KR101382910B1 - Galvanized steel sheet having excellent surface property and coating adhesion and method for manufacturing the same - Google Patents

Abstract

The method of manufacturing a hot-dip galvanized steel sheet having excellent plating surface quality and plating adhesion, which is one side of the present invention, preparing a steel sheet, on the prepared steel sheet, one or two of Fe and Co 0.2 to 3 g A first plating step of plating with an adhesion amount of / m 2; Heating the first plated steel sheet at a heating rate of 2 ° C./s or more at a dew point temperature of −30 to 10 ° C., H ₂ : 2 to 20 vol%, and a balance N ₂ atmosphere, to maintain the heated steel sheet. The method may include a step of cooling the retained steel sheet and a second plating step of immersing the cooled steel sheet in a hot dip galvanizing bath. In addition, the hot-dip galvanized steel sheet excellent plating surface quality and plating adhesion of another aspect of the present invention is a steel sheet; A first plating layer comprising one or two of Fe and Co formed on the base steel sheet; And a second plating layer including Zn formed on the first plating layer, wherein the total amount of one or two of SiO ₂ and Al ₂ O ₃ at the interface between the first plating layer and the second plating layer is 0.01 g / m 2. 1 or 2 or more of Si oxide, Mn oxide, Al oxide, and a composite oxide thereof may be discontinuously dispersed within 1 μm from the interface between the first plating layer and the hot dip galvanized layer within 1 μm. have.

Description

Hot-dip galvanized steel sheet with excellent plating surface quality and plating adhesion and manufacturing method {GALVANIZED STEEL SHEET HAVING EXCELLENT SURFACE PROPERTY AND COATING ADHESION AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a hot-dip galvanized steel sheet used for automobiles, household appliances, building materials, and the like, and a manufacturing method thereof.

The hot-dip galvanized steel sheet has excellent corrosion resistance and is widely used for building materials, structures, household appliances, and automobile bodies. The most commonly used hot-dip galvanized steel sheet can be classified into hot-dip galvanized steel sheet (GI steel sheet) and galvannealed hot-dip galvanized steel sheet (GA steel sheet). In recent years, the steel sheet used as a steel sheet for automobiles has been steadily increasing in strength to improve collision stability and fuel economy. However, when the strength is increased, the ductility is relatively lowered. Therefore, a study is being conducted on a method for improving such ductility.

As such technologies, recently developed steel types include Dual Phase (Ferrite and Martensite Phase (DP) steel, Complex Phase (Ferrite, Martensite and Precipitate Phase, hereinafter referred to as CP) steel in which Mn, Si and / Steel, and TRIP (Transformation Induced Plasticity) steel. As described above, when Mn, Si, and / or Al are added to steel, steel sheets having high ductility and high ductility can be manufactured.

Generally, the process for producing a hot-dip galvanized steel sheet is performed by degreasing a cold-rolled steel sheet (aka Full Hard steel sheet) to remove oils and foreign substances on the surface in a pretreatment step, annealing the steel sheet by heating it to a predetermined temperature in the annealing step After cooling to a suitable temperature, it is immersed in a hot-dip galvanizing bath to attach zinc to the steel sheet, and then to control the amount of plating adhered with an air knife and finally cooling to room temperature.

In the ordinary hot dip galvanizing step, the annealing furnace atmosphere in the annealing process of the steel sheet lowers the dew point to -30 占 폚 or less in a reducing atmosphere, so that the iron is not oxidized. However, steel sheets containing Si, Mn, and Al, which are easily oxidized in steel, react with trace amounts of oxygen or water vapor present in the annealing furnace to form Si, Mn, or Al alone or complex oxides on the steel sheet surface, Uneven plating which is not attached to the surface of the coated steel sheet locally or globally occurs, and the quality of the surface of the coated steel sheet is greatly deteriorated.

Various techniques have been proposed to solve this problem, and Patent Document 1 has been proposed as a representative example. However, in Patent Document 1, in order to suppress the diffusion of oxidative components such as Si and Mn to the surface during reduction annealing, the amount of lead coating should be increased by 10 g / m 2 as in the embodiment of Patent Document 1. In this case, there is a problem in that the electroplating equipment for forming a thick pre-plated layer is large, and thus the cost increases.

In addition, although Patent Document 2 has been proposed as a method of suppressing diffusion of Si, Mn, and Al present in the steel to the surface, Si, Mn, and Al immediately below the surface and the surface before the formation of the initial internal heating of annealing Since it is not possible to prevent oxidation on the surface, a considerable amount of Si, Mn, Al and their composite oxides are formed on the surface of the steel sheet after annealing, so that the plating surface quality is improved when plating on the steel sheet. It is difficult to secure the quality of the surface.

Therefore, it is a very urgent time for the technology to be able to secure the plating property and plating adhesion of the hot-dip galvanized steel sheet.

Japanese Patent Application Laid-Open No. 2002-322551 Japanese Patent Publication No. 2004-323970

With respect to hot-dip galvanized steel sheet, it is possible to prevent unplated phenomenon by preventing the formation of oxides due to the surface diffusion of Si, Mn or Al, which is a non-plating element contained in the steel, during annealing. There is a demand for technology that can be secured.

The method of manufacturing a hot-dip galvanized steel sheet having excellent plating surface quality and plating adhesion, which is one side of the present invention, preparing a steel sheet, on the prepared steel sheet, one or two of Fe and Co 0.2 to 3 g A first plating step of plating with an adhesion amount of / m 2; Heating the first plated steel sheet at a heating rate of 2 ° C./s or more at a dew point temperature of −30 to 10 ° C., H ₂ : 2 to 20 vol%, and a balance N ₂ atmosphere, to maintain the heated steel sheet. The method may include a step of cooling the retained steel sheet and a second plating step of immersing the cooled steel sheet in a hot dip galvanizing bath.

In addition, the hot-dip galvanized steel sheet excellent plating surface quality and plating adhesion of another aspect of the present invention is a steel sheet; A first plating layer comprising one or two of Fe and Co formed on the base steel sheet; And a second plating layer including Zn formed on the first plating layer, wherein the total amount of one or two of SiO ₂ and Al ₂ O ₃ at the interface between the first plating layer and the second plating layer is 0.01 g / m 2. 1 or 2 or more of Si oxide, Mn oxide, Al oxide, and a composite oxide thereof may be discontinuously dispersed within 1 μm from the interface between the first plating layer and the hot dip galvanized layer within 1 μm. have.

According to an aspect of the present invention, it is possible to manufacture a high-strength hot-dip galvanized steel sheet that suppresses the surface concentration and oxidation of Si, Mn, or Al and is excellent in surface quality and plating adhesion of the plated steel sheet.

The present inventors have studied in depth how to provide a hot-dip galvanized steel sheet having excellent surface quality and plating adhesion, but can improve the strength and ductility at the same time by adding Mn, Si or Al to the base steel sheet, zinc When plating, there was a problem of forming oxide at the interface between the base steel plate and the plated layer. Recognizing that it can be prevented, and controlling the dew point, heating rate, heating temperature, etc. during annealing, Si, Mn or Al reacts with oxygen diffused into the steel, and most of it is oxidized in the lead gold layer to By forming it, it recognized that it can suppress that it spreads to the steel plate surface, and came to this invention.

Hereinafter, a method of manufacturing a hot-dip galvanized steel sheet which is one aspect of the present invention will be described in detail.

First, prepare the steel sheet. The base steel sheet may include one or more selected from the group consisting of Si, Mn and Al. The steel sheet added with less than 0.5% by weight of Si, Mn, or Al has a slight amount of oxide formed on the surface of the steel sheet, and the steel sheet exceeding 6.0% by weight is less practical, so that 0.5% to 6.0% of Si, Mn, or Al is used. Steel plate added with may be suitable to maximize the oxide formation inhibiting effect. However, the present invention can be applied even when the content is lower than the above, and steel grades containing a large amount of the elements are only limited to these lower limits because unplating or plating peeling may be a problem. In addition, the base steel sheet of the C, Cr, P, Ti, V, Ni, Nb, Mo, B, Co, Cu and other unavoidable impurities added for the purpose of improving the strength, ductility, bending workability, hole expandability of the steel sheet It may include one or two or more, each element may be included in less than 0.5% by weight. In the above content range can exhibit the effects of the present invention. The base steel sheet may be a cold rolled steel sheet, or may be a cold rolled steel sheet subjected to a degreasing process by a conventional degreasing method.

The first plating layer may be formed on the prepared steel sheet. Subsequently, Si, Mn, or Al contained in the steel under the first plating layer diffuses toward the surface of the first plating layer during heating, and oxygen diffuses into the steel due to the high dew point inside the annealing furnace. Therefore, since Si, Mn, or Al react with oxygen diffused to the inside, most of them are oxidized in the first plating layer to form internal oxides, thereby suppressing diffusion to the surface.

It is preferable that the said 1st plating layer contains 1 type or 2 types of Fe and Co. By forming the first plating layer of the metal, it is easy to prevent the diffusion of Si, Mn or Al contained in the steel, and can improve the adhesion with the second plating layer. Moreover, it is preferable to control the adhesion amount to 0.2-3 g / m <2>. When the adhesion amount is less than 0.2 g / m 2, since the first plating layer is too thin, there may be a part where the first plating layer does not exist, and in this area, Si, Mn or Al present on the surface of the initial steel sheet is subjected to oxidation. In addition, in the state where the internal annealing has not yet occurred in the annealing device, Si, Mn or Al existing directly below the surface can also diffuse to the surface to form an oxide. On the other hand, even if the adhesion amount exceeds 3g / ㎡, the internal oxide dispersion effect which is the effect of the present invention is excellent, but it is preferable to control the upper limit for economic reasons. In addition, the method of plating the metal is not particularly limited, but electroplating is most preferable in consideration of economical efficiency. The plating solution used in the electroplating is not particularly limited as it can be a water soluble sulfuric acid bath, a chlorinated bath, or a fluorinated bath.

Thereafter, the steel plate on which the first plating layer is formed may be heated. At this time, the atmosphere gas is preferably controlled by a gas in which H ₂ and N ₂ are mixed. And, H _2: it is more preferred to conduct the heating step in 2 ~ 20 vol% and the balance N ₂ atmosphere. However, in the present invention, the atmosphere gas may include other unavoidable gas components in the annealing furnace in the process, and in particular, oxygen of 20 ppm or less may be inevitably included. Reducing atmosphere can be maintained through the atmosphere gas. When the content of H ₂ is less than 2%, trace amounts of Fe or Co oxides present on the surface of the steel sheet may not be reduced and may exist on the surface until the annealing is completed, thereby degrading the plating quality. Although the upper limit is not specifically limited. It is controlled by considering the saturation of the effect and the risk of explosion. In addition, it is preferable to control dew point temperature at the time of heating to -30-10 degreeC. When the dew point temperature in the annealing furnace is lower than -30 ° C, internal oxidation hardly occurs. If the dew point temperature is higher than 10 ° C, Fe, Ni, or Co part of the surface may be oxidized. .

And, the heating rate is a factor affecting the diffusion rate of Si, Mn or Al, it is important to control this. If the heating rate is too slow, it is preferable to control the temperature at least 2 ° C per second since the interval between the annealing is completed and the amount of diffusion of Si, Mn or Al to the surface may increase. Moreover, it is preferable to heat up to 750-850 degreeC at the said heating rate. If it is less than 750 degreeC, sufficient annealing does not occur, and even if it exceeds 850 degreeC, since the effect of this invention is the same, the upper limit can be controlled in consideration of economical efficiency.

After that, it is preferable to hold the base steel sheet for 10 to 70 seconds. If the holding time is less than 10 seconds, sufficient annealing does not occur, but within 70 seconds, annealing occurs sufficiently. It is not preferable because more than 70 seconds may increase the amount of Si, Mn or Al diffusion to the surface.

Thereafter, the base steel sheet can be cooled. The method of cooling here is not specifically limited, Any method may be used.

In addition, the surface layer portion of the steel sheet after the reduction is mostly Fe or Co metal, and the oxide composed of Si, Mn, Al alone or in combination is not formed or is formed in an extremely small amount. In this case, it is possible to produce a high strength zinc galvanized steel sheet having excellent surface quality due to excellent wettability with zinc on the annealing surface.

The cooled base steel sheet may be immersed in a plating bath to perform a second plating process. The method of forming the plating layer is not particularly limited. However, when the plating bath temperature is lower than 440 DEG C, the wettability of zinc and the steel sheet is decreased. When the plating bath temperature is higher than 480 DEG C, the plating bath temperature is lowered to 440 to 480 DEG C, , The rate of dissolution of the refractory iron is increased, accelerating the generation of Fe-Zn compound dross in the plating bath, thereby deteriorating the cleanliness of the plating bath.

After the plating step, the hot-dip galvanized steel sheet may be further subjected to an alloying heat treatment. By controlling the alloying heat treatment temperature to 480 DEG C or higher, it is possible to secure a sufficient Fe content in the zinc plated layer and to control the temperature to 650 DEG C or less to prevent the powdering phenomenon in which the plating layer is dropped in the process of excessive Fe content in the plated layer have.

Through the above manufacturing method, it is possible to prevent the non-plating element Si, Mn or Al from diffusing to the steel surface during annealing, and most of the Si, Mn or Al reacts with oxygen diffused into the steel By oxidizing in the first plating layer to form internal oxides, it is possible to suppress diffusion to the surface of the steel sheet.

Hereinafter, a hot-dip galvanized steel sheet according to another aspect of the present invention will be described in detail. In the present invention, the hot-dip galvanized steel sheet may be an alloyed hot-dip galvanized steel sheet.

The hot dip galvanized steel sheet may include a base steel sheet. As described above, the base steel sheet may include one or two or more selected from the group consisting of Si, Mn and Al. The steel sheet to which Si, Mn, or Al is added in less than 0.5% by weight has a slight amount of oxide formed on the surface of the steel sheet, and the steel sheet exceeding 6.0% by weight is not practical, so that one or two of Si, Mn, and Al It is preferable to control the sum total of a type or more to 0.5 to 6.0 weight%. In addition, the base steel sheet of the C, Cr, P, Ti, V, Ni, Nb, Mo, B, Co, Cu and other unavoidable impurities added for the purpose of improving the strength, ductility, bending workability, hole expandability of the steel sheet It may include one or two or more, each element may be included in less than 0.5% by weight. In the above content range can exhibit the effects of the present invention.

The hot dip galvanized steel sheet may include a first plating layer formed on the base steel sheet. The first plating layer includes one or two of Fe and Co, the adhesion may be 0.2 to 3 g / ㎡. However, other elements in addition to one or two of the Fe and Co may be included, and the base steel sheet, Co may be diffused. Therefore, the boundary between the first plating layer and the base steel sheet may be blurred. As described above, when the adhesion amount is less than 0.2 g / m 2, since the first plating layer is too thin, there may exist a part where the first plating layer does not exist, and in the site, the first plating layer may exist. In the state where Si, Mn or Al are oxidized and the annealer has not yet internally oxidized, Si, Mn or Al existing directly under the surface can also diffuse to the surface to form an oxide. On the other hand, even if the adhesion amount exceeds 3g / ㎡, the internal oxide dispersion effect which is the effect of the present invention is excellent, but it is preferable to control the upper limit for economic reasons. In addition, Si, Mn or Al contained in the steel reacts with oxygen diffused into the interior, and most of them are oxidized in the first plating layer to form internal oxides. Therefore, in the surface layer portion, most of Fe or Co metal, and oxides composed of Si, Mn, and Al alone or in combination may not be formed or may be formed in extremely small amounts. The first plating layer may include one or two of Fe oxides and Co oxides, and the sum of the oxides may be included in an amount of 5 wt% or less in the first plating layer. This is because some of the metal may be electrodeposited with an oxide during plating.

The hot dip galvanized steel sheet may include a second plating layer formed on the first plating layer. As described above, the second plating layer may be formed by a hot dip galvanizing process, and is preferably performed under the above-described plating bath conditions. When the alloying heat treatment is performed, the Fe content in the plating layer can be controlled to 7 to 13%.

The total amount of one or two of SiO ₂ and Al ₂ O ₃ at the interface between the first plating layer and the second plating layer may be 0.01 g / m 2 or less. One or two or more kinds of Si oxide, Mn oxide, Al oxide, and composite oxides thereof may be discontinuously dispersed within 1 μm in the direction of the base steel sheet from the interface between the first plating layer and the hot dip galvanized layer. The range within 1 μm may be a diffusion layer that may include an upper portion of the steel sheet as well as the first plating layer.

Therefore, the hot-dip galvanized steel sheet which is one aspect of the present invention can provide a steel sheet excellent in plating quality by suppressing diffusion of Si, Mn and / or Al to the surface by the first plating layer to form an oxide.

Hereinafter, the present invention will be described more specifically by way of examples. It should be noted, however, that the following examples are intended to illustrate the invention in more detail and not to limit the scope of the invention. The scope of the present invention is determined by the matters set forth in the claims and the matters reasonably inferred therefrom.

(Example)

A thickness of 1.2 mm, including 1.0 wt% of Si, 1.7 wt% of Mn, and 0.03 wt% of Al was used as the steel sheet, and after removing foreign substances and rolling oil from the steel sheet, the following Table 1 The first plating layer was formed under the conditions shown, and the adhesion amount of the plating layer was measured and shown in Table 2 below. In addition, the annealing process was performed according to the conditions shown in Table 2 (dew point, heating rate, hydrogen content, annealing temperature and holding time). Thereafter, after performing the hot dip galvanizing process, the surface of the steel sheet was inspected to determine the surface quality according to the presence and the degree of unplating.

In the case of the Fe first plating layer, in order to analyze the adhesion amount between the base steel plate and the plating layer, Fe wire plating is performed using a Cu plate as a material for each plating condition, and after dissolving Fe plated on the Cu plate, ICP (Inductively It was measured by the amount of adhesion after analysis through coupled plasma). In the other Co 1st plating layer, the plating layer was dissolved and analyzed by ICP.

The surface quality was determined under the following conditions.

⊚: Excellent (steel plate having no plating at all over plated steel plate)

Good: Excellent (less than 2 pieces per 100 cm &lt; 2 &gt; of spotless plating less than 0.5 mm in thickness)

?: Poor (steel plate having a large amount of unexploded spot plating of 0.5 mm to 3 mm size)

X: extremely poor (steel plate having an unplated size exceeding 3 mm is observed)

Fe ²⁺ / Co ²⁺

(g / l) SO ₄ ^2- (g / l) pH Current density
(A / dm ² ) Plating bath temperature
(° C) 40 80 2.5 40 60

division First Plating
Adhesion
(g / m 2) dew point
Temperature
(° C) Heating
speed
(° C / sec) Hydrogen
content
(Vol%) heating
Temperature
(° C) maintain
time
(second) Molten zinc
Coated steel plate
Surface quality Inventory 1 Fe 0.3 -10 5 5 800 40 ◎ Inventive Example 2 Fe 0.5 -5 7 20 800 40 ◎ Inventory 3 Fe 0.5 0 15 5 850 30 ◎ Honorable 4 Fe 1.0 5 20 5 850 20 ◎ Inventory 5 Fe 2.0 -25 7 3 800 40 ◎ Proposition 9 Co 0.5 -5 5 10 850 30 ◎ Inventory 10 Co 0.5 5 5 5 800 40 ◎ Exhibit 11 Co 1.0 -10 10 5 800 60 ◎ Comparative Example 1 - -45 5 5 800 40 X Comparative Example 2 - -10 5 5 800 40 ? Comparative Example 3 Fe 0.5 -45 5 5 800 40 ? Comparative Example 4 Fe 1.0 -5 0.5 5 800 40 ? Comparative Example 5 Fe 1.0 5 3 0 800 40 ? Comparative Example 6 Ni 0.5 5 3 5 850 200 ? Comparative Example 7 Co 0.1 -60 3 5 800 40 X

As shown in Table 2 above, Fe or Co is leaded to 0.2 ~ 3g / ㎡, then the dew point temperature of -30 ~ 10 ℃, at a heating rate of 2 ℃ or more per second in a reducing annealing furnace of hydrogen content of 2% or more From the annealing temperature to 750 ~ 850 ℃ and maintained at that temperature for 10 to 70 seconds after annealing the steel sheet and then cooled and immersed in a zinc plating bath galvanized steel sheet, it can be confirmed that the plating surface was excellent. .

On the contrary, Comparative Example 1 is a case where the dew point temperature in the annealing furnace is lower than the range controlled by the present invention without forming the first plating layer, and a large amount of surface oxide is formed, resulting in extremely poor plating surface quality.

In Comparative Example 2, the dew point temperature, heating rate, hydrogen content, heating temperature and holding time are within the range controlled by the present invention. However, when the first plating is not performed, a large amount of surface oxide is formed and the plating surface is poor. It was.

In Comparative Example 3, the Fe plating was carried out in the range controlled by the present invention before annealing, but the dew point temperature in the annealing furnace was lower than the range controlled by the present invention. Diffused to the surface to form a surface oxide was poor plating surface.

In addition, in Comparative Example 4, the Fe plating deposition amount, dew point temperature, hydrogen content, heating temperature, holding time is a range controlled by the present invention, but the heating rate is slower than the range controlled by the present invention, a part of the oxidizing component surface The surface quality was poor due to diffusion.

In Comparative Example 5, the Fe plating deposition amount, dew point temperature, heating rate, heating temperature, holding time is a range controlled by the present invention, but when there is no hydrogen in the annealing furnace, the trace amount of Fe oxide present on the surface of the steel sheet is reduced It was not present on the surface of the steel sheet until the annealing was completed, the surface quality was poor.

In addition, Comparative Example 7 is a case where the amount of Co plating deposition is less than the range controlled by the present invention and the dew point temperature in the annealing furnace is lower than the range controlled by the present invention, and the diffusion inhibiting effect of the oxidizing component by the first plating layer is small. Since no internal oxides were formed, the plating surface was extremely poor.

Claims (14)

Preparing a base steel sheet;
A first plating step of plating one or two of Fe and Co on the prepared base steel sheet with an adhesion amount of 0.2 to 3 g / m 2;
Heating the first plated steel sheet at a rate of 2 ° C./s or more in a dew point temperature of −30 to 10 ° C., H ₂ : 2 to 20 vol% and the balance N ₂ atmosphere;
Maintaining the heated steel sheet;
Cooling the maintained steel plate; And
Including a second plating step of immersing the cooled steel plate in a hot dip galvanizing bath to plate
A first plating layer comprising one or two of Fe and Co formed on the base steel sheet; And a second plating layer including Zn formed on the first plating layer.
The first plating layer includes one or two of Fe oxide and Co oxide, the total of one or two of the Fe oxide and Co oxide is 5 wt% or less of the first plating layer,
At the interface between the first plating layer and the second plating layer, the total amount of one or two of SiO ₂ and Al ₂ O ₃ is 0.01 g / m 2 or less,
Hot-dip zinc plating, in which one or two or more of Si oxide, Mn oxide, Al oxide, and composite oxides thereof are discontinuously contained within 1 μm in the direction of the base steel sheet from the interface between the first plating layer and the hot dip galvanized layer. Method for producing hot-dip galvanized steel sheet with excellent plating surface quality and plating adhesion for producing steel sheet.
The method of claim 1, wherein the base steel sheet is in weight percent, one or two or more of Si, Mn, and Al is 0.5 to 6.0% of the plating surface quality and the plating adhesion is excellent manufacturing method of the hot-dip galvanized steel sheet.
The method of claim 1, wherein the steel sheet comprises one or two or more of C, Cr, P, Ti, V, Ni, Nb, Mo, B, Co, Cu and other unavoidable impurities, each element is 0.5 Method for producing a hot-dip galvanized steel sheet excellent in plating surface quality and plating adhesion contained in the wt% or less.
The method of manufacturing a hot-dip galvanized steel sheet according to claim 1, wherein the first plating step is excellent in plating surface quality and plating adhesion performed by an electroplating method.
The method according to claim 1, wherein the heating step is a method of manufacturing a hot-dip galvanized steel sheet excellent in plating surface quality and plating adhesion is heated to 750 ~ 850 ℃.
The method of claim 1, wherein the maintaining is performed for 10 to 70 seconds.
The method of claim 1, wherein the hot dip galvanizing bath is a temperature of 440 ~ 480 ℃ plating surface quality and excellent adhesion of the hot dip galvanized steel sheet manufacturing method.
The method of claim 1, wherein the manufacturing method further comprises a step of alloying heat treatment at 480 ° C. to 650 ° C. after the second plating step.
Base steel sheet; A first plating layer comprising one or two of Fe and Co formed on the base steel sheet; And a second plating layer including Zn formed on the first plating layer.
The first plating layer includes one or two of Fe oxide and Co oxide, the total of one or two of the Fe oxide and Co oxide is 5 wt% or less of the first plating layer,
At the interface between the first plating layer and the second plating layer, the total amount of one or two of SiO ₂ and Al ₂ O ₃ is 0.01 g / m 2 or less,
Hot-dip zinc plating, in which one or two or more of Si oxide, Mn oxide, Al oxide, and composite oxides thereof are discontinuously contained within 1 μm in the direction of the base steel sheet from the interface between the first plating layer and the hot dip galvanized layer. Grater.
The hot-dip galvanized steel sheet according to claim 9, wherein the base steel sheet is in weight percent, and one or two or more of Si, Mn, and Al are contained in 0.5 to 6.0%.
The method of claim 9, wherein the steel sheet comprises one or two or more of C, Cr, P, Ti, V, Ni, Nb, Mo, B, Co, Cu and other unavoidable impurities, each element is 0.5 Hot-dip galvanized steel sheet with excellent plating surface quality and plating adhesiveness contained in weight% or less.
10. The hot-dip galvanized steel sheet according to claim 9, wherein the deposition amount of the first plating layer is 0.2 to 3 g / m2.
delete The hot-dip galvanized steel sheet according to claim 9, wherein the hot-dip galvanized steel sheet is an alloyed hot-dip galvanized steel sheet, and the second plating layer is 7 to 13 wt% Fe.