High-strength hot-dip galvanized steel sheet excellent in plating properties and method for producing the same

Abstract

One embodiment of the present invention provides a high-strength hot-dip galvanized steel sheet having an excellent plateability, the hot-dip galvanized steel sheet having a base steel sheet and a hot-dip galvanized layer formed on one or both sides of the base steel sheet, the base steel sheet containing, by weight, 0.1-0.3% carbon (C), 0.1-2.0% silicon (Si), 0.1-1.5% aluminum (Al), 1.5-3.0% manganese (Mn), with the balance being Fe and unavoidable impurities, the total of the Si and Al satisfying 1.2-3.5%, the ratio of the Al and Si (Al / Si) satisfying 0.5-2.0, the surface roughness (Ra) of the base steel sheet being 0.5 μm or more, and the base steel sheet including an internal oxide layer having a thickness of less than 4 μm immediately below the surface thereof, and a manufacturing method thereof.

Description

Technical Field

[0001] The present invention relates to a high-strength hot-dip galvanized steel sheet excellent in plating properties and a method for producing the same.

Background Art

[0002] Recently, due to emerging environmental regulations, there has been a rapid increase in the demand for ultra-high-strength steel sheets as a solution to meet the strict fuel consumption regulations and enhanced collision stability regulations for automobiles. In addition, while fuel efficiency improvement is required to achieve national carbon emission reduction targets, the weight of automobiles has been continuously increasing due to performance improvement and the addition of various convenience devices. To solve such problems, the demand for ultra-high-strength steel sheets has also been continuously increasing. Therefore, steel manufacturers are focusing on the development of high-strength steel sheets such as Dual Phase (DP) steel, Transformation Induced Plasticity (TRIP) steel, and Complex Phase (CP) steel.

[0003] To increase the strength of steel sheets for automobiles, it is common to add a large amount of elements such as Si, Mn, and Al to the steel. However, in steel sheets containing these elements, during the annealing heat treatment process, these elements generate oxides on the surface of the steel sheet, which may deteriorate the plating properties when the steel sheet is immersed in the hot-dip galvanizing bath, leading to plating peeling. Also, later, during the spot welding process, it may cause Liquid Metal Embrittlement, where the liquid-phase molten metal penetrates through the base metal grain boundaries and induces cracks, potentially deteriorating the spot weldability.

[0004] To improve the plating properties of the steel sheets with a large amount of Si, Mn, and Al added as described above, it is necessary to suppress the oxides generated on the surface of the steel sheet. For this purpose, the addition amounts of Si and Al added to the steel must be reduced. However, in such cases, there is a problem that it is difficult to ensure the target material properties.

[0005] As a typical technique for solving this problem, there is Patent Document 1. Patent Document 1 relates to a technique for suppressing the formation of SiO2 or the like on the surface by preferentially concentrating trace components such as Sb in steel at grain boundaries by adding them.

[0006] However, in reality, there is still a demand for the development of a technique that can more reliably prevent the diffusion of alloy elements in steel during the manufacture of steel sheets.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] One aspect of the present invention aims to provide a hot-dip galvanized steel sheet with excellent plating properties and a method for manufacturing the same.

Means for Solving the Problems

[0009] One embodiment of the present invention is a hot-dip galvanized steel sheet having a base steel sheet and a hot-dip galvanized layer formed on one or both sides of the base steel sheet, wherein the base steel sheet contains, by weight%, carbon (C): 0.1 to 0.3%, silicon (Si): 0.1 to 2.0%, aluminum (Al): 0.1 to 1.5%, manganese (Mn): 1.5 to 3.0%, and the balance Fe and unavoidable impurities, the total of Si and Al satisfies 1.2 to 3.5%, the ratio of Al to Si (Al / Si) satisfies 0.5 to 2.0, the surface roughness (Ra) of the base steel sheet is 0.5 μm or more, and the base steel sheet provides a hot-dip galvanized steel sheet with excellent plating properties that contains an internal oxide layer with a thickness of less than 4 μm immediately below the surface.

[0010] Other embodiments of the present invention include, by weight%, carbon (C): 0.1 to 0.3%, silicon (Si): 0.1 to 2.0%, aluminum (Al): 0.1 to 1.5%, manganese (Mn): 1.5 to 3.0%, the balance being Fe and unavoidable impurities, wherein the total of Si and Al satisfies 1.2% or more, and the ratio of Al to Si (Al / Si) satisfies 0.5 to 2.0. The method includes reheating a slab at 1000 to 1300°C, hot finish rolling the reheated slab at 800 to 950°C to obtain a hot-rolled steel sheet, coiling the hot-rolled steel sheet at 630 to 700°C, pickling the coiled hot-rolled steel sheet for more than 30 seconds and less than 60 seconds, cold rolling, annealing, and cooling the pickled hot-rolled steel sheet to obtain a cold-rolled steel sheet, and hot-dip galvanizing the cold-rolled steel sheet, thereby providing a method for manufacturing a high-strength hot-dip galvanized steel sheet with excellent plating properties.

Advantages of the Invention

[0011] According to one aspect of the present invention, it is possible to provide a high-strength hot-dip galvanized steel sheet with excellent plating properties and a method for manufacturing the same.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0013] The following describes a hot-dip galvanized steel sheet with excellent plating properties according to an embodiment of the present invention. The hot-dip galvanized steel sheet of the present invention has a base steel sheet and a hot-dip galvanized layer formed on one or both surfaces of the base steel sheet. First, the alloy composition of the base steel sheet of the present invention will be described. Unless otherwise specified, the contents of the alloy compositions described below mean weight %.

[0014] Carbon (C): 0.1 to 0.3% The above C is an element that contributes to the stabilization of the austenite structure, and the increase in its content has an advantageous aspect in ensuring the austenite structure. In order to obtain the above effect, the C content is preferably 0.1% or more. However, when it exceeds 0.3%, slab defects may occur and there is a problem that weldability also deteriorates. Therefore, the content of the above C preferably has a range of 0.1 to 0.3%. The lower limit of the C content is more preferably 0.15%. The upper limit of the C content is more preferably 0.25%.

[0015] Silicon (Si): 0.1 to 2.0% Silicon (Si) is an element that suppresses the precipitation of carbides in ferrite, promotes the diffusion of carbon in ferrite into austenite, and contributes to the stabilization of retained austenite. In order to obtain the above-described effects, it is preferable that the above Si is added in an amount of 0.1% or more. However, when its content exceeds 2.0%, not only is the rollability inferior, but oxides are formed on the surface of the steel sheet during the heat treatment process, which may lead to deterioration of plating properties and adhesion. Therefore, the content of the above Si preferably has a range of 0.1 to 2.0%. The lower limit of the Si content is more preferably 0.2%. The upper limit of the Si content is more preferably 1.8%.

[0016] Aluminum (Al): 0.1 to 1.5% Aluminum (Al) is an element that combines with oxygen in steel to deoxidize it. Moreover, like the above-mentioned Si, Al is an element that suppresses the formation of carbides in ferrite and contributes to the stabilization of retained austenite. To obtain the above-described effects, it is preferable to add 0.1% or more of the above Al. However, when its content exceeds 1.5%, not only is the soundness of the slab inferior, but since it is an element with strong oxygen affinity, it may form oxides on the surface of the steel sheet, resulting in inhibition of plating properties and adhesion. Therefore, it is preferable that the content of the above Al has a range of 0.1 to 1.5%. It is more preferable that the lower limit of the above Al content is 0.2%. It is more preferable that the upper limit of the above Al content is 1.4%.

[0017] Manganese (Mn): 1.5 - 3.0% The above Mn is an element that stabilizes the austenite structure together with carbon. When the above Mn content is less than 1.5%, it becomes difficult to ensure the target strength due to the occurrence of ferrite transformation. When it exceeds 3.0%, due to the formation of martensite caused by the delay of phase transformation in the secondary annealing heat treatment process, difficulties occur in ensuring the target ductility. Therefore, it is preferable that the content of the above Mn has a range of 1.5 - 3.0%. It is more preferable that the lower limit of the above Mn content is 1.7%. It is more preferable that the upper limit of the above Mn content is 2.9%.

[0018] In addition to the above-described steel composition, the remainder can contain Fe and unavoidable impurities. Unavoidable impurities are those that can be inadvertently mixed in during normal steel manufacturing processes, and it is impossible to completely eliminate them. A person skilled in the ordinary steel manufacturing field can easily understand its meaning. Note that the present invention does not completely exclude the addition of other compositions other than the above-described steel composition.

[0019] On the one hand, as described above, both Si and Al are elements that contribute to the stabilization of retained austenite. In order to effectively achieve this, it is preferable that the total content of Si and Al satisfies the range of 1.2% to 3.5%. When the total content of the above Si and Al is less than 1.2%, it may be difficult to sufficiently obtain the effect of increasing the elongation rate. On the contrary, when the total content of the above Si and Al exceeds 3.5%, problems such as poor castability and rollability may occur. The lower limit of the total content of the above Si and Al is more preferably 1.3%. The upper limit of the total content of the above Si and Al is more preferably 3.4%.

[0020] Also, the ratio of Al to Si (Al / Si) preferably satisfies 0.5 to 2.0. When the ratio of the above Al to Si is less than 0.5, the sensitivity of spot welding LME (Liquid Metal Embrittlement) increases due to Si-based matrix formation, which may lead to deterioration of weldability. On the contrary, when the ratio of Al to Si exceeds 2.0, the oxygen affinity becomes relatively high due to Al-based matrix formation, and the formation of oxides on the surface of the steel sheet becomes easy, which may result in poor plating properties and adhesion. The lower limit of the ratio of the above Al to Si is more preferably 0.6. The upper limit of the ratio of the above Al to Si is more preferably 1.9.

[0021] For the hot-dip galvanized steel sheet of the present invention, the surface roughness (Ra) of the base steel sheet is preferably 0.5 μm or more. In this way, by imparting surface roughness to the base steel sheet, adhesion due to the anchoring effect can be ensured between the hot-dip galvanized layer and the base steel sheet. In order to obtain the above effect, the surface roughness (Ra) of the above base steel sheet is preferably 0.5 μm or more. The surface roughness (Ra) of the above base steel sheet is more preferably 0.7 μm or more. On the other hand, in the present invention, the larger the surface roughness of the above base steel sheet, the more advantageous it is to ensure the above-described effect, so the upper limit is not particularly limited. However, due to the limitations in the manufacturing process, the surface roughness of the above base steel sheet may not easily exceed 2 μm.

[0022] The hot-dip galvanized steel sheet of the present invention preferably contains an internal oxide layer with a thickness of less than 4 μm immediately below the surface of the base steel sheet. By forming the internal oxide layer immediately below the surface of the base steel sheet, the present invention prevents Al and Si present in the base steel sheet from diffusing into the surface layer of the steel sheet, and by preventing the formation of Al or Si oxides in the surface layer, one of the features is to improve the plating property. However, when the thickness of the internal oxide layer is 4 μm or more, there is a drawback that oxides on the steel sheet surface may be picked up by the roll during the annealing heat treatment process, resulting in surface defects such as dents. Therefore, the thickness of the internal oxide layer is preferably less than 4 μm. More preferably, the thickness of the internal oxide layer is 3.5 μm or less.

[0023] The internal oxide layer can contain oxides with a maximum length of less than 4 μm. When the maximum length of the oxides is 4 μm or more, there is a drawback that oxides on the steel sheet surface may be picked up by the roll during the annealing heat treatment process, resulting in surface defects such as dents. Therefore, the maximum length of the oxides is preferably less than 4 μm. More preferably, the maximum length of the oxides is 3.5 μm or less.

[0024] The oxides can be composed of Al, Si composite oxides. In this way, since the oxides are composed of Al, Si composite oxides, an effect can be obtained in which the form of the oxides forms discontinuous oxides rather than a continuous form such as a layer, and the plating adhesion can be improved.

[0025] The above Al, Si composite oxide can exist either within the crystal grains or at the grain boundaries, but it will exist relatively more at the grain boundaries. At this time, it is preferable that the above Al, Si composite oxide exists intermittently at the grain boundaries. Thus, by making the above Al, Si composite oxide exist intermittently at the grain boundaries, it can be advantageous for ensuring plating adhesion compared to making it exist continuously. More specifically, among the Al contained in the above Al, Si composite oxide, the Al existing at the grain boundaries can have an interval of 20 nm or more. When the interval of the Al existing at the above grain boundaries is less than 20 nm, it may be difficult to ensure plating adhesion. It is more preferable that the interval of the Al existing at the above grain boundaries is 30 nm or more.

[0026] The hot-dip galvanized steel sheet of the present invention provided as described above has a yield strength of 600 MPa or more, a tensile strength of 950 MPa or more, and an elongation of 20% or more, and can ensure excellent mechanical properties. Also, while the area of the hot-dip galvanized layer with respect to the total area of the base steel sheet is 95% or more, the plating adhesion is good, and it can have excellent plating properties. Also, no LME cracks occur, and it can have excellent LME crack resistance.

[0027] Hereinafter, a method for manufacturing a high-strength hot-dip galvanized steel sheet with excellent plating properties according to an embodiment of the present invention will be described.

[0028] First, a slab satisfying the above alloy composition is reheated at 1000 to 1300°C. When the above slab reheating temperature is less than 1000°C, there may be a problem that the rolling load increases significantly, and when it exceeds 1300°C, there may be a problem that the surface scale becomes excessive. Therefore, it is preferable that the above slab reheating temperature has a range of 1000 to 1300°C. The lower limit of the above slab reheating temperature is more preferably 1050°C. The upper limit of the above slab reheating temperature is more preferably 1250°C.

[0029] Thereafter, the reheated slab is hot finish rolled at 800 to 950 °C to obtain a hot rolled steel sheet. When the hot finish rolling temperature is less than 800 °C, there is a problem that the rolling load increases and rolling becomes difficult. When it exceeds 950 °C, there is a drawback that the roll life is shortened due to an increase in thermal fatigue of the rolling roll. Therefore, the hot finish rolling temperature preferably has a range of 800 to 950 °C. The lower limit of the hot finish rolling temperature is more preferably 830 °C. The upper limit of the hot finish rolling temperature is more preferably 930 °C.

[0030] Thereafter, the hot rolled steel sheet is coiled at 630 to 700 °C. When the coiling temperature is less than 630 °C, since an internal oxide layer is not formed, the formation of oxides is promoted in the surface layer portion of the steel sheet during the annealing heat treatment process, and there is a possibility of poor plating properties. When it exceeds 700 °C, the depth of the internal oxide layer becomes considerably deep, and oxides are picked up by the roll during the subsequent annealing heat treatment process, which may induce surface defects such as dents. Therefore, the coiling temperature preferably has a range of 630 to 700 °C. The lower limit of the coiling temperature is more preferably 650 °C. The upper limit of the coiling temperature is more preferably 680 °C.

[0031] Thereafter, the wound hot-rolled steel sheet is pickled for more than 30 seconds and less than 60 seconds. If the pickling time is 30 seconds or less, the hot-rolled scale may not be completely removed, which may cause unplated areas and peeling of the plating due to the residual scale. On the other hand, if it is 60 seconds or more, the pickling solution penetrates along the grain boundaries of the internal oxide layer and causes the internal oxide layer to fall off, so that the internal oxide layer of the finally obtained steel sheet is completely removed, and alloying elements cannot be suppressed from diffusing to the surface layer of the steel sheet during the annealing heat treatment process, and there is a possibility of inferior plating properties and adhesion. Also, if the pickling time is not satisfied, the surface roughness (Ra) of the base steel sheet becomes less than 0.5 μm, and a smooth surface is obtained. Therefore, it is difficult to expect an anchoring effect with the hot-dip galvanized layer in the subsequent plating process, and it becomes difficult to ensure adhesion. Therefore, it is preferable that the pickling time has a range of more than 30 seconds and less than 60 seconds. The lower limit of the pickling time is more preferably 35 seconds, and even more preferably 40 seconds. The upper limit of the pickling time is more preferably 55 seconds, and even more preferably 50 seconds.

[0032] Thereafter, the pickled hot-rolled steel sheet is cold-rolled, annealed, and cooled to obtain a cold-rolled steel sheet. In the present invention, the cold rolling, annealing, and cooling conditions are not particularly limited, and conditions usually used in the art can be used.

[0033] Thereafter, the cooled cold-rolled steel sheet is hot-dip galvanized. In the present invention, the hot-dip galvanizing method is not particularly limited, and conditions usually used in the art can be used. However, for example, it can be carried out by immersing the cold-rolled steel sheet in a hot-dip galvanizing bath at 440 to 460°C. When the temperature of the hot-dip galvanizing bath is less than 440°C, the viscosity of the plating bath increases, the mobility of the roll for winding the steel sheet decreases, and slip between the steel sheet and the roll may be induced, which may induce defects in the steel sheet. When it exceeds 460°C, the phenomenon of the steel sheet dissolving in the plating bath is promoted, and the generation of dross in the form of Fe-Zn compounds is accelerated, which may induce surface defects.

[0034] On the other hand, after the hot-dip galvanizing, the hot-dip galvanized steel sheet can further include a step of performing an alloying heat treatment at 480 to 600°C. When the alloying heat treatment temperature is less than 480°C, Fe in the base material may not sufficiently diffuse into the plating layer, and it may not be possible to sufficiently ensure the Fe content in the plating layer. When the temperature exceeds 600°C, the Fe content in the plating layer becomes excessive, and a powdering phenomenon may occur in which the plating layer peels off during the process of processing the steel sheet.

Example

[0035] Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples are illustrative for explaining the present invention in more detail and do not limit the scope of the rights of the present invention.

[0036] (Example) A molten metal having the alloy composition shown in Table 1 below was produced into an ingot with a width of 175 mm and a thickness of 90 mm in a vacuum melting furnace, and then reheated at 1200°C for 1 hour for homogenization treatment. After hot finish rolling at 900°C, which is a temperature above Ar3, it was wound up under the conditions shown in Table 2 below to produce a hot-rolled steel sheet. This hot-rolled steel sheet was pickled by immersing it in a pickling solution of 15% HCl under the conditions shown in Table 2. Thereafter, a cold-rolled steel sheet was produced by cold rolling with a cold reduction rate of 50 to 60%. This cold-rolled steel sheet was subjected to an annealing heat treatment while blowing nitrogen gas containing 5% by volume of hydrogen into a reduction furnace at 860°C, then cooled, immersed in a hot-dip galvanizing bath for 5 seconds, and the plating adhesion amount was adjusted to a level of 60 g / m on a single-sided basis by air wiping 2 to produce a hot-dip galvanized steel sheet.

[0037] After measuring the mechanical properties, the roughness of the base steel sheet, the thickness of the internal oxide layer, the maximum length of the oxide, the interval of Al present at the grain boundaries, the plating property, and the LME crack resistance of the hot-dip galvanized steel sheet thus produced, the results are shown in Tables 2 and 3 below. On the other hand, the measured oxides were Al, Si composite oxides.

[0038] The mechanical properties were measured by cutting a hot-dip galvanized steel sheet into a size of 40 mm × 200 mm in the direction perpendicular to the rolling direction, milling and grinding the side surface, then preparing a tensile test piece according to JIS No. 5 standard and measuring the yield strength (YS), tensile strength (TS) and elongation (EL) with a tensile testing machine.

[0039] For the surface roughness (Ra), thickness of the internal oxide layer, and maximum length of the oxide of the base steel sheet, ten locations were randomly selected from the microstructural photographs of the cross-section obtained through a scanning electron microscope (SEM), measured at a magnification of 5000, and the average value was recorded.

[0040] The spacing of Al present at the grain boundaries among the Al contained in the Al, Si composite oxide was measured by compositional mapping using EDS (Energy Dispersive Spectroscopy) through a transmission electron microscope (TEM).

[0041] The plating property was evaluated by measuring the formation area fraction of the hot-dip galvanized layer with respect to the total area of the hot-dip galvanized steel sheet using image analysis, and after applying a structural adhesive on the hot-dip galvanized steel sheet, curing it at 175 °C for 20 minutes, and then checking whether it adheres to the sealer (plating adhesion) when bent at 90° (bending).

[0042] The LME crack resistance was evaluated by checking whether LME cracks occurred at the upper limit current after welding the hot-dip galvanized steel sheet. At this time, welding was performed under the conditions of a welding current flowing using a Cu-Cr electrode with a tip diameter of 6 mm, a pressure of 2.6 kN, a current application time of 16 cycles, and a holding time of 15 cycles. When the thickness of the steel sheet was t, the welding current at the point when the nugget diameter became smaller than 4√t was defined as the lower limit current, and the welding current at the point when spattering occurred was defined as the upper limit current (expulsion current).

[0043]

Table 1

[0044]

Table 2

[0045]

Table 3

[0046] As can be seen from Tables 1 to 3 above, in the case of Invention Examples 1 to 4 that satisfy the alloy composition and manufacturing conditions proposed by the present invention, by ensuring the conditions of the surface roughness of the base steel sheet, the thickness of the internal oxide layer, the maximum length of the oxide, and the interval of Al present at the grain boundaries that the present invention aims to obtain, it can be seen that they have excellent plating properties and LME crack resistance.

[0047] On the other hand, in Comparative Example 1, since the total of Si and Al proposed by the present invention is not satisfied, it can be seen that the elongation rate is at a low level.

[0048] In Comparative Example 2, it is at a level lower than the ratio of Al and Si proposed by the present invention, and it can be seen that LME cracks occurred.

[0049] In Comparative Example 3, since it exceeds the ratio of Al and Si proposed by the present invention, it can be seen that a large amount of non-plating occurs and the plating quality is inferior.

[0050] In Comparative Example 4, since the coiling temperature proposed by the present invention is not satisfied, no internal oxide layer is formed, not only does non-plating occur, but it can also be seen that the plating adhesion is inferior.

[0051] In Comparative Example 5, since the pickling speed proposed by the present invention is not satisfied, no internal oxide layer is formed, not only does non-plating occur, but it can also be seen that the plating adhesion is inferior.

[0052] FIG. 1 is a surface photograph of Invention Example 1, and FIG. 2 is a surface photograph of Comparative Example 4. As can be seen from FIGS. 1 and 2, in Invention Example 1, there is almost no unplated area and the plating quality is good, while in Comparative Example 4, it can be seen that the unplated area increases and the plating quality is inferior.

[0053] FIG. 3 is a photograph of the cross-section of the cold-rolled steel sheet of Invention Example 1 observed with a scanning electron microscope (SEM), and FIG. 4 is a photograph of the cross-section of the cold-rolled steel sheet of Comparative Example 3 observed with a scanning electron microscope (SEM). As can be seen from FIGS. 3 and 4, in Invention Example 1, an appropriate surface roughness was formed on the base steel sheet and an internal oxide layer was formed with an appropriate thickness, while in Comparative Example 4, it can be confirmed that not only is the surface roughness of the base steel sheet very low, but also no internal oxide layer is formed.

Claims

1. A hot-dip galvanized steel sheet having a base steel sheet and a hot-dip galvanized layer formed on one or both surfaces of the base steel sheet, wherein the base steel sheet contains, by weight %, carbon (C): 0.1 to 0.3%, silicon (Si): 0.1 to 2.0%, aluminum (Al): 0.1 to 1.5%, and manganese (Mn): 1.5 to 3.0%, with the balance being Fe and unavoidable impurities, the total of Si and Al satisfies 1.2 to 3.5%, and the ratio of Al to Si (Al / Si) satisfies 0.5 to 2.0, the surface roughness (Ra) of the base steel sheet is 0.5 μm or more, and the base steel sheet contains an internal oxide layer having a thickness of less than 4 μm immediately below the surface, and is a high-strength hot-dip galvanized steel sheet excellent in plating properties.

2. The high-strength hot-dip galvanized steel sheet excellent in plating properties according to Claim 1, wherein the internal oxide layer contains oxides having a maximum length of less than 4 μm.

3. The high-strength hot-dip galvanized steel sheet excellent in plating properties according to Claim 2, wherein the oxides are composed of Al, Si composite oxides.

4. The high-strength hot-dip galvanized steel sheet excellent in plating properties according to Claim 3, wherein the Al, Si composite oxides are discontinuously present at grain boundaries.

5. The high-strength hot-dip galvanized steel sheet excellent in plating properties according to Claim 4, wherein Al present at grain boundaries among the Al contained in the Al, Si composite oxides has an interval of 20 nm or more.

6. The high-strength hot-dip galvanized steel sheet excellent in plating properties according to Claim 1, wherein the hot-dip galvanized steel sheet has a yield strength of 600 MPa or more, a tensile strength of 950 MPa or more, and an elongation of 20% or more.

7. The high-strength hot-dip galvanized steel sheet excellent in plating properties according to Claim 1, wherein the area of the hot-dip galvanized layer with respect to the total area of the base steel sheet is 95% or more.

8. Reheating a slab containing, by weight %, carbon (C): 0.1 to 0.3%, silicon (Si): 0.1 to 2.0%, aluminum (Al): 0.1 to 1.5%, and manganese (Mn): 1.5 to 3.0%, with the balance being Fe and unavoidable impurities, the total of Si and Al satisfying 1.2% or more, and the ratio of Al to Si (Al / Si) satisfying 0.5 to 2.0 at 1000 to 1300 °C, hot-rolling the reheated slab at 800 to 950 °C to obtain a hot-rolled steel sheet, and coiling the hot-rolled steel sheet at 630 to 700 °C. Pickling the wound hot-rolled steel sheet for a period exceeding 30 seconds and less than 60 seconds; Cold rolling, annealing, and cooling the pickled hot-rolled steel sheet to obtain a cold-rolled steel sheet; A method for manufacturing a high-strength hot-dip galvanized steel sheet excellent in plating properties according to any one of claims 1 to 7, including hot-dip galvanizing the cold-rolled steel sheet.

9. The method for manufacturing a high-strength hot-dip galvanized steel sheet excellent in plating properties according to claim 8, wherein the hot-dip galvanizing step includes immersing the cold-rolled steel sheet in a hot-dip galvanizing bath at 440 to 460°C.

10. The method for manufacturing a high-strength hot-dip galvanized steel sheet excellent in plating properties according to claim 8, further including a step of alloying heat treatment of the hot-dip galvanized cold-rolled steel sheet at 480 to 600°C after the hot-dip galvanizing step.

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