KR100381670B1 - Mold Win Plating Method of Continuous Molding Copper Mold - Google Patents

Abstract

The present invention relates to a copper plate mold having excellent heat resistance and high hardness when performing a continuous casting operation, and also excellent wear resistance, comprising a copper plate, a nickel layer attached on the copper plate, and a nickel-boron alloy layer attached on the nickel layer. It is done by

The method of manufacturing a copper mold includes the steps of preparing a copper plate for copper mold, forming a nickel layer on the surface of the copper plate, and forming a nickel-boron or nickel compound alloy layer on the upper surface of the nickel layer. Include.

In the nickel-boron alloy layer forming process, the surface of the nickel layer is subjected to electrolytic cleaning and washing, pretreated, and then nickel is formed on the surface of the nickel layer using a copper plated electrode as an anode in an electrolyte solution containing sulfuric acid, hydrofluoric acid, and nickel sulfate. After the plating nucleus is formed, mold-win plating is performed to form a nickel-boron alloy layer.

Description

Mold Win Plating Method of Continuous Molding Copper Mold

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a copper mold for continuous casting of molten steel and a method of manufacturing the same, and to a method of forming a nickel (Ni) layer and a nickel-boron alloy layer on the surface of a copper mold continuously cast of molten steel, and manufactured by the method. It relates to a copper plate mold.

As shown in FIG. 1, a general process of manufacturing slab by continuously casting molten steel such as high carbon steel, low carbon steel, stainless steel, and special steel is carried out by ladleing molten steel in a blast furnace and then tundish When poured into the slab, it is moved from a tundish into a continuous casting mold and cooled.

Continuous casting mold plays a role of making a certain shape while cooling the surface of hot steel.

The conventional continuous casting mold is composed of long side molds (11-12, 13-14) and short side molds (15-16, 17-18), and these long side and short side molds are formed of a copper plate mold 12 in contact with hot molten steel. And 14, 16, 17, and coolant jackets 11, 13, 15, and 18 for cooling the copper mold.

The jacket portion is connected to the cooling system so that the cooling water maintains a constant temperature, and the copper plate mold is coupled so that the heat of the copper plate mold heated by the high temperature of the molten steel is transferred to the cooling water jacket well.

The copper mold may be made of a material having good heat transfer rate. Currently, copper is mainly used, so it is generally called copper mold. Since the copper plate is weak in strength, when the molten steel solidifies and solidifies and moves, the surface of the copper plate is easily worn. Therefore, the copper plate forms a reinforcement part using a material that is hardly worn on only one surface of the copper plate in contact with the molten steel. This reinforcing part is formed by using copper or a copper alloy material as it is or by plating soft Ni or soft Ni-Cr to improve thermal conductivity. In order to improve wear resistance, chromium is used, and reinforcing parts are formed in order of copper-nickel-chromium in consideration of adhesion to copper plates.

The reinforcement part using copper alloy material which is mainly used in conventional continuous casting copper molds or plating with soft Ni or soft Ni-Cr, when the copper alloy material is used as it is, Not only does it shorten the life of copper casting molds for continuous casting, but it also melts and mixes copper or copper alloy on the surface of mold slab products, causing cracks (star cracks) in the products during radiant heat and rolling. It can also be a cause.

In order to compensate for these problems, the use of soft Ni or soft Ni-Cr plating prevented copper from fusion on the surface and improved wear resistance, but did not meet expectations. In addition, a poor adhesion between the flexible Ni plating layer and the Cr plating layer is often caused to occur peeling phenomenon.

The present invention is nickel plated (Ni) on the surface of the copper plate in order to meet the demands of the prior art, the Ni surface is processed by activation treatment, and Mold Win plating to perform a continuous casting operation at a high temperature is excellent in heat resistance and high hardness The purpose is to provide a copper mold having excellent wear resistance.

The copper plate mold of the present invention is a copper plate mold constituting a continuous casting mold used when continuously casting molten steel, the copper plate, a nickel layer attached on the copper plate, and a nickel-boron alloy attached on the nickel layer It comprises a layer.

Preferably, the thickness of the copper plate is gradually changed so that the thickness of one side is thinner than the thickness of the other side, the nickel layer is formed to be the thickness in the direction opposite to the change in the thickness of the copper plate so that the total thickness of the copper plate and the nickel layer It became constant. In addition, the thickness of the nickel-boron alloy layer may be changed in a direction opposite to the change in the thickness of the copper plate so that the total thickness of the copper plate and the nickel-boron alloy layer may be constant, and the nickel layer together with the nickel-boron alloy layer. It is more preferable if the thickness of is also formed so that the total thickness which summed the thickness of the copper plate nickel layer and the said nickel- boron alloy layer became constant.

The present invention provides a method for producing a copper plate mold constituting a continuous casting mold used for continuously casting molten steel, comprising the steps of: preparing a copper plate for copper mold; forming a nickel layer on the surface of the copper plate; And forming a nickel-boron alloy layer on the upper surface of the nickel layer.

In the copper plate preparation step, the copper plate is processed to be inclined so that the thickness of one side is smaller than the thickness of the other side opposite to each other, and in the nickel layer forming step, the nickel layer is formed to be inclined in the opposite direction to the copper plate, and the nickel- In the boron alloy layer forming process, the surface of the nickel-boron alloy layer is formed to be inclined in the same direction as the nickel layer, so that the total thickness of the total thickness of the copper plate, the nickel layer, and the nickel-boron alloy layer is constant.

In the nickel-boron alloy layer forming step, the surface of the nickel layer is subjected to electrolytic cleaning and washing with pretreatment, followed by nickel plating on the surface of the nickel layer using a nickel electrode as an anode in an electrolyte solution containing sulfuric acid, hydrofluoric acid, and nickel sulfate. The nucleus is formed, and a nickel-boron alloy layer is formed by mold win plating.

In the inclined nickel layer forming process, the nickel layer is uniformly formed, and then a part of the surface is mechanically cut to reduce the thickness by machining, and the nickel-boron alloy layer forming process is the nickel-boron alloy. It is advantageous to control the thickness of the plating by lowering the level of the plating liquid at a constant rate during plating the layer or by lifting the anode plate little by little from the plating liquid.

1 is a schematic explanatory view of a general continuous casting process

Figure 2 is a plan view of a typical continuous casting mold

3 is a cross-sectional view of a typical copper plate mold cut by the III-III line of FIG.

4 is a cross-sectional view of the copper plate mold of the present invention cut by line III-III of FIG.

5 is a schematic plan view of a plating apparatus schematically shown for explaining the method of the present invention;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5 of the plating apparatus schematically shown for explaining the method of the present invention. FIG.

7 is a schematic diagram of a plating apparatus used for explaining the method of the present invention;

8 is a cross-sectional view of a plating apparatus used for explaining the method of the present invention.

※ Explanation of code about main part of drawing ※

11, 13, 15, 18, 41: coolant jacket

12, 14, 16, 17: copper plate mold

51 working table 55 electrode 52 mold for continuous casting

53: outlet

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In the process of preparing the copper plate for the copper mold of the present invention, the copper plate is machined to make the surface inclined, so that the thickness is different, and the pretreatment is performed to plate the nickel layer 43 on the surface of the copper plate 42. The process of forming by the general plating method is performed.

Next, 2 g / L of fluoride (hydrofluoric acid) was added to 20% sulfuric acid, and electrolysis was performed for 1 minute at an anode current density of 4 A / dm 2 in the activating solution to increase the activity. Nickel protruding particle formation process, in which numerous particles are produced (observable at 100-150 times magnification). And it protects the surface of Ni protruding particle (plating nucleus) produced by electrolysis for 2 minutes at a cathode current density of 4A / dm 2 and promotes activation.

After the nickel plating nucleus forming process is performed, a nickel-boron alloy layer 44 is formed by performing mold win plating on the soft Ni surface. Forming the nickel-boron alloy layer by the plating method is called moldwin plating. When the mold window plating is activated after the nickel surface is activated, the adhesion of the nickel-boron alloy layer is very good and strong, and the hardness of the Mold Win plating is very high. MoldWin plating is described in detail below.

In addition, the pH is gradually increased during Ni plating or Mold Win plating, so it is adjusted to pH-3.5 using Formic Acid.

In Mold Win plating, Mold Win A solution (see Example Table) was temporarily added before plating, and Mold Win B solution (see Example Table) was added in small portions together with the filtrate to ensure good mixing. The hardness of the Mold Win plating plated in this way is Lockel hardness Hrb 125, which is excellent in heat resistance and abrasion resistance, and also excellent in thermal conductivity, allowing fast cooling.

Example 1

The mold shaping surface copper plate 42 of the copper casting mold for continuous casting is machined to be inclined to be scraped off. At this time, the upper part was processed less and the lower part was processed more so that the thickness of the cut out was Top / Bottom 300 / 1,400 um (mean micrometer: below) and the surface was polished and cleaned. That is, the upper part is inclined so that the lower part is 300um and the lower part is 1,400um.

As shown in Figs. 7 and 8, the copper mold is placed in the electrolytic cell 60 so as to face the mold processing surface of the mold 52, the Ni cathode 54 is installed in the center, and the electrolyte is placed in the electrolytic cell. ), A current such as electroplating or electrolytic degreasing, electrolytic cleaning can be performed.

In this electrolytic cell, a continuous casting copper plate mold was placed in an alkaline degreasing solution in which 40 g / L caustic soda and 60 g / L sodium carbonate were dissolved, and the plate was energized at an anode current density of 5 A / dm 2 (119.5 A) for 30 minutes at room temperature. After removing the foreign matter completely, wash the surface thoroughly with water. At this time, make sure to neutralize using pH test paper, wash once with 5% sulfuric acid solution, and deposit in Ni plating solution with pH and concentration adjusted to cathodic current density 2-3A / d㎡ (47.8-71.7A) temperature 56-60 The plating was carried out at 50 DEG C for 50 hours to form a Ni plating layer having a plating thickness of 1000 um.

Then, the copper plate mold for continuous casting was washed with water, cooled, and machined so that the thickness of the flexible Ni plating layer was 200/800 um. The processed Ni-plated surface was treated with sandpaper and electrolytic degreasing for 3 minutes at room temperature with an anode current density of 5 A / dm 2 (119.5 A) in alkaline solution of caustic soda 40 g / L and sodium carbonate 60 g / L. After sufficiently washing with water (up to pH check, of course), it was electrolyzed for 1 minute at room temperature with an anode current density of 4 A / dm 2 (95.6 A) in an activating solution in which 2 g / L of fluorine (hydrofluoric acid) was added to a 20% sulfuric acid solution. After making numerous Ni particles protruding particles in the surface of Ni, the polarity was reversed and electrolyzed for 2 minutes at a cathode current density of 4 A / dm 2 (95.6 A) to promote activation on the surface of the Ni protruding particles.

When the initial Ni of hard Ni plating is electrodeposited and adhered to this activated numerous Ni protruding particles, the adhesion is very excellent compared to any conventional activation treatment when the MoldWin plating is electrodeposited on the entire surface.

After the activation process, the solution is quickly washed and then poured into a MoldWin bath (see the following table). Mold Win plating is performed at 50-60 ° C with a current of 0.5-10.5 A / dm 2 (11.95-35.85A) at a cathode current density of 50 to 60 ° C. (At this time, Mold Win plating solution was supplemented with 40 kg of Sulfuric Acid, Mold Win A solution 940 ml, which was insufficient.)

In addition, while mold win plating, the liquid is filtered and circulated through a filter pump (not shown), mold win plating, and the thickness of the mold win plating is about 100um, and the cathode current is reduced by 24.4mA / min while releasing the mold win liquid by 330ml / min. Plated for 35 hours with decreasing current with a rectifier programmed to.

After setting the cathode current to 2.14A / dm² (51.20A) and reducing the current, secondary analysis of the Mold Win plating solution was carried out. As a result, the Mold Win A solution and 800mL were added and the Mold Win B solution was added for 34 hours at 34mL / h. The plating was continued for 18 hours.

The plated continuous copper plate was soft Ni plating thickness 200 / 800um, Mold Win plating thickness 100 / 600um and showed Rockwell hardness Hrb 120. It was excellent in abrasion resistance and heat resistance and the service life was about 200-300%.

Example data are shown in the following table.

Plating thickness

Plating thickness Remarks Top Bottom Soft Ni 200um 800um Mold win 100um 600um Total plating gold 300um 1400um

* Liquid draining process: 35 hours

Liquid height: -25.7mm / h

Liquid volume: 330mL / min

Total electrolyte: 330 X 60 X 35 = 693 litter

* Cathode current density control: 35 hours

51.20 A / Front (current before bleeding)

Allows current to be reduced to -1.46 A / h

(The process is carried out using a programmable rectifier)

* Mold Win Plating Solution

Compounding (g / L) Primary analysis Secondary analysis Remarks Be 25.0 24.0 pH 3.5 3.7 Sulfuric acid Ni 300 275 60% 40Kg Replacement Embrittlement Ni 10 9.5 Sulfuric acid Ni 50 48 Boric acid 25 24 Zaccarin Soda 1.2 1.5 Ascorbic acid 0.15 0.18 Borite Na 1.12 0.14

** Be and pH are physical properties.

* Mold Win A

division Compounding (g / L) Range of use Zaccarin Soda 30 25-40 Formic acid 20 10-30

* Mold Win B amount

division Compounding (g / L) Range of use Askic acid 30 20-40 Borite Na 20 10-30 Methanol 500 450-650

Example 2

Machining the copper plate surface for mold making of the continuous casting copper plate mold so that the slope becomes Top / Bottom 250 / 1,600 um, polishing the surface to be cleaned, and as shown in Figs. 7 and 8, It puts in the electrolytic cell 60 so that the mold process surface may face, and it installs so that Ni cathode 54 may be 20 cm apart in the center, respectively.

When a voltage is applied to the electrode 55 through the electrode rod 54 to the electrolytic cell, electroplating or electrolytic degreasing, electrolytic cleaning and the like can be performed.

After doing this, an alkaline degreasing solution containing 40 g / L caustic soda and 60 g / L of sodium carbonate was added to the degreasing bath, and the processed copper casting mold for continuous casting was added, and the anode current density was 5 A / dm 2 (119.5 A for 30 minutes at room temperature). ) To completely remove the foreign substance on the surface, and wash the surface thoroughly with water. At this time, check the neutralization using pH test paper, wash once with 5% sulfuric acid solution, and deposit it in Ni plating bath 60, pH and concentration of which are adjusted, and the cathode current density is 2-3 A / dm 2 (47.8-71.7). 50 hours were plated with A) to form a flexible Ni plating layer having a plating thickness of 1000 um.

Then, the copper plate mold for continuous casting was washed with water, cooled, and machined so that the thickness of the flexible Ni plating layer was 200/800 um. The processed Ni-plated surface was treated with Sand Paper and electrolytic degreasing for 3 minutes at room temperature with an anode current density of 5A / dm 2 (119.5A) in an alkaline degreasing solution of caustic soda 40g / L and 60g / L caustic soda. After degreasing, wash it thoroughly with water (check pH), and then, in an activation solution in which 2 g / L of fluorine (hydrofluoric acid) is added to a 20% sulfuric acid solution, electrolyte at room temperature for 1 minute at an anode current density of 4 A / dm 2 (95.6 A). Numerous protruding particles of Ni kernels were made on the surface of Ni, and the polarity was changed to electrolyze for 2 minutes at a cathode current density of 4 A / dm 2 (95.6 A) to promote activation on the surface of the Ni protruding particles.

The initial Ni of hard Ni plating is electrodeposited and adhered to a myriad of Ni protruding particles thus activated, and thus, the Win mold is plated on the entire surface to form a nickel-boron alloy layer, which is incomparable to any conventional activation process. The adhesion was very excellent.

The activation treatment solution was quickly washed and Mold Win liquid was added to mold Win plating at a current of 0.5-1.5 A / dm 2 (11.9-38.9A) for cathode current density at 50-60 ° C. (Mold Win plating solution was first analyzed and supplemented with 40 kg of insufficient sulfamic acid, 16.8 kg of embrittlement, and 950 ml of Mold Win A solution.)

During mold win plating, the liquid is filtered through a 5um filter bag and the mold win solution is added in small amounts of 42.2ml / h, and plated at 0.5 to 1 A / dm for 10 hours to adjust the thickness to about 50um and adjust the cathode current to 61.7 A. The Win solution was plated for 40 hours while the cathode current density was reduced by 25.6 mA / min while extracting the Win solution by 288.8 ml / min.

At this time, after reducing the current, 700 ml of Mold Win A solution was added according to the result of secondary analysis of the Mold Win plating solution, and the Mold Win B solution was added in small amounts for 20 hours at 32 mL / h. Then, 20 hours were plated.

The soft plating thickness of continuous copper plate mold plated for 40 hours was 200 / 800um, Mold Win plating thickness was 50 / 800um, and it showed Rockwell hardness Hrb 121, and it was excellent in wear resistance and heat resistance. It was satisfactory as it was 2-3 times higher than that.

Plating thickness

Plating thickness Remarks Top Bottom Soft Ni 200um 800um Mold win 50um 800um Total plating gold 250um 1600um

* Liquid draining (40 hours)

Liquid level -22.5mm / h

Liquid volume 288.8 mL / min

* Cathode current density control: 40 hours

61.66 A / Full area (current before bleeding)

Programmable rectifier for reduced current at -1.54 A / h.

* Mold Win Plating Solution

Compounding (g / L) Primary analysis Secondary analysis Remarks Be 25.0 24.5 pH 3.5 3.6 Sulfuric acid Ni 300 274 60% 40kg replacement Embrittlement Ni 20 9.8 Only 50% 16.8kg supplement Sulfuric acid Ni 40 39 Boric acid 25 24.5 Zaccarin Soda 1.1 1.7 Ascorbic acid 0.13 0.16 Borite Na 0.11 0.12

* Mold Win A

Compounding (g / L) Range of use Zaccarin Soda 30 25-40 Formic acid 20 10 -30

* Mold Win B amount

Compounding (g / L) Scope of use Askic acid 30 25 -40 Borite Na 20 10 -30 Methanol 500 450-650

Example 3

The mold-forming copper plate surface of the continuous casting copper plate mold was machined to have a slope of Top / Bottom of 250/1200 um by the same method as in the above example, and the surface was polished and cleaned. As in Example 1 and Example 2, the plating may be performed using a general plating bath, but when the object to be plated is large, it is somewhat inconvenient to use a new method.

That is, to face the mold processing surface and put the FRP plate with a width of 45um at both ends and assembled as shown in Figures 5 and 6 to assemble a square mold group. This was placed on the FRP workbench and closely adhered to the mold group (electrolyzer) and the workbench so that liquid did not leak with a sponge.

Next, an alkaline degreasing solution in which 40 g / L of caustic soda and 60 g / L of sodium carbonate was dissolved was pumped into the mold group, and the foreign substance on the surface was completely removed by applying an anodic current density of 7 A / dm 2 (2400 A) at room temperature. After removing the degreasing solution and washing with water sufficiently, it was confirmed to be neutral using a pH paper.

Next, the copper surface was washed once with hydrochloric acid (1: 1), washed with water, and treated once with 5% sulfuric acid solution.

50 hours of plating was carried out with a cathode current density of 2-3 A / dm 2 (700-1045 A) to obtain a Ni plating thickness of 1000 um.

The Ni plating solution was removed, washed well with water, the mold group was transferred from the FRP work table, dismantled, and machined so that the thickness of the Ni layer plated on the copper mold was 200 / 800um and treated with sand paper to maintain the flatness of the surface. .

Next, the group of molds was transferred to the FRP workbench in the same manner as the Ni plating, and the alkaline degreasing solution was added, followed by electrolytic degreasing and surface washing for 3 minutes at anodic current density of 7 A / dm 2 (2400 A) at room temperature (pH). Add 35% sulfuric acid (add 2g / L hydrogen fluoride) activating solution and electrolyze for 3 minutes with anode current density 5A / dm 2 (1740A) and cathode for 2 minutes with cathode current density 5A / dm 2 (1740A). I made a lot of kernels of protruding particles.

Remove the activating solution in a short time, wash it with water, insert the Mold Win plating solution heated to about 60 ℃, and mold the nickel-boron alloy layer by Mold Win plating with a current of cathode current density of 0.5-1.5A / dm (174-530A). Formed. (Mold Win plating solution was analyzed to replenish 700 mL of Mold Win A solution and 400 mL of Mold Win B solution.)

The plating was continued for 10 hours, and when the thickness reached 52um, the anode was increased by 250 mm and plated for 160 minutes with current of 3.2 A / dm 2 (850 A). (At this time, the Mold Win plating solution was analyzed to supplement 350 mL of B solution.) Continue to increase the anode by 250mm, plate the current for 160 minutes at 3.2A / dm (585A), raise 160mm, plate the current for 180 minutes at 3.2A / dm (410A), raise 160mm again and increase the current 3.2A / d After plating for 200 minutes in m 2 (256A), the liquid was removed and the mold group was disassembled as in the Ni plating.

Ni plating thickness of the plated mold was 200 / 800um, Mold Win plating thickness was 50 / 420mm, and Rockwell hardness Hrb 110 was excellent in wear resistance and heat resistance.

Plating thickness

Plating thickness Remarks Top Bottom Soft Ni 200um Mold win 50um 630um Total plating gold 250um 830um

Anode Rise and Current

0 Primary Secondary 3rd 4th 5th Anode location 0 160mm Up 160mm Up 160mm Up 160mm Up - electric current 350 A 850 A 585A 410A 256 A -

* Mold Win Plating Solution

Compounding (g / L) Primary analysis Secondary analysis Remarks Be 25.0 24.5 pH 3.5 3.6 Sulfuric acid Ni 300 295 Embrittlement Ni 20 19 Sulfuric acid Ni 40 39 Boric acid 25 25.0 Zaccarin Soda 1.5 1.6 Ascorbic acid 0.18 0.17 Borite Na 0.13 0.12

* Mold Win A

Compounding (g / L) Range of use Zaccarin Soda 25 25-40 Formic acid 25 10-30

* Mold Win B amount

Compounding (g / L) Scope of use Askic acid 25 20-40 Borite Na 25 10-30 Methanol 500 450-650

(Example 4-8)

As a result of plating experiment, the copper casting mold for continuous casting same as Example 1-3 was added to the Mold Win A and B liquids in the mixing ratios as shown in the following table, and showed excellent results in hardness, wear resistance, and durability.

Example Mold Win A liquid (g / L) Mold Win B Liquid (g / L) Remarks Zaccarin Na Formic Acid Ascorbic Acid Borite-Na 4 25 15 25 15 N / F Mold 5 25 10 25 20 N / F Mold 6 30 10 20 25 B / F Mold 7 25 10 20 15 B / F Mold 8 20 20 30 20 B / F Mold

Example Plating thickness (um) Hardness (Hrb) Use count (times) Remarks Ni M / W 4 200/1200 50/1000 110 250-300 5 250/800 50/800 115 200-300 6 200/1000 50/600 105 200-300 7 200/1200 100/1000 100 250-300 8 250/1000 100/800 120 250-300

The method of forming the nickel-boron or nickel compound alloy layer by the process described above is called Mold Win plating.

As the nickel compound, NiW, NiP, NiSb, NiCo, NiBe, or the like can be used.

As described above, when the mold is manufactured by using the copper casting mold for continuous casting of the present invention, its life can be extended up to three times as compared with the copper mold used before.

Claims (11)

A copper plate mold constituting a continuous casting mold used when continuously casting molten steel, Copper Plate, A nickel layer attached to the copper plate, Copper plate mold for continuous casting comprising a nickel-boron alloy layer attached on the nickel layer. The method according to claim 1, The thickness of the copper plate is gradually changed so that the thickness of one side is thinner than the thickness of the other side, The nickel layer is changed in thickness in a direction opposite to the copper plate thickness change, Copper plate mold for continuous casting, characterized in that the overall thickness of the copper plate and the nickel layer is constant. The method according to claim 1, The thickness of the copper plate is gradually changed so that the thickness of one side is thinner than the thickness of the other side, The nickel-boron alloy layer is changed in thickness in a direction opposite to the copper plate thickness change, The copper plate mold for continuous casting, characterized in that the overall thickness of the copper plate and the nickel-boron alloy layer is constant. The method according to claim 1, The thickness of the copper plate is gradually changed so that the thickness of one side is thinner than the thickness of the other side, The nickel layer is changed in thickness in a direction opposite to the copper plate thickness change, The nickel-boron alloy layer also changes its thickness in a direction opposite to the copper plate thickness change, The copper plate mold for continuous casting, characterized in that the total thickness of the sum of the thickness of the copper plate, the nickel layer and the nickel-boron alloy layer is constant. In the method for producing a copper plate mold constituting the mold for continuous casting used when continuously casting molten steel, Preparing a copper plate for the copper mold; Forming a nickel layer on the surface of the copper plate; A copper plate mold manufacturing method comprising the step of forming a nickel-boron alloy layer on the upper surface of the nickel layer. The method of claim 5, In the copper plate preparation process, the copper plate is processed to be inclined so that the surface of the copper plate is smaller than the thickness of the other side of the opposite side, In the nickel layer forming process, the nickel layer is formed so that the surface is inclined in the direction opposite to the copper plate, In the nickel-boron alloy layer forming process, the nickel-boron alloy layer is formed to be inclined in the same direction as the nickel layer, The copper plate mold manufacturing method characterized in that the thickness of the entire sum of the thickness of the copper plate, the nickel layer and the nickel-boron alloy layer is constant. The method of claim 5, wherein the nickel-boron alloy layer forming process, After the electrolytic cleaning and washing process on the surface of the nickel layer is pretreated, In an electrolyte solution containing sulfuric acid, hydrofluoric acid, and nickel sulfate, a nickel plating core is formed on the surface of the nickel layer by using a nickel electrode as an anode, the voltage applied to the electrode is changed, activated briefly, and washed with water. A copper plate mold manufacturing method characterized by forming a boron alloy layer. The method of claim 7, wherein The mold win plating method is a copper plate mold manufacturing method characterized in that the plating method for forming a nickel-boron alloy layer using an electrolyte containing boron and nickel. The method of claim 7, wherein The electrolytic solution containing boron and nickel is a copper plate mold manufacturing method characterized in that it comprises a sulfamic acid Ni, embrittlement Ni, Ni sulfate, and boric acid. The method of claim 6, The inclined nickel layer forming process is to form a nickel layer and then scrape a part of the surface by machining to reduce the thickness, The nickel-boron alloy layer forming process may reduce the level of the plating solution at a constant rate during plating of the nickel-boron alloy layer, or adjust the thickness of the plated by lifting the positive electrode plate little by little from the plating solution. . The method of claim 5, Copper nickel mold manufacturing method characterized in that to form a nickel compound alloy layer by selecting one or more of the nickel compound NiW, NiP, NiSb, NiCo, NiBe on the nickel layer instead of forming the nickel-boron alloy layer.