Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
  • B22D11/059—Mould materials or platings

Definitions

• the present invention relates to a mold for continuous flange construction of iron and copper, for example, low carbon steel, high carbon steel, stainless copper, special steel, and the like, and more particularly, to a mold for continuous steel construction having a long life.
• the mold for continuous steelmaking is a mold that injects molten steel from the upper part and pulls out the solidified pieces from the lower part to continuously produce the steel.A long life is required from the viewpoint of productivity improvement. .
• a type described in Japanese Patent Publication No. 55-43041 has been known.
• This type II is composed of an intermediate plating layer made of at least one of (A) nickel and cobalt, and (B) 3 to 20% by weight of phosphorus on the molten steel injection surface of copper or copper alloy constituting the type III.
• An alloy coating layer consisting of at least one of boron 2 to 15% by weight and at least one of the remaining niger and cobalt is sequentially applied.
• the reason why this mold has a long life is that the use of the intermediate layer (A) makes the hardness gradient between the mold base made of copper or copper alloy having extremely low hardness and the alloy layer (B) having high hardness gentle.
• the adhesion between the ⁇ ⁇ -type substrate, the intermediate layer and the alloy layer is high. It is based on the fact that the alloy layer has a high heat resistance and a high wear resistance at high temperatures.
• the type II Japanese Patent Publication No. 52-50734
• the above-mentioned alloy layer (B) in which a chromium plating layer is further provided on the above-mentioned alloy layer (B) are oxidized.
• a fong type with an oxide film layer formed Japanese Patent Publication No. 52-50733
• the chrome-plated layer or the oxide film layer eliminates the adhesion of the molten copper splash (splash) generated at the beginning of the molten copper pouring on the mold surface, so-called breakage accident.
• Each of the type II with the above two or three layers of protective coating requires an intermediate layer consisting of at least one of nickel and cobalt, and an alloy layer is provided on the intermediate layer to form a three-layer structure.
• an alloy layer is provided on the intermediate layer to form a three-layer structure.
• a chromium plating layer or an oxide film layer is further provided, the manufacturing process is complicated and the cost is high.
• the inventor injects molten copper from the upper part and removes the piece from the lower part.
• the pull-out type ⁇ we are keen to develop a protective coating for the ⁇ -type substrate (a copper or copper alloy plate or tube constituting the inner surface of the ⁇ ) that is structurally simple and easy to manufacture.
• the nickel-boron alloy coating having a low boron content in a specific range, although having a low adhesion to the base copper or copper alloy, was considered Or, it has excellent adhesion to copper alloy and becomes an extremely excellent protective coating layer alone without using the above-mentioned conventional type I intermediate layer.
• a plating layer substantially consisting of at least one of nickel and cobalt is formed as an underlayer, and a nickel layer having a lower boron content is formed thereon. Even when a boron alloy plating layer is provided, it has been found from conventional knowledge that type III having an unexpectedly long life can be obtained. The present invention has been completed based on these findings.
• FIG. 1 is a longitudinal sectional view showing an example of a type II in which a nickel-boron alloy coating layer of the present invention is applied in a taper shape
• FIGS. 2 to 5 show nickel-boron coating layers of the present invention.
• FIG. 41 is a longitudinal sectional view showing another example of the ⁇ type.
• FIG. 6 is a longitudinal sectional view showing an example of a type III in which the underlayer of the present invention and the nickel-boron alloy plating layer are tapered.
• FIGS. 7 to 10 show the underlayer and the underlayer of the present invention. It is a longitudinal cross-sectional view which shows another example of the type
• the present invention relates to a mold for continuous steelmaking made of copper or a copper alloy, which has a nickel-boron alloy plating layer containing 0.05 to 1.5% by weight of boron on its inner surface.
• the present invention provides a steel dies for continuous steelmaking.
• the simple structure of simply providing the nickel-boron alloy-coated layer having the specific boron content on the type substrate has a similar or higher quality than the conventional type having two or three protective coatings.
• the nickel-boron alloy coating film was said to have poor adhesion to the base copper or copper alloy. If the boron content was less than 2% by weight, heat resistance and hardness were low. In order to prevent splash adhesion, it is necessary to provide a chromium plating layer on the alloy layer or oxidize the alloy layer to form an oxide film. Considering what was needed, it is extremely unexpected. Although the reason why the type I of the present invention has such a long life is not necessarily completely elucidated, the boron content
• the nickel-boron alloy layer of 0.05 to 1.5% by weight has high adhesion to the copper or copper alloy of the ⁇ -type substrate and has a similar thermal expansion coefficient to the copper or copper alloy of the substrate.
• the alloy layer has a micro Vickers hardness of about 500 to 800 HV and has excellent wear resistance at high temperatures, and the alloy layer has excellent lubricity at high temperatures.
• the alloy layer has extremely high thermal conductivity and good heat removal, so there is no large temperature gradient, and the alloy layer is not easily compatible with the molten copper and the splash is difficult to adhere. It seems to be based on such factors.
• the boron content of the alloy layer is as high as 2 to 15% by weight, and since it is extremely high in hardness, stress distortion Cracking force may be generated due to the occurrence of cracks, a low thermal conductivity and a large temperature gradient.
• the alloy plating layer of the present invention has a low possibility of such cracks, and thus has high reliability of the type III.
• the mold base constituting the mold is made of copper or a copper alloy.
• the copper alloy those conventionally used in this field can be used without any particular limitation.
• a small amount of copper particularly about 0.02 to 0.12% by weight of silver, iron, tin, zirconium, Those containing at least one element selected from phosphorus and the like are exemplified.
• Particularly preferred copper alloys include deoxidized copper containing a small amount of phosphorus in copper, and copper containing 0.1% by weight of iron, 0.04% by weight of tin, and 0.03% by weight of phosphorus. Alloys and the like.
• the specific nickel-boron alloy layer is formed on such a ⁇ -shaped substrate.
• the method is not particularly limited, and various methods can be adopted. For example, the following method is used.
• the surface of the ⁇ -type substrate is pretreated according to a conventional method.
• the pretreatment is, for example, using an iron plate as a cathode, performing electrolytic degreasing at 1 OA / dm 2 for 30 minutes, washing with water, rinsing with 50% hydrochloric acid, washing again with water, and then washing with 3% sulfamic acid. Can be performed.
• a nickel-boron alloy plating layer having the above-mentioned specific boron content is applied.
• the boron content of the alloy layer falls below 0.05% by weight, The Vickers hardness decreases, and the wear resistance and lubricity at high temperatures tend to decrease. On the other hand, if it exceeds 1.5% by weight, the coefficient of thermal expansion decreases, and the adhesion to the substrate becomes insufficient. The internal stress of the alloy film also increases along with the decrease in heat resistance and the heat removal, which tends to cause cracks.
• the boron content is preferably set to about 0.05 to 0.7% by weight from the viewpoints of abrasion resistance at high temperature, lubricity, thermal conductivity, prevention of cracking, and the like.
• the content is about 0.6 to 0.3% by weight.
• the thickness of the alloy layer can be appropriately selected from a wide range according to the purpose of use of the mold, and generally, the thickness of the alloy layer is 50 A / m2 to 50 A / m2 over the entire surface of the mold base. mm, preferably about 50 ⁇ m: U should be about 5 mm, more preferably about 100 m to 1 mm. If the thickness is less than, partial wear will occur due to operational scratches, which will affect the mold life. : May be given. Even if the thickness is 2 mm or more, further improvement in effect cannot be expected, and it is often not economical.
• the thickness of the nickel-boron alloy coating layer in the mold of the present invention is preferably about 50 ⁇ m to 2 mm in the lower half region of the mold base.
• About 50 111 to 1.511111, or preferably about 100 ⁇ m ⁇ : L mm should be within the range, it may be less than 50 / zm in the upper half area of the ⁇ -type substrate, and there is no alloy layer at all and the copper of the ⁇ -type substrate Alternatively, the alloy may be exposed. Therefore, in the present invention, as shown in FIG. 1, the rectangular substrate (1) is processed so that its thickness continuously decreases from the upper end to the lower end, and the alloy layer (2) of the present invention is further formed thereon.
• the slope of the taper can be appropriately selected from a wide range, but generally, the thickness of the alloy layer of the present invention is about 0 to L at the upper end; about L00 m, and about 150 / m to 2 mm at the lower end, preferably about It is desirable to be about 200 ⁇ m to lmm. More preferably, the tapered alloy-coated layer is formed such that the difference in thickness between the upper end and the lower end is about 500 to 1,000 m. Also, as shown in FIGS. 2 and 3, the alloy layer (2) can be applied so that the upper half region is thinner and the lower half region is thicker. Also, as shown in FIGS.
• the alloy layer (2) can be applied only to the lower half region of the ⁇ -shaped substrate.
• the thickness of the alloy layer (2) may be appropriately determined so as to be about 50 m to 2 mm in the lower half region of the ⁇ -shaped base according to the case of FIG. .
• the formation of the nickel-boron alloy plating layer can be performed by any of a conventionally used electrolytic plating method and an electroless plating method. When increasing the thickness of the alloy layer, the electrolytic plating method is advantageous.
• the above alloy layer is formed by an electroless plating method, for example,
• the bath can be used.
• the electroplating method for example,
• Surfactant 0- L.5 g ⁇ £ P H 3.0-4.0
• a plating bath with a current density of 1-3 AZ d nf can be used. Limited to these baths Instead, any plating bath capable of forming the nickel-boron alloy plating layer having the specific boron content can be used.
• the nickel-boron alloy plating layer having a thickness that changes from the upper end to the lower end of the ⁇ -type substrate is, for example, plated by tilting the plate, and then, if necessary, coating the resulting coating film as needed. It can be formed by a method such as finishing by machining.
• a plating layer substantially consisting of at least one of Nigel and Cobalt is applied on copper or copper alloy of a ⁇ -type substrate, Even when a nickel-boron alloy coating layer having a boron content of about 0.05 to 0.5% by weight, preferably about 0.050.30% by weight is successively applied on the plating layer, the spraying is also performed. It has been found that a long-life type ⁇ ⁇ ⁇ with which the shoe is not easily fixed can be obtained.
• the present invention relates to an iron-copper continuous casting type mold made of copper or an alloy, and has on its inner surface a plating layer consisting essentially of at least one of nickel and cobalt and a plating layer on the plating layer.
• Iron mesh continuous structure characterized in that a nickel-hydrogen alloy coating layer containing about 0.05 to 0.5% by weight, preferably about 0.05 to 0.30% by weight of boron is formed thereon. It also provides.
• a plating layer composed of at least one of nickel and cobalt (hereinafter referred to as an “underlayer”) has good adhesion to the above-mentioned alloy-coated layer and good adhesion to the base copper or copper alloy.
• the type III of the present invention having the underlayer and the alloy layer has a long life and also has an underlayer, so that even if the alloy layer is damaged to some extent by a physical external force, for example, It also has advantages such as being usable.
• the underlayer consisting essentially of at least one of nickel and cobalt is pretreated on the surface of the ⁇ ⁇ -type substrate in accordance with a conventional method, and then subjected to a conventional electroplating method or the like, which has been used for a long time. It can be easily formed.
• the alloy layer is exactly the same as above, and is formed by an electrolytic plating method or an electroless plating method after the formation of the underlayer.
• the thicknesses of the underlayer and the alloy layer thus applied can also be appropriately selected from a wide range as described above. In general, the thickness of the alloy layer is at least about 50 / im, and The total thickness of about 100 m to 3 mm, preferably
• the distance may be determined to be about m to 2 mm.
• the dream of the underlayer and the nickel-boron alloy plating layer is in the lower half region of the ⁇ -type substrate.
• the thickness of the nickel-boron alloy plating layer is at least about 50 m and the total thickness of the underlayer and the alloy layer is about 100 ⁇ m to 3 mm, preferably 100 ⁇ ⁇ ! 22 mm only, and may be less than 100 m in the upper half region of the ⁇ -type substrate, or ⁇ -type substrate without any underlayer and alloy layer. May be in a state where the copper or copper alloy is exposed. Therefore, in the present invention, as shown in FIG.
• the underlayer (3) and the alloy layer (2) can be formed in a tapered shape.
• the slope of the taper can be appropriately selected from a wide range, but in general, the total thickness of the underlayer and the alloy layer is Approximately 50 m to 300 m at the upper end of the register base, approximately 150 m to 2 mm at the lower end, preferably 200! ⁇ 1.5 mm is desirable.
• a base layer (3) and a metal layer (2) are formed so as to be thin in the upper half region of the rectangular body and thicker in the lower half region. You can also. Further, as shown in FIGS. 9 and 10, the underlayer (3) and the alloy layer (2) can be applied only to the lower half region of the ⁇ -shaped substrate.
• the thickness of the alloy layer (2) and the underlayer (3) should be about 50 ⁇ m or more in the lower half region of the ⁇ -type substrate. And the total thickness of the alloy layers may be determined as appropriate so as to be about 100 m to 3 mm.
• the nickel-boron alloy-coated layer alone is formed on the surface of a copper-based or copper-alloy-shaped substrate, or an undercoated layer consisting essentially of at least one of Nigel and cobalt.
• a steel mold for continuous production of steel, in which a nickel-boron alloy plating layer is sequentially formed, can be used for manufacturing slabs, blooms, billets, etc., and in each case, a long life is achieved.
• Example 1 Example 1
• a nickel-boron alloy of 0.3% by weight was applied in a tapered shape of 100 m at the upper end and 400 m at the lower end (see Fig. 1) of the ⁇ -type substrate to remove the masking.
• Nickel bromide (50%) 10 c / I
• Bath temperature 5 CTC using a nickel plating bath comprising, subjected to p H 3. 0 cathodic current density 2.30 0 thickness of the nickel plated layer of m on the entire surface by 0 AZdni 2 as an underlayer.
• the boron content A nickel-boron alloy of 0.3% by weight was tapered so as to have a thickness of 50 m at the upper end and a thickness of 200 / m at the lower end of the base. The masking was then removed.
• the type II used in this example is iron 0.1 weight, tin
• It is made of copper alloy containing 0.04% by weight and 0.03% by weight of phosphorus. Its cross section perpendicular to its longitudinal direction is rectangular, and its lower end is 40% thicker than its upper end. It is a steel for continuous blooming for blooming (diameter 6 1 2 minx 39 2, height 900 mm) composed of a ⁇ -shaped go body tapered so as to be 0 m smaller.
• the inside of the mold was filled with an electrolytic degreasing solution, subjected to electrolytic degreasing as in Example 1, rinsed with water, rinsed with 50% hydrochloric acid, rinsed with water, rinsed with 3% sulfamic acid, and pretreated. Went.
• Electroplating was performed under the conditions of a current density of 3. OA / dn, a bath temperature of 40, and a pH of 4.0 while circulating the plating bath having the composition described above.
• the nickel-containing boron alloy plating layer containing 0.06% by weight of boron was made thinner at the upper end and thicker toward the lower end. Then, the surface was finished by machining, and a tapered nickel-boron alloy coating layer having a thickness of 100 m at the upper end and 500 m at the lower end of the ⁇ -shaped substrate was provided.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Electroplating Methods And Accessories (AREA)

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• 1989
  • 1989-07-20 JP JP50792489A patent/JPH0459064B2/ja not_active Expired
  • 1989-07-20 WO PCT/JP1989/000723 patent/WO1990000945A1/ja active IP Right Grant
  • 1989-07-20 EP EP19890908510 patent/EP0383934B1/en not_active Expired - Lifetime

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