JP2002086248A - Die for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die for continuous casting whose inside surface is coated with a film having excellent crack resistance, welding resistance and wear resistance. SOLUTION: In this die for continuous casting whose inside surface is coated with a thermal spray coating 12, the fine powder forming the thermal spray coating 12 is composed of a metallic matrix of a nickel based self-fluxing alloy composed of, by mass, 0 or >0 to <=8% Cr, 1.0 to 4.5% B, 1.5 to 5.0% Si, <=1.1% C, <=5.0% Fe, <=1.0% Co, <=4.0% Mo and <=4.0% Cu, and the balance Ni and the fine particles of wear resistant hard ceramics, where 5 to 50% wear resistant hard ceramics are contained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting mold having a long life and improved welding resistance, crack resistance and wear resistance by forming a thermal spray coating on the inner surface of a mold body.

[0002]

2. Description of the Related Art Conventionally, a continuous casting mold (hereinafter, also referred to as a mold) has a pair of long side mold parts (one piece of a long side mold) and one
It is manufactured by joining a pair of short side mold parts (one piece of the short side mold) by, for example, a quadruple set. And FIG.
As shown in FIG.
Has a copper plate 51 made of copper or a copper alloy material having good heat conductivity, and a rigid cooling water box called a back frame 52 that is provided on the back surface of the copper plate 51 to cool the copper plate 51. Therefore, the casting is performed by adding a high temperature molten steel 5 to this mold.
3 (for example, about 1600 ° C.). However, in the vicinity 55 of the upper molten steel level where the high-temperature molten steel 53 contacts the surface of the copper plate 51 via the molten powder (lubricant) 54, the surface temperature of the copper plate 51 becomes 3 during casting.
It reaches about 00 to 350 ° C. On the other hand, on the lower surface of the copper plate 51, the solidified shell 56 at a high temperature and in a semi-solid state is formed.
Is pulled out while being in mechanical contact with the copper plate 51,
Abrasion damage occurs on the surface of the copper plate 51 to shorten the life of the copper plate. Therefore, the lower part of the copper plate 51 is required to have wear resistance. Therefore, a thermal spray coating (also referred to as a coating) is formed on the surface of the copper plate 51 by using a thermal spraying machine (not shown) to improve the wear resistance of the copper plate, thereby greatly improving the life of the mold.

[0003]

However, the above-described mold has the following problems due to severe use environment (for example, insufficient cooling of the mold body 50 due to trouble during casting). By forming the thermal spray coating on the surface of the copper plate 51, there is a problem that the thermal conductivity between the molten steel 53 and the copper plate 51 decreases, and the surface temperature of the thermal spray coating increases.
In addition, the surface temperature of the copper plate 51 tends to be higher as the operation speeds up, and when the molten steel 53 comes into direct contact with the sprayed coating due to an operation abnormality (for example, breakout, powder breakage, etc.), the molten steel and the sprayed coating become separated. Welding may occur and the slab may be pulled out of the mold body 50 as it is. In this case, there is also a problem that the sprayed coating is peeled off from the surface of the copper plate 51 and the mold cannot be used. Then, a crack (crack) occurs in the sprayed coating due to a decrease in the toughness of the sprayed coating,
Due to this crack, a phenomenon occurs in which the sprayed coating peels off from the inner surface of the mold body 50, and there is a problem that the mold cannot be used. The present invention has been made in view of such circumstances, and has excellent crack resistance on the inner surface of the mold body.
An object of the present invention is to provide a casting mold for continuous casting in which a film having welding resistance and wear resistance is formed.

[0004]

According to a first aspect of the present invention, there is provided a continuous casting mold in which a sprayed coating is formed on an inner surface of a mold body. Is Cr: more than 0 or 0 to 8% by mass or less, B: 1.0 to 4.5% by mass, Si: 1.5 to 5.0%
Mass%, C: 1.1 mass% or less, Fe: 5.0 mass% or less, Co: 1.0 mass% or less, Mo: 4.0 mass% or less, Cu: 4.0 mass% or less, balance Ni And 5 to 50% by mass of wear-resistant hard ceramics comprising a metal matrix of a nickel-based self-fluxing alloy and fine powder of wear-resistant hard ceramics. By using such a metal matrix of a nickel-based self-fluxing alloy, the toughness and thermal conductivity of the thermal spray coating are improved, so that the crack resistance and welding resistance of the molten steel cast into the continuous casting mold for the thermal spray coating are improved. It is possible to improve the performance. Further, by using fine powder of wear-resistant hard ceramics, it becomes possible to improve the wear resistance of the sprayed coating.

In a continuous casting mold according to a second aspect of the present invention, the sprayed coating is formed on the inner surface of the mold body, and the fine powder forming the sprayed coating is Cr: 0 or 0 to 8% by mass, B: 1.0 to
4.5% by mass, Si: 1.5 to 5.0% by mass, C: 1.
1 mass% or less, Fe: 5.0 mass% or less, Co: 1.0
% By mass, Mo: 4.0% by mass or less, Cu: 4.0% by mass or less, a nickel-based self-fluxing alloy metal matrix composed of the balance of Ni, fine powder of wear-resistant hard ceramics, Co, Ni, and Cr , Fe or a cermet containing at least one of these alloys,
Contains 50% by mass. By using such a metal matrix of a nickel-based self-fluxing alloy, the toughness and thermal conductivity of the thermal spray coating are improved, so that the crack resistance and welding resistance of the molten steel cast into the continuous casting mold for the thermal spray coating are improved. It is possible to improve the performance. In addition, it is possible to improve the wear resistance of the thermal spray coating by using a commercially available cermet.

Here, in the continuous casting mold according to the first and second aspects of the present invention, the wear-resistant hard ceramic is at least one of carbide, oxide, boride, nitride, and silicide. Is preferred. This makes it possible to further improve the wear resistance of the thermal spray coating. Also,
In the continuous casting mold according to the first and second aspects of the present invention, it is preferable that the thermal spray coating is formed on an inner surface of the mold body via a plating layer of Ni or an alloy mainly composed of Ni. In this way, by including Ni in both the thermal spray coating and the plating layer, it is possible to prevent oxidation of the inner surface layer of the mold main body. For example, when heat treatment is performed at 900 to 1100 ° C., the thermal spray coating and the plating layer Therefore, mutual diffusion easily occurs between the molds, so that the adhesion strength of the thermal spray coating to the mold body can be stabilized. Then, in the continuous casting mold according to the first and second aspects of the present invention, after forming the thermal spray coating on the inner surface of the mold main body, the thermal spray coating is applied to 900 to 110.
Heat treatment at 0 ° C. is preferred. As a result, diffusion between the sprayed coating and the inner surface layer of the mold main body starts, and the adhesion of the sprayed coating to the mold main body can be improved. Then, the metal matrix and the fine powder of the wear-resistant hard ceramic, and the fine powder of the metal matrix and the cermet in the thermal spray coating are also diffused with each other, so that the strength of the thermal spray coating can be improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a plan cross-sectional view of a main part of a long side mold portion of a continuous casting mold according to a first embodiment of the present invention, and FIGS. A perspective view of the long side mold portion of the casting mold, an explanatory diagram in which an inclined spray coating is applied to the continuous casting mold, an explanatory diagram in which a partial spray coating is applied to the continuous casting mold, FIG. 3 is an explanatory view of a test method of a crack resistance test, FIG. 4 is an explanatory view of a test result of a crack resistance test, FIG. 5 is an explanatory view of a test result of a welding resistance test, and FIG. 6 is a test method of a wear resistance test. Explanatory diagram,
FIG. 7 is an explanatory diagram of test results of the wear resistance test.

As shown in FIGS. 1 and 2A, a continuous casting mold according to a first embodiment of the present invention includes a pair of long-side mold parts (one piece of a long-side mold) and one pair of long-side mold parts. It is manufactured by, for example, assembling four pairs of short side mold parts (not shown). A thermal spray coating 12 is formed on the inner surface of the mold main body 11 constituting the long side mold portion. The fine powder that forms the thermal spray coating 12 includes Cr: 0 or more than 0 and not more than 8% by mass, B: 1.0 to 4.5% by mass, Si: 1.
5 to 5.0% by mass, C: 1.1% by mass or less, Fe: 5.0% by mass.
0 mass% or less, Co: 1.0 mass% or less, Mo: 4.0
Mass% or less, Cu: 4.0 mass% or less, a metal matrix of a nickel-based self-fluxing alloy consisting of a balance of Ni, and a wear-resistant hard ceramic (for example, carbide, oxide, boride,
A fine powder of at least one of a nitride and a silicide).
% By mass. The thermal spray coating 12 is formed on the inner surface of the mold body 11 via a plating layer 13 of Ni or an alloy mainly composed of Ni. The details will be described below.

[0009] As shown in FIG.
Has a copper plate 14 made of copper or a copper alloy material, and a back plate (water box) 15 provided on an outer surface of the copper plate 14 for cooling the copper plate 14. This copper plate 1
The entire inner surface of 4 can be ground evenly,
As in the first and second modifications shown in FIGS. 2B and 2C,
The thermal spray coating 18 can be thinned (inclined coating) from the lower side to the upper side (along) of the copper plate 16 or the copper plate 17
Is formed on the lower side of the copper plate 17, for example, 1 / th of the entire height, so that the lower side forms a thermal spray coating 19 thicker than the upper side of the copper plate 17.
It is preferable to preprocess a range corresponding to 3 to 2/3 partially (partially). The processed surface prepared in this way is plated with Ni or a Ni alloy having a thickness R of, for example, more than 0 and about 0.2 mm or less, and a copper plate 14 is formed.
The plating layer 13 is formed inside the substrate. This makes it possible to prevent oxidation of the inner surface (surface layer portion) of the mold body 11, so that the adhesion strength of the thermal spray coating 12 to the mold body 11 can be stabilized.

Next, a fine powder of a metal matrix of a nickel-based self-fluxing alloy and a fine powder of a wear-resistant hard ceramic of 5 to 50% by mass are uniformly mixed to produce a fine powder for forming a thermal sprayed coating 12. I do. Here, the chemical composition of the metal matrix and its numerical range are based on nickel-based self-fluxing alloy (JI
1 to 5 kinds of nickel-based self-fluxing alloys (see Table 1) specified in SH8303 (SFNi1 to SFNi5)
It was determined in consideration of various conditions such as toughness and thermal conductivity.

[0011]

[Table 1]

The wear-resistant hard ceramics forming the thermal spray coating 12 include, for example, WC, CrC, NbC,
carbides such as iC, ZrC, HfC, VC, MoC, for example, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ),
Oxides such as titania (TiO ₂ ), for example, borides such as BN (cubic boron nitride) synthesized by an ultra-high pressure method;
For example, it is preferable to use a nitride, which is a compound containing nitrogen as a nonmetal constituent element, such as Si ₃ N ₄ , AlN, or TiN, or a silicide. The reason why the content ratio of the wear-resistant hard ceramic is set to 5 to 50% by mass is that when the content is less than 5% by mass, the thermal sprayed coating 12 is not sufficient to exhibit the wear resistance. If the temperature exceeds the above, the hardness of the thermal spray coating 12 becomes too high, and the thermal spray coating 12 may be cracked by repeatedly using the mold. Therefore, in order for the thermal sprayed coating 12 to exhibit abrasion resistance without cracking in the thermal sprayed coating 12 and to obtain the required hardness, 10 to 40% by mass, and more preferably 15 to 40% by mass.
It is preferable to set it to 40 mass%. Furthermore, thermal spray coating 1
It is preferable that the particle diameter of the fine powder of the metal matrix and the wear-resistant hard ceramics forming the second material is selected in the range of 10 to 100 μm. When the particle size is less than 10 μm, the production cost rises, and the momentum received during thermal spraying becomes small, so that the particle size is easily flown into the air stream.
If it exceeds μm, the thermal spray coating 12 becomes coarse and the thermal spray coating 12
The particle size was selected in the range of 10 to 100 μm because of the substantial strength of

The fine powder is sprayed on the upper surface of the plating layer 13 by using a method such as plasma spraying, flame spraying or high-speed flame spraying, and the surface of the sprayed film 12 is finished by grinding. Here, the plasma spraying is to heat the powdered sprayed material with the plasma jet of the plasma spray gun,
This is a method of forming a sprayed coating on a target surface to be sprayed by accelerating to a state of melting or close to it. The plasma spraying includes a method using argon, helium, nitrogen, hydrogen or the like as a working gas, and a water plasma spraying using oxygen and hydrogen generated by decomposition of water. Also, flame (flame) spraying is a method of heating a powdered sprayed material using a combustion flame of oxygen and a flammable gas, melting it or a state close to it, and spraying the sprayed material on a surface to be sprayed to form a sprayed film. How to Note that a jet of compressed gas may be used to accelerate the fine powder to be sprayed. And high-speed flame spraying increases the speed of the flame three times or more as compared with normal spraying (specifically, 2000 to 2700 m /
Second) to form a thermal spray coating.

The thickness T of the thermal spray coating 12 is, for example, about 0.3 to 1.5 mm. Further, in the first modified example shown in FIG. 2B, in the case of the inclined film, the upper end of the copper plate 16 has a thickness of 0.1 to 1.0 mm (0.3 mm in this embodiment).
mm), it is preferable that the thermal spray coating 18 be continuously thickened toward the lower side, and be 1.0 to 2.0 mm (1.5 mm in this embodiment) at the lower end of the copper plate 16. In the second modification shown in FIG. 2C, in the case of a partial coating, the thickness of the upper part of the copper plate 17 is set to 0.1 to 1.0 mm.
(0.3 mm in this embodiment), the thickness of the lower portion of the copper plate 17 is 0.5 to 2.0 mm (1.5 in this embodiment).
mm) is preferably formed.
As described above, since both the thermal spray coatings 12, 18, 19 and the plating layer 13 contain Ni, during the heat treatment (for example,
(900 to 1100 ° C.), mutual diffusion easily occurs between the sprayed coatings 12, 18, 19 and the plating layer 13. Therefore,
It is possible to stabilize the adhesion strength of the thermal spray coatings 12, 18, 19 to the copper plates 14, 16, 17 of the mold body 11.

Here, the copper plates 14, 1,
The case where the plating layer 13 made of Ni or an alloy mainly composed of Ni is applied to the inner surfaces (worked surfaces) of Nos. 6 and 17 is shown, but the thermal spraying is performed by the above method without the interposition of the plating layer 13 (R = 0). It is also possible to form the coatings 12, 18, 19 on the inner surfaces of the copper plates 14, 16, 17 of the mold body 11, respectively. Since the thermal spray coatings 12, 18, 19 and the copper plates 14, 16, 17 are different from each other only in shape, the following description will be made only for the thermal spray coating 12 and the copper plate 14.

As described above, after the thermal spray coating 12 is formed on the inner surface of the mold body 11, the thermal spray coating 12 is
Heat treatment (fusing) at 100 ° C. Note that this heat treatment is preferably performed in an oxygen-free atmosphere or in an inert atmosphere filled with, for example, nitrogen gas, for example, for about 10 to 30 minutes. Here, the reason why the heat treatment is set to 900 to 1100 ° C. is that by performing the heat treatment at 900 ° C. or more, diffusion near the interface between the thermal spray coating 12 and the plating layer 13 starts, and the adhesion of the thermal spray coating 12 is reduced. It is to improve. Further, the metal matrix in the thermal spray coating 12 and the fine powder of the wear-resistant hard ceramic are also diffused with each other, and the coating strength is improved. On the other hand, the reason why the heat treatment is set to 1100 ° C. or less is that the melting point of the thermal spray coating 12 is about 1100 ° C. Therefore, in order to efficiently diffuse the vicinity of the interface between the thermal spray coating 12 and the plating layer 13 and to diffuse the fine powder in the thermal spray coating 12 without lowering the strength of the thermal spray coating 12, heat treatment is performed at 950 to 950. 1100 ° C, even 1
It is preferable to carry out at 000 to 1050 ° C. Also,
If the plating layer 13 is not used, diffusion near the interface between the thermal spray coating 12 and the copper plate 14 starts.

The heat treatment is preferably carried out in a furnace using a heating furnace, in view of stabilizing the quality. However, from the interface between the thermal spray coating 12 and the plating layer 13 to the plating layer 13 side, and also from the thermal spray coating 12 to the copper plate 14.
The position of about 0.2 mm on the copper plate 14 side from the boundary surface with
As long as the heat treatment can be performed at a temperature of 00 to 1100 ° C., the heat treatment can be performed using, for example, a burner or a laser. In this embodiment, the mold body 1
After forming the thermal spray coating 12 on the inner surface of the thermal spray coating 1,
Although the case of heat-treating the mold 2 has been described, it is also possible to use the mold without performing the heat treatment in consideration of the use environment and use frequency of the mold.

Next, a description will be given of a continuous casting mold according to a second embodiment of the present invention, which forms a sprayed coating 12 of the continuous casting mold according to the first embodiment of the present invention. Instead of the fine powder of wear-resistant hard ceramics, fine powder of wear-resistant hard ceramics and Co, Ni,
A cermet containing one or more of Cr, Fe, or an alloy thereof is used. Therefore, the thermal spray coating 12
Only the composition of the thermal spraying, that is, the thermal spraying method of the thermal spray coating, the thickness of the thermal spray coating, the pre-processing of the copper plate, etc. are the same as those of the continuous casting mold according to the first embodiment of the present invention. , And the detailed description thereof will be omitted. In addition, a detailed description of the method of forming the thermal spray coating and the heat treatment will be omitted. The continuous casting mold according to the second embodiment of the present invention includes, for example, four long-side mold parts (one piece of a long-side mold) and one pair of short-side mold parts (not shown). It is manufactured in combination. A thermal spray coating 12 is formed on the inner surface of the mold main body 11 constituting the long side mold portion. The fine powder forming the thermal spray coating 12 is Cr: 0 or more than 0 and 8% by mass or less.
1.0 to 4.5% by mass, Si: 1.5 to 5.0% by mass,
C: 1.1% by mass or less, Fe: 5.0% by mass or less, C
o: 1.0% by mass or less, Mo: 4.0% by mass or less, C
u: 4.0 mass% or less, a nickel-based self-fluxing alloy consisting of the balance Ni is used as a metal matrix. Further, as the wear-resistant material of the thermal spray coating 12, a wear-resistant hard ceramic (for example, one or more of carbide, oxide, boride, nitride, and silicide) and Co, Ni, Cr, Fe, or It consists of a cermet containing one or more of these alloys. In addition, this cermet is used for the thermal spray coating 12.
Is contained in an amount of 5 to 50% by mass in the fine powder. The thermal spray coating 12 is formed on the inner surface of the mold body 11 via a plating layer 13 of Ni or an alloy mainly composed of Ni. The details will be described below.

The cermet is composed of 10 to 90% by mass of a wear-resistant hard ceramic and 90 to 1% of a matrix of at least one of Co, Ni, Cr, Fe or an alloy thereof.
It is preferable to use one having 0% by mass.
Here, the reason that the other component is set to 10 to 90% by mass with respect to one component is that if the matrix is less than 10% by mass, the bondability of the wear-resistant hard ceramic becomes poor,
If the amount exceeds 0% by mass, the wear-resistant hard ceramics (aggregate) in the matrix becomes insufficient, and sufficient strength cannot be obtained.

The wear-resistant hard ceramic used for the cermet is the same as the wear-resistant hard ceramic used for the continuous casting mold according to the first embodiment of the present invention. Here, the content ratio of the cermet is 5 to 50.
If the amount is less than 5% by mass, the amount is not sufficient for the thermal sprayed coating 12 to exhibit abrasion resistance.
If the content exceeds mass%, the hardness of the thermal spray coating 12 increases, and cracks may occur in the thermal spray coating 12 by repeatedly using the mold. Therefore, in order for the thermal sprayed coating 12 to exhibit more abrasion resistance without cracking in the thermal sprayed coating 12 and to obtain the required hardness, the content should be 10 to 40% by mass, more preferably 15 to 40% by mass. preferable. In the case of this embodiment, the thermal spray coating 12 is 900 to 1100
By heat treatment (fusing) at a temperature of .degree.
The diffusion near the interface between the metal layer and the plating layer 13 starts, and the metal matrix and the fine powder of the cermet in the thermal spray coating 12 also begin to diffuse with each other. Therefore, it is possible to improve the adhesion of the thermal spray coating 12 to the mold body 11 and further improve the strength of the thermal spray coating 12. Here,
The case where the plating layer 13 of Ni or an alloy mainly composed of Ni is applied to the inner surface (working surface) of the copper plate 14 of the mold body 11 is shown, but without the plating layer 13 (R =
0) It is also possible to form the thermal spray coating 12 on the inner surface of the copper plate 14 of the mold body 11 by the method described above. In this case, the heat treatment of the thermal spray coating 12 at 900 to 1100 ° C. starts diffusion near the interface between the thermal spray coating 12 and the copper plate 14.

[0021]

EXAMPLE Using a part (inventive material) of a continuous casting mold according to the present invention, a crack resistance test, a welding resistance test, and a wear resistance test of a thermal sprayed coating were performed. A comparison will be described. Here, the metal matrix of the fine powder used to form the thermal spray coating used in the invention material is Cr:
0 or more than 0 and 8% by mass or less, B: 1.0 to 4.5% by mass, Si: 1.5 to 5.0% by mass, C: 1.1% by mass or less, Fe: 5.0% by mass Hereinafter, it is a nickel-based self-fluxing alloy composed of 1.0 mass% or less of Co, 4.0 mass% or less of Mo, 4.0 mass% or less of Cu, and the balance of Ni. Cermet is a wear-resistant hard ceramic with C
It contains fine powder of r ₂ C ₃ and NiCr. First, FIG.
As shown in the figure, the crack resistance test was conducted by the flame 21 from the flame (frame) device 20 with various moving speeds.
Was sprayed onto the thermal spray coating 22. As described above, by changing the moving speed of the flame device 20, the heating speed and the cooling speed of the sprayed coating 22 are changed, and the average crack interval (the size of cracks) generated in the surface layer portion of the sprayed coating 22 is measured. To evaluate the crack resistance. FIG.
As shown in Table 2, the average crack interval value of the current material is high, but no crack occurs in the invention material, so that the invention material has better crack resistance than the current material.

Next, the welding resistance test was carried out using a square copper piece having a side of 50 cm and a thickness of 30 cm and a sprayed coating having a thickness of 0.5 mm formed on the surface of a rectangular solid copper piece having a thickness of 30 cm. By flowing molten steel having a melting temperature of 1650 ° C. on the thermal spray coating, the surface temperature of the copper lump on the thermal spray coating side was measured, and further, the welding state of the molten steel to the thermal spray coating was confirmed. Was evaluated. As shown in FIG. 5, in the case of the current material, welding of the molten steel to the sprayed coating starts when the surface layer temperature of the copper ingot is about 400 ° C., while in the case of the invention material, the welding of the molten steel to the sprayed coating is performed at about 690 ° C. Starts. Therefore, the welding temperature of the thermal spray coating of the invention material can be increased by about 290 ° C. as compared with the current material, and it can be seen that the invention material has better welding resistance than the current material. Then, as shown in FIG. 6, in the wear resistance test, the atmosphere temperature was set to 300 ° C., and the columnar steel material (S45C) 24 was rotated clockwise around the axis of the steel material 24 on the thermal sprayed coating 23. went. The wear resistance was evaluated by measuring the wear amount and the friction coefficient of the inventive material and the current material, respectively. As shown in FIG. 7, it can be seen that the invented material has improved abrasion resistance because the abrasion loss is about half and the friction coefficient is reduced as compared with the current material. From the test results described above, it can be seen that the inventive material is a material excellent in crack resistance, welding resistance, and abrasion resistance as compared with the current material.

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 embodiment, and is described in the claims. The present invention also includes other embodiments and modifications that can be considered within the scope of the matters. For example, in the above-described embodiment, the case where the thermal spray coating is formed on the inner surface of the mold main body constituting the long side mold portion has been described, but the thermal spray coating is formed on the inner surface of the mold main body constituting the short side mold portion. It is also possible to form.

[0024]

According to the first aspect and the third aspect dependent thereon,
In the continuous casting molds described in 4 and 5, the use of a metal matrix of a nickel-based self-fluxing alloy improves the toughness, thermal conductivity, and the like of the sprayed coating. It is possible to improve the crack resistance and welding resistance of the molten steel. Further, by using fine powder of wear-resistant hard ceramics, it becomes possible to improve the wear resistance of the sprayed coating. As a result, even when the continuous casting mold is not sufficiently cooled, the semi-solidified molten steel can be easily removed from the mold without welding to the sprayed coating and without generating cracks in the sprayed coating. It becomes possible to pull out. Even when the semi-solidified molten steel is drawn out while in contact with the sprayed coating, the semi-solidified molten steel can be spray-coated like a conventional mold by the sprayed coating with improved wear resistance. Can be pulled out of the mold without abrasion. Therefore, the life of the mold can be extended, and the economy is improved.

Claim 2 and dependent claims 3,
In the continuous casting molds described in 4 and 5, the use of a metal matrix of a nickel-based self-fluxing alloy improves the toughness, thermal conductivity, and the like of the sprayed coating. It is possible to improve the crack resistance and welding resistance of the molten steel. In addition, it is possible to improve the wear resistance of the thermal spray coating by using a commercially available cermet. As a result, even when the continuous casting mold is not sufficiently cooled, the semi-solidified molten steel can be easily removed from the mold without welding to the sprayed coating and without generating cracks in the sprayed coating. It becomes possible to pull out. In addition, even if the molten steel in the semi-solid state is drawn out while contacting with the sprayed coating, the molten steel in the semi-solidified state is not It is possible to pull out the sprayed coating from the mold without abrasion of the sprayed coating as in the case of the mold. Therefore, it is possible to manufacture a mold with good economy, and it is also possible to extend the life of the mold.

In particular, in the continuous casting mold according to the third aspect, the wear resistance of the sprayed coating can be further improved, so that the life of the mold can be further extended. In the continuous casting mold according to the fourth aspect, since the thermal spray coating and the plating layer both contain Ni, it is possible to prevent oxidation of the inner surface layer of the mold main body, and for example, heat-treat at 900 to 1100 ° C. Occasionally, mutual diffusion between the sprayed coating and the plating layer is likely to occur, so that the adhesion strength of the sprayed coating to the mold body can be stabilized. Therefore, the sprayed coating can be easily sprayed on the inner surface of the mold main body, and the sprayed coating is hardly peeled off from the inner surface of the mold main body, so that a mold having stable quality can be manufactured. In the continuous casting mold according to the fifth aspect, diffusion of the thermal spray coating and the inner surface layer portion of the mold main body starts, and the adhesion of the thermal spray coating to the mold main body can be improved. Then, the metal matrix and the fine powder of the wear-resistant hard ceramic, and the fine powder of the metal matrix and the cermet in the thermal spray coating are also diffused with each other, so that the strength of the thermal spray coating can be improved. Therefore, it is possible to manufacture a mold having more stable quality.

[Brief description of the drawings]

FIG. 1 is a plan cross-sectional view of a main part of a long side mold portion of a continuous casting mold according to a first embodiment of the present invention.

2 (A), 2 (B), and 2 (C) are perspective views of a long-side mold portion of the continuous casting mold, respectively, and an explanatory diagram in the case where an inclined thermal spray coating is applied to the continuous casting mold. It is explanatory drawing in the case of applying a partial spray coating to the casting mold for continuous casting.

FIG. 3 is an explanatory diagram of a test method of a crack resistance test.

FIG. 4 is an explanatory diagram of test results of a crack resistance test.

FIG. 5 is an explanatory diagram of a test result of a welding resistance test.

FIG. 6 is an explanatory diagram of a test method of a wear resistance test.

FIG. 7 is an explanatory diagram of test results of a wear resistance test.

FIG. 8 is a schematic diagram when molten steel is filled in a continuous casting mold and a graph showing a temperature distribution at that time.

[Explanation of symbols]

11: Mold body, 12: Thermal spray coating, 13: Plating layer, 1
4: Copper plate, 15: Back plate (water box), 16: Copper plate, 17: Copper plate, 18: Thermal spray coating, 19: Thermal spray coating, 2
0: Flame (frame) device, 21: Flame, 22: Thermal spray coating, 23: Thermal spray coating, 24: Steel material

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E004 AB04 4K031 AA03 AB08 BA05 CB30 CB39 CB42 CB44 CB45 CB46 CB47 FA01

Claims (5)

[Claims] In a continuous casting mold in which a sprayed coating is formed on the inner surface of a mold body, the fine powder forming the sprayed coating is Cr: 0 or more than 0 and 8% by mass or less, B:
1.0 to 4.5% by mass, Si: 1.5 to 5.0% by mass,
C: 1.1% by mass or less, Fe: 5.0% by mass or less, C
o: 1.0% by mass or less, Mo: 4.0% by mass or less, C
u: 4.0 mass% or less, comprising a metal matrix of a nickel-based self-fluxing alloy composed of a balance of Ni and a fine powder of a wear-resistant hard ceramic, containing 5 to 50 mass% of the wear-resistant hard ceramic. Characteristic continuous casting mold. 2. In a continuous casting mold in which a thermal spray coating is formed on the inner surface of a mold body, the fine powder forming the thermal spray coating is Cr: 0 or more than 0 and 8% by mass or less, B:
1.0 to 4.5% by mass, Si: 1.5 to 5.0% by mass,
C: 1.1% by mass or less, Fe: 5.0% by mass or less, C
o: 1.0% by mass or less, Mo: 4.0% by mass or less, C
u: 4.0% by mass or less, containing a metal matrix of a nickel-based self-fluxing alloy composed of the balance Ni, fine powder of wear-resistant hard ceramics, and one or more of Co, Ni, Cr, Fe, and alloys thereof. A continuous casting mold comprising cermet and containing the cermet in an amount of 5 to 50% by mass. 3. The continuous casting mold according to claim 1, wherein the wear-resistant hard ceramic is at least one of carbide, oxide, boride, nitride, and silicide. Characteristic continuous casting mold. 4. The continuous casting mold according to claim 1, wherein the thermal spray coating is made of Ni or Ni.
A continuous casting mold formed on the inner surface of the mold body via a plating layer of an alloy mainly composed of: 5. The continuous casting mold according to claim 1, wherein the sprayed coating is formed on the inner surface of the mold body, and then the sprayed coating is formed in a range of 900 to 1100.
A continuous casting mold characterized by being heat-treated at a temperature of ° C.