JP2005256040A - Equipment and method for manufacturing hot-dip alloyed steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide equipment and a method for manufacturing a hot-dip alloyed steel sheet which realize efficient production of multiple models in smaller lots and production of various kinds of alloy plating. <P>SOLUTION: The equipment for manufacturing the hot-dip alloyed steel sheet performs the hot-dip coating on the steel sheet by continuously passing the steel sheet in a molten metal bath, wherein a deposition means to deposit metal on a coating surface and a heating means to heat the steel sheet to alloy the coating metal with the deposited metal are successively arranged on the outlet side of the molten metal bath. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manufacturing facility for hot-dip galvanized steel sheets, and in particular, manufacture of hot-dip galvannealed steel sheets capable of (1) efficiently carrying out high-mix low-volume production and (2) producing a wide variety of alloy plating. The present invention relates to equipment and a manufacturing method.

  Hot dip plated steel is one of the steel products that has shown a quantitative expansion along with diversification of varieties. The reasons for this are (1) social demands such as resource and energy savings, (2) technological innovation and development of advanced fields in the demand industry, and (3) improvement of living standards and lifestyle changes, resulting in consumer needs. As a result of the diversification, upgrading, and multifunctionality, there has been a change in the application range of hot-dip galvanized steel sheets.

  Hot dip galvanized steel sheets have long been used as the cheapest and most reliable rust prevention method for steel because of the excellent sacrificial corrosion resistance of Zn. It is widely used in large quantities for applications such as architectural civil engineering, home appliances and automobiles. In addition, hot-dip aluminized steel sheets are used in automobile exhaust system parts, heat appliances and the like, taking advantage of heat resistance and corrosion resistance. On the other hand, many alloy plated steel sheets have been developed for the purpose of improving various properties.

  Alloyed hot-dip galvanized steel sheet is a diffusion-alloyed alloy by heating hot-dip zinc and iron in the steel, and the plating film is made of Fe-Zn alloy, which has excellent coating corrosion resistance and weldability. Used in large quantities in automobiles and automobiles.

  The hot-dip Zn-Al alloy-plated steel sheet was developed for the purpose of improving the corrosion resistance of steel materials and lowering the product cost by utilizing the features of Zn and Al simultaneously. Many of 5% Al and 55% Al are produced. 5% Al is used as a high-grade material for Zn plating by taking advantage of corrosion resistance, and 55% Al is used for applications that require heat resistance and corrosion resistance because it has an intermediate character between Zn plating and Al plating. ing. Furthermore, recently, a plated steel sheet in which Mg is added to a Zn—Al alloy has been developed. This is due to the fact that acid rain, which has become a global problem in recent years, has affected the corrosion resistance of pure Zn plating, which has been the mainstream in the past. For improvement, the addition of Al to Zn is effective, and these Zn-Al alloy platings have been extended as an alternative to Zn plating.

  The main hot-dip plated products have been described above, but the demand for required performance has been further advanced due to the upgrading and diversification of customer needs. Among them, the most important weight is high corrosion resistance. However, high paintability, high workability, high heat resistance, etc. are also mentioned. From this point of view, the types of products are increasingly diversified, and a wide variety of alloy-plated steel sheets are expected to be required.

  The production of hot dip galvanized steel sheets is carried out in a continuous process (for example, continuous galvanizing line: CGL), and the hot dip galvanized steel sheet production line has progressed in the direction of increasing size and speed with the aim of increasing the amount and reducing costs. . The current continuous hot dipping line has been speeded up, increased in capacity, saved in labor, and saved in energy by pursuing high productivity, and is suitable for mass production of small varieties. It is not necessarily suitable as a multi-product production line that produces diversified products in one line. In order to cope with the upgrading and diversification of products, it is one method to manufacture on a dedicated line that is most suitable for extracting the performance for a certain application. However, as product diversification progresses, the amount of production of a single product inevitably decreases because it is used in relatively small amounts for various applications. Therefore, it is indispensable to produce a small amount and a variety of products on one line in order to supply diversified surface-treated steel sheets.

  Conventionally, hot-dip galvanized steel sheets such as zinc, aluminum, and alloys thereof are generally manufactured as follows. That is, the steel sheet after cold rolling is subjected to surface cleaning in a pretreatment step, the surface oxide film is removed in an annealing furnace maintained in a non-oxidizing or reducing atmosphere, annealing is performed, and then cooling is performed. Then, it is cooled to about the same temperature as the molten metal bath, and molten plating metal such as zinc, aluminum, and its alloy is allowed to enter the molten molten metal bath. Thereafter, the steel plate is pulled up from the bath, and excess molten metal adhering to the surface of the steel plate is wiped away with a gas wiper.

  FIG. 1 is a schematic cross-sectional view showing the arrangement of main parts of a hot-dip plated steel sheet manufacturing facility used for manufacturing a conventional hot-dip plated steel sheet. After the material is adjusted in the annealing furnace 2, the steel plate 1 is drawn into the molten metal bath 4 held in the plating pot 4 a from the snout 3 kept in a non-oxidizing atmosphere, and passes through the sink roll 5 in the vertical direction. The excess molten metal is wiped off by the gas wiper 6. In the case of producing an alloyed hot-dip galvanized steel sheet, the zinc plated by heating in the alloying furnace 8 and the Fe of the base iron are diffusion-alloyed so that the plating film is an Fe—Zn alloy. Then, it cools to about normal temperature with the cooling device 9, is led to a post process, and becomes a product.

  As a method of manufacturing various types of alloy plating in a continuous hot dipping line, the method of replacing the plating metal without changing the pass line, the method of replacing the plating pot, and changing the pass line after the pot with two plating pots. There is a way to do it. Since the method of replacing the plating metal is performed by pumping out the molten metal with a pump, the pumping speed is slow, it takes time to adjust the plating bath composition, the operation stop time becomes long, and the problem of contamination of the bath components also arises. In addition, changing the pot and changing the pass line requires a large amount of labor and time due to structural problems of the apparatus. From the above, it can be said that the cause that hinders the high-mix low-volume production in the current continuous hot dipping line is the use of a plating pot that holds the corresponding molten metal for each type of alloy to be produced.

  On the other hand, in order to cope with such problems, the molten metal is held in a bath having an opening at the bottom for the purpose of reducing the size of the plating pot and facilitating the supply and switching of the molten plating metal. A so-called aerial pot has been developed in which a steel plate is passed from below the plate to perform plating. For example, Patent Document 1 discloses an aerial pot by circulation, and describes that a static pressure is applied to a steel plate introduction portion. Patent Document 2 discloses an aerial pot that holds molten metal by electromagnetic force and injects gas at a steel plate passage position.

The problem with the above-mentioned air pot is how to hold the molten metal so that it does not flow down from the opening at the bottom of the bath, and many of the techniques disclosed so far have focused on this point. However, as described in Patent Document 1 and Patent Document 2 described above, the technique for preventing the molten metal from flowing down by the gas pressure or electromagnetic force is based on the gas pressure depending on the height of the bath surface, the complicated flow state of the flowing molten metal, or the like. In addition to these conventional techniques, not only a sufficient control method is obtained, but also the control range is limited. In addition, the method for preventing the molten metal from flowing down by injecting the gas also has a problem of poor plating due to scattering of the molten metal or entrainment of bubbles.
JP 63-109148 A JP 63-303045 A

  Thus, it is difficult for any of the above-described prior art so-called air pots to prevent the molten metal from flowing down for a long time at a level that does not cause operational problems.

  Accordingly, an object of the present invention is to provide a hot-dip galvannealed steel sheet that can solve the above-described problems, and (1) can efficiently produce a variety of products in small quantities, and (2) can produce a wide variety of alloy plating. It is in providing the manufacturing equipment and method of this.

  The present inventors can efficiently produce a variety of products in small quantities without having a plurality of plating pots for holding molten metals having different component compositions, that is, without changing the plating pots or changing the pass line. In addition, the present inventors have intensively studied the manufacturing equipment and method for hot-dip galvannealed steel sheets capable of producing a wide variety of alloy plating.

  As a result, hot dip plating is performed in a single plating bath (pure metal or alloy), and the metal to be alloyed is supplied and adhered to the plating surface after the hot dip plating is completed, and then heated to produce the plated metal. It has been found that by alloying with the deposited metal, (1) high-mix low-volume production can be efficiently performed, and (2) a wide variety of alloy plating can be produced.

  Means of the present invention for solving the above problems are as follows.

1st invention is a manufacturing apparatus of the hot dip galvanized steel plate which carries out hot dip plating on the steel plate through a molten metal bath continuously,
An adhering means for adhering metal to the plating surface and a heating means for heating the steel plate to alloy the plated metal and the adhering metal are sequentially disposed on the outlet side of the molten metal bath. This is a production facility for hot-dip alloyed steel sheets.

2nd invention is a manufacturing apparatus of the hot dip galvanized steel plate which carries out hot dip plating of the steel plate by continuously passing a molten metal bath,
On the outlet side of the molten metal bath, a steel plate cooling means, an adhesion means for attaching metal to the plating surface, and a heating means for heating the steel plate to alloy the plated metal with the metal are sequentially disposed. This is a facility for manufacturing a hot-dip galvannealed steel sheet.

  3rd invention is the manufacturing equipment of the hot-dip galvannealed steel plate characterized by the above-mentioned attachment means being a metal-powder spraying apparatus which sprays and adheres metal powder to the plating surface in 1st or 2nd invention. is there.

  According to a fourth aspect of the present invention, in the first or second aspect of the invention, the attaching means is an electroplating apparatus that performs metal plating on the plating surface.

  5th invention is the manufacturing equipment of the hot-dip galvannealed steel plate characterized by the above-mentioned attachment means being a coating device which apply | coats metal powder to the plating surface in 1st or 2nd invention.

6th invention is the manufacturing method of the hot dip galvanized steel plate which makes a steel plate pass continuously through a molten metal bath and carries out hot dip plating on the at least one surface of a steel plate,
An adhesion step of adhering a metal having a component composition different from that of the molten metal to the plating surface of at least one surface of the steel plate that has been passed through the molten metal bath;
A heating step of heating the steel plate to alloy the plated metal and the metal deposited in the deposition step;
It is a manufacturing method of the hot-dip galvannealed steel plate characterized by having.

7th invention is the manufacturing method of the hot dip galvanized steel plate which makes a steel plate pass continuously through a molten metal bath, and carries out the hot dip plating on the at least one surface of a steel plate,
A cooling step for cooling the steel sheet that has passed through the molten metal bath;
An adhesion step of attaching a metal having a component composition different from that of the molten metal to the plating surface of at least one surface of the steel sheet after the cooling step;
A heating step of heating the steel plate to alloy the plated metal and the metal deposited in the deposition step;
It is a manufacturing method of the hot-dip galvannealed steel plate characterized by having.

  An eighth invention is the hot-dip galvannealed steel sheet according to the sixth or seventh invention, wherein in the attaching step, the metal powder having a component composition different from that of the plating metal is sprayed and attached to the plating surface. It is a manufacturing method.

  A ninth invention is the method of producing a hot dipped alloyed steel sheet according to the sixth or seventh invention, wherein the attaching step comprises electroplating a metal having a component composition different from that of the plated metal on the plating surface. is there.

  A tenth aspect of the invention is the method of manufacturing a hot-dip galvannealed steel sheet according to the sixth or seventh aspect of the invention, wherein the adhering step applies metal powder having a component composition different from that of the plated metal to the plating surface. is there.

  An eleventh aspect of the invention is the hot-dipped alloy according to the sixth aspect of the invention, wherein in the attaching step, metal powder having a component composition different from that of the plated metal is sprayed and attached to the surface of the plated metal in a molten state. It is a manufacturing method of a chemical conversion treatment steel plate.

  According to a twelfth aspect of the invention, in the tenth aspect, the attaching step includes a pressure-bonding step in which metal powder having a component composition different from that of the plating metal is sprayed onto the plating surface and then the metal powder is pressure-bonded to the plating surface. Is a method for producing a hot-dip galvannealed steel sheet.

  As described above, according to the present invention, hot dip plating is performed in a single plating bath (pure metal or alloy), and after hot dip plating is completed, the metal to be alloyed is supplied and adhered to the plating surface. Furthermore, by subsequently heating and alloying the plated metal and the deposited metal, (1) high-mix low-volume production can be efficiently performed, and (2) a wide variety of alloy plating can be manufactured. Moreover, since it is easy to change the metal species to be alloyed, high-mix low-volume production can be performed efficiently.

  Embodiments of the present invention will be described below. In the following drawings, the same parts as those shown in the already described figures are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 2 is a schematic cross-sectional view showing the main part of the manufacturing equipment for the hot-dip galvannealed steel sheet according to the embodiment of the first invention of the present invention. In FIG. 2, 7a is a metal depositing device, 8a is an alloying furnace, and 9a is a cooling device.

  FIG. 3 is a diagram illustrating a first embodiment of a metal deposition apparatus disposed in a production facility for hot-dip galvannealed steel sheets according to an embodiment of the present invention. The metal deposition apparatus according to the present embodiment is an embodiment of a metal powder spraying apparatus in which metal powder is mixed into a gas and metal powder is sprayed onto the plated steel sheet to be deposited.

  3, 10a is a metal powder supply device, 11 is a blower, 12 is a metal powder supply pipe, 13 is a metal powder return pipe, and 14 is a metal powder spray box. The metal powder is sprayed on both sides of the steel plate 1 so that the metal powder can be attached to both sides of the steel plate. The traveling direction of the steel plate 1 is the direction of the arrow in the figure.

  The metal powder is supplied from the metal powder supply device 10 a to the metal powder return pipe 13 of the blower 11, mixed with gas, pressurized by the blower blower 11, passed through the metal powder supply pipe 12, and sprayed by the metal powder spraying box 14. It feeds to the chamber 15 and is sprayed on the steel plate 1 from the slit 16 of the spraying chamber 15 to adhere to the plating surface of the steel plate 1. Excess metal powder returns to the exhaust chamber 17 from the upper and lower slits 18 of the metal powder spray box 14, passes through the metal powder return pipe 13, is pressurized again by the blower 11, and is circulated for use. In order to prevent oxidation of the metal powder, it is preferable to use nitrogen gas as the gas, but it is also possible to use air. The supply amount of the metal powder must be adjusted according to the plate width, line speed, plating adhesion amount and target alloying rate of the steel sheet, and also consider the yield (= adhesion efficiency) of the metal powder adhering to the plating surface. It needs to be adjusted.

  As the metal powder, one produced by a physical pulverization method, a liquid phase method, a gas phase method, or the like can be used. The particle diameter of the metal powder is the same after classification. The metal powder having an average particle diameter of 0.01 μm to 200 μm is used. The smaller the average particle size, the easier it is to adjust the alloying rate. On the other hand, if the average particle diameter exceeds 200 μm, the alloying rate may be uneven, which is not preferable. In addition, an alloying rate is a content rate of the metal powder contained in a plating metal.

  When the metal spraying device 7c of FIG. 3 is disposed in the facility of FIG. 2, the metal powder spraying box 14 is disposed so that the traveling direction of the steel plate 1 is in the vertical direction. To spray metal powder onto the surface of the plated metal.

  The alloying furnace 8a heats the steel sheet to alloy the hot-plated metal and the metal deposited by the metal deposition apparatus 7a. The heating condition of the alloying furnace 8a is adjusted by the hot-dip metal species and their adhesion amount, the deposited metal species and their adhesion amount, and the alloying rate. The heating method of the alloying furnace 8a is not particularly limited. A known apparatus such as a gas heating furnace or a high-frequency induction heating furnace can be employed, but a high-frequency induction heating furnace is advantageous in terms of controllability of the alloying rate.

  The cooling device 9a cools the alloyed steel sheet to a temperature of about room temperature. A known cooling device such as an air cooling device that blows air on the surface of the steel plate to cool it can be employed.

  When the metal spraying device 7c of FIG. 3 is installed in the facility of FIG. 2, an alloyed hot dip galvanized steel sheet is manufactured as follows. After the material is adjusted in the annealing furnace 2, the steel plate 1 is drawn into the molten metal bath 4 from the snout 3 kept in a non-oxidizing atmosphere, pulled up in the vertical direction through the sink roll 5, and hot-dip plated. Excess molten metal is wiped off by the gas wiper 6 and adjusted to a predetermined plating adhesion amount. Immediately after that, the metal to be alloyed is adhered to the surface of the plated metal in the molten state by the metal deposition apparatus 7a, and further, the steel sheet is heated in the alloying furnace 8a to adhere to the molten plated metal. And are alloyed. The form of alloying of the plating film is not limited to the case where all of the adhered metal and the plated metal are alloyed, but also part of the adhered metal is alloyed with the plated metal, and part of the adhered metal is dispersed in the film. It may be alloyed or the deposited metal may be alloyed in layers in the film. Then, it cools to about normal temperature with the cooling device 9a, and after it winds up in a coil shape, or before it winds up in a coil shape, it performs a temper rolling or a post-treatment to form a chemical conversion treatment / lubricating film, etc. After a subsequent process, a required product (hot-dip alloyed steel sheet) is obtained.

  FIG. 4 is a diagram for explaining a second embodiment of the metal deposition apparatus disposed in the manufacturing facility for the hot dip alloyed steel sheet according to the embodiment of the present invention. Another embodiment of the metal spraying apparatus which sprays and adheres metal powder to a plated steel plate is shown. The metal spraying device 7d according to the present embodiment projects and attaches metal powder onto the plated steel sheet.

  In FIG. 4, (a) is a schematic diagram for explaining the structure of the metal spraying device 7d, and the metal spraying device 7d includes metal powder projecting devices 21a and 21b that project the metal powder facing the upper and lower surfaces of the steel plate. . FIG. 4B is a schematic diagram for explaining the structure of a metal powder projection device 21a that projects metal powder onto the upper surface of the steel sheet, 10b is a metal powder supply device, 22 is a motor, and 23 is a centrifugal rotor. The metal powder 24 is supplied from the metal powder supply apparatus 10b, the centrifugal rotor 23 is rotated by the motor 22, and the supplied metal powder 24 is projected onto the upper surface of the steel plate 1 to adhere the metal powder to the plating surface. The metal powder projection device 21b that projects metal powder onto the lower surface of the steel plate has the same configuration, and projects the metal powder onto the lower surface of the metal surface to adhere the metal powder to the plating surface.

  As the metal powder, one produced by a physical pulverization method, a liquid phase method, a gas phase method, or the like can be used. The particle diameter of the metal powder is the same after classification. When projecting metal powder, it is necessary to make the average particle diameter of metal powder 10-300 micrometers. This is because, if the average particle diameter is less than 10 μm, the speed of the projected metal powder decreases in the air, and therefore, it cannot be adhered unless the projection speed is made very high. On the other hand, when the average particle diameter exceeds 300 μm, it is difficult to adjust the alloying rate. Further, the projection speed of the metal powder needs to be 30 m / sec or more. This is because if the projection speed is less than 30 m / s, sufficient kinetic energy is not imparted to attach the metal powder to the plating surface. From this point of view, the upper limit of the projection speed is not particularly set, but if the projection speed is high, the metal powder kinetic energy becomes excessive and may damage the plating film. The supply amount of the metal powder needs to be adjusted according to the plate width, the line speed, the plating adhesion amount, and the target alloying rate, and the yield of the powder adhering to the plating surface (= adhesion efficiency) needs to be considered.

  When the metal spraying device 7d shown in FIG. 4 is installed in the facility shown in FIG. 2, the metal spraying device 7d is used to spray metal powder onto the surface of the plated metal in the molten state so that the metal powder adheres to the surface of the plated metal. In addition, the steel sheet is heated in the alloying furnace 8a to alloy the hot-plated metal with the adhered metal, and the hot-dip alloyed steel sheet is manufactured by cooling to a room temperature with the cooling device 9a. it can.

  FIG. 5 is a schematic cross-sectional view showing the main part of the manufacturing equipment for the hot-dip galvannealed steel sheet according to the second embodiment of the present invention. In FIG. 5, 7b is a metal depositing device, 8b is an alloying furnace, and 9b and 9c are cooling devices. The alloying furnace 8b heats the steel plate 1 to alloy the hot-plated metal and the metal deposited by the metal deposition apparatus 7b. The heating method is not particularly limited. A known apparatus such as a gas heating furnace or a high-frequency induction heating furnace can be employed, but a high-frequency induction heating furnace is advantageous in terms of controllability of the alloying rate. The cooling devices 9b and 9c each cool the steel plate to a temperature of about room temperature. A known cooling device such as an air cooling device that blows air on the surface of the steel plate to cool it can be employed.

  5 can use the metal spraying apparatus shown in FIGS. 3 and 4 described above.

  When the metal spraying device 7c device of FIG. 3 is disposed in the facility of FIG. 5, the metal powder spraying box 14 is disposed such that the traveling direction of the steel plate 1 is in the horizontal direction. When the metal deposition apparatus of FIG. 3 is arranged in the facility of FIG. 5, a hot-dip galvannealed steel sheet is manufactured as follows. After the material is adjusted in the annealing furnace 2, the steel plate 1 is drawn into the molten metal bath 4 from the snout 3 kept in a non-oxidizing atmosphere, pulled up in the vertical direction through the sink roll 5, and hot-dip plated. Excess molten metal is wiped off by the gas wiper 6 and adjusted to a predetermined plating adhesion amount. Then, after cooling to room temperature by the cooling device 9b, the metal adhering device 7b sprays and attaches the metal to be alloyed to the plating surface, and further reheats the steel sheet in the alloying furnace 8b, thereby hot dipping. The metal and the deposited metal are alloyed. The alloying of the hot-plated metal and the deposited metal may be either alloying by solid phase diffusion or alloying by solid-liquid diffusion by melting the plating metal. Then, it cools to about normal temperature with the cooling device 9c, is led to a post process, and becomes a required product (hot-dip alloyed steel sheet).

  When the apparatus of FIG. 4 is arranged in the facility of FIG. 5, as shown in FIG. 4, the metal adhering apparatus 7d is arranged so that the traveling direction of the steel sheet 1 is horizontal. When the metal adhesion apparatus of FIG. 4 is arranged in the facility of FIG. 5, the metal powder is projected onto the plated metal surface by projecting the metal powder onto the surface of the plated steel sheet cooled to about room temperature by using the metal adhesion apparatus. In the same manner as described above, an galvannealed steel sheet can be produced.

  3 and 4, the metal powder is configured to adhere to both surfaces of the steel plate 1, but if necessary, the metal powder may be configured to adhere to only one surface of the steel plate. May be.

  FIG. 6 is a diagram for explaining a third embodiment of the metal deposition apparatus disposed in the production facility for the hot dip alloyed steel sheet according to the embodiment of the present invention. The present embodiment is a schematic cross-sectional view showing an embodiment when the metal deposition apparatus is an electroplating apparatus. In FIG. 6, the electroplating device 7 e includes a pretreatment device 31, a plating device 32, and a water washing and drying device 33.

  The pretreatment device 31, the plating device 32, and the water washing / drying device 33 may be devices generally used in electroplating of steel plates. For example, the pretreatment device 31 may be an alkaline degreasing device, and if necessary, a washing device, a pickling and pickling device, and a washing scrubber may be sequentially arranged after the alkaline degreasing device. The plating device 32 may be a normal electroplating device, and the water washing and drying device 33 may be a surface adjustment device or a hot water washing device for neutralizing the electroplating solution.

  The metal deposition apparatus (electroplating apparatus 7e) of FIG. 6 is disposed in the hot dip alloyed steel sheet manufacturing facility of FIG. 5, and manufactures the hot dip alloyed steel sheet as follows. The plated steel sheet that has been subjected to molten metal plating and cooled to about room temperature by the cooling device 9 b is pretreated by the pretreatment device 31, electroplated with the metal to be alloyed by the plating device 32, and washed and dried by the water washing and drying device 33. . Next, the steel sheet is heated in the alloying furnace 8b to alloy the hot-plated metal and the deposited metal, and is cooled to about room temperature by the cooling device 9c.

  FIG. 7 is a diagram for explaining a fourth embodiment of a metal deposition apparatus arranged in a manufacturing facility for hot-dip galvannealed steel sheets according to an embodiment of the present invention. The present embodiment is a schematic cross-sectional view showing one embodiment when the metal deposition apparatus is a coating apparatus that applies metal powder to be alloyed to a plated metal surface.

  In FIG. 7, the coating device 7 f includes a powder coating device 41, a drying device 42, and a pressure bonding device 43.

  The powder coating apparatus 41 should just be what can apply | coat the slurry of a metal powder to the plated steel plate surface. A known coating apparatus used for slurry application, such as a curtain coater, a roll coater, or a spray coater, can be used. The drying device 42 is preferably a high-frequency induction heating device, and a known drying device (hot air drying furnace, baking furnace) can be used. The crimping device 43 can use a rolling roll.

  The metal powder to be alloyed is supplied as a slurry. As the metal powder, the same metal powder as that used in the apparatus shown in FIGS. 3 and 4 can be used. The metal deposition apparatus (powder coating apparatus 7f) in FIG. 7 is arranged in the hot dip alloyed steel sheet manufacturing facility in FIG. 5 and manufactures the hot dip alloyed steel sheet as follows. The steel plate is subjected to molten metal plating and cooled to about room temperature by the cooling device 9b. The slurry in which the metal powder to be alloyed is mixed is applied to the surface of the plated steel sheet cooled to about room temperature by using the powder application device 41, and is heated and dried by the drying device 42 to adhere the metal powder to the plating surface. Next, the plated steel sheet to which the metal powder is adhered is rolled using the crimping device 43 to crimp the metal powder to the plating surface. The crimping device 43 is used as necessary. Next, the steel sheet is heated in the alloying furnace 8b to alloy the hot-plated metal and the deposited metal, and is cooled to about room temperature by the cooling device 9c. When slurry-like metal powder is applied by an application device such as a roll coater, the slurry made of metal powder, water, and a small amount of a reaction inhibitor needs to appropriately adjust the content and particle size of the metal powder. That is, the viscosity of the slurry needs to be 200 cp or more when applied by a roll coater.

  The powder coating apparatus 41 may use an electrostatic coating apparatus that electrostatically attaches the dried metal powder to the steel plate. When using an electrostatic coating apparatus, for example, a metal powder is introduced into a chamber by a gas jet ejected from a nozzle, charged by corona discharge generated in the chamber, and electrostatically attached to a grounded steel sheet. Since the dry method does not include water as in the case of using a slurry, the drying device 42 may not be provided.

  The present invention can be variously modified without being limited to the above embodiment.

  In the present invention, various metals or alloys can be used as the hot-dip plated metal as a base, and various types of metals can be obtained by appropriately selecting a metal species to be deposited and alloying the plated metal and the deposited metal. A variety of alloy plating can be produced.

  For example, for example, when producing a hot dip galvanized steel sheet, an alloyed hot dip galvanized steel sheet (hot Fe-Zn alloy plated steel sheet), 5% Al-Zn alloy plated steel sheet and 55% Al-Zn alloy plated steel sheet, Hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets are manufactured using hot-dip zinc baths with different Al concentrations, and 5% Al—Zn alloy plated steel sheets and 55% Al—Zn alloy plated steel sheets Since it is manufactured using a molten metal bath having a corresponding component composition, it has been problematic in terms of cost and productivity to manufacture these products with one steel plate manufacturing facility.

  According to the present invention, when zinc is selected as the hot-dip plating metal and iron is selected as the metal to be deposited, the Fe—Zn alloy plating with different iron content in the film is controlled by controlling the amount of iron to be deposited. Can be easily manufactured. In addition, when zinc is selected as the hot dip metal and aluminum is selected as the metal to be deposited, Zn-Al alloy plating with different aluminum content in the film, for example 5 % Al—Zn alloy plating, 22% Al—Zn alloy plating (superplastic alloy plating), and 55% Al—Zn alloy plating can be easily produced.

  Conversely, when aluminum is selected as the hot-dip plating metal and zinc is selected as the metal to be deposited, by controlling the amount of zinc to be deposited, Zn-Al alloy plating with different aluminum content in the film, For example, 5% Al—Zn alloy plating, 22% Al—Zn alloy plating (superplastic alloy plating), and 55% Al—Zn alloy plating can be easily manufactured.

  In addition, not only a single metal but also two or more kinds of metals can be blended as the metal to be deposited, so that a wide variety of alloy plating can be manufactured. For example, it is possible to manufacture a wide variety of alloy plating by selecting zinc as the hot dip plating metal and mixing other elements such as magnesium and silicon with aluminum as the metal to be deposited.

  On the other hand, not only a single metal but also various alloys can be used as the hot dipped metal. That is, pure metals include zinc, aluminum, lead, etc., and alloys include Al—Zn alloys (5% Al—Zn alloy plating, 22% Al—Zn alloy plating (superplastic alloy plating), 55% Al—Zn. Alloy plating), Sn—Zn alloy, Pb—Zn alloy, and the like can be used.

  In the present invention, the steel plate to be plated may be not only a cold rolled steel plate but also a descaled hot rolled steel plate.

  In the present invention, the plating method of the hot dip metal may be a known method. The hot dipping equipment is not limited. The present invention can also be applied to all continuous hot-dip plating equipment such as all-reduction-type hot-dip continuous hot-dip plating equipment and direct fire heating-type hot-dip continuous hot-dip plating equipment.

  As is clear from the above description, according to the present invention, it is possible to efficiently produce a small amount of various types of plated steel sheets. Moreover, it can respond easily to manufacture of a wide variety of alloy-plated steel sheets.

Hereinafter, a production example of the Fe—Zn alloyed steel sheet will be described.
Three types of steel plates (plating original plates) with different component compositions were prepared. The prepared steel sheet is a cold-rolled steel sheet with a thickness of 0.8 mm, a general-purpose low-carbon Al-killed steel (= material A), and extremely low-carbon Ti that is prone to powdering when alloyed by conventional methods for high processing. An additive steel (material B) and a high-tensile steel (material C) having a low alloying speed when alloyed by a conventional method. The component composition of each steel sheet is shown in Table 1 (the balance is Fe and inevitable impurities).

  The prepared steel sheet is charged into a continuous hot-dip plating facility equipped with a non-oxidation furnace and a reduction heating furnace, annealed and hot-dip galvanized, and after depositing Fe on the plating surface in the metal adhesion process, alloying The hot-dip galvanized layer and Fe were alloyed by heating in the treatment step, and the hot-dip galvannealed steel sheet of the present invention example was produced. At that time, hot dip galvanizing conditions, Fe adhesion conditions, and alloying treatment conditions were changed.

  In the example of the present invention, an alloying reaction between the hot dip galvanized film and Fe deposited in the metal adhering step is caused, so that the hot galvanized film and the base steel plate need not be alloyed. Therefore, in order to suppress the alloying reaction between the hot dip galvanized film and the underlying steel plate, plating with an Al concentration of 0.20% used when producing a normal hot dip galvanized steel plate that is not subjected to alloying treatment after hot dip galvanizing. Hot dip galvanization was performed in a bath.

The coating weight is 50 g / m ² , which is the basis weight of a normal alloyed hot-dip galvanized steel sheet, and is 100 g / m ² , 150 g for the purpose of improving the corrosion resistance. / M ² was adjusted.

Fe adhesion to the plating surface is (1) Fe powder spraying with gas (Fig. 3), (2) Fe powder spraying with projection (Fig. 4), (3) Electric Fe plating (Fig. 6), (4) Slurry coating ( This was carried out by any one of the methods shown in FIG. Each condition is described below.
(1) Fe powder spraying with gas (test materials No. 1 to 20)
Average particle size: 0.1 μm, 1 μm
-Flow rate (injection port): 300-1000 g / min, nitrogen gas spraying (2) Fe powder spraying by projection (test materials No. 21-25)
-Average powder particle size: 10 μm
-Projection speed (projection port): 100 m / s
・ Projection distance: 500mm
Projection amount: 7.5 to 30 g / m ²
(3) Electrical Zn-Fe plating (test material No. 26-30)
Plating solution: ferrous sulfate (150 to 200 g / l), zinc sulfate (30 to 200 g / l),
Plating bath pH 1.5,
Plating conditions: bath temperature 50 ° C., current density 20-100 A / dm ²
(4) Slurry coating method (test materials No. 31 to 36)
-Slurry: Metal Fe powder (average powder particle size 1 μm) dispersed in water, metal Fe powder amount 100 g / l
-Application drying with a roll coater An induction heating furnace was used for the alloying treatment, and the cooling after the alloying treatment was air-cooled.

  Tables 2 to 5 show hot dip galvanizing conditions, Fe adhesion conditions, and alloying conditions.

  For comparison, the production conditions of the galvannealed steel sheet produced by a normal method (conventional method) are shown in Tables 2 to 5 as comparative examples.

The cross section of the plating film of the hot-dip galvannealed steel sheet produced above was observed with an SEM, and the alloyed state of the plating film was classified as follows.
A: A state in which all of the adhered metal and the plated metal are alloyed.
B: A state in which a part of the adhered metal is alloyed with the plating metal.
C: A state in which the adhered metal is dispersed in the film and partly alloyed.
D: State in which the adhered metal is alloyed in layers in the film.

Moreover, the characteristic of the produced hot-dip galvannealed steel plate was evaluated as follows.
(1) Powdering resistance The evaluation of the powdering resistance is carried out by performing a draw bead test and measuring the film peeling amount per unit area. When the film peeling amount is less than 5 g / m ² , “very good: ◎”, 5 g / m ² or more and less than 10 g / m ^{2 was} evaluated as “good: ◯”, 10 g / m ² or more and less than 15 g / m ² as “ordinary: Δ”, and 15 g / m ² or more as “inferior: x”.
Here, the draw bead test is a test in which a steel plate coated with lubricating oil is pulled out in a state of being sandwiched between a bead and a die, and then a tape peeling test is performed, and the amount of peeling of the plating film is evaluated from the weight difference before and after the test. Is the method. The bead was a triangular bead with a tip angle of 90 °, the molding height was 4 mm, and the pressing load between the bead and the die was 500 kgf.

(2) Corrosion resistance Corrosion resistance was evaluated by the corrosion resistance after electrodeposition coating. That is, after performing a phosphate treatment (PBL-3080 manufactured by Nihon Parkerizing Co., Ltd.), coating with a film thickness of 20 μm was performed under normal electrodeposition coating conditions using an electrodeposition coating Electron GT-10 manufactured by Kansai Paint Co., Ltd. . Thereafter, it was subjected to a combined corrosion cycle test (CCT). The test conditions were the vehicle material corrosion test method (JASO M 609-91) established by the Automotive Engineers Association, and the state of rust generation after 30 cycles was observed. The evaluation criteria are as follows.
A: Swelling minimum (very good). ○: Small swelling (good). Δ: Small swelling and red rust occurred (normal). X: Large swelling and red rust occurred.

(3) Electrodeposition paintability The electrodeposition paintability is obtained by applying a phosphate treatment (PBL-3080, manufactured by Nihon Parkerizing Co., Ltd.) to a 70 x 150 mm test piece, and then applying an electrodeposition paint Electron GT-10 manufactured by Kansai Paint Co., Ltd. The electrodeposition coating was performed, and the degree of occurrence of electrodeposition coating defects was visually evaluated. In the electrodeposition coating, a paint used for about three months was used as the electrodeposition paint so that craters are likely to occur unlike normal conditions. Coating was performed at an electrodeposition temperature of 30 ° C. and a voltage of 280V. The evaluation criteria are as follows.
A: No occurrence of crater defects (very good). ○: No more than 5 occurrences of crater defects (good). (Triangle | delta): 6-20 or less crater-like defect generation | occurrence | production (normal). X: Many crater-like defects are generated (inferior). The number of occurrences of crater-like defects is the number of occurrences per test piece.

  The observation results of the state of the alloy layer and the evaluation results of the properties are shown in Tables 2 to 5.

  In the examples of the present invention, a film having good or very good powdering resistance was obtained. Test material No. aimed at thickening. In the case of 11 to 25 or 31 to 35, a film having better or very good corrosion resistance was obtained. Moreover, since alloying is performed from the surface of the plating film, the outermost surface of the film has a high Fe content, and thus the paintability is good. Further, test materials No. 1 aiming at high Fe content were used. In 5, 10, 15, 20, 25, 30, and 35, the paintability was very good.

In the case where the high-tensile steel (material C) is the base steel plate, the test method No. is used in the conventional method (comparative example). 37, an alloying treatment at a high temperature was required and the powdering resistance was inferior. As shown in 6 to 10, good powdering resistance was exhibited. Further, when high-tensile steel (material C) is used as the base steel plate and the plating amount is set to 100 g / m ² aiming at thickening, in the conventional method, the test material No. As shown in FIG. 38, the alloy is not alloyed. As shown in 16-20, it was easily alloyable.

  Further, in the conventional method, the test material No. is used in the plating bath having an Al concentration of 0.20% in the bath. As shown in 40, since the plating film is not alloyed, when producing alloyed hot dip galvanizing, the Al concentration in the bath must be lowered to 0.12%. Therefore, when producing hot-dip galvanized steel sheet and alloyed hot-dip galvanized steel sheet that are not alloyed in the same equipment, the former has an Al concentration in the bath of 0.20%, and the latter has an Al concentration of 0.12% in the bath and Al in the bath. It is necessary to change the concentration, which causes production loss.

  On the other hand, in the method of the present invention, since plating can be performed using the same plating bath with Al concentration in the bath as that not subjected to alloying treatment, production loss due to change in Al concentration in the bath does not occur. In addition, by performing the metal deposition in the metal deposition process and stopping it, it becomes possible to easily and easily make both the above products without switching loss.

  In the present invention, after the metal (Fe) to be alloyed is adhered, the Fe and the plating film are alloyed. At this time, an alloying reaction with the base steel plate may be caused, and therefore a normal alloy is used. A plating bath having an Al concentration (for example, about 0.12% Al) in the bath used when producing the hot dip galvanized steel sheet may be used.

  In the conventional method, the alloying rate of the galvannealed steel sheet was adjusted by changing the output of the alloying furnace. However, the difference in the steel type and plating conditions (Al concentration in the bath) caused the alloying reaction. Therefore, it takes a long time to adjust to a predetermined Fe%, so that a yield loss due to poor alloying occurs. According to the method of the present invention, by adjusting the amount of Fe to be adhered, it becomes possible to easily and easily form a desired Fe% plating film instantly.

  In this example, a continuous hot dip plating facility equipped with a non-oxidation furnace and a reduction heating furnace was used. However, the present invention is not limited to this plating equipment. Any continuous hot dipping equipment such as plating equipment can be used.

  The steel plate having the component composition of material A shown in Table 1 of Example 1 is placed in a continuous hot-dip plating facility equipped with a non-oxidation furnace and a reduction heating furnace, and is subjected to annealing and hot-metal plating, and further plating is performed in a metal adhesion process. A metal having a composition different from that of the molten metal plating seed was adhered to the surface, and then heated in the alloying process to alloy the molten metal plating layer and the metal deposited in the metal adhesion process.

  The hot-dip metal plating includes 0.2% Al—Zn bath, 5% Al—Zn plating (Galfan), 55% Al—Zn plating (Galbalium), and 91% Al used when manufacturing a normal hot-dip galvanized steel sheet. -9% Si (Al plating) bath is used, and after depositing a metal with a component composition different from the molten metal plating type in the metal adhesion step, the plated steel sheet is heated and adhered in the molten metal plating and metal adhesion step. Metal alloying treatment was performed.

  The metal adhesion to the plating surface was performed by any one of (1) metal powder spraying with gas, (2) metal powder spraying with projection, (3) electrometal plating, and (4) slurry coating. Each condition is described below.

(1) Metal powder spraying with gas (test materials No. 41 to 54)
Metal powder: Al, Mg, Ni, Si, Mn, Cu, Cr, Co, Mo, Sn, V, W
・ Average powder particle size: 1μm
-Flow rate (injection port): 300-1000 g / min, nitrogen gas spraying (2) Metal powder spraying by projection (test material No. 55-68)
Metal powder: Al, Mg, Ni, Si, Mn, Cu, Cr, Co, Mo, Sn, V, W
-Average powder particle size: 10 μm
-Projection speed (projection port): 100 m / s
・ Projection distance: 500mm
Projection amount: 7.5 to 30 g / m ²
(3) Electroplating (test material Nos. 69 to 74)
・ Plating metal: Ni, Cu, Co, Zn
・ Plating solution:
In the case of single metal plating MeSO ₄ · 7 (5) H ₂ O: 350 g / L + additive In the case of zinc alloy plating MeSO ₄ · 7 (5) H ₂ O: 350 g / L + zinc sulfate (30 to 200 g / L) + Additive However, Me is Ni, Cu, Co, Zn. Copper sulfate is pentahydrate.
・ Plating bath pH: 1.5
Plating conditions: bath temperature 50 ° C., current density 20-100 A / dm ²
(4) Slurry coating method (test material No. 75 to 78)
Metal powder: Al, Mg, Ni, Si, Mn, Cu, Cr, Co, Mo, Sn, V, W, Zn
-Slurry: Metal powder (average powder particle size: 1 μm) dispersed in water, metal powder amount 100 g / l
-Application drying with a roll coater An induction heating furnace was used for the alloying treatment, and the cooling after the alloying treatment was air-cooled.

  Tables 6 and 7 show the hot dipping conditions, the conditions for the metal adhesion process, and the alloying treatment conditions.

The cross section of the plating film of the hot-dip galvannealed steel sheet produced above was observed with an SEM, and the alloyed state of the plating film was classified as follows.
A: A state in which all of the adhered metal and the plated metal are alloyed.
B: A state in which a part of the adhered metal is alloyed with the plating metal.
C: A state in which the adhered metal is dispersed in the film and partly alloyed.
D: State in which the adhered metal is alloyed in layers in the film.

  Tables 6 and 7 show the observation results of the state of the alloy layer.

  According to the method of the present invention, it is possible to easily make an alloy plating film having a desired component composition by adjusting the kind and amount of a metal to be deposited with respect to a plating metal to be hot-plated.

  The steel plate production facility of the present invention can be used as a facility for efficiently producing a small amount of various types of plated steel plates, and can also be used as a facility for producing a wide variety of alloy-plated steel plates.

  The method for producing a steel sheet of the present invention can be used as a method for efficiently producing a small quantity of various types of plated steel sheets, and can also be used as a method for producing a wide variety of alloy-plated steel sheets.

It is a schematic sectional drawing which shows the principal part arrangement | positioning of the hot dip galvanized steel plate manufacturing equipment used for manufacture of the conventional hot dip galvanized steel plate. It is a schematic sectional drawing which shows the principal part of the manufacturing equipment of the hot dip alloying steel plate which concerns on embodiment of 1st invention of this invention. It is a figure explaining 1st Embodiment of the metal adhering apparatus arrange | positioned at the manufacturing equipment of the hot dip alloying steel plate which concerns on embodiment of this invention. It is a figure explaining 2nd Embodiment of the metal adhesion apparatus arrange | positioned at the manufacturing equipment of the hot dip alloying steel plate which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the manufacturing equipment of the hot dip alloying steel plate which concerns on embodiment of 2nd invention of this invention. It is a figure explaining 3rd Embodiment of the metal adhesion apparatus arrange | positioned at the manufacturing equipment of the hot dip alloying steel plate which concerns on embodiment of this invention. It is a figure explaining 4th Embodiment of the metal adhesion apparatus arrange | positioned at the manufacturing equipment of the hot dip alloying treatment steel plate which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel plate 2 Annealing furnace 3 Snout 4 Molten metal bath 4a Plating pot 5 Sink roll 6 Gas wiper 7a, 7b Metal adhesion apparatus 7c, 7d Metal powder spraying apparatus 7e Electroplating apparatus 7f Coating apparatus 8, 8a, 8b Alloying furnace 9, 9a, 9b, 9c Cooling device 10a, 10b (metal powder supply device)
DESCRIPTION OF SYMBOLS 11 Blower 12 Metal powder supply pipe 13 Metal powder return pipe 14 Metal powder spray box 15 Spray chamber 16 Slit 17 Exhaust chamber 18 Slit 21a, 21b Metal powder projection apparatus 22 Motor 23 Centrifugal rotor 24 Metal powder 31 Pretreatment apparatus 32 Plating apparatus 33 Washing and drying equipment 41 Powder coating equipment 42 Drying equipment 43 Crimping equipment

Claims (12)

In the manufacturing apparatus of the hot dip galvanized steel sheet, which continuously passes the molten metal bath and galvanizes the steel sheet,
An adhering means for adhering metal to the plating surface and a heating means for heating the steel plate to alloy the plated metal and the adhering metal are sequentially disposed on the outlet side of the molten metal bath. Production equipment for hot dip alloyed steel sheets. In the manufacturing apparatus of the hot dip galvanized steel sheet, which continuously passes the molten metal bath and galvanizes the steel sheet,
On the outlet side of the molten metal bath, a steel plate cooling means, an adhesion means for attaching metal to the plating surface, and a heating means for heating the steel plate to alloy the plated metal with the metal are sequentially disposed. Manufacturing equipment for hot-dip galvannealed steel sheets. The said adhesion | attachment means is a metal powder spraying apparatus which sprays and adheres metal powder on the plating surface, The manufacturing apparatus of the hot dip alloying treatment steel plate of Claim 1 or 2 characterized by the above-mentioned. The said attachment means is an electroplating apparatus which metal-plates on the plating surface, The manufacturing equipment of the hot-dip galvannealed steel plate of Claim 1 or 2 characterized by the above-mentioned. The said adhesion | attachment means is a coating device which apply | coats a metal powder to the plating surface, The manufacturing equipment of the hot-dip galvannealed steel plate of Claim 1 or 2 characterized by the above-mentioned. In the manufacturing method of a hot-dip galvanized steel sheet, in which the steel sheet is continuously passed through a molten metal bath and hot-plated on at least one surface of the steel sheet,
An adhesion step of adhering a metal having a component composition different from that of the molten metal to the plating surface of at least one surface of the steel plate that has been passed through the molten metal bath;
A heating step of heating the steel plate to alloy the plated metal and the metal deposited in the deposition step;
A method for producing a hot-dip galvannealed steel sheet, comprising: In the manufacturing method of a hot-dip galvanized steel sheet, in which the steel sheet is continuously passed through a molten metal bath and hot-plated on at least one surface of the steel sheet,
A cooling step for cooling the steel sheet that has passed through the molten metal bath;
An adhesion step of attaching a metal having a component composition different from that of the molten metal to the plating surface of at least one surface of the steel sheet after the cooling step;
A heating step of heating the steel plate to alloy the plated metal and the metal deposited in the deposition step;
A method for producing a hot-dip galvannealed steel sheet, comprising: The method for producing a hot-dip galvannealed steel sheet according to claim 6 or 7, wherein in the attaching step, metal powder having a component composition different from that of the plated metal is sprayed onto the plating surface. The method for producing a hot-dip galvannealed steel sheet according to claim 6 or 7, wherein in the attaching step, a metal having a component composition different from that of the plated metal is electroplated on a plated surface. The method for producing a hot-dip galvannealed steel sheet according to claim 6 or 7, wherein in the attaching step, a metal powder having a component composition different from that of the plating metal is applied to a plating surface. The said adhesion process sprays and adheres the metal powder of a component composition different from the said plated metal with respect to the plated metal surface in a molten state, The hot-dip plated alloyed steel plate of Claim 6 characterized by the above-mentioned. Production method. The said adhesion process has a crimping | compression-bonding process which crimps | bonds a metal powder to the plating surface, after spraying and adhering the metal powder of a component composition different from the said plating metal to the plating surface. Method for producing a hot-dip galvannealed steel sheet.

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