Specification
Title of the invention: Solution composition for surface treatment of steel sheet containing trivalent chromium, and method for manufacturing hot-dip galvanized steel sheet and hot-dip galvanized steel sheet surface-treated using the same
Technical field
[One]
The present invention relates to a surface treatment solution composition containing a trivalent chromium compound, an alloyed galvanized steel sheet surface-treated using the composition, and a method of manufacturing the same.
Background
[2]
The hot-dip plated material on which the alloyed zinc (Zn) plated layer is formed not only exhibits excellent corrosion resistance by the protection effect of the base iron by the sacrificial method, but also has excellent welding characteristics compared to the pure zinc plated layer due to the zinc-iron alloy phase. It is widely used as a material for automobile parts such as cycle and passenger car fuel tanks.
[3]
However, the alloyed hot dip galvanizing material has an exposed surface of zinc and zinc-iron alloy, so when exposed to a general corrosive environment, especially, a wet atmosphere, white rust, which is a zinc oxide, is easily generated on the surface, resulting in poor quality characteristics of the material. Fall out. In addition, when the alloyed molten zinc plating material is exposed to a high-temperature, high-humidity environment, there is a problem that a blackening phenomenon in which the surface color changes to black easily occurs.
[4]
In order to solve this problem, in the past, corrosion resistance and blackening resistance have been secured by performing a hexavalent chromate treatment on an alloyed hot dip galvanized steel sheet. However, as such hexavalent chromium is designated as a hazardous environmental substance, regulations on the use of hexavalent chromium are strengthened, and the use thereof is restricted. Moreover, when hexavalent chromium is used as a surface treatment agent for a hot-dip galvanized steel sheet, there has been a problem of a defect in which the surface of the steel sheet turns black or black spots occur. In addition, in the case of products that require high corrosion resistance and fuel resistance characteristics, such as a fuel tank steel plate for automobiles, when exposed to a more severe corrosive environment by fuel and condensate inside the fuel, the corrosion prevention effect is insufficient, and the vehicle stops while the vehicle is running. It is causing serious problems such as.
[5]
Recently, in order to solve the environmental hazard of hexavalent chromium, a method of securing corrosion resistance and blackening resistance of a galvanized steel sheet by coating a surface treatment solution composition containing trivalent chromium on a steel sheet has been applied. For example, in Korean Patent Application Publication Nos. 2006-0123628, 2005-0052215 and 2010-0106031, corrosion resistance and blackening are secured by immersing a steel sheet in a composition containing trivalent chromium and chemically treating it. The immersion time is long to be applied, and the chemical conversion method has problems such as lowering of fingerprint resistance.
[6]
In addition, in Korean Patent Publication No. 10-2004-0046347 and Japanese Patent Publication No. 2002-069660, a composition containing trivalent chromium is coated on a plated steel sheet by spraying or a roll coater method, so that it can be applied to a continuous line of steel companies and secure fingerprint resistance. Do. However, since the composition contains a porous silica component, there is a problem that discoloration occurs severely in a moist atmosphere, and the porous silica has a strong moisture absorption property, causing rapid discoloration in the alloyed galvanized steel sheet.
[7]
On the other hand, the present inventors have confirmed that when a film is formed on a steel plate for a fuel tank, when the film contains an organic component such as urethane resin, there is also a problem that the corrosion prevention effect due to the condensate inside the fuel is lowered. . In addition, in manufacturing a fuel tank, if considering manufacturing a container by welding, weldability should be excellent, but such an organic component causes a problem that significantly degrades weldability. Further, it was confirmed that such a resin component has a problem in that it is dissolved in the fuel during a long-term contact with the fuel, and thus there is a problem of lowering the fuel resistance of the film.
[8]
Accordingly, there is an urgent need to form a film excellent in fuel resistance, corrosion resistance, weldability and workability by forming an inorganic film that does not contain organic components in a steel sheet for a fuel tank.
Detailed description of the invention
Technical challenge
[9]
According to one aspect of the present invention, it provides a surface treatment solution composition that does not contain hexavalent chromium, which is a hazardous environmental substance, is harmless to the human body, and does not contain an organic component, and alloyed molten zinc By applying it to the surface of a plated steel sheet, it provides an alloyed hot-dip galvanized steel sheet having a surface-treated trivalent chromium compound excellent in corrosion resistance, blackening resistance, fuel resistance, weldability, and alkali resistance.
Means of solving the task
[10]
According to an embodiment of the present invention, 10 to 30% by weight of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B), and the content ratio A/(A+B) satisfying 0.3 to 0.6 ( Based on a solution with a solid content of 28.6% by weight), 5 to 50% by weight of a silane compound (based on a solution with a solid content of 1.27% by weight), 0.2 to 3% by weight of a vanadium-based anticorrosive agent, 0.5 to 5% by weight of a cobalt-based anticorrosive agent It provides a surface treatment solution composition for forming an inorganic film of a fuel tank steel sheet, comprising 12 to 84.3% by weight and water.
[11]
The vanadium-based anticorrosive agent is vanadium pentoxide (V 2 O 5 ), metavanadium acid (HVO 3 ), ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride (VOCl 3 ), vanadium trioxide (V 2 O 3 ) , Vanadium dioxide (VO 2 ), vanadium oxysulfate (VOSO 4 ), vanadium oxyoxalate [VO(COO) 2 ], vanadium oxyacetylacetonate [VO(OC(CH 3 )=CHCOCH 3 )) 2 ], vanadium acetyl Acetonate [V(OC(CH 3 )=CHCOCH 3 )) 3 ], vanadium trichloride (VCl 3 ), vanadium sulfate (VSO 4 ㆍ8H 2O), vanadium dichloride (VCl 2 ), and may be at least one selected from the group consisting of vanadium oxide (VO).
[12]
The cobalt-based anticorrosive agents are cobalt (II) nitrate, cobalt (II) sulfate, cobalt (II) acetate), and cobalt oxalate (II). )(cobalt (II) oxalate), cobalt (III) nitrate), cobalt (III) acetate), cobalt (III) oxalate), cobalt chloride It may be at least one selected from the group consisting of (IV) (cobalt (IV) chloride), cobalt (III) oxide), and cobalt (IV) oxide.
[13]
According to an embodiment of the present invention, an alloyed hot dip galvanizing layer formed on at least one surface of a steel sheet and a trivalent chromated inorganic coating layer formed on the alloyed hot dip galvanizing layer, wherein the trivalent chromated inorganic coating layer is chromium phosphate (A) Trivalent chromium compound 49.8 to 78.9% by weight, silane compound 1.8 to 3.7% by weight, vanadium-based anticorrosive agent containing chromium pernitrate (B), and content ratio A/(A+B) satisfying 0.80 to 0.98 It provides a surface-treated alloyed hot-dip galvanized steel sheet containing 5.5 to 17.5% by weight and 13.8 to 29% by weight of a cobalt-based anticorrosive agent.
[14]
The silane compound is 2-(3,4 epoxycyclohexyl)-ethyltrimethoxysilane, 3-glycyloxypropyl trimethoxysilane, 3-glycyloxypropyl methyldiethoxysilane, 3-glycyloxypropyl tri Ethoxysilane, N-2-(aminoethyl)-3-aminopropyl methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyl trimethoxysilane, N-2-(aminoethyl)-3 -It may be at least one selected from the group consisting of aminopropyl triethoxysilane, 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, 3-ureido propyl trimethoxy silane, and tetraethylorthosilicate. .
[15]
The vanadium-based anticorrosive agent is vanadium pentoxide (V 2 O 5 ), metavanadium acid (HVO 3 ), ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride (VOCl 3 ) vanadium trioxide (V 2 O 3 ), Vanadium dioxide (VO 2 ), vanadium oxysulfate (VOSO 4 ), vanadium oxyoxalate [VO(COO) 2 ], vanadium oxyacetylacetonate [VO(OC(CH 3 )=CHCOCH 3 )) 2 ], vanadium acetylaceto Nate [V(OC(CH 3 )=CHCOCH 3 )) 3 ], vanadium trichloride (VCl 3 ), vanadium sulfate (VSO 4 ㆍ8H 2O), vanadium dichloride (VCl 2 ), and may be at least one selected from the group consisting of vanadium oxide (VO).
[16]
The cobalt-based anticorrosive agents are cobalt (II) nitrate, cobalt (II) sulfate, cobalt (II) acetate), and cobalt oxalate (II). )(cobalt (II) oxalate), cobalt (III) nitrate), cobalt (III) acetate), cobalt (III) oxalate), cobalt chloride It may be at least one selected from the group consisting of (IV) (cobalt (IV) chloride), cobalt (III) oxide), and cobalt (IV) oxide.
[17]
The trivalent chromate inorganic coating layer may have a thickness of 0.3 to 0.5 μm.
[18]
According to an embodiment of the present invention, coating the surface treatment solution composition on an alloyed hot dip galvanized steel sheet on which an alloyed hot dip galvanizing layer is formed, and drying the surface treatment solution composition to form a trivalent chromate inorganic film layer. It provides a method for manufacturing a surface-treated alloyed hot-dip galvanized steel sheet including.
[19]
The surface treatment solution composition may be coated to a thickness of 2.14 to 3.57 μm.
[20]
The coating may be made by any one method selected from the group consisting of roll coating, spray, dipping, spray squeezing, and dip squeezing.
[21]
The drying may be performed at a temperature of 50 to 60° C. based on a final steel sheet temperature (PMT).
[22]
The drying may be performed in a hot air drying furnace or an induction heating furnace.
[23]
The hot air drying furnace may have an internal temperature of 100 to 200°C.
[24]
A current of 1000 ~ 3500A may be applied to the induction heating furnace.
[25]
It may further include air-cooling the trivalent chromate inorganic coating layer.
[26]
The method of manufacturing the alloyed hot dip galvanized steel sheet may be made in a continuous process, and the speed of the continuous process may be 80 to 100 mpm.
Effects of the Invention
[27]
The alloyed hot-dip galvanized steel sheet treated with a surface treatment coating containing trivalent chromium and inorganic compounds according to an embodiment of the present invention has excellent effects in corrosion resistance, blackening resistance, fuel resistance, weldability and alkali resistance.
Brief description of the drawing
[28]
1 is a view schematically showing a cross-sectional structure of a steel plate according to the present invention.
Best mode for carrying out the invention
[29]
Hereinafter, preferred embodiments of the present invention will be described with reference to various examples. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.
[30]
The present invention relates to a surface treatment solution composition containing trivalent chromium for forming an inorganic film of a fuel tank steel sheet, an alloyed hot-dip galvanized steel sheet surface-treated using the composition, and a method for manufacturing the alloyed hot-dip galvanized steel sheet.
[31]
The surface treatment solution composition according to an embodiment of the present invention includes a trivalent chromium compound, a silane compound, a vanadium-based rust-preventing agent, a cobalt-based rust-preventing agent, and water.
[32]
The surface treatment solution composition according to an embodiment of the present invention is to provide excellent corrosion resistance, blackening resistance, fuel resistance, weldability and alkali resistance of an alloyed hot dip galvanized steel sheet using trivalent chromium. In addition, the surface treatment solution composition of the present invention does not contain hexavalent chromium, which is a harmful environmental substance, does not contain organic components that reduce fuel resistance and weldability, and contains trivalent chromium harmless to the human body as a main component. It is intended to prevent damage and environmental pollution.
[33]
The trivalent chromium compound is a component included as a main component in the surface treatment solution composition of the present invention, has a self-healing effect and self-lubrication similar to hexavalent chromium, and secures corrosion resistance and blackening resistance. Do it.
[34]
The trivalent chromium compound included in the composition of the present invention includes chromium phosphate and chromium nitrate. The chromium phosphate has a function of providing corrosion resistance, and chromium nitrate has a function of providing blackening resistance. Accordingly, in the present invention, it is preferable to use the chromium phosphate (A) and chromium nitrate (B) in the range of A/(A+B) satisfying 0.3 to 0.6. As the chromium phosphate ratio increases, the corrosion resistance is improved, while the blackening resistance may be inferior. On the other hand, as the chromium nitrate ratio increases, the blackening resistance is improved, whereas the corrosion resistance may be poor.
[35]
Specifically, when the inorganic film is formed on the surface of the steel sheet with the chromium phosphate, the phosphoric acid component is not volatilized, so the chromium phosphate film is formed on the surface of the inorganic film to improve corrosion resistance, but blackening resistance may be reduced due to the hygroscopicity of the chromium phosphate. . On the other hand, when the chromium nitrate is used to form a film on the surface of the steel sheet, most of the nitrate components are volatilized and do not affect the blackening resistance. I can.
[36]
Therefore, it is preferable to use the content of chromium phosphate (A) and chromium nitrate (B) so that A/(A+B) satisfies 0.3 to 0.6, and if the content ratio is less than 0.3, corrosion resistance after processing may decrease. And, if it exceeds 0.6, blackening resistance may be deteriorated.
[37]
The total content of the trivalent chromium compound including chromium phosphate and chromium nitrate is preferably 10 to 30 wt% based on a solution having a solid content of 28.6 wt%. If the content of the trivalent chromium compound is less than 10% by weight, the solid insoluble inorganic film layer becomes thin, so that the surface of the plated steel sheet requiring corrosion resistance cannot effectively block moisture penetration, resulting in black discoloration, and a problem of lowering corrosion resistance. have.
[38]
On the other hand, when the content of the trivalent chromium compound exceeds 30% by weight, the content of the vanadium-based anticorrosive agent, the cobalt-based anticorrosive agent, and the silane coupling agent serving as a binder are relatively reduced to provide sufficient corrosion resistance. And it is difficult to secure blackening resistance.
[39]
The surface treatment solution composition of the present invention contains a silane coupling agent. The silane coupling agent is added to promote drying and secure high corrosion resistance through the role of crosslinking inorganic components.
[40]
The kind of the silane coupling agent is not particularly limited, but, for example, 2-(3,4 epoxycyclohexyl)-ethyltrimethoxysilane, 3-glycyloxypropyl trimethoxysilane, 3-glycyloxypropyl Methyldiethoxysilane, 3-glycyloxypropyl triethoxysilane, N-2-(aminoethyl)-3-aminopropyl methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyl trimethoxy Silane, N-2-(aminoethyl)-3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, 3-ureido propyltrimethoxy silane and tetraethyl Orthosilicates, etc. are mentioned. These silane coupling agents may be used alone or in combination of two or more.
[41]
The content of the silane coupling agent is preferably 5 to 50% by weight (based on a solution having a solid content of 1.27% by weight). If the content of the silane coupling agent is less than 5% by weight, alkali resistance and fuel resistance are deteriorated, and if it exceeds 50% by weight, the dryness of the film is increased to form an excessively hard film, resulting in weak corrosion resistance in the processed part. Fuelability becomes inferior.
[42]
The surface treatment solution composition of the present invention contains a vanadium-based anticorrosive agent. The vanadium-based anticorrosive agent is a component included in order to improve the corrosion resistance of the plated steel sheet by forming a passive inorganic film on the surface of the alloyed hot-dip galvanized steel sheet surface-treated with the surface treatment solution composition of the present invention. When the vanadium-based anticorrosive agent is damaged, for example, tetravalent vanadium in the film existing close to the damaged area is eluted and reduced to trivalent, thereby forming a passive inorganic film on the plated surface exposed by the damage. Formed, and thereby may have an effect of inhibiting corrosion. In addition, the vanadium-based rust-preventing agent is preferentially eluted under a corrosive environment, and since it suppresses an increase in pH due to dissolution of the plating component, it is effective in improving corrosion resistance.
[43]
The vanadium-based anticorrosive agent is, for example, vanadium pentoxide (V 2 O 5 ), metavanadium acid (HVO 3 ), ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride (VOCl 3 ) vanadium trioxide (V 2 O 3 ), vanadium dioxide (VO 2 ), vanadium oxysulfate (VOSO 4 ), vanadium oxyoxalate [VO(COO) 2 ], vanadium oxyacetylacetonate [VO(OC(CH 3 )=CHCOCH 3 )) 2 ], vanadium acetylacetonate [V(OC(CH 3 )=CHCOCH 3 )) 3 ], vanadium trichloride (VCl 3 ), vanadium sulfate (VSO 4 ㆍ8H 2O), vanadium dichloride (VCl 2 ), vanadium oxide (VO), and the like. These may be used alone, or two or more may be mixed.
[44]
It is preferable that the content of the vanadium-based anticorrosive agent is 0.2 to 3% by weight. If the content of the anticorrosive agent is less than 0.2% by weight, it is difficult to secure corrosion resistance, and if it exceeds 3% by weight, it is difficult to secure blackening resistance and alkali resistance.
[45]
The surface treatment solution composition of the present invention also contains a cobalt-based anti-corrosive agent. The cobalt-based anticorrosive agent reacts with the plating layer on the surface of the alloyed hot-dip galvanized steel sheet surface-treated with the surface treatment solution composition of the present invention to modify the surface of the plating layer, thereby improving the blackening resistance of the coated steel sheet. . In addition, even when the acidic liquid passes through the inorganic film and reaches the surface of the plating layer, the cobalt compound protects the surface of the plating layer and suppresses its discoloration. In addition, there is an effect of contributing to the improvement of corrosion resistance of an alloyed hot-dip galvanized steel sheet by forming an insoluble salt together with the phosphoric acid group contained in the surface treatment solution composition.
[46]
Examples of the cobalt-based anticorrosive agent include cobalt (II) nitrate, cobalt (II) sulfate, and cobalt (II) acetate. , Cobalt (II) oxalate), cobalt (III) nitrate), cobalt (III) acetate), cobalt (III) oxalate oxalate), cobalt (IV) chloride, cobalt (III) oxide, cobalt (IV) oxide), etc. It can be used, of course, can also be used by mixing two or more.
[47]
The content of the cobalt-based anticorrosive agent is preferably 0.5 to 5% by weight. If the content of the cobalt-based anticorrosive agent is less than 0.5% by weight, it is difficult to secure blackening resistance, and if it exceeds 5% by weight, the effect of improving the blackening resistance is insignificant, and corrosion resistance is greatly reduced.
[48]
The surface treatment solution composition of the present invention contains water. The water is a solvent of the surface treatment solution composition of the present invention, and is used to dilute the components of the surface treatment solution composition. The water is not particularly limited, but deionized water or distilled water may be used. The water is included as a balance in addition to each component of the present invention, and the content may be 12 to 84.3% by weight.
[49]
According to another embodiment of the present invention, there is provided an alloyed hot-dip galvanized steel sheet surface-treated with the surface treatment solution composition containing trivalent chromium and a method for manufacturing the same.
[50]
Specifically, the surface-treated alloyed hot-dip galvanized steel sheet includes a base steel sheet, an alloyed hot-dip zinc plating layer formed on at least one surface of the base steel sheet, and an inorganic coating layer of trivalent chromate formed on the alloyed hot-dip zinc plating layer.
[51]
The trivalent chromate inorganic coating layer contains a trivalent chromium compound, a silane compound, a vanadium-based rust preventive agent, and a cobalt-based rust preventive agent, and does not contain other organic components.
[52]
The trivalent chromate inorganic coating layer is an inorganic coating layer formed by the surface treatment solution composition described above, and components and contents remaining on the surface of the steel sheet after all volatile components such as solvents contained in the surface treatment solution composition are volatilized. As shown, it corresponds to the content based on 100% by weight of the total solids.
[53]
The trivalent chromate inorganic coating layer of the present invention contains a trivalent chromium compound as a main component. The trivalent chromium compound includes chromium phosphate and chromium nitrate, and the content is 49.8 to 78.9% by weight based on solid content. If the content of the trivalent chromium compound is less than 49.8% by weight, the solid insoluble inorganic film layer becomes thin, and it does not effectively block moisture penetration on the surface of the plated steel sheet requiring corrosion resistance, causing blackening, and reducing the corrosion resistance. have. On the other hand, if the content of the trivalent chromium compound exceeds 78.9% by weight, the content of the vanadium-based rust preventive agent, cobalt-based rust preventive agent, and the silane coupling agent serving as a binder is relatively reduced, thereby providing sufficient corrosion resistance. And it is difficult to secure blackening resistance.
[54]
In addition, the content ratio A/(A+B) of chromium phosphate (A) and chromium nitrate (B) is preferably 0.80 or more and 0.98 or less, and more preferably 0.89 to 0.95. If the content ratio is less than 0.80, corrosion resistance may decrease after processing, and if it exceeds 0.98, blackening resistance may decrease.
[55]
The trivalent chromate inorganic coating layer of the present invention contains a silane compound. The content of the silane compound is preferably 1.8 to 3.7% by weight based on solid content. If the content of the silane compound is less than 1.8% by weight, alkali resistance and crude pipe oil invasion are poor, and if it exceeds 3.7% by weight, the dryness of the film is increased to form an excessively hard film, resulting in poor corrosion resistance and fuel resistance. It is not preferable in that it becomes inferior.
[56]
The trivalent chromate inorganic coating layer of the present invention contains a vanadium-based anticorrosive agent. The content of the vanadium-based anticorrosive agent is preferably 5.5 to 17.5% by weight based on solid content. If the content of the anticorrosive agent is less than 5.5% by weight, it is difficult to secure corrosion resistance, and if it exceeds 17.5% by weight, it is difficult to secure blackening resistance and alkali resistance.
[57]
On the other hand, the trivalent chromate inorganic coating layer of the present invention contains a cobalt-based anti-corrosive agent. The content of the cobalt-based anticorrosive agent is preferably 13.8 to 29% by weight based on solid content. If the content of the cobalt-based anticorrosive agent is less than 13.8% by weight, it is difficult to secure blackening resistance, and if it exceeds 29% by weight, the effect of improving the blackening resistance is insignificant, and corrosion resistance is not preferable in that it is significantly lowered.
[58]
According to an embodiment of the present invention, preparing a galvanized steel sheet having a galvanized layer formed thereon, coating a surface treatment solution composition on the alloyed hot dip galvanizing layer, and drying the coated surface treatment solution composition to trivalent chromate It provides a method for manufacturing an alloyed hot dip galvanized steel sheet comprising the step of forming an inorganic coating layer.
[59]
The surface treatment solution composition contains chromium phosphate (A) and chromium nitrate (B), and the content ratio A/(A+B) is 10 to 30% by weight of a trivalent chromium compound satisfying 0.3 to 0.6 (solid content Based on a solution having a content of 28.6% by weight), 5 to 50% by weight of a silane compound (based on a solution having a solid content of 1.27% by weight), 0.2 to 3% by weight of a vanadium-based anticorrosive agent, 0.5 to 5% by weight of a cobalt-based anticorrosive agent And the balance water. The technical meaning of the content range of each component included in the surface treatment solution composition is as described above.
[60]
It is preferable to coat the surface treatment solution composition to a thickness of 2.14 ~ 3.57㎛. The surface treatment solution composition coated with such a thickness may have a dry film layer thickness of 0.3 to 0.5 μm through a drying process. If the coating thickness of the surface treatment solution composition is less than 2.14 µm, the surface treatment solution composition is thinly applied to the acid site of the steel plate, resulting in a problem of lowering corrosion resistance. If it exceeds 3.57 µm, the weldability and Problems such as deterioration of workability may occur.
[61]
The method of coating the surface treatment solution composition is not particularly limited as long as it is a commonly performed coating method, but is performed by any one coating method selected from roll coating, spray, immersion, spray squeezing and immersion squeezing. It is desirable.
[62]
The process of drying the surface treatment solution composition coated on the alloyed hot-dip galvanized steel sheet is preferably performed at 50 to 60°C based on the final steel sheet temperature (PMT). If the drying temperature is less than 50°C based on the material steel sheet final reach temperature (PMT), drying may not be done completely, so that alkali resistance and oil intrusion may be inferior.If it exceeds 60°C, the cooling process in the air (air cooling ), the steel plate is not sufficiently cooled and the blackening resistance due to condensation may be inferior due to packaging.
[63]
Meanwhile, the drying is preferably performed in a hot air drying furnace or an induction heating furnace. When the surface treatment coating composition is dried using the hot air drying furnace, the internal temperature of the hot air drying furnace is preferably 100 to 200°C. On the other hand, when drying the surface treatment coating composition using the induction heating furnace, the current applied to the induction heating furnace is preferably 1000 ~ 3500A, more preferably 1500 ~ 3000A.
[64]
If the internal temperature of the hot air drying furnace is less than 100°C or the current applied to the induction heating furnace is less than 1000A, the surface treatment coating composition is not completely dried, and thus alkali resistance and intrusion of crude pipe oil may be poor. In addition, when the internal temperature of the hot air drying furnace exceeds 200°C or the current applied to the induction heating furnace exceeds 3500A, the steel sheet is not sufficiently cooled during the cooling process (air cooling) in the air and is packaged to prevent blackening due to condensation. You can lose for this heat.
[65]
In addition, after drying the surface treatment solution composition to form a trivalent chromate inorganic coating layer, the trivalent chromate inorganic coating layer may be air-cooled to provide a final surface-treated alloyed hot-dip galvanized steel sheet.
[66]
The method for manufacturing the alloyed hot-dip galvanized steel sheet according to an embodiment of the present invention may be made in a continuous process, and the speed of the continuous process is preferably 80 to 100 mpm. If the continuous process speed is less than 80mpm, there may be a problem of lowering productivity, and if it exceeds 100mpm, the solution may scatter in the process of drying the surface treatment solution composition, resulting in surface defects.
[67]
In the present invention, the steel sheet may be a galvanized steel sheet having a galvanized layer. If it is a galvanized steel sheet, it is not particularly limited, but it is more preferable to apply it to an alloyed hot dip galvanized steel sheet.
Mode for carrying out the invention
[68]
Example
[69]
Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.
[70]
Example 1
[71]
Changes in physical properties according to the content of trivalent chromium compounds
[72]
Trivalent chromium compound prepared by adding chromium phosphate and chromium nitrate to distilled water and reacting at 80° C. for 1 hour and then cooling to room temperature, vanadium acetylacetonate as a vanadium-based rust inhibitor, cobalt nitrate (III) as a cobalt-based rust inhibitor, And a mixture of tetraethylorthosilicate and 3-glycyloxypropyl trimethoxysilane in a weight ratio of 1:1 as a silane coupling agent, and water, and in the amount shown in Table 2 below (based on the solid content of the composition) By mixing, a surface treatment solution composition containing trivalent chromium was prepared.
[73]
Meanwhile, in the following Examples, the case where the surface treatment solution composition satisfies the content range of Table 1 below was described as an invention example, and the case where at least one component did not satisfy the content range of Table 1 was described as a comparative example.
[74]
After cutting the hot-dip galvanized steel sheet into 7 cm x 15 cm (width x length) and removing oil, the prepared surface treatment solution composition is bar-coated on the hot-dip galvanized steel sheet so that the dry film layer thickness is 0.4 μm. It was applied by. Thereafter, the steel sheet coated with the surface treatment solution composition was completely dried using a hot air drying furnace under the condition of PMT 60° C. to prepare a specimen with a trivalent chromate inorganic film as shown in FIG. 1.
[75]
The plate corrosion resistance, the corrosion resistance and the blackening resistance of the fabricated specimen were evaluated, and the evaluation results are shown in Table 2. The evaluation method of the plate corrosion resistance, the corrosion resistance of the processed portion, and the blackening resistance are as follows.
[76]

[77]
According to the method specified in ASTM B117, after the specimen was treated, the white rust generation time of the steel sheet over time was measured and evaluated. At this time, the evaluation criteria are as follows.
[78]
◎: White rust generation time is 144 hours or more
[79]
○: White rust generation time is 96 hours or more and less than 144 hours
[80]
△: White rust generation time is less than 55 hours and less than 96 hours
[81]
×: White rust generation time is less than 55 hours
[82]

[83]
The specimen was pushed up to a height of 6 mm using an Erichsen tester, and then the degree of white rust generation was measured after 24 hours. At this time, the evaluation criteria are as follows.
[84]
◎: Less than 5% of white rust occurrence after 48 hours
[85]
△: White rust occurrence 5% or more and less than 7% after 48 hours
[86]
×: 7% or more of white rust occurrence after 48 hours
[87]

[88]
The specimen was allowed to stand for 120 hours in a thermo-hygrostat maintained at 50° C. and 95% relative humidity, thereby observing a color change (color difference: ΔE) before/after the test. At this time, the evaluation criteria are as follows.
[89]
◎: ΔE ≤ 2
[90]
○: 2 <ΔE ≤ 3
[91]
△: 3 <ΔE ≤ 4
[92]
×: ΔE> 4
[93]
[Table 1]
division Content (% by weight) Solid content (% by weight) Component ratio after drying Content in dry film (% by weight)
ingredient Ieast maximum Ieast maximum Ieast maximum
Trivalent chromium compounds 10 30 28.6 2.86 8.58 68.3 50.6
Silane compound 5 50 1.27 0.13 0.38 3.1 2.2
Vanadium-based anticorrosive agent 0.1 5 100 0.2 3 4.8 17.7
Cobalt-based anticorrosive agent 0.5 7 100 One 5 23.9 29.5
water 78.8 32 0 0 0 0 0
Sum 100 100 - 4.19 16.96 100 100
[94]
[Table 2]
division Composition content (% by weight) Flat plate corrosion resistance Corrosion resistance Resistance to blackening
Trivalent chromium compounds Silane compound Anti-corrosive agent
Vanadium Cobalt
Comparative Example 1 49.5 4 17.5 29 × × ×
Invention Example 1 49.8 3.7 17.5 29 ○ ◎ ○
Invention Example 2 60 2.5 11.5 26 ◎ ◎ ◎
Invention Example 3 68 2.5 6.5 23 ◎ ◎ ◎
Invention Example 4 78.5 2.5 5 14 ○ ◎ ○
Comparative Example 2 79.2 1.8 5.2 13.8 × × ○
[95]
* The content of the composition is based on a solid content of 14% As shown in Table 2 above, when the content of the trivalent chromium compound satisfies the content proposed by the present invention (Invention Examples 1 to 4), all physical properties showed good or higher results. .
[96]
On the other hand, when too little trivalent chromium compound was added (Comparative Example 1), poor results were shown in plate corrosion resistance, processed part corrosion resistance, and blackening resistance, and when too much was added (Comparative Example 2), all except blackening resistance It showed poor results in physical properties.
[97]
Example 2
[98]
Changes in physical properties according to the ratio of chromium (III) phosphate and nitrate (III)
[99]
The trivalent chromium surface treatment solution composition according to Inventive Example 3 was used, except that the ratio of chromium phosphate and chromium nitrate was controlled to be the ratio of chromium phosphate and chromium nitrate shown in Table 3 below. Was carried out in the same manner as in Example 1 to prepare a hot-dip galvanized steel sheet specimen with a trivalent chromate inorganic film formed thereon.
[100]
Plate corrosion resistance and blackening resistance were evaluated in the same manner as in Example 1 for the prepared specimen, and the evaluation results are shown in Table 3.
[101]
[Table 3]
division Trivalent chromium compound (% by weight) Content ratio of chromium phosphate and chromium nitrate Flat plate corrosion resistance Resistance to blackening
Chromium phosphate (A) Chromium nitrate (B) A/(A+B)
Comparative Example 3 58.2 7 0 One ○ ×
Comparative Example 4 58.2 0 0.35 0 × ○
Comparative Example 5 58.2 One 0.3 0.769 × ○
Invention Example 5 58.2 One 0.25 0.80 ○ ◎
Inventive Example 6 58.2 3 0.2 0.938 ◎ ◎
Invention Example 7 58.2 4.9 0.1 0.980 ◎ ○
Comparative Example 6 58.2 7 0.1 0.986 ○ ×
[102]
* The content of the composition is based on a solid content of 14% As shown in Table 3 above, as the chromium phosphate ratio increases, the corrosion resistance is improved, whereas the blackening resistance tends to be improved as the chromium nitrate ratio increases. However, when the ratio of chromium phosphate and chromium nitrate shown in the present invention is below or above, corrosion resistance or blackening resistance tends to be poor.
[103]
Example 3
[104]
Changes in physical properties depending on the content and type of silane compound
[105]
Trivalent chromium compounds such as chromium nitrate and chromium phosphate, vanadium acetylacetonate as a vanadium-based rust inhibitor, cobalt (III) nitrate as a cobalt-based rust inhibitor, tetraethylorthosilicate and 3-glycyloxypropyl trime as a silane coupling agent Hot-dip galvanizing in which a trivalent chromate inorganic film was formed by carrying out in the same manner as in Example 1, except that the silane compound in which oxysilane was mixed in a 1:1 ratio was mixed in the content (based on the solid content of the composition) shown in Table 4 below. A steel plate specimen was prepared.
[106]
Plate corrosion resistance, processed part corrosion resistance and blackening resistance were evaluated in the same manner as in Example 1, and further, alkali resistance, fuel resistance and fingerprint resistance were evaluated as follows, and the evaluation results are shown in Table 4.
[107]

[108]
The specimen was immersed in an alkali degreasing solution at 60° C. for 2 minutes, washed with water, and then before/after the color difference (ΔE) was measured. As an alkaline degreasing solution, Finecleaner L 4460 A: 20g/2.4L + L 4460 B 12g/2.4L (pH=12) manufactured by Daehan Pakalizing was used. At this time, the evaluation criteria are as follows.
[109]
◎: ΔE ≤ 2
[110]
○: 2 <ΔE ≤ 3
[111]
△: 3 <ΔE ≤ 4
[112]
×: ΔE> 4
[113]

[114]
Weldability was evaluated by using a pneumatic AC spot welding machine to maintain a constant strength without spatter at a pressing force of 250kg and a welding time of 15 cycles at 7.5kA. At this time, the evaluation criteria are as follows.
[115]
○: Welding possible
[116]
△: Poor welding quality
[117]
×: welding impossible
[118]

[119]
The fuel resistance evaluation evaluated the high temperature fuel resistance of deteriorated gasoline and biodiesel. The following deteriorated gasoline and biodiesel were used for fuel resistance evaluation.
[120]
Depleted gasoline: 78.58 vol% gasoline + 20 vol% ethanol + 1.42 vol% pure + 100 ppm formic acid + 100 ppm acetic acid
[121]
Biodiesel: 81% by volume diesel + 9% by volume BIO diesel + 5% by volume pure + 5% by volume methanol + 20ppm formic acid + 0.3% by weight peroxide
[122]
After processing the obtained specimen into a cup shape, each of the fuels was filled, the surface was covered with a glass plate, and the specimen and the glass plate were sealed using an O-ring. Then, after leaving it for 3 months at 85°C, the corrosion state of the steel plate was observed to evaluate the fuel resistance. The evaluation criteria are as follows.
[123]
◎: Corrosion area 0%
[124]
○: Corrosion area is more than 0% and less than 5%
[125]
□: Corrosion area exceeds 5% and less than 30%
[126]
△: Corrosion area more than 30% and less than 50%
[127]
×: Corrosion area exceeds 50%
[128]
[Table 4]
division Composition content (% by weight) Alkali resistance Fuel resistance Weldability Flat plate corrosion resistance Corrosion resistance Resistance to blackening
Silane compound Trivalent chromium compounds Vanadium-based anticorrosive agent Cobalt-based anti-corrosive agent
Comparative Example 7 1.7 60 13.8 24.5 × × ○ ○ ◎ ○
Inventive Example 8 1.8 60 13.8 24.4 ○ ○ ○ ◎ ◎ ○
Inventive Example 9 2.5 60 13.3 24.2 ○ ◎ ○ ◎ ◎ ◎
Inventive Example 10 3.1 60 13.5 23.4 ◎ ◎ ◎ ◎ ◎ ◎
Invention Example 11 3.7 60 13.6 22.7 ◎ ○ ◎ ◎ ◎ ○
Comparative Example 8 3.9 60 13.4 22.7 ○ ○ △ ◎ × ×
[129]
* The content of the composition is based on a solid content of 14% As shown in Table 4 above, when the content of the silane compound satisfies the content range of the present invention (Invention Examples 8 to 11), all physical properties showed good or higher results.
[130]
On the other hand, when too little of the silane compound is added (Comparative Example 7), the result is poor in alkali resistance and fuel resistance, and when too much is added (Comparative Example 8), the dryness of the coating increases and a hard coating is formed. The result was poor corrosion resistance, poor blackening resistance, and poor welding quality.
[131]
Example 4
[132]
The trivalent chromium surface treatment solution composition according to Inventive Example 10 was used, except for the use of the silane compound shown in Table 5, in the same manner as in Example 1 to prepare a hot-dip galvanized steel sheet specimen with a trivalent chromate inorganic film formed thereon. Was produced.
[133]
For each specimen, plate corrosion resistance was evaluated in the same manner as in Example 1, and the results are shown in Table 5.
[134]
[Table 5]
division A B C D E F G H I J K Flat plate corrosion resistance
content content content content content content content content content content content
Inventive Example 12 3.1 0 0 0 0 0 0 0 0 0 0 ○
Inventive Example 13 0 3.1 0 0 0 0 0 0 0 0 0 ◎
Inventive Example 14 0 0 3.1 0 0 0 0 0 0 0 0 ○
Inventive Example 15 0 0 0 3.1 0 0 0 0 0 0 0 ◎
Inventive Example 16 0 0 0 0 3.1 0 0 0 0 0 0 ○
Inventive Example 17 0 0 0 0 0 3.1 0 0 0 0 0 ◎
Inventive Example 18 0 0 0 0 0 0 3.1 0 0 0 0 ○
Inventive Example 19 0 0 0 0 0 0 0 3.1 0 0 0 ○
Inventive Example 20 0 0 0 0 0 0 0 0 3.1 0 0 ○
Inventive Example 21 0 0 0 0 0 0 0 0 0 3.1 0 ◎
Inventive Example 22 0 0 0 0 0 0 0 0 0 0 3.1 ○
Inventive Example 23 1.55 1.55 0 0 0 0 0 0 0 0 0 ○
Inventive Example 24 1.55 0 0 1.55 0 0 0 0 0 0 0 ○
Inventive Example 25 0 1.55 0 0 0 1.55 0 0 0 0 0 ◎
Inventive Example 26 0 0 0 1.55 0 1.55 0 0 0 0 0 ○
Inventive Example 27 0 0 0 0 1.55 0 1.55 0 0 0 0 ○
Inventive Example 28 0 0 0 0 0 1.55 0 0 0 1.55 0 ◎
Inventive Example 29 0 0 1.55 0 0 1.55 0 0 0 0 0 ○
Inventive Example 30 0 0 0 0 0 0 1.55 0 0 1.55 0 ○
Inventive Example 31 1.55 0 0 0 0 0 0 0 0 1.55 0 ○
Inventive Example 32 0 0 0 0 0 0 0 0 0 1.55 1.55 ○
Inventive Example 33 0 0 0 1.55 0 0 0 0 1.55 0 0 ○
Inventive Example 34 0 0 0 0 1.55 0 0 1.55 0 0 0 ○
Inventive Example 35 0 0 0 0 0 0 0 1.55 0 0 1.55 ○
Inventive Example 36 0 1.55 1.55 0 0 0 0 0 0 0 0 ◎
Inventive Example 37 0 0 1.55 0 0 0 0 0 0 0 1.55 ○
Inventive Example 38 0 0 0 0 0 0 1.55 0 1.55 0 0 ○
Inventive Example 39 0 0 0 0 1.55 0 0 0 1.55 0 0 ○
Inventive Example 40 0 1.55 0 1.55 0 0 0 0 0 0 0 ○
Inventive Example 41 0 1.55 0 0 0 0 0 0 0 0 1.55 ◎
Inventive Example 42 1.55 0 1.55 0 0 0 0 0 0 0 0 ○
Inventive Example 43 0 0 0 0 0 0 0 0 1.55 1.55 0 ○
Inventive Example 44 0 1.55 0 0 1.55 0 0 0 0 0 0 ○
Inventive Example 45 0 0 0 0 0 0 1.55 1.55 0 0 0 ○
A: 2-(3,4 epoxycyclohexyl)-ethyltrimethoxysilane G: N-2-(aminoethyl)-3-aminopropyltriethoxysilane
B: 3-glycyloxypropyl trimethoxysilane H: 3-aminopropyl trimethoxy silane
C: 3-glycyloxypropyl methyldiethoxysilane I: 3-aminopropyl triethoxy silane
D: 3-glycyloxypropyl triethoxysilane J: 3-ureido propyltrimethoxy silane
E:N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane K: tetraethylorthosilicate
F: N-2-(aminoethyl)-3-aminopropyl trimethoxysilane
[135]
* The content of the composition is based on 14% solid content
[136]
As shown in Table 5, Inventive Examples 12 to 45 showed good or excellent results in plate corrosion resistance. In particular, in the case of the test specimen treated with the trivalent chromium surface treatment solution composition prepared according to the composition of Inventive Example 41, white rust did not occur even after 144 hours or more, showing the best results.
[137]
Example 5
[138]
Changes in physical properties according to the content of vanadium-based anticorrosive agents
[139]
Trivalent chromium compounds such as chromium nitrate and chromium phosphate, vanadium acetylacetonate as a vanadium-based rust inhibitor, cobalt(III) nitrate as a cobalt-based rust inhibitor, and tetraethylorthosilicate and 3-glycyloxypropyl trime as a silane coupling agent. Molten zinc with a trivalent chromate inorganic film formed in the same manner as in Example 1, except that the silane compound in which oxysilane was mixed in a ratio of 1:1 was mixed in the content (based on the solid content of the composition) shown in Table 6 below. A plated steel plate specimen was prepared.
[140]
The prepared specimens were evaluated in the same manner as in Examples 1 and 3, and the corrosion resistance of the plate, the corrosion resistance of the processed portion, the blackening resistance and the alkali resistance were evaluated, and the evaluation results are shown in Table 6.
[141]
[Table 6]
division Composition content (% by weight) Flat plate corrosion resistance Corrosion resistance Resistance to blackening Alkali resistance
Vanadium-based anti-corrosive agent Trivalent chromium compounds Silane compound Cobalt-based anti-corrosive agent
Comparative Example 9 5.3 65.5 3.0 26.2 × × ◎ ◎
Inventive Example 46 5.5 65.0 2.9 26.6 ○ ◎ ◎ ◎
Inventive Example 47 10.5 60.0 2.9 26.6 ○ ◎ ◎ ◎
Inventive Example 48 17.5 53.5 2.5 26.5 ◎ ◎ ○ ○
Comparative Example 10 18.0 53.5 2.5 26.0 ◎ ◎ ○ ×
Comparative Example 11 20.0 52.5 2.5 25.0 ◎ ◎ × ×
[142]
* The content of the composition is based on a solid content of 14% As shown in Table 6, when the content of the anti-corrosive agent satisfies the content proposed by the present invention (Invention Examples 46 to 48), all physical properties showed good or higher results.
[143]
On the other hand, when too little rust-preventing and corrosion-resistant agents were added (Comparative Example 9), all physical properties except for blackening resistance and alkali resistance showed poor results, and when too much was added (Comparative Examples 10 and 11), all properties except for corrosion resistance It showed poor results in physical properties.
[144]
Example 6
[145]
Changes in physical properties according to the content of cobalt-based anti-corrosive agents
[146]
Chromium nitrate and chromium phosphate as a trivalent chromium compound, vanadium acetylacetonate as a vanadium-based rust inhibitor, cobalt(III) nitrate as a cobalt-based rust inhibitor, and tetraethylorthosilicate and 3-glycyloxypropyl trime as a silane coupling agent. Molten zinc with a trivalent chromate inorganic film formed in the same manner as in Example 1, except that a silane compound in which oxysilane was mixed in a ratio of 1:1 was mixed in the content (based on the solid content of the composition) shown in Table 7 below. A plated steel plate specimen was prepared.
[147]
The prepared specimens were evaluated in the same manner as in Example 1, and the corrosion resistance of the plate, the corrosion resistance of the processed portion, and the blackening resistance were evaluated, and the evaluation results are shown in Table 7.
[148]
[Table 7]
division Composition content (% by weight) Flat plate corrosion resistance Corrosion resistance Resistance to blackening
Cobalt-based anti-corrosive agent Trivalent chromium compounds Silane compound Vanadium-based anti-corrosive agent
Comparative Example 12 13.5 75.0 3.0 8.5 ◎ ○ ×
Inventive Example 49 13.8 75.0 3.0 8.2 ◎ ○ ○
Inventive Example 50 21.0 65.5 2.9 10.8 ○ ◎ ○
Inventive Example 51 29.0 54.0 2.5 14.5 ○ ○ ◎
Comparative Example 13 29.5 54.5 2.5 13.5 × × ◎
Comparative Example 14 32.5 52.5 2.5 12.5 × × ◎
[149]
* The content of the composition is based on a solid content of 14% As shown in Table 7 above, when the content of the anticorrosive agent satisfies the content proposed by the present invention (Invention Examples 49 to 51), all physical properties showed good or higher results.
[150]
On the other hand, when too little of the anticorrosive agent was added (Comparative Example 12), the blackening resistance was poor, and when too much was added (Comparative Examples 13 and 14), the corrosion resistance was poor.
[151]
Example 7
[152]
Changes in physical properties depending on film thickness and drying temperature
[153]
After drying, the thickness of the inorganic film and the PMT temperature in the drying process were performed in the same manner as in Example 1, except for performing as shown in Table 8 below, to prepare a hot-dip galvanized steel sheet specimen with a trivalent chromate inorganic film formed thereon.
[154]
For the prepared specimens, alkali resistance, fuel resistance, weldability, plate corrosion resistance, corrosion resistance and blackening resistance of the processed portion were evaluated in the same manner as in Examples 1 and 3, and the evaluation results are shown in Table 8.
[155]
[Table 8]
division Film layer thickness (㎛) Drying temperature (℃) Alkali resistance Fuel resistance Weldability Flat plate corrosion resistance Processed part corrosion resistance Resistance to blackening
Comparative Example 15 0.1 50 △ △ ◎ △ × △
Inventive Example 52 0.3 50 ◎ ◎ ◎ ◎ ◎ ◎
Inventive Example 53 0.4 50 ◎ ◎ ◎ ◎ ◎ ◎
Inventive Example 54 0.5 50 ◎ ◎ ◎ ◎ ◎ ○
Comparative Example 16 0.8 50 ◎ ◎ △ ◎ ◎ ○
Inventive Example 55 0.4 40 △ △ ◎ ○ ○ ○
Inventive Example 56 0.4 60 ◎ ◎ ◎ ◎ ◎ ◎
Inventive Example 57 0.4 70 ◎ ◎ ◎ ◎ ◎ △
[156]
As shown in Table 8, when the inorganic coating layer was formed in the range of 0.3 to 0.5 μm (Invention Examples 52 to 57), all physical properties showed good or higher results. On the other hand, when the formed inorganic film was too thin (Comparative Example 15), the result was normal (△) in all physical properties other than the weldability, and the corrosion resistance of the processed portion was poor. On the other hand, in the case of forming too thick (Comparative Example 16), all the physical properties except for the weldability show satisfactory results, but rather show a tendency to decrease the weldability. It is not preferable to form an inorganic film with a thickness exceeding 0.5 μm. Also, it is not desirable in terms of economy.
[157]
In addition, as shown in Table 8, when the inorganic coating layer was formed by setting the drying temperature of the inorganic coating to 50 to 60°C (Inventive Examples 52 to 54 and 56), all physical properties showed good or higher results.
[158]
On the other hand, when the drying temperature was too low (Invention Example 55), sufficient drying was not performed, and the alkali resistance and fuel resistance were normal (△). On the other hand, when the drying temperature was too high (Invention Example 57), the steel sheet was not sufficiently cooled during the cooling process (air cooling) in air, and the blackening resistance due to condensation was normal (△) by packaging.
[159]
Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of the present invention described in the claims. It will be obvious to those of ordinary skill in the field.
Claims
[Claim 1]
10-30% by weight of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B) and satisfying the content ratio A/(A+B) of 0.3-0.6 (a solution having a solid content of 28.6% by weight standard); 5 to 50% by weight of a silane compound (based on a solution having a solid content of 1.27% by weight); 0.2 to 3% by weight of a vanadium-based anticorrosive agent; 0.5 to 5% by weight of a cobalt-based anticorrosive agent; And 12 to 84.3% by weight of water, surface treatment solution composition for forming an inorganic film.
[Claim 2]
The method of claim 1, wherein the silane compound is 2-(3,4 epoxycyclohexyl)-ethyltrimethoxysilane, 3-glycyloxypropyl trimethoxysilane, 3-glycyloxypropyl methyldiethoxysilane, 3 -Glycyloxypropyl triethoxysilane, N-2-(aminoethyl)-3-aminopropyl methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyl trimethoxysilane, N-2- Group consisting of (aminoethyl)-3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, 3-ureido propyltrimethoxy silane, and tetraethylorthosilicate At least one selected from the surface treatment solution composition for forming an inorganic film.
[Claim 3]
The method of claim 1, wherein the vanadium-based anticorrosive agent is vanadium pentoxide (V 2 O 5 ), metavanadium acid (HVO 3 ), ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride (VOCl 3 ), vanadium trioxide. (V 2 O 3 ), vanadium dioxide (VO 2 ), vanadium oxysulfate (VOSO 4 ), vanadium oxyoxalate [VO(COO) 2 ], vanadium oxyacetylacetonate [VO(OC(CH 3 )=CHCOCH 3 ) ) 2 ], vanadium acetylacetonate [V(OC(CH 3 )=CHCOCH 3 )) 3 ], vanadium trichloride (VCl 3 ), vanadium sulfate (VSO 4 ㆍ8H 2O), at least one selected from the group consisting of vanadium dichloride (VCl 2 ) and vanadium oxide (VO), a surface treatment solution composition for forming an inorganic film.
[Claim 4]
The method of claim 1, wherein the cobalt-based anticorrosive agent is cobalt (II) nitrate, cobalt (II) sulfate, and cobalt (II) acetate. ), cobalt (II) oxalate), cobalt (III) nitrate), cobalt (III) acetate), cobalt (III) oxalate (cobalt (III) ) oxalate), cobalt (IV) chloride), cobalt (III) oxide) and at least one selected from the group consisting of cobalt (IV) oxide, Surface treatment solution composition for forming an inorganic film.
[Claim 5]
Grater; An alloyed hot dip galvanizing layer formed on at least one surface of the steel sheet; And a trivalent chromate inorganic coating layer formed on the alloyed hot dip zinc plating layer, wherein the trivalent chromate inorganic coating layer includes chromium phosphate (A) and chromium nitrate (B), and the content ratio A/(A+B) ) 49.8 to 78.9% by weight of a trivalent chromium compound satisfying 0.80 to 0.98; 1.8 to 3.7% by weight of a silane compound; 5.5 to 17.5% by weight of a vanadium-based anticorrosive agent; And 13.8 to 29% by weight of a cobalt-based anticorrosive agent, surface-treated alloyed hot dip galvanized steel sheet.
[Claim 6]
The method of claim 5, wherein the silane compound is 2-(3,4 epoxycyclohexyl)-ethyltrimethoxysilane, 3-glycyloxypropyl trimethoxysilane, 3-glycyloxypropyl methyldiethoxysilane, 3 -Glycyloxypropyl triethoxysilane, N-2-(aminoethyl)-3-aminopropyl methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyl trimethoxysilane, N-2- Group consisting of (aminoethyl)-3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, 3-ureido propyltrimethoxy silane, and tetraethylorthosilicate At least one selected from the surface-treated alloyed hot-dip galvanized steel sheet.
[Claim 7]
The method of claim 5, wherein the vanadium-based anticorrosive agent is vanadium pentoxide (V 2 O 5 ), metavanadium acid (HVO 3 ), ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride (VOCl 3 ) vanadium trioxide ( V 2 O 3 ), vanadium dioxide (VO 2 ), vanadium oxysulfate (VOSO 4 ), vanadium oxyoxalate [VO(COO) 2 ], vanadium oxyacetylacetonate [VO(OC(CH 3 )=CHCOCH 3 )) 2 ], vanadium acetylacetonate [V(OC(CH 3 )=CHCOCH 3 )) 3 ], vanadium trichloride (VCl 3 ), vanadium sulfate (VSO 4 ㆍ8H 2O), at least one selected from the group consisting of vanadium dichloride (VCl 2 ) and vanadium oxide (VO), surface-treated alloyed hot-dip galvanized steel sheet.
[Claim 8]
The method of claim 5, wherein the cobalt-based anticorrosive agent is cobalt (II) nitrate, cobalt (II) sulfate, and cobalt (II) acetate. ), cobalt (II) oxalate), cobalt (III) nitrate), cobalt (III) acetate), cobalt (III) oxalate (cobalt (III) nitrate) ) oxalate), at least one selected from the group consisting of cobalt (IV) chloride, cobalt (III) oxide, and cobalt (IV) oxide, Alloyed hot-dip galvanized steel plate with surface treatment.
[Claim 9]
The zinc-based plated steel sheet according to claim 5, wherein the trivalent chromate inorganic coating layer has a thickness of 0.3 to 0.5 μm.
[Claim 10]
Coating the surface treatment solution composition of any one of claims 1 to 4 on the alloyed hot-dip galvanized steel sheet on which the alloyed hot-dip galvanizing layer is formed; And drying the coated surface treatment solution composition to form a trivalent chromate inorganic film layer.
[Claim 11]
The method of claim 10, wherein the surface treatment solution composition is coated with a thickness of 2.14 to 3.57 μm.
[Claim 12]
11. The method of claim 10, wherein the coating is made by any one method selected from the group consisting of roll coating, spray, dipping, spray squeezing, and dip squeezing.
[Claim 13]
11. The method of claim 10, wherein the drying is performed at 50 to 60°C based on a final steel sheet temperature (PMT).
[Claim 14]
The method of claim 10, wherein the drying is performed in a hot air drying furnace or an induction heating furnace.
[Claim 15]
The method of claim 14, wherein the hot air drying furnace has an internal temperature of 100 to 200°C.
[Claim 16]
The method of claim 14, wherein the induction heating furnace is applied with a current of 1000 to 3500A.
[Claim 17]
The method of claim 10, further comprising air-cooling the trivalent chromate inorganic coating layer.
[Claim 18]
11. The method of claim 10, wherein the method of manufacturing the alloyed hot-dip galvanized steel sheet is made in a continuous process, and the speed of the continuous process is 80 to 100 mpm.