the rounded portion has the following formula (1):
0.2 ≦ R ≦ d / 2 (1)
The mold for continuous casting according to claim 1, wherein:   The continuous casting mold according to claim 1, wherein the recess has a chamfered portion at the opening end. The chamfered portion has a chamfer height of a (mm), a chamfer width of L (mm), a recess depth of H (mm), and a recess opening width of d (mm),
0.5 ≦ a ≦ H / 2 (2)
0.5 ≦ L ≦ d / 2 (3)
The mold for continuous casting according to claim 3, wherein: On the surface of the mold wall that forms the casting space, a recess is formed which is defined by a bottom wall and a side wall connected to the edge of the bottom wall, and has an open end opened at the outer surface of the mold wall. In this recess, a continuous casting mold provided with a metal filling layer formed by plating or spraying,
A continuous casting mold characterized in that a side wall of the recess has a taper that becomes a tapered cross-sectional shape toward the bottom wall. When the recess has a taper machining allowance of b (mm) and the aperture size of the recess is d (mm),
0.5 ≦ b ≦ d / 2 (4)
The mold for continuous casting according to claim 5, wherein: In the method for producing a continuous casting mold according to any one of claims 1 to 4,
A continuous casting characterized in that a rounded portion is formed at a portion where the bottom wall and the side wall of the recess intersect, and then a metal filling layer is formed in the recess by applying a plating process or a thermal spraying method. A method for manufacturing a mold for use in a process. The method for producing a continuous casting mold according to claim 7,
Prior to forming the metal filling layer, chamfering is performed on the open end of the recess, and after forming the metal filling layer, at least the thickness of the chamfered portion is provided as a mold wall. A method for producing a casting mold for continuous casting, wherein the entire surface of the part is removed. The method for producing a continuous casting mold according to claim 5 or 6,
A method for producing a casting mold for continuous casting, characterized in that, prior to forming a metal filling layer in the recess by plating or spraying, the side wall of the recess is tapered.

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