JP2001247950A - Hot dip galvanized steel sheet excellent in press formability and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot dip galvanized steel sheet excellent in press formability, and in which a problem with the conventional technology is solved and to provide its production method. SOLUTION: In this hot dip galvanized steel sheet excellent in press formality, the surface of plating has surface roughness in which the arithmetic average roughness Ra is >=1.0μm, and also, the number of crests per 25.4 mm of a length in the direction of the average line of a roughness curve, i.e., PPI is 80 to 250 pieces, and, in this method for producing a hot dip galvanized steel sheet excellent in press formability, a steel sheet is subjected to hot dip galvanizing, and thereafter, the obtained hot dip galvanized steel is subjected in skinpass rolling by using a roll having surface roughness in which the arithmetic average roughness Ra is >=1.0μm, and also, the number of crests per 25.4 mm of a length in the direction of the average line of a roughness curve, i.e., PPI is 60 to 300 pieces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-dip galvanized steel sheet used for automobiles and the like, and more particularly to a hot-dip galvanized steel sheet excellent in press formability and a method of manufacturing the same.

[0002]

2. Description of the Related Art In order to improve the press formability of galvanized steel sheets for automobile parts, a method of smoothing the surface roughness or hardening the surface to reduce the sliding resistance is used. That is, as a method of reducing the sliding resistance, a method of setting the surface roughness: Wca of a galvanized steel sheet to 0.6 μm or less and applying a zinc-based oxide to the surface (see JP-A-4-325665); By increasing the degree of alloying of the plated steel sheet and hardening the plating layer, by changing the rolling reduction using a rolling roll in which the pitch of the fine recesses was changed during laser dull finishing, the fine recess volume per unit area was reduced. A method is known in which the sum is defined in an optimum range according to the hardness of the plating layer (see Japanese Patent Application Laid-Open No. 7-136701).

[0003] However, in the case of a method of reducing the surface roughness: Wca of a galvanized steel sheet and smoothing the surface, the slidability in an oil-free state is improved, but this method is commonly used by automobile manufacturers. In a press in a lubricated state, the oil retention is poor and ineffective. Further, in the case of hardening with a zinc-based oxide, it should be avoided because the chemical conversion property deteriorates.

[0004] Further, in the case of a method of increasing the degree of alloying and hardening the plating layer, the adhesion of the plating is deteriorated, and it is impossible in a manufacturing facility for a pure galvanized steel sheet having no alloying furnace. Furthermore, in the case of a method of optimizing the relationship between the hardness of the plating layer and the sum of the fine concave volume, measurement of the concave volume is not realistic.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a galvanized steel sheet excellent in press formability and a method for producing the same, which has solved the above-mentioned problems of the prior art.

[0006]

According to a first aspect of the present invention, a galvanized steel sheet has an arithmetic average roughness Ra of 1.0 μm.
m or more, more preferably arithmetic average roughness: Ra is 1.0 to 2.5
Hot-dip galvanized steel sheet with excellent press formability, characterized in that the number of peaks per μm and the average length of the roughness curve in the direction of the average line is 25.4 mm: PPI has a surface roughness of 80 to 250 pieces. It is.

[0007] In the first aspect of the present invention, in the hot-dip galvanized steel sheet, Fe
The content is preferably 5% by mass or less. According to a second invention, after hot-dip galvanizing is applied to a steel sheet, the obtained hot-dip galvanized steel sheet is subjected to arithmetic mean roughness: Ra of 1.0 μm or more, more preferably arithmetic mean roughness: Ra of 1.0 to 5.0 μm.
And the number of peaks per 25.4 mm in the average line direction length of the roughness curve: 60 to 300 PPI, more preferably the number of peaks:
This is a method for producing a hot-dip galvanized steel sheet having excellent press formability, characterized by temper rolling using a roll (work roll) having a surface roughness of 80 to 290 PPIs.

In the second aspect of the present invention, the roll having the above-mentioned surface roughness (work roll) is preferably a roll processed by an electric discharge dull machine (a preferred embodiment of the second aspect of the invention). . Further, in the above-described second invention and preferred embodiments of the second invention, the Fe content in the hot-dip galvanized film of the hot-dip galvanized steel sheet is 5% by mass.
The following is preferred.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The present inventors have studied the difference in the surface properties between the hot-dip galvanized steel sheet and the alloyed hot-dip galvanized steel sheet, and as a result, the hardness of the plating film of the hot-dip galvanized steel sheet (hereinafter, also referred to as GI) is Hv ≒ 52. On the other hand, the hardness of the galvannealed steel sheet (hereinafter, also referred to as GA) is about Hv = 284 to 300. It was considered that the sliding property was poor as a result.

In order to improve the press formability of the hot-dip galvanized steel sheet based on the basic difference in the surface properties between the hot-dip galvanized steel sheet and the alloyed hot-dip galvanized steel sheet, Various studies were made on the roughness. As a result, even in GI, where the hardness of the plating film is softer than GA, preferably by temper rolling a hot-dip galvanized steel sheet using a roll having a specific surface roughness, the GI plating film has a GA or higher. By giving a large arithmetic average roughness and limiting the number of peaks in the roughness curve to a specific range, a non-alloyed hot-dip galvanized steel sheet (GI) with excellent slidability during press forming can be obtained. This led to the present invention.

That is, in the first invention, the galvanized steel sheet has a plated surface having an arithmetic average roughness Ra of 1.0 μm or more and a peak of 25.4 mm per length in the average line direction of the roughness curve. Number: Hot-dip galvanized steel sheet with a surface roughness of 80 to 250 PPI and excellent press formability. In the first invention, the arithmetic average roughness Ra
More preferably, it is 1.0 to 2.5 μm.

In a second aspect of the present invention, the steel sheet is hot-dip galvanized, and the resulting hot-dip galvanized steel sheet is provided with an arithmetic mean roughness Ra of 1.0 μm or more and an average line of a roughness curve. Number of peaks per 25.4 mm length in the direction: This is a method for producing hot-dip galvanized steel sheet excellent in press formability by temper rolling using rolls having a surface roughness of 60 to 300 PPI. In the second aspect, it is more preferable that the arithmetic average roughness Ra is 1.0 to 5.0 μm.

In the second aspect, it is more preferable that the number of peaks: PPI is 80 to 290. Further, in the second aspect, it is preferable that the roll having the surface roughness described above is a roll processed by an electric discharge dull machine. In addition, the first
In the inventions of the second and the second aspects, the Fe content in the hot-dip galvanized film of the hot-dip galvanized steel sheet is preferably 5% by mass or less (hereinafter, the mass% is referred to as%).

As described above, the PPI in the present invention refers to the number of peaks per inch (peaks per in) in the surface roughness roughness curve defined by the US SAE standard.
ch), and a smaller value means a larger cross-sectional area of one peak. FIG. 5 shows the SAE standard in the United States of America Engineering Society for Advancing.
Mobility Land Sea Air and Space: SAE J911-JUN 86
`` SURFACE TEXTURE MEASUREMENT OF COLD ROLLED SHEET
Fig. 3 shows a roughness curve of surface roughness in relation to the definition of PPI defined in "STEEL".

That is, in FIG. 5, a constant reference level H is provided in both the positive and negative directions from the average line of the roughness curve, and after exceeding the negative reference level, when the reference level exceeds the positive reference level, one count is performed. . This count is repeated until the length reaches the evaluation length Ln, and the value represented by the counted number is defined as PPI.

In the present invention, Ln = 1 inch (=
25.4 mm), 2H (peak count level: width between positive and negative reference levels) = 50 μinch (= 1.27 μm). Also,
Arithmetic mean roughness in the present invention: Ra is JIS B 0601-1994.
based on. According to the present invention, the arithmetic average roughness of the galvanized steel sheet: Ra is set to 1.0 μm or more, which is equal to or more than that of the galvannealed steel sheet, and the PPI is 80 to 25.
By setting the number to zero, excellent slidability can be obtained during press molding.

This is because, by setting the arithmetic mean roughness: Ra to 1.0 μm or more and the PPI to 80 to 250, even if the projections are crushed to some extent during the press forming, the recesses remaining on the plating surface are required. It is considered that a large amount of oil can be maintained. On the other hand, when the arithmetic average roughness: Ra is less than 1.0 μm, the height of the convex portion is low, so the convex portion is crushed during press molding, the depth of the remaining concave portion is small, and oil cannot be retained, Moldability deteriorates.

In the present invention, it is more preferable to limit the arithmetic mean roughness Ra of the galvanized steel sheet to 2.5 μm or less. This is the arithmetic mean roughness:
If Ra exceeds 2.5 μm, the initial coefficient of friction during press molding becomes large, and the press formability may be reduced. When the number of PPIs is less than 80, as shown in FIGS. 1 and 3 of the embodiment described later, a low surface pressure of about 9.8 N / mm ² (1 kgf / mm ² ) as in the case of pressing an outer panel for automobiles is used. Under the pressing conditions, the mold and the steel plate only locally contact each other at the peaks where the number is small, the protrusions (peaks) are crushed, the oil cannot be held, and the formability deteriorates.

Conversely, when the number of PPIs exceeds 250, as shown in FIGS. 1 and 2 of the embodiment described later, the cross-sectional area of the peak (convex portion) is small, and the drag of the peak (convex portion) is small. Under pressing conditions of a high surface pressure of about 49 N / mm ² (5 kgf / mm ² ), such as when pressing an inner plate for automobiles, the convex portions on the entire surface are crushed and oil cannot be retained, resulting in poor moldability. . For the reasons described above, in the present invention, the PPI is limited to the range of 80 to 250 PPIs.

In the present invention, in the case of a hot-dip galvanized steel sheet for an automobile outer panel, the PPI is particularly preferably in the range of 150 to 250 in the above-mentioned range of the PPI. In the case of a hot-dip galvanized steel sheet for a sheet, the PPI is particularly preferably in the range of 80 to 100 pieces. Further, in the present invention, the content of Fe in the hot-dip galvanized steel sheet is preferably 5% or less, and more preferably 1% or less.

This is because when the Fe content in the plating film exceeds 5%, the adhesion of the plating during press molding is reduced due to the growth of the Fe-Zn alloy layer which reduces the adhesion of the plating. In the present invention, in the plating film
The lower the Fe content, the better, and the lower limit is not limited, but in practice, Fe is inevitably in the plating bath.
In the plating film during plating
The diffusion of Fe inevitably occurs in the plating film
Contains 0.01% or more of Fe.

The coating weight of the hot-dip galvanized steel sheet according to the present invention can be determined according to the required corrosion resistance, and is not particularly limited. It is preferably 30 to 300 g / m ² per area. If the coating weight is less than 30 g / m ² , the corrosion resistance will be reduced, and if it exceeds 300 g / m ² , the plating film will peel off during processing.

In the present invention, the arithmetic average roughness described above:
The manufacturing method for manufacturing a hot-dip galvanized steel sheet having a plating surface of Ra and PPI is not particularly limited,
In view of simplification of the process and uniformity of the properties of the obtained plated steel sheet, it is particularly preferable to manufacture the hot-dip galvanized steel sheet by temper rolling using a roll having a specific surface roughness.

That is, in the method for producing a hot-dip galvanized steel sheet according to the present invention, as described above, the hot-dip galvanized steel sheet is subjected to arithmetic average roughness Ra of 1.0 μm or more and the average line direction of the roughness curve. Number of peaks per 25.4mm in length: PPI
60 to 300, more preferably the number of peaks: PPI is 80 to 29
Temper rolling is performed using a roll having zero surface roughness to produce a hot-dip galvanized steel sheet having the above-mentioned arithmetic average roughness: Ra and PPI.

The arithmetic average roughness of the surface of the temper roll: Ra is
If less than 1.0 μm, the surface before temper rolling is smooth (Ra ≒
Even if the GI is rolled at 0.2μm), the desired surface roughness (Ra) cannot be obtained and the surface roughness of the temper roll does not exceed 60 or exceeds 300 even if the surface roughness exceeds 300. (PPI) cannot be obtained. In the present invention, it is preferable to use a roll processed by an electric discharge dull machine as the above-mentioned roll.

This is because, according to the electric discharge dull machining, a roll having a wide machining range and having the arithmetic average roughness: Ra and the number of peaks of the roughness curve: PPI surface roughness required in the present invention is obtained. Is easy. In the present invention described above, the arithmetic average roughness of the surface of the temper rolling roll: Ra is 5.0 μm
It is more preferable to limit to the following.

[0027] This is because, when a temper roll having an arithmetic average roughness Ra of more than 5.0 µm is used, the initial friction coefficient at the time of press forming the resulting hot-dip galvanized steel sheet becomes large, and the press formability may be reduced. This is also because the processing cost increases from the viewpoint of surface processing of the roll and the service life of the roll is shortened. Although the present invention has been described above, in the case of an alloyed hot-dip galvanized steel sheet, an alloying step is required, and the manufacturing cost is higher than that of the non-alloyed hot-dip galvanized steel sheet of the present invention. Since the amount of adhesion cannot be increased, there is a limit in corrosion resistance.

On the other hand, the non-alloyed hot-dip galvanized steel sheet of the present invention is not subject to restrictions on the amount of galvanized coating, and therefore has a simple process, is excellent in formability, and has an alloyed hot-dip galvanized steel sheet. A galvanized steel sheet having better corrosion resistance than a steel sheet can be provided.

[0029]

EXAMPLES The present invention will be described below more specifically based on examples. The arithmetic mean roughness of the plating surface in this example: Ra is based on JIS B 0601-1994, and the number of peaks of the roughness curve of the surface roughness of the plating surface: PPI is SAE J911-JUN86 described above. (: SAE J911-1986) Indicates the number of peaks per 25.4 mm in the average line direction of the roughness curve.

Example 1 A cold-rolled steel sheet was passed through a continuous hot-dip galvanizing line, hot-dip galvanized, and then temper rolled to produce a hot-dip galvanized steel sheet. In the above temper rolling, the arithmetic average roughness of the roll surface: Ra
And number of peaks on the roughness curve: Arithmetic average roughness of the plated surface of the coated steel sheet (hereinafter referred to as “plated steel sheet surface”) using discharge dulling rolls or shot dulling rolls with different PPIs: Ra and roughness curve Number of mountains: Hot dip galvanized steel sheets with different PPIs were manufactured.

A part of the hot-dip galvanized steel sheet was subjected to a heat alloying treatment to produce a hot-dip galvanized steel sheet. The coating weight of hot-dip galvanized steel sheet was 90 g / m ² per one side of the steel sheet, and the Fe content in the plating film was 0.7% by controlling the temperature of the sheet entering the plating bath, the temperature of the plating bath, and the line speed. The coating weight of the galvannealed steel sheet was 45 g / m ² per one side of the steel sheet, and the Fe content in the plating film was 10%.

Next, a slidability test was performed on the obtained hot-dip galvanized steel sheet or alloyed hot-dip galvanized steel sheet based on the test method shown in FIG. 4 and the following test conditions. In FIG. 4, 1 is a test piece of a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet, 2a and 2b are dies, 3 is a chuck, F is a drawing force by the chuck, L
Denotes a mold length, l denotes a sliding distance, and P denotes a load.

(Sliding property test condition) Sliding condition: repeated plane sliding test (FIG. 4) During repeated sliding, the test was repeated at the same position. Specimen width: 20mm Mold length L: 10mm Sliding distance l: 100mm Load P: 1960N, 9800N (: 200kgf, 1000kgf) Pulling speed (sliding speed): 20mm / s Oiling conditions: Cleaning oil R303P [ Sugimura Chemical Co., Ltd.] Oiling The test piece is first oiled only once. The pull-out force F (unit:
N) was measured, and the friction coefficient μ calculated from the following equation (1) was determined.

Μ = F / P (1) Next, the friction coefficient μ of each time when the flat sliding test was repeated for the same test piece was calculated as follows.
The index μ ^* with the friction coefficient μ _GA-1 of the first time as 1 is calculated by the following equation (2).
And the slidability of each test piece was evaluated. Index of slidability: μ ^* = μ / μ _GA-1 (2) (In the above formula (2), μ _GA-1 indicates the first friction coefficient of the galvannealed steel sheet.) 2 and 3 show the obtained test results.

FIG. 2 shows a high surface pressure [49 N / mm ² (5 kgf / mm ² )].
FIG. 3 shows the test results under the conditions of low surface pressure [9.8 N
/ mm ² (1 kgf / mm ² )]. As shown in FIG. 2, when the surface pressure is high, Ra on the surface of the plated steel sheet is
1.2μm, hot-dip galvanized steel sheet (GI) with 50 and 90 PPIs
Shows a low coefficient of friction comparable to that of galvannealed steel sheets (GA), the surface of the coated steel sheets has a Ra of 1.2 μm, a PPI of 120,
180 and 220 hot-dip galvanized steel sheets (GI) and hot-dip galvanized steel sheets (GI) with a surface Ra of 2.0 μm and a PPI of 180 showed the second lowest coefficient of friction.

However, the PPI of the surface of the plated steel sheet is 2
60 hot-dip galvanized steel sheets (GI)
Even when the thickness was 1.2 μm, galling occurred, and the slidability test could not be repeated. In addition, as shown in FIG. 3, when the surface pressure is low, Ra on the surface of the plated steel sheet is 1.2 μm, and the PPI
180, 220 and 260 hot-dip galvanized steel sheets (GI)
Shows a low coefficient of friction comparable to that of galvannealed steel sheet (GA), with a surface roughness of 2.0 μm Ra and 180 PPI for hot-dip galvanized steel sheet (GI) and Ra
1.2μm, 90, 120 PPI hot-dip galvanized steel sheet (G
I) showed the second lowest coefficient of friction.

However, the PPI of the surface of the plated steel sheet is 50
Hot-dip galvanized steel sheet (GI)
Even at 1.2 µm, the coefficient of friction increased. FIG. 1 collectively shows the results obtained in the present embodiment described above. As shown in FIG. 1, a predetermined arithmetic average roughness (1.
0 μm or more) and the number of peaks in the roughness curve: by limiting the PPI to a specific range (80 to 250), non-alloyed hot-dip galvanizing with excellent slidability during press forming It was found that a steel plate (GI) was obtained.

Example 2 (Inventive Examples 1 to 3, Comparative Examples 1 and 2) A cold-rolled steel sheet was passed through a continuous hot-dip galvanizing line, hot-dip galvanized, and then temper rolled. To produce a hot-dip galvanized steel sheet. The coating weight of the hot-dip galvanized steel sheet was 90 g / m ² per one side of the steel sheet, and the Fe content in the plating film was 0.5% by controlling the sheet temperature entering the plating bath, the plating bath temperature, and the line speed. %.

In the above-mentioned temper rolling, the roll (: workpiece) which has been subjected to discharge dulling or shot dulling so that the arithmetic average roughness of the roll surface: Ra and the number of peaks of the roughness curve: PPI becomes the following values: Roll) to produce hot-dip galvanized steel sheets having different arithmetic average roughness of the surface of the coated steel sheet: Ra and the number of peaks of the roughness curve: PPI.

The elongation at the time of temper rolling by the discharge dulling roll was 1%, and the elongation at the time of temper rolling by shot dulling was 1%. Electric discharge dulling roll: Ra = 1.9 μm, PPI = 100 Ra = 2.0 μm, PPI = 150 Ra = 3.0 μm, PPI = 60 Shot dulling roll: Ra = 2.1 μm, PPI = 110 Ra = 0.7 μm Next, the formability of the obtained hot-dip galvanized steel sheet was evaluated by the following test method.

(Method of evaluating moldability :) A fender material for automobiles was pressed with a real mold and evaluated for the occurrence of cracks.
Table 1 shows the obtained results together with the specifications of the rolls for temper rolling. As shown in Table 1, according to the present invention, it was found that a hot-dip galvanized steel sheet (non-alloyed hot-dip galvanized steel sheet (GI)) having excellent formability without press cracking during press forming was obtained.

[0042]

[Table 1]

Example 3 (Examples 4 to 7 of the present invention, Comparative Example 3)
~ 5) The cold-rolled steel sheet was passed through a continuous hot-dip galvanizing line, subjected to hot-dip galvanizing, and then temper rolled to produce a hot-dip galvanized steel sheet. The coating weight of the hot-dip galvanized steel sheet was 90 g / m ² per one side of the steel sheet, and the Fe content in the plating film was 0.5% by controlling the sheet temperature entering the plating bath, the plating bath temperature, and the line speed. %.

In the temper rolling described above, the work roll is formed by using a discharge dulling roll or a shot dulling roll having different arithmetic average roughness of the roll surface: Ra and the number of peaks of the roughness curve: PPI. Rolling was performed to produce a hot-dip galvanized steel sheet having different arithmetic average roughness of the surface of the coated steel sheet: Ra and the number of peaks of the roughness curve: PPI. The elongation at the time of temper rolling by the discharge dulling roll is
The elongation at the time of temper rolling by shot dull processing was 1%.

Table 2 shows the obtained hot-dip galvanized steel sheet (GI).
The surface roughness after temper rolling is shown together with the specifications of the temper roll. Next, for the obtained hot-dip galvanized steel sheet (GI), based on the test method described above and the following test conditions,
A slidability test was performed. That is, in this test, the plane sliding test was repeated for the test piece of the alloyed hot-dip galvanized steel sheet (GA), which is the reference test piece, and the slidability of each test piece was changed to the alloyed hot-dip galvanized steel sheet (GA). The test pieces were compared with each other and evaluated.

That is, μ ^* at the time of the 10th and 15th slidings of each test piece obtained by the following equation (3) or (4) ^.
₁₀ , the slidability was evaluated based on μ ^* ₁₅ . Sliding of the _{^{indicator: μ * 10 = μ 10 /}} μ GA-10 ......... (3) sliding of the _{^{indicator: μ * 15 = μ 15 /}} μ GA-15 ......... (4) The above formula In (3) and (4), μ ₁₀ and μ ₁₅ are
The coefficient of friction for the 10th and 15th slides of the same test piece of galvanized steel sheet (GI), μ _GA-10 and μ _GA-15 , are the 10th time of the galvannealed steel sheet (GA), respectively. Shows the friction coefficient at the time of the 15th sliding.

Table 2 shows the test results obtained. As shown in Table 2, the present invention example in which the arithmetic average roughness of the surface of the plated steel sheet: Ra and the number of peaks per 25.4 mm in the average line direction length of the roughness curve: PPI are within the preferred range of the present invention. 4-7 hot-dip galvanized steel sheet (non-alloyed hot-dip galvanized steel sheet) (G
I) showed excellent slidability comparable to that of the galvannealed steel sheet (GA).

[0048]

[Table 2]

[0049]

According to the present invention, even in a non-alloyed hot-dip galvanized steel sheet (GI) in which the hardness of a plating layer is soft, excellent press formability equivalent to that of an alloyed hot-dip galvanized steel sheet (GA) can be obtained. It became possible. In addition, since the non-alloyed hot-dip galvanized steel sheet is not subject to the limitation of the amount of galvanized coating on the galvannealed steel sheet, it is excellent in formability in a simple process, and moreover, compared with the hot-dip galvanized steel sheet. Can also provide a galvanized steel sheet having excellent corrosion resistance.

Further, there is no problem of deterioration in chemical conversion treatment due to hardening of a plating film due to formation of a zinc-based oxide on a plating surface in the prior art.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between Ra and PPI of a plated surface of a plated steel sheet and slidability in a slidability test.

FIG. 2 is a graph showing the relationship between Ra and PPI of a plated surface of a plated steel sheet and slidability in a slidability test (under high surface pressure conditions).

FIG. 3 is a graph showing the relationship between Ra and PPI of a plated surface of a plated steel sheet and slidability in a slidability test (under low surface pressure conditions).

FIG. 4 is an explanatory view (longitudinal sectional view) showing a method of testing slidability.

FIG. 5 is a graph showing a surface roughness curve relating to the definition of PPI defined by the SAE standard.

[Explanation of symbols]

 1 Test pieces 2a, 2b Mold 3 Chuck F Pull-out force L Mold length l Sliding distance P Load

Claims (5)

[Claims] The plated surface of a hot-dip galvanized steel sheet has an arithmetic average roughness: Ra of 1.0 μm or more, and the number of peaks per 25.4 mm length in the average line direction of the roughness curve: PPI is 80 to 250
A hot-dip galvanized steel sheet having excellent press formability, characterized by having a surface roughness of individual pieces. 2. The hot-dip galvanized steel sheet according to claim 1, wherein the content of Fe in the hot-dip galvanized steel sheet is 5% by mass or less. 3. A hot-dip galvanized steel sheet is subjected to hot-dip galvanizing, and the resulting hot-dip galvanized steel sheet is subjected to arithmetic mean roughness Ra of 1.0 μm.
Number of peaks per m of length and 25.4 mm in average line direction of roughness curve: Temper rolling using rolls with surface roughness of 60 to 300 PPI Manufacturing method of hot-dip galvanized steel sheet with excellent formability. 4. The method for producing a hot-dip galvanized steel sheet excellent in press formability according to claim 3, wherein the roll having the surface roughness is a roll processed by an electric discharge dull machine. 5. The hot-dip galvanized steel sheet according to claim 3, wherein the content of Fe in the hot-dip galvanized steel sheet is 5% by mass or less. Steel plate manufacturing method.