Zinc-aluminum-magnesium coated steel plate with patterns on surface and manufacturing method of zinc-aluminum-magnesium coated steel plate

Abstract

The invention discloses a zinc-aluminum-magnesium coated steel plate with patterns on the surface, which comprises a steel base plate and a zinc-aluminum-magnesium coating plated on the surface of the steel base plate, the same outer surface of the zinc-aluminum-magnesium coating is provided with a plurality of areas, adjacent areas have different average surface roughness, and the average surface roughness of the areas is larger than that of the areas. The outer surface of the zinc-aluminum-magnesium plating layer is provided with patterns formed by visual color difference generated by difference values of different average surface roughness. The invention further discloses a manufacturing method of the zinc-aluminum-magnesium coated steel plate with the patterns on the surface. The manufacturing method comprises the following steps: annealing a cold-rolled steel plate; performing hot dipping to form a zinc-aluminum-magnesium plating layer; a patterned roller is adopted to flatten the zinc-aluminum-magnesium coated steel plate, and different areas of the patterned roller have different average surface roughness.

Description

Technical Field

[0001] The present invention relates to a steel plate and a manufacturing method thereof, and in particular to a coated steel plate and a manufacturing method thereof. Background Art

[0002] Galvanized steel plates, represented by hot-dip galvanized aluminum-magnesium, usually do not require further coating to improve their corrosion resistance due to their strong corrosion resistance. Therefore, they can be used directly bare in some scenarios. Printing patterns or designs on the surface of such bare steel plates can significantly improve the aesthetics of the material.

[0003] In order to realize the needs of patterns, designs or trademarks on the surface of steel plates, existing technologies such as chemical etching, electroplating, spray printing, laser marking, and mechanical embossing can all achieve patterns or design effects on the surface of steel plates. However, since the preparation of patterns or designs requires additional processing steps, some technologies also require the use of additional consumables, the processing cost is relatively high.

[0004] In addition, methods such as etching and electroplating often require the use of chemical reagents, which poses certain environmental risks; spray printing on the surface of steel plates usually destroys the original metallic color of the steel plate surface due to the presence of non-metallic inks or coatings; laser marking has low processing efficiency; although mechanical embossing is relatively low in cost, it will cause plastic deformation of the material during the mechanical embossing process, increase the yield strength of the material, and increase the yield-to-strength ratio, which greatly reduces the stamping performance of the material.

[0005] For example, a Chinese patent document with publication number CN101077676B, publication date September 21, 2011, and titled “A printed metal plate capable of being processed by sheet metal and a method for manufacturing the same” discloses a printed metal plate capable of being processed by sheet metal and a method for manufacturing the same. The method requires the use of paint transfer to print patterns on the surface of a steel plate, which is costly and also requires curing treatment.

[0006] Another example: A Chinese patent document with publication number CN104368660B, publication date February 10, 2016, and titled "A continuous galvanizing flat embossing process", discloses a continuous galvanizing flat embossing process, which uses an engraved roller through a hot-dip galvanizing flattening process to obtain a hot-dip galvanized steel plate with embossing on the surface. The pattern on the steel plate surface is imprinted by the engraved roller, and the engraved roller needs to be processed with special equipment, the cost is relatively high, and the pattern effect is based on the concave and convex three-dimensional sense of the surface contour. Even after the steel plate is color-coated, the three-dimensional sense can still be maintained. This macroscopic concave and convex texture on the surface will be significantly damaged due to the plastic deformation of the material during stamping. Summary of the invention

[0007] One of the purposes of the present invention is to provide a zinc-aluminum-magnesium coated steel plate with a pattern on the surface. The upper and lower surfaces of the steel plate are coated with zinc-aluminum-magnesium coatings, and the coating surface on one or both sides has a pattern. The surface pattern effect is achieved by the visual color difference caused by the difference in roughness of different areas on the surface of the steel plate, so it will not reduce the mechanical properties of the material.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a zinc-aluminum-magnesium coated steel plate with a pattern on the surface, which includes a steel substrate and a zinc-aluminum-magnesium coating coated on the surface of the steel substrate, the same outer surface of the zinc-aluminum-magnesium coating has a plurality of areas, wherein adjacent areas have different average surface roughnesses, and the outer surface of the zinc-aluminum-magnesium coating has a pattern formed by visual color difference caused by the difference in different average surface roughnesses.

[0009] Furthermore, in the zinc-aluminum-magnesium coated steel sheet with a pattern on the surface of the present invention, the average surface roughness difference ΔSa of adjacent areas of the same outer surface of the zinc-aluminum-magnesium coating is 板 ≥0.4μm.

[0010] Furthermore, in the zinc-aluminum-magnesium coated steel sheet with a pattern on the surface of the present invention, the average surface roughness difference ΔSa of adjacent areas of the same outer surface of the zinc-aluminum-magnesium coating is 板 ≥0.8μm.

[0011] Furthermore, in the zinc-aluminum-magnesium coated steel plate with a pattern on the surface described in the present invention, there is a transition zone with a width of ≤0.1mm between adjacent areas on the same outer surface of the zinc-aluminum-magnesium coating, and the difference ΔSa′ between the average surface roughness of the transition zone and the average surface roughness of any one of the adjacent areas is less than ΔSa plate.

[0012] Furthermore, in the zinc-aluminum-magnesium coated steel sheet with a pattern on the surface of the present invention, the steel substrate contains Fe and the following chemical elements in the following mass percentages:

[0013] 0<C≤0.1%, 0<Si≤0.02%, 0<Mn≤0.5%, P≤0.035%, S≤0.025%, N≤0.01%.

[0014] Furthermore, in the zinc-aluminum-magnesium coated steel sheet with a pattern on the surface of the present invention, the mass percentage of each chemical element of the steel substrate is:

[0015] 0<C≤0.1%, 0<Si≤0.02%, 0<Mn≤0.5%, P≤0.035%, S≤0.025%, N≤0.01%; the balance is Fe and unavoidable impurity elements.

[0016] Furthermore, the zinc-aluminum-magnesium coated steel plate with a pattern on the surface of the present invention has a yield strength of ≤240MPa, a tensile strength of ≥270MPa, a yield strength ratio of ≤0.7, and an elongation after fracture A 80 ≥30%.

[0017] In the zinc-aluminum-magnesium coated steel sheet with a pattern on the surface described in the present invention, the zinc-aluminum-magnesium coating contains Zn, 1-15wt% Al, and 0.1-5wt% Mg.

[0018] In the zinc-aluminum-magnesium coated steel plate with a pattern on the surface described in the present invention, the mass percentage of chemical elements in the zinc-aluminum-magnesium coating is: Al: 1-15wt%, Mg: 0.1-5wt%, and the remainder is Zn and unavoidable impurities.

[0019] The zinc-aluminum-magnesium coated steel plate with patterns on the surface described in the present invention has a thickness of 0.4-2.0 mm.

[0020] Correspondingly, another object of the present invention is to provide a method for manufacturing a zinc-aluminum-magnesium coated steel plate with a pattern on the surface. This method can directly impart the pattern in the flattening process in the conventional production process of the steel plate without the need for additional processes and consumables. It has the advantages of low cost and environmental protection, and retains the metal's own gloss. At the same time, the lower flattening reduction rate also enables the steel plate to maintain good stamping forming performance.

[0021] In order to achieve the above object, the present invention proposes a method for manufacturing a zinc-aluminum-magnesium coated steel plate with a pattern on the surface, comprising the steps of:

[0022] Annealing the cold rolled steel sheet;

[0023] Hot dip coating to form zinc-aluminum-magnesium coating;

[0024] A zinc-aluminum-magnesium coated steel sheet is flattened by a patterned roller, wherein different areas of the patterned roller have different average surface roughnesses.

[0025] Furthermore, in the method for manufacturing the zinc-aluminum-magnesium coated steel sheet of the present invention, the average surface roughness difference ΔSa of adjacent areas of the patterned roller is 辊 ≥1.5μm.

[0026] Furthermore, in the method for manufacturing the zinc-aluminum-magnesium coated steel sheet of the present invention, the flattening rate is 1 to 3%.

[0027] In the present invention, when the flattening rate is lower than 1%, due to the small flattening reduction, the contact pressure between the roller and the strip surface is insufficient, and the surface pattern of the roller is difficult to be effectively transferred to the strip surface; when the flattening rate is higher than 3%, due to the excessive flattening reduction, the yield strength of the steel plate increases significantly, the yield strength ratio of the material is too high, and the stamping forming performance of the material is affected.

[0028] Furthermore, in the method for manufacturing the zinc-aluminum-magnesium coated steel plate described in the present invention, the pattern on the surface of the patterned rolling roller is obtained by a laser texturing process.

[0029] In the present invention, the power of the laser can be dynamically adjusted according to the shape of the target pattern, so as to process different roughness areas on the roller surface.

[0030] Furthermore, in the method for manufacturing the zinc-aluminum-magnesium coated steel sheet of the present invention, when the pattern roller is laser textured, the following relationship is satisfied:

[0031]

[0032] Among them, Ф represents the diameter of the pattern roller, and its unit parameter is mm; v represents the rotation speed of the pattern roller, and its unit parameter is r / min; f represents the laser switching frequency, and its unit parameter is Hz.

[0033] By controlling the diameter of the pattern roller, the rotation speed of the pattern roller and the switching frequency of the laser, the width of the transition zone can be controlled within 0.01 mm.

[0034] Compared with the prior art, the zinc-aluminum-magnesium coated steel plate with a pattern on the surface of the present invention has the following advantages and beneficial effects:

[0035] The zinc-aluminum-magnesium coated steel plate described in the present invention has a pattern on its surface and has a better visual appearance. Since the pattern is directly imparted in the flattening process in the conventional production process of the steel plate, no additional process and consumables are required. It has the advantages of low cost and environmental protection, and retains the metal's own luster. At the same time, the lower flattening reduction rate also enables the steel plate to maintain good stamping forming performance.

[0036] In a preferred embodiment of the present invention, the zinc-aluminum-magnesium coated steel plate with a pattern on the surface has a yield strength of ≤240MPa, a tensile strength of ≥270MPa, a yield strength ratio of ≤0.7, and an elongation after fracture A80 of ≥30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The schematic diagram of the cross-sectional profile of the surface morphology of the zinc-aluminum-magnesium coated steel plate described in the present invention is schematically shown.

[0038] Figure 2 The surface pattern effect of the zinc-aluminum-magnesium coated steel plate described in the present invention is exemplarily shown.

[0039] Figure 3 The surface microstructure of the zinc-aluminum-magnesium coated steel plate of Example 1 described in the present invention is shown. DETAILED DESCRIPTION

[0040] The zinc-aluminum-magnesium coated steel sheet with a pattern on the surface and the manufacturing method thereof described in the present invention will be further explained and illustrated below in conjunction with specific embodiments. However, such explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0041] Figure 1 The schematic diagram of the cross-sectional profile of the surface morphology of the zinc-aluminum-magnesium coated steel plate described in the present invention is schematically shown.

[0042] like Figure 1 As shown, the surface pattern of the zinc-aluminum-magnesium coated steel plate described in the present invention is formed by at least two areas with different roughness levels, for example, a high roughness area 2 with larger micro-contour fluctuations and a low roughness area 1 with smaller micro-contour fluctuations.

[0043] By controlling different areas to have different roughness, a pattern based on the visual color difference effect of surface roughness can be formed on the surface of the zinc-aluminum-magnesium coated steel plate, such as Figure 2 The surface pattern effect of the zinc-aluminum-magnesium coated steel sheet of the present invention is shown by way of example.

[0044] like Figure 2 As shown, by controlling the first region A and the second region B to have different roughness, a cross pattern can be formed on the surface of the zinc-aluminum-magnesium coated steel sheet.

[0045] The present invention is further described below using Examples 1-5, and the implementation effect of this case is further verified.

[0046] Examples 1-5

[0047] The zinc-aluminum-magnesium coated steel sheets of Examples 1-5 described in the present invention are all prepared by the following steps:

[0048] (1) The cold-rolled steel sheet is subjected to annealing treatment, and the annealing soaking temperature can be controlled between 730-830° C. The mass percentages of the chemical elements of the cold-rolled steel sheet are shown in Table 1, and the thickness of the steel sheet can be controlled between 0.4-2.0 mm.

[0049] (2) The annealed steel sheet is placed in a zinc-aluminum-magnesium plating solution for hot dip plating, and an air knife is used to scrape off excess plating solution, so that a zinc-aluminum-magnesium coating is attached to the surface of the steel sheet; wherein the mass percentage of each chemical element of the zinc-aluminum-magnesium coating is shown in Table 2.

[0050] (3) The zinc-aluminum-magnesium coated steel sheet is flattened by a patterned roller, and the flattening rate is controlled between 1-3%, so as to obtain a zinc-aluminum-magnesium coated steel sheet with a pattern on the surface. The specific process parameters are shown in Table 3.

[0051] In some embodiments, the roller with a pattern on the surface is subjected to selective texturing of the roller surface by controlling the on and off of the laser pulse according to the target pattern shape during roller laser texturing, so that the roller surface has a texturing area and a non-texturing area. The surface roughness of the texturing area and the non-texturing area is measured according to ISO25178-1:2016 standard.

[0052] In the above embodiments, the roller with a pattern on the surface is obtained by roller laser texturing. According to the target pattern shape, the laser pulse is turned on and off to achieve selective texturing of the roller surface, so that the roller surface has a texturing area and a non-texturing area. The surface roughness of the texturing area and the non-texturing area is measured with reference to ISO25178-1:2016 standard.

[0053] In some more specific embodiments, during the roller texturing process, the roller diameter Φ, the pulse switching frequency f of the laser, and the roller speed v can be controlled to satisfy the following relationship:

[0054]

[0055] Among them, Ф represents the diameter of the pattern roller, and its unit parameter is mm; v represents the rotation speed of the pattern roller, and its unit parameter is r / min; f represents the laser switching frequency, and its unit parameter is Hz.

[0056] The above relationship can be satisfied to make the width of the transition zone ≤ 0.1 mm, where the transition zone is defined as the difference ΔSa′ between its average surface roughness and the average surface roughness of any of the adjacent regions is less than ΔSa 板 .

[0057] Table 1 lists the mass percentages of the chemical elements of the zinc-aluminum-magnesium coated steel sheets of Examples 1-5.

[0058] Table 1. (wt%, the balance is Fe and other inevitable impurities except P, S, N)

[0059] C Si Mn P S N Example 1 0.03 0.001 0.21 0.020 0.005 0.001 Example 2 0.05 0.008 0.12 0.025 0.025 0.006 Example 3 0.08 0.007 0.35 0.030 0.007 0.003 Example 4 0.10 0.003 0.28 0.017 0.013 0.002 Example 5 0.02 0.020 0.43 0.035 0.010 0.009

[0060] Table 2 lists the mass percentages of the chemical elements in the zinc-aluminum-magnesium coatings of Examples 1-5.

[0061] Table 2. (wt%, balance is Zn and unavoidable impurities)

[0062] Al Mg Example 1 8.3 1.5 Example 2 6.2 3.5 Example 3 14.3 2.1 Example 4 12.6 0.6 Example 5 3.5 4.5

[0063] Table 3 lists the specific process parameters for processing the surface patterns of the zinc-aluminum-magnesium coated steel plates of Examples 1-5.

[0064] Table 3.

[0065]

[0066] The surface morphology of the zinc-aluminum-magnesium coated steel sheet obtained in Example 1 was observed. Figure 3 The observations are shown.

[0067] from Figure 3 It can be seen that the average surface roughness Sa of the low roughness area 1 is l =0.64μm, the average surface roughness Sa of high roughness area 2 h =1.45μm, difference ΔSa=0.81μm, transition zone width d=0.05mm, from which we can know that the adjacent areas A and B obviously have different roughness, thus forming a pattern on the surface of the zinc-aluminum-magnesium coated steel plate.

[0068] The zinc-aluminum-magnesium coated steel sheets of Examples 1-5 were sampled respectively, and the mechanical properties of each example were tested with reference to GB / T228.1-2021 standard, and the test results are listed in Table 4. At the same time, the surface pattern effect of the zinc-aluminum-magnesium coated steel sheet was visually evaluated, and the evaluation results are listed in Table 4.

[0069] Table 4.

[0070]

[0071] Note: "+" in Table 4 means that the surface pattern is visible to the naked eye. The more "+" there are, the higher the clarity or recognition.

[0072] Combining Table 1, Table 2, Table 3 and Table 4, it can be seen that the zinc-aluminum-magnesium coated steel sheets of Examples 1-5 have excellent mechanical properties, the yield strength is less than 240 MPa, the tensile strength is greater than 270 MPa, the yield strength ratio is less than or equal to 0.7, and the elongation after fracture A is less than 1.0. 80 At the same time, from the actual pattern effect point of view, increasing the leveling reduction rate and the difference in the roughness of the roller surface can effectively enhance the clarity of the pattern.

[0073] It should be noted that the combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0074] It should also be noted that the above-listed embodiments are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made therewith can be directly derived or easily associated with the contents disclosed by those skilled in the art from the present invention, and all should belong to the protection scope of the present invention.

Claims

1. A zinc-aluminum-magnesium coated steel sheet with patterns on its surface, which comprises a steel substrate and a zinc-aluminum-magnesium coating plated on the surface of the steel substrate. It is characterized in that The same outer surface of the zinc-aluminum-magnesium coating has several regions, and adjacent regions have different average surface roughnesses. The outer surface of the zinc-aluminum-magnesium coating has patterns formed by visual color differences generated by the differences in average surface roughnesses.

2. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 1. It is characterized in that The average surface roughness difference ΔSa between adjacent regions on the same outer surface of the zinc-aluminum-magnesium coating 板 ≥ 0.4 μm.

3. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 1. It is characterized in that The average surface roughness difference ΔSa between adjacent regions on the same outer surface of the zinc-aluminum-magnesium coating 板 ≥ 0.8 μm.

4. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 1. It is characterized in that The adjacent regions on the same outer surface of the zinc-aluminum-magnesium coating have a transition zone with a width ≤ 0.1 mm, and the difference ΔSa′ between the average surface roughness of the transition zone and the average surface roughness of any one of the adjacent regions is less than ΔSa 板 .

5. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 1. It is characterized in that Its steel substrate contains Fe and the following chemical elements with mass percentages as follows: 0 < C ≤ 0.1%, 0 < Si ≤ 0.02%, 0 < Mn ≤ 0.5%, P ≤ 0.035%, S ≤ 0.025%, N ≤ 0.01%.

6. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 5. It is characterized in that The mass percentages of the chemical elements of its steel substrate are: 0 < C ≤ 0.1%, 0 < Si ≤ 0.02%, 0 < Mn ≤ 0.5%, P ≤ 0.035%, S ≤ 0.025%, N ≤ 0.01%; the balance is Fe and unavoidable impurity elements.

7. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 5 or 6. It is characterized in that Its yield strength ≤ 240 MPa, tensile strength ≥ 270 MPa, yield ratio ≤ 0.7, elongation after fracture A 80 ≥30％。 8. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 1. It is characterized in that The zinc-aluminum-magnesium coating contains Zn, as well as 1 - 15 wt% of Al and 0.1 - 5 wt% of Mg.

9. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 8. It is characterized in that The mass percentages of the chemical elements of the zinc-aluminum-magnesium coating are: Al 1 - 15 wt%, Mg 0.1 - 5 wt%, and the balance is Zn and unavoidable impurities.

10. The zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to claim 1. It is characterized in that Its thickness is 0.4 - 2.0 mm.

11. The manufacturing method of the zinc-aluminum-magnesium coated steel sheet with patterns on its surface according to any one of claims 1 - 10. It is characterized in that It includes the steps of: Annealing the cold-rolled steel sheet; Hot-dip coating to form a zinc-aluminum-magnesium coating; Leveling the zinc-aluminum-magnesium coated steel sheet with a pattern roll, and different regions of the pattern roll have different average surface roughnesses.

12. The manufacturing method according to claim 11. It is characterized in that The average surface roughness difference ΔSa between adjacent regions of the pattern roll 辊 ≥ 1.5 μm.

13. The manufacturing method according to claim 11. It is characterized in that The leveling rate of the leveling is 1 - 3%.

14. The manufacturing method according to claim 11. It is characterized in that The patterns on the surface of the pattern roll are obtained by laser texturing technology.

15. The manufacturing method according to claim 14. It is characterized in that When laser texturing a pattern roll, the following relationship is satisfied: Among them, Ф represents the diameter of the pattern roll, and its unit parameter is mm; v represents the rotational speed of the pattern roll, and its unit parameter is r / min; f represents the laser switching frequency, and its unit parameter is Hz.

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