JP2003113456A - HOT DIP Al-Zn ALLOY PLATED STEEL SHEET - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot dip Al-Zn alloy plated steel sheet having a plated film superior in bending processability. SOLUTION: This steel sheet has a hot dip Al-Zn alloy plated film formed on the surface, which comprises 30-70 mass% Al, and 0.1-5 mass% Si, has at least a dendrite region, and which has β-Zn particles with an average particle diameter of 0.5 μm or less in terms of a diameter of equivalent circle in the dendrite region, that are precipitated and dispersed with average spaces between particles, of five times as large as the above particle size, or smaller. A half- width ratio ΔD of a X-ray diffraction peak of Al in the dendrite region, is preferably 0.70 times or less of a half-width ratio ΔD0 of a X-ray diffraction for a standard sample. Thereby, the bend formability becomes adequate, and furthermore, does not degrade even after a long time storage at a room temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten Al-Zn alloy plated steel sheet, which is particularly suitable for building materials and home electric appliances, and has excellent bending workability in which the coating film contains 30 to 70 mass% of Al. Hot-dip Al-Zn alloy plated steel sheet.

[0002]

2. Description of the Related Art Hot-dip Al-Zn alloy plated steel sheet containing 30 to 70 mass% of Al in the plating film has excellent corrosion resistance as compared with ordinary hot-dip galvanized steel sheet or 5 mass% Al-Zn plated steel sheet. Therefore, it is widely used in the fields such as building materials and home appliances. However, since the hot-dip Al—Zn alloy plated steel sheet has a hard coating film, there is a problem that cracks are likely to occur at locations where severe processing is applied during forming.

To address this problem, for example, Japanese Patent Publication No. 61
-28748 discloses that in order to improve the workability, the plated product (hot-dip Al-Zn alloy plated steel sheet) is heat-treated in the temperature range of 93 to 427 ° C, and then slowly cooled to at least 205 ° C. A method has been proposed in which a plating film having no age hardening is used and the hardness thereof is 110 Hv or less. However, the method disclosed in Japanese Patent Publication No. 61-28748 has a problem in that there is a large variation in hardness and cracks may be generated during processing. In addition, the method described in Japanese Patent Publication No. 61-28748 has a problem that the manufacturing process takes a long time and the productivity is extremely low.

Further, Japanese Patent Laid-Open No. 9-111433 and Japanese Patent Laid-Open No. 9-111433
-256132 discloses a method of adding a trace amount of a metal element belonging to the genus 4a to 6a to miniaturize a plating film. However, although the plating film is miniaturized by these methods, the workability is not sufficiently improved. Furthermore, after plating, 150 ~
It is said that the improvement in workability will be recognized only after heat treatment at 350 ° C for 2 to 10 minutes. However, in the plated steel sheet produced by this technique, although the workability is temporarily improved by the heat treatment, the workability is slightly improved as described above, which is not sufficient for the required workability. Moreover, if the product is left at room temperature for one month, the workability deteriorates again.

Richard Ley also added that "Theorized Effec
t of Strontium Addition on Al-Si Alloys "(I
nter ZAC 98 Conference, Los Angels, CA USA, Septem
ber 1998), 55% Al-Zn by adding Sr to the plating film
It is shown that the workability of the plated steel sheet may be improved. However, the workability was not improved enough to withstand severe processing.

[0006] Further, JP-A-11-246958, JP-A-11-246958
-302813, JP11-302814, JP11-30
2815 gazette states, "Melted Al, which has excellent workability and white rust resistance.
-Zn alloy plated steel sheet "is described. JP 11-246
According to Japanese Patent Laid-Open No. 958, the plating film has a one-layer dendrite structure in the film thickness direction.
In Japanese Patent Laid-Open No. 11-302813, the Al concentration ratio between the dendrite portion and the dendrite gap portion in the plating film is set to less than 1.5, and in Japanese Laid-Open Patent Publication No. 11-302814, the Al concentration in the plating film is the lowest. By setting the ratio of Al concentration in the dendrite part to 0.20 to 1.0, it is also possible to obtain
In JP-A-15, it is stated that the workability of plated steel sheets is improved by setting the ratio of the average Al concentration in the plating film to the Al concentration in the dendrite portion to 0.6 or more. However, these plated steel sheets have a problem that the workability is not always stable and may not be improved.

Further, Japanese Patent Laid-Open No. 11-343555 describes a hot dip Al-Zn plated steel sheet in which the hardness ratio of the dendrite part and the interdendrite part in the plating film is 0.40 or more. The technique disclosed in Japanese Patent Laid-Open No. 11-343555 discloses that the crack resistance of the plating film is improved by reducing the hardness difference between the dendrite part and the interdendrite part. However, JP-A-11-343555
The plated steel sheet described in Japanese Patent Publication can withstand relatively light processing such as 3T bending, but has a problem that plating peeling easily occurs in severe bending processing such as 0T bending.

[0008]

DISCLOSURE OF THE INVENTION The present invention advantageously solves the above-mentioned problems of the prior art and has a molten Al-Zn having a plating film excellent in bending workability equal to or higher than that of a 5 mass% Al-Zn plated steel sheet. The purpose is to propose a system alloy plated steel sheet. Another feature of the alloy-plated steel sheet of the present invention is that the change in bending workability with time is small, that is, the aging resistance is excellent.

[0009]

In order to achieve the above-mentioned objects, the inventors of the present invention have found that the microstructure of the plating film, especially the microstructure of the dendrite region, which affects the bending workability and the change with time of the bending workability. I researched the effect.
As a result, not only in the interdendrite region but also in the dendrite region, the average particle diameter was 0.5 in terms of equivalent circle diameter.
It was found that bending workability is remarkably improved by depositing and dispersing fine β-Zn particles having a size of μm or less. It was also found that there is a deep relationship between the change in bending workability with time and the half-value width ratio ΔD of the X-ray diffraction pattern in the dendrite region. The full width at half maximum ΔD is ΔD = cot θ · Δθ (rad) × 100 (%) (where, θ: Bragg angle of X-ray diffraction peak- (deg or rad), Δθ: X-ray diffraction peak Half width of − (rad)
It is a value defined by.

The present invention has been completed by further studies based on the above findings. That is, the present invention is a molten Al-Zn alloy-plated steel sheet formed by forming a molten Al-Zn alloy-plated film on the steel sheet surface,
-Zn-based alloy plating film contains Al of 30 to 70 mass% and Si of 0.1 to
5 mass% content, at least dendrite region,
In the dendrite region, the average particle diameter is 0.5 μ in equivalent circle diameter.
β-Zn particles of m or less are precipitated and dispersed at an average inter-particle distance of 5 times or less of the particle diameter, which is a hot-dip Al-Zn alloy plated steel sheet having excellent bending workability.

In the present invention, the following equation (1) of the dendrite region ΔD = cot θ · Δθ × 100 (%) (1) (where, θ: X-ray diffraction of Al in the plating film) Bragg angle (deg or rad) of the diffraction peak, Δθ: half-value width (rad) of X-ray diffraction peak of Al in the plating film X-ray diffraction peak half-width ratio ΔD is 2) Formula ΔD ₀ = cot θ ₀ · Δθ ₀ × 100 (%) (2) (where θ ₀ : Bragg angle (deg or deg of the X-ray diffraction peak of Al in the plating film of the standard sample) rad), Δθ ₀ : half-width of the X-ray diffraction peak of the standard sample defined by the half-value width (rad) of the X-ray diffraction peak of Al in the plating film of the standard sample, 0.70 times or less than the half-value width ratio ΔD ₀ of the standard sample Is preferred.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The hot-dip Al-Zn alloy plated steel sheet of the present invention is a steel sheet having a hot-dip Al-Zn alloy-plated film formed on the surface thereof.
A molten Al-Zn alloy plating film containing 30 to 70 mass% and 0.1 to 5 mass% of Si and having at least a dendrite region. In order to make the precipitation state of Si proper,
In addition to Al and Si, Sr may be contained in the range of 0.2 to 2% of Si content.

The plating film in the steel sheet of the present invention is characterized in that β-Zn particles having an average particle diameter of 0.5 μm or less in equivalent circle diameter are uniformly deposited and dispersed in the dendrite region. By uniformly depositing and dispersing fine β-Zn particles in the dendrite region, the ductility of the plating film is improved, cracking is suppressed during processing, and bending workability is significantly improved. If the average particle size of the β-Zn particles precipitated and dispersed in the dendrite region exceeds 0.5 μm in terms of equivalent circle diameter, a difference in hardness between the Zn particles and the surrounding dendrite region occurs, and the bending workability of the plating film deteriorates. On the other hand, if no precipitation dispersion of β-Zn particles is observed in the dendrite region of the plating film, the ductility of the plating film decreases and the risk of cracking during bending increases. In addition, the precipitation dispersion of the β-Zn particles can be clearly confirmed by observing a secondary electron image of the cross section of the plated coating with a scanning electron microscope (SEM). In SEM secondary electron image observation, it is important to observe at a magnification of at least 5000 times in order to confirm the presence or absence of precipitation dispersion of β-Zn particles.

Further, the β-Zn particles in the dendrite region are uniformly precipitated and dispersed at an average interparticle distance of 5 times or less of the β-Zn particle diameter (circle equivalent diameter). If the average inter-particle distance of β-Zn particles is more than 5 times the β-Zn particle diameter (equivalent circle diameter), there is a problem that the total precipitation amount is insufficient and workability is insufficiently improved. In the dendrite region, the mechanism for improving the bending workability when uniform precipitation dispersion of the fine β-Zn particles as described above is observed is not clear at present, but the workability of the dendrite region is improved. It is thought that this is because the GP zone, which is considered to be inhibiting, and the interfacial dislocations around it were eliminated by the precipitation of β-Zn particles.

On the other hand, even if a uniform precipitation dispersion of fine β-Zn particles of 0.5 μm or less is observed, bending workability may be somewhat deteriorated when left at room temperature for a long time. In this case, the precipitation of β-Zn particles is insufficient, and it is considered that a new GP zone precipitates when left for a long time at room temperature. In order to suppress such deterioration of bending workability with time, in the present invention, X of the dendrite region in the plating film is prevented.
The line diffraction peak full width at half maximum ΔD is preferably limited to 0.70 times or less of the X-ray diffraction peak full width at half maximum ΔD ₀ of the standard sample. It is more preferably 0.60 times or less. The X-ray diffraction peak full width at half maximum ΔD in the dendrite region is expressed by the following equation (1) ΔD = cot θ · Δθ × 100 (%) (1) (where θ: Al in the plating film) Bragg angle (deg or rad) of X-ray diffraction peak, Δθ: half-value width (rad) of X-ray diffraction peak of Al in the plating film. In addition, the X-ray diffraction peak half width ratio ΔD of the standard sample
₀ is the following formula (2) ΔD ₀ = cot θ ₀ · Δθ ₀ × 100 (%) (2) (where θ _{0 is} the X-ray diffraction peak of Al in the plating film of the standard sample) Bragg angle (deg or rad), Δθ ₀ :
It is defined by the half width (rad) of the X-ray diffraction peak of Al in the plating film of the standard sample.

In measuring the X-ray diffraction peak full width at half maximum ΔD of the dendrite region in the plating film and the X-ray diffraction peak full width at half maximum ΔD ₀ in the plating film of the standard sample, CuK α was used as the X-ray source. Using a line, with little overlap with β-Zn, α-
Al, (111), (220), (311), (33
The full width at half maximum of each peak is measured using the four X-ray diffraction peaks of 1), and the average value of these four peaks is taken as the full width at half maximum Δθ of the sample. Note that α-Al (220)
The surface spacing is 1.431 nm, which almost overlaps with the β-Zn (220) surface spacing of 1.4332 nm, but the information depth of X-ray diffraction, t = 0.316 sin θ / μ (where θ: The Bragg angle, μ: linear absorption coefficient of the sample), which does not detect the information of the base steel sheet, is 17 μm or more.
It is considered that the (220) peak of α-Al does not include diffraction information from the base steel sheet.

Further, the standard sample of the plating film used for the measurement of ΔD ₀ is to use the plating film without precipitation of β-Zn particles in the dendrite region.
4 of (111), (220), (311), and (331)
The full width at half maximum of each peak is measured using the peaks of the book, and the average value thereof is defined as the half width Δθ ₀ of the standard sample.
When ΔD / ΔD ₀ exceeds 0.70, the amount of β-Zn particles precipitated is small, and bending workability deteriorates with time. In Figure 1,
The relationship between ΔD / ΔD ₀ and the 0T bending crack area ratio is shown.

FIG. 1 shows molten Al-Zn on the surface of a low carbon cold rolled steel sheet.
For plated steel sheets with an alloy-based (55mass% Al-1.6mass% Si-Zn) plating film (amounts of coating on both sides of 200g / m ² ), ΔD and ΔD ₀ were measured immediately after the production of the plated steel sheets, and After storing at 23 ℃ for 6 months, 0
A T-bending test was performed and the area ratio of cracks generated in the processed part (crack area ratio) was measured. The obtained result was ΔD /
This is illustrated in the relationship between ΔD ₀ and 0T bending crack area ratio. The crack area ratio is 50 mm (actual size: 1 mm) sandwiching the bending line after taking a backscattered electron image of the outside of the bent portion with SEM at 50 times, and using the backscattered electron image (photograph).
), The area of cracks existing in a region having a length of 220 mm (actual size: 4.4 mm) was measured by using an image analysis device and defined as a crack area ratio (%).

From FIG. 1, when ΔD / ΔD ₀ is 0.70 or less, the 0T bending crack area ratio is at most 5% or less even after being stored at 23 ° C. for 6 months. If the crack area ratio is 5% or less, the bending workability is 5 mass% Al with the same plating film thickness.
-As good as Zn steel, ΔD / ΔD ₀
When it is 0.70 or less, the bending workability is less deteriorated with time. Especially when ΔD / ΔD ₀ is 0.60 or less, the 0T bending crack area ratio after long-term storage at room temperature is 1% or less,
Almost no deterioration in bending workability was observed. ΔD /
The reason why ΔD ₀ is 0.70 or less and the deterioration of the workability due to holding at room temperature for a long time is not clear at present, but the present inventors have found that when the amount of β-Zn particles precipitated exceeds a certain value. The reason for this is that the regeneration of the GP zone due to long-term storage at room temperature is significantly reduced.

As described above, the plated steel sheet of the present invention has a fine (average particle diameter: 0.5 μm or less) β in the dendrite region.
-Zn particles are precipitated and dispersed, and more preferably a steel sheet having a plating film in which the ΔD of the dendrite region is 0.70 or less of the ΔD ₀ of the standard sample. FIG. 2 shows a scanning electron micrograph (secondary electron image) of a cross section of the plated coating in the plated steel sheet of the present invention. Fine (0.03 to 0.2 μm in equivalent circle diameter) Zn particles are clearly precipitated and dispersed in the dendrite region. The average interparticle distance was 0.34 μm. The ΔD / ΔD ₀ of the plating film on this steel sheet is 0.53
The 0T bending crack area ratio is 0.5 immediately after production.
%, 0.6% after stored at 23 ° C. for 6 months, and no deterioration in bending workability with time is observed.

FIG. 3 is a scanning electron microscope structure of the cross section of the plating film outside the scope of the present invention in which no fine (average particle diameter: 0.5 μm or less) β-Zn particles are precipitated and dispersed in the dendrite region of the plating film. It is an example of a photograph (secondary electron image). The Zn particles are mainly dispersed in the interdendrite region. A sample (plating film) in which Zn particles were not precipitated and dispersed in the dendrite region was used as a standard sample.
Used for ΔD ₀ measurement. This standard sample is a sample as it is after the plating treatment, and is not subjected to the processing treatment or the reheating treatment.

Next, a preferred method for producing the hot-dip Al—Zn alloy-based plated steel sheet of the present invention will be described. Produced by a conventional method, for example, low carbon aluminum killed steel sheet, ultra-low carbon steel sheet, immersed in a plating bath having a predetermined bath composition, to form a molten Al-Zn alloy-based plating film on the surface, molten Al-Zn
Use alloy-plated steel sheet. During plating, after appropriately adjusting the plating bath composition, bath temperature, plating bath penetration plate temperature of steel sheet, immersion time, cooling rate after plating, etc., shot blasting, laser irradiation, skin pass rolling, tensioning It is preferable that fine β-Zn particles are precipitated and dispersed in the dendrite region by performing one or more kinds of processing such as a leveler and then performing reheating.

A preferable plating bath composition is Al: 30 to 70 mass.
%, Si: 0.1 to 5 mass%, or even Sr: 0.005 to
0.1mass%, balance Zn. The preferable plating bath temperature is 590 to 620 ° C, the preferable immersion time is 2 to 7 s, the preferable plating bath penetration plate temperature of the steel sheet is 590 to 620 ° C, and the preferable cooling rate after plating is 5 to 70 ° C / s. After performing the plating treatment under the appropriate conditions as described above, one or more kinds of treatment treatments such as shot blasting, laser irradiation, skin pass rolling, and tension leveler are further performed, and then reheating treatment is performed to make fine β in the dendrite region. −Zn
It is preferable to deposit and disperse the particles.

As processing, shot blasting with an injection pressure of 10 to 100 kPa, laser irradiation of 5 kW or more at 1 to 10 kHz,
Elongation rate: 0.5-3% skin pass rolling, rolling rate: 0.3-
A 3% tension leveler is preferred. When the condition is not within the above range, the β-Zn particles cannot be finely precipitated by the short-time reheating treatment, and the bending workability cannot be improved. Needless to say, the processing method is not limited to the above.

As the reheating treatment, heating temperature: 15
0 to 250 ℃, holding time: 30 to 2000s or heating temperature: 40
0-520 ° C, holding time: 5-60s, β-Zn
It is effective for fine precipitation of particles. If the heating temperature is less than 150 ° C, G. P. In the zone, at 270 to 400 ° C, two layers are separated in the dendrite region, resulting in a marked decline in workability. On the other hand, if the heating temperature is higher than 520 ° C, the alloy layer at the interface grows and the workability deteriorates. If the holding time of the reheating treatment is short, β-Zn is not sufficiently precipitated, so that the bending workability cannot be remarkably improved. Conversely, if the holding temperature is too long, 150 to 2
When kept heated at 50 ° C., the precipitated β-Zn particles are coarsened, so that the corrosion resistance is deteriorated. Further, when heated at 400 to 520 ° C, the alloy layer at the interface grows and the workability deteriorates.

In order to set ΔD / ΔD _O to 0.70 or less and further improve the aging resistance, it is necessary to further carry out the above treatment method within the following range. In processing, shot blast injection pressure is 40kPa or more, laser irradiation frequency is 5kHz or less, output is 15kW or more, skin pass rolling and tension leveler are used together, and elongation is 2% as total elongation.
That is all. If the condition is out of the above range, the amount of fine precipitation of β-Zn particles cannot be obtained, and the workability gradually deteriorates when left at room temperature.

In addition to the above processing, it is preferable that the reheating treatment is performed at a heating temperature of 180 to 270 ° C. and a holding time of 600 to 2000 s. When the heating temperature is lower than 180 ° C. or when the holding time is less than 600 s, a sufficient amount of β-Zn particles cannot be deposited, and the workability gradually deteriorates when left at room temperature. Further, at a heating temperature of 400 to 520 ° C, it is not possible to secure both the amount of Zn deposited and the growth of the alloy layer.

[0028]

[Example] Mass%, C: 0.045%, Si: 0.01%, Mn:
Low-carbon Al-killed steel sheet (sheet thickness 0.4 mm) containing 0.17%, P: 0.018%, S: 0.005%, Al: 0.019% and the balance Fe and unavoidable impurities, and molten Al-Zn at a temperature of 605 ° C.
After immersing in the plating bath for 1 s, it was cooled at a cooling rate of 30 ° C./s to perform a plating treatment so that the amount of adhesion on both sides was 200 g / m ² .
99.99% Zn and 99.99% are used for adjusting the components of the plating bath.
Al, 15% Si-Al master alloy and 10% Sr-Al master alloy were used appropriately.

After the plating treatment, the plating film is melted and ICP
The composition was measured using emission spectroscopy. The results are shown in Table 1. Further, this plated steel sheet was subjected to shot blasting, laser irradiation, skin pass rolling under the conditions shown in Table 1,
After the processing with the tension leveler was performed alone or in combination, the reheating treatment was performed. In the shot blasting, iron powder of about 300 μmφ was projected from the vertical direction. The laser irradiation was linearly applied at a pitch of 2 mm in the rolling direction of the steel sheet.

Immediately after the production of the plated steel sheet, a 0T bending test was carried out to evaluate bending workability. Immediately after the production of the plated steel sheet, the microstructure observation of the cross section of the plated coating by SEM,
Also, ΔD in the dendrite region was measured by X-ray diffraction. The average particle diameter of β-Zn particles in the dendrite region and the average interparticle distance were determined by observing the structure of the cross section of the plated coating by SEM. The average particle size was converted into the equivalent circle diameter by using the obtained structure photograph and determining the average particle area by an image analyzer. The average grain spacing was also calculated by the image analyzer using the obtained structure photograph.

The bending test complies with JIS Z 2248.
A 0T bend was performed. After the bending test, the state of crack generation around the bent portion was observed and the crack area ratio was measured. The method of measuring the crack area ratio was the same as that described above. Also, the measurement of ΔD in the dendrite region by X-ray diffraction
The same method as described above was used. The standard sample ΔD
₀ was measured for the sample as it was after the plating treatment without the processing treatment and the reheating treatment (standard sample without precipitation of β-Zn particles in the dendrite region).

Further, these plated steel sheets were stored at 23 ° C. for 6 months and then further subjected to a 0T bending test to evaluate the change in bending workability with time. The obtained results are shown in Table 2.

[0033]

[Table 1]

[0034]

[Table 2]

In the dendrite region, β-Zn particles having an average particle diameter of 0.5 μm or less in equivalent circle diameter are uniformly observed.
In all of the examples of the present invention, the bending test immediately after production showed few cracks and showed good bending workability.
Further, β-Zn particles were uniformly observed, and ΔD / ΔD ₀
It can be seen that, in all of the examples of the present invention having a value of 0.70 or less, there are few cracks even after storage at room temperature for a long time, good bendability, and little deterioration in bendability over time. On the other hand, the comparative examples outside the scope of the present invention are inferior in bending workability immediately after production.

[0036]

EFFECTS OF THE INVENTION According to the present invention, it is possible to easily and inexpensively produce a hot-dip Al—Zn alloy plated steel sheet having a plating film, which is excellent in bending workability and has little deterioration in bending workability over time. It produces a marked effect.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between a crack area ratio in a 0T bending test and ΔD / ΔD ₀ .

FIG. 2 is a scanning electron microscope structure photograph of a cross section of a plated coating of the plated steel sheet of the present invention.

FIG. 3 is a scanning electron microscope structure photograph of a cross section of a coating film of a conventional plated steel sheet.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Susumu Sato             1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Made in Kawasaki             Technical Research Institute of Iron Co., Ltd. (72) Inventor Chiaki Kato             1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Made in Kawasaki             Technical Research Institute of Iron Co., Ltd. (72) Inventor ▼ High ▲ Hideo Mura             Kawatetsu, 1025 Hamano-cho, Chuo-ku, Chiba-shi, Chiba Prefecture             Steel Sheet Co., Ltd. Product Research Center (72) Inventor Hiroshi Hashimoto             11 Kawatetsu, 8252, Oshima, Oshima, Kurashiki, Okayama Prefecture             Steel Sheet Co., Ltd. Tamashima Factory F-term (reference) 4K027 AA05 AA22 AB02 AB05 AB06                       AB26 AB34 AB44 AB48 AC26                       AC72 AC87

Claims (2)

[Claims] 1. A hot-dip Al-Zn alloy-plated steel sheet comprising a hot-dip Al-Zn alloy-plated film formed on the surface of a steel sheet,
The molten Al-Zn alloy plating film contains Al of 30 to 70 mass%, Si
Content of 0.1 to 5 mass% and having at least a dendrite region, β-Zn particles having an average particle diameter of 0.5 μm or less in circle equivalent diameter in the dendrite region have an average interparticle distance of 5 times or less the particle diameter. A hot-dip Al-Zn alloy plated steel sheet characterized by being precipitated and dispersed in. 2. An X-ray diffraction peak full width at half maximum ΔD defined by the following formula (1) in the dendrite region is given by the following (2).
X-ray diffraction peak half-width ratio ΔD of standard sample defined by equation
The hot-dip Al-Zn alloy plated steel sheet according to claim 1, which is 0.70 times or less than ₀ . Note ΔD = cot θ · Δθ × 100 (%) ……… (1) ΔD ₀ = cot θ ₀ · Δθ ₀ × 100 (%) ……… (2) where θ: X of Al in the plating film Bragg angle of line diffraction peak, θ ₀ : Bragg angle of X-ray diffraction peak of Al in the plating film of the standard sample, Δθ: Half width (rad) of X-ray diffraction peak of Al in the plating film, Δθ ₀ : half-value width (rad) of X-ray diffraction peak of Al in the plating film of the standard sample