JP3180715B2 - Multi-layer plated metal material and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plated metal material excellent in design and a method for producing the same.

[0002]

2. Description of the Related Art Plated steel sheets and stainless steel sheets used for building materials such as roofs and walls, kitchen equipment, various kinds of utensils, and the like include:
There is a demand for a steel sheet that is not only corrosion-resistant and workable, but also has excellent design such as surface beauty, texture, and feel. For applications requiring such a design, a method of improving the coating method such as applying a powder coating to give a texture to the surface has been mainly used. However, in order to enhance the texture by painting, it is necessary to increase the thickness of the painted film, which is problematic in that the cost is high and the productivity is low.

[0003] Japanese Patent Application Laid-Open No. 7-275787 discloses a coated steel sheet capable of imparting a yuzu skin appearance with a sense of solidity. However, since this steel sheet has many coating steps, the production cost is high and the productivity is low. Another problem is that the beautiful luster inherent in metal is lost in painting.

There is a method in which a smooth steel plate is subjected to mechanical processing such as rolling to form a regular pattern, or a pattern is developed by selectively corroding the surface. However, in the method of performing machining, the planar pattern and the depth of unevenness are uniform and the texture is poor. In addition, when machining is performed on a plated steel sheet to form a pattern, there arises a problem that a plated film is peeled off or corrosion resistance is impaired. As described above, these methods have a limited design property, and are inferior in cost and productivity.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-layer plated metal material having a metallic luster and having a surface appearance excellent in design and a method for producing the same.

[0006]

The gist of the present invention is to provide the following metal materials (1) and (2) and (3) and (4):
In its manufacturing method.

(1) A multi-layer plating layer comprising a lower plating layer having a lower melting temperature than the base metal and an upper plating layer having a higher melting temperature than the lower plating layer is provided on the surface of the metal base material. A multilayer plating metal material having a mask-melon skin-like pattern composed of a mesh-like projection having a height of 5 μm or more and a flat portion surrounded by the projection.

(2) The uppermost layer of the multilayer plating layer is Al-Mn
The multilayer plated metal material according to the above (1), wherein the alloy plated layer and a layer thereunder are a plated layer made of Zn or a Zn-based alloy.

(3) After the upper plating layer is formed of a metal having a higher melting temperature than the plating layer on the surface to be plated, the melting temperature of the plating layer on the surface to be plated is higher than the melting temperature of the plating layer on the surface to be plated. The method for producing a multi-layer plated metal material according to the above (1), wherein the material is also heated to a low temperature.

(4) After an Al-Mn alloy is plated on a plating layer made of Zn or a Zn-based alloy to a thickness of 0.5 to 10 μm, the Al-Mn alloy is plated at a temperature not lower than the melting temperature of the Zn or Zn-based alloy. The method for producing a multilayer plated metal material according to the above (2), wherein the material is heated to a temperature lower than the melting temperature.

The present inventors have found that the melting temperature of the uppermost layer is lower than that of the plating layer immediately below (hereinafter, the uppermost layer is simply referred to as “surface plating”, and the plating immediately below is simply referred to as “lower plating”). When a multi-layer plated steel sheet plated with a high metal is heat-treated to a temperature range higher than the melting temperature of the lower plating layer and lower than the melting temperature of the surface plating layer, the surface plating layer will have a net-like projection with a dam-like cross section. The pattern surrounded by the mesh-like projections is formed to form a mask-melon skin-like appearance in which the inside forms a flat portion. The configuration of the plating layer and the heat treatment conditions are specified. It has been found that by adjusting the height and size of the mesh, etc., it is possible to obtain a multi-layer plated steel sheet having a surface having a concavo-convex pattern excellent in texture and feel, and completed the present invention.

FIG. 1 is a view schematically showing an example of the appearance and a cross section of a steel sheet of the present invention. As shown in (a), a mesh-shaped projection and a flat portion surrounded by the projection are formed on the surface of the steel sheet. FIG. 2B is an enlarged cross-sectional view showing an example of the state of the protrusion. The cross section of the projection has a bank shape with a height (h) of about several μm to about 200 μm, and the inside of the mesh is almost flat. The shape and size of the mesh are irregular,
The surface appearance of the steel sheet has a three-dimensional appearance and is extremely excellent in design.

The reason why the above-mentioned muskmelon skin-like pattern can be obtained by heating a multi-layer plated steel sheet composed of metals having different melting temperatures is not clear, but is presumed as follows. When a multi-layer plated steel sheet composed of plating layers with different melting temperatures is heated to a temperature range between the melting temperatures of the respective plating layers, the lower plating layer melts but the surface plating layer does not melt, and the surface plating layer does not melt. Is obtained as a thin film in which a molten layer is present. When this is cooled, the lower plating layer starts to solidify from the part where solidification nuclei have formed, the solidification part gradually expands, and finally the adjacent solidification parts collide and the unsolidified part remaining at the boundary part Finally solidifies. It is presumed that some stress acts on the solidified portion, and the unsolidified portion is collected at the boundary portion that finally solidifies, and this portion rises to form a dam-shaped protrusion in cross section.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described specifically and in detail. The percentages of the chemical compositions shown below mean% by weight.

A. Base material on which the lower plating layer is plated There is no particular limitation on the type, shape, dimensions, etc. of the base material on which the lower plating layer is plated. As the base material, steel materials such as carbon steel and stainless steel, aluminum, copper and other non-ferrous metals can be used. In addition, the shape thereof may be a plate, a tube, or a shape processed or formed into various shapes using these materials. Extremely mild steel, mild steel,
High tensile steel or the like can be applied. As the stainless steel, austenitic stainless steel, ferritic stainless steel, or the like can be used. Further, steel plated with a metal having a melting temperature higher than the heat treatment temperature may be used as a base material (hereinafter, the plating applied as the base material is simply referred to as “base material plating”). When the plated steel is used as a base material, a multi-layer plated steel sheet having three or more layers is finally obtained. In this case, for the lower plating layer, a plating type that is easy to obtain a mask-melon skin-like pattern during heat treatment can be selected, and for the base metal plating layer, a plating type that is optimal for corrosion resistance and workability can be selected. Thus, it is possible to obtain a plated steel sheet having excellent overall performance.

B. Lower plating and surface plating A lower plating layer is plated on the above base material. The plating type of the lower plating layer only needs to have a melting temperature lower than the melting temperature of the surface plating layer, and the type is not particularly limited.From the viewpoint of improving corrosion resistance, particularly sacrificial corrosion resistance, pure zinc or the like is used. , Zn-Al alloy, Zn-Fe alloy, Zn
-A Zn-based alloy such as a Ni alloy is preferable.

When a Zn-based alloy is used for the lower plating layer, the Zn content is set to 4 to maintain good sacrificial corrosion protection.
A Zn alloy of 0% or more is preferable. The lower plating layer is
Since the workability of the plating layer is impaired as the thickness increases, when used for applications requiring workability, the thickness of the lower plating layer before the heat treatment is desirably 30 μm or less. The thickness of the lower plating layer is not particularly limited, but is preferably 1 μm or more before heating.

The plating type of the surface plating layer may be any metal or alloy whose melting temperature is higher than that of the lower plating layer, and is not particularly limited. However, from the viewpoint of the appearance, corrosion resistance, workability, etc. of the plated steel sheet, Al, Ni, Cr, Al-Mn alloy, Al
-It is preferable to use a Ti alloy or the like.

The melting temperature in the present invention means a temperature at which a liquid phase or a solid-liquid mixed phase is formed. The melting point, peritectic temperature, eutectic temperature, etc. correspond.

Although the absolute value of the melting temperature of the surface plating layer and the lower plating layer is not particularly limited, the melting temperature of the surface plating layer needs to be relatively higher than the melting temperature of the lower plating layer. If the difference between the two melting temperatures is too small, there is an increased risk that the constituent elements of the plating layer will diffuse between the two plating layers during the heat treatment. For this reason, it is preferable to combine plating types whose melting temperatures are separated by 50 ° C. or more.

When an Al--Mn alloy plating is applied as the surface plating layer, its Mn content is preferably set to 1 to 50%. If the Mn content is less than 1%, the effect of improving corrosion resistance by adding Mn is not sufficient, and the Mn content is 50%.
%, The uppermost plating film becomes hard and the workability of the plating film deteriorates.

The thickness of the surface plating layer is not particularly limited, but it is preferable that the plating thickness be 10 μm or less in order to facilitate the appearance of a mask-melon skin-like pattern. The lower limit is 0.1 in order to ensure corrosion resistance and plating uniformity.
The thickness is preferably 5 μm or more. Conventionally used methods can be applied to the method of applying the lower plating and the surface plating. Specifically, a hot-dip plating method, an electroplating method, a vacuum evaporation method, or the like is suitable.

C. Heat treatment After the surface plating, heating is performed to a temperature range between the melting temperature of the surface plating layer and the melting temperature of the lower plating layer, followed by cooling. When the heating temperature is equal to or higher than the melting temperature of the surface plating layer or lower than the melting temperature of the lower plating layer, no network-like projections are formed, and a desired mask-melon skin-like pattern cannot be obtained. If the heating temperature is excessively higher than the melting temperature of the lower plating layer, an alloying reaction may proceed between the lower plating layer and the base material or the surface plating layer, and the performance of the plating film may be deteriorated. On the other hand, when the heating temperature is too close to the melting temperature of the lower plating layer, the formation of mesh-like projections becomes uneven, and a desired pattern may not be obtained. Therefore, the heat treatment temperature is the melting temperature of the lower plating layer plus 5 to 50
The temperature is preferably in the range of ° C. The time for maintaining the heating temperature is not particularly limited, and cooling may be started immediately after the entire lower plating layer has reached the processing temperature. If the holding time is excessively long, a diffusion reaction may proceed between the lower plating layer and the base material or the surface plating layer to deteriorate various performances of the plating film. Therefore, the heating time is preferably 1 hour or less.

The heating rate is set at 6 in order to suppress the alloying reaction between the lower plating layer and the base metal plating layer or the surface plating layer.
The temperature is preferably set to 0 ° C./min or more. The cooling rate is preferably set to 60 ° C./min or more for the same reason. The atmosphere during the heat treatment may be an air atmosphere, but is preferably a nitrogen atmosphere or a nitrogen-hydrogen mixed atmosphere in order to suppress surface oxidation. The heat treatment method is not particularly limited,
A continuous heat treatment furnace capable of rapidly heating and cooling is preferable.
The timing of performing the heat treatment is not limited. For example, the heat treatment may be performed in the apparatus immediately after the surface plating is performed,
After the surface plating, cooling may be performed once, and heat treatment may be performed using another apparatus.

D. Mask-melon skin-like pattern The height of the mesh-like projections forming the mask-melon skin-like pattern and the size of the flat portion formed by these projections greatly affect the design of the surface appearance. The height (h) of the protrusion shown in FIG. 1 (b) needs to be 5 μm or more in average. If the average height is less than 5 μm, the pattern cannot be recognized visually. In order to improve the texture and feel, it is desirable that the average height be 20 μm or more. The upper limit of the height of the mesh-like projections is not particularly limited, but when it exceeds 200 μm, the appearance of the design property is saturated, and
Since it is difficult to generate irregularities having a depth greater than this, it is preferable to set the thickness to 200 μm or less. The height of the projections is an average of the values obtained by measuring the heights of a total of 20 projections by two methods, such as cross-sectional observation, for each of two line segments orthogonal to each other, for a total of 20 protrusions Evaluated by value.

The mask-melon skin-like pattern of the present invention may be applied to at least one surface of the steel plate, and may be applied to both surfaces or the entire surface of the steel plate. The surface after the heat treatment may be subjected to a post-treatment usually applied to the plated steel sheet, for example, a chromate treatment, a phosphate treatment, or the like. In addition, the product of the present invention does not have any problem even if various coatings using an acrylic resin-based or fluororesin-based coating are applied.

[0027]

【Example】

(Example 1) Thickness: 0.6 mm, width:
A cold-rolled steel sheet made of 100 mm low carbon aluminum killed steel was used. These test pieces were immersed in a 10% by volume aqueous solution of NaOH to be degreased, and Zn was plated as lower plating under the following conditions.
Plating, Zn-5% Al alloy plating, or Sn plating was performed.

Zn plating: heated to 600 ° C. in a nitrogen atmosphere and held for 30 seconds, in a 25% by volume of hydrogen and in a remaining nitrogen atmosphere (hereinafter,% of atmosphere gas means volume%)
And heated to 750 ° C., held for 30 seconds, cooled to 460 ° C., and placed in a hot-dip Zn plating bath containing 0.10% effective Al.
After dipping for 2 seconds and plating, high pressure nitrogen gas is blown to adjust the plating thickness to 10 μm or 40 μm, and cooled to room temperature. Zn-5% Al alloy plating: heated to 600 ° C. in a nitrogen atmosphere for 30 seconds Hold, heated to 750 ° C. in an atmosphere of 25% hydrogen and residual nitrogen, held for 30 seconds, cooled to 450 ° C., and immersed in a hot-dip plating bath composed of 5% by weight of Al, residual Zn and unavoidable impurities for 1 second. Then, high pressure nitrogen gas was sprayed to adjust the adhesion amount to 10 μm, and the mixture was cooled to room temperature.

Sn plating: Electroplating of 10 and 20 μm in thickness was performed under the following processing conditions. The amount of plating was adjusted by changing the energization time.

[0030] On these plated steel sheets, Ni, C
r, Al or Al-Mn alloy was plated by the method shown below.

Ni plating: Electroplating with a thickness of 2 to 15 μm was performed under the following processing conditions while changing the energization time.

[0032] Cr plating: Electroplating with a thickness of 2 μm was performed under the following processing conditions.

[0033] Al-Mn alloy plating: Electroplating with a thickness of 2 μm or 5 μm is performed under the following processing conditions. The Mn content in the film was adjusted by changing the bath composition.

[0034] Al plating: 5 μm thick by vacuum evaporation under the following processing conditions
Of Al plating. Vacuum degree 10 ^-4 Torr. A crucible containing Al is placed in a container, and an electron beam with an output of 100 kW is directly applied to the Al in the crucible to be heated and melted, and vapor is generated by generating Al vapor.

These multi-layer plated steel sheets were placed in an electric furnace in an air atmosphere and heat-treated under various conditions. The heating rate was 150 ° C./min and the cooling rate was 200 ° C./min. The performance of the steel sheet test piece after the heat treatment was evaluated by the method described below.

Surface Observation: The height of the mesh-like projection is determined for every two line segments orthogonal to each other by the protrusions 10
And a total of 20 protrusions were measured by observing the height of the cross section, and the average value was determined. And those that did not show protrusions:
×, average height of less than 5 μm: Δ, 5 μm or more and 20 μm
Less than m: 、, 20 μm or more: ◎, average height 5
If the thickness is not less than μm, the design is good, and the results of the measurement of the protrusion height are ○ and ◎.

The results are shown in Table 1 together with the composition of the plating film and the heat treatment conditions.

[0038]

[Table 1]

As shown in Table 1, all of the examples of the present invention in which the height of the mesh-like projections was 5 μm or more exhibited excellent design properties. In particular, Test Nos. 1, 2, 4, 7, 8, 10 to 12 and 16 in which the height of the projection is 20 μm or more
Had an excellent appearance with texture and depth. On the other hand, in Test Nos. 3, 9, and 14 in which the heat treatment temperature was lower than the melting temperature of the lower plating layer, and in Test No. 13 in which the thickness of the surface plating layer was too thick, no protrusion was observed, and the mask melon skin was not observed. No pattern was formed. Test numbers 5 and 15
In the case of Sn-Fe
The alloying reaction or the Zn-Fe alloying reaction proceeded, and the height of the protrusion was slightly lower. In Test No. 6, since the heat treatment temperature exceeded the melting temperature of the surface plating layer, the plating layer was completely melted, and a desired mask melon-like pattern could not be obtained.

(Example 2) Thickness of the plating base material:
A 2D-finished ferritic stainless steel sheet specified in JIS G 4305 and having a width of 6 mm and a width of 100 mm was used. The test piece was immersed in an aqueous solution of 10% by volume of NaOH to degrease it, and as a base metal plating layer, the energization time was adjusted by the method described in Example 1 to perform a 0.5 μm-thick Ni electroplating. Then, Zn plating having a thickness of 15 μm was applied by electroplating as a lower layer plating by the method described below.

[0041] Various thicknesses of Al were plated by vacuum evaporation as surface plating. The plating conditions were the same as in Example 1, and the plating thickness was adjusted by changing the deposition time. These steel sheets were subjected to a heat treatment under the same conditions as in Example 1, and the performance was evaluated under the same conditions. Table 2 shows the results.

[0042]

[Table 2]

As shown in Table 2, test numbers a and b showed good design properties. On the other hand, in Test No. c, in which the holding time during the heat treatment was slightly too long, the height of the protrusion was slightly low because the alloying reaction proceeded. In Test No. d in which the heat treatment temperature exceeded the melting temperature of the surface plating layer, a good pattern was not obtained because the plating film was completely dissolved.

[0044]

The metal material of the present invention has a metallic luster,
Since the projections are formed in a mesh on the surface, an appearance with a high texture can be obtained, and the design is high because the touch is excellent.
Equipped with multiple layers of plating film, it has excellent corrosion resistance. Since the metal material of the present invention can be produced by heat-treating a multi-layer plated product, it can be produced at low cost and with good productivity.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a metal material according to the present invention, wherein FIG. 1 (a) is a plan view and FIG. 1 (b) is a partially enlarged cross-sectional view.

[Explanation of symbols]

1 ... base material, 2 ... lower plating layer, 3 ... surface plating layer, H ... protrusion spacing, h ... protrusion height.

──────────────────────────────────────────────────続 き Continued on the front page (72) Katsuo Hirayama, Inventor Sumitomo Metal Industries, Ltd. 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka (56) References JP-A-6-270597 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 28/02 C23C 2 / 06,2 / 12,2 / 28

Claims (4)

(57) [Claims] 1. A multi-layer plating layer comprising a lower plating layer having a lower melting temperature than the base metal and an upper plating layer having a higher melting temperature than the lower plating layer on the surface of the metal base material, wherein the multi-layer plating layer has an average height. A multi-layer plated metal material having a mask-melon skin-like pattern composed of mesh-like projections of 5 μm or more and flat portions surrounded by the projections. 2. The multi-layer plating metal material according to claim 1, wherein the uppermost layer of the multi-layer plating layer is an Al—Mn alloy plating layer, and the lower layer is a plating layer made of Zn or a Zn-based alloy. 3. After forming an upper plating layer with a metal having a higher melting temperature than the plating layer on the surface to be plated, the melting temperature of the plating layer on the surface to be plated is higher than the melting temperature of the plating layer on the upper surface. The method for producing a multilayer plated metal material according to claim 1, wherein the metal material is heated to a low temperature. 4. An Al—Mn alloy having a thickness of 0.5 to 10 μm is plated on a plating layer made of Zn or a Zn-based alloy, and the Al—Mn alloy is plated at a temperature equal to or higher than the melting temperature of the Zn or Zn-based alloy.
3. The method according to claim 2, wherein the Mn alloy is heated to a temperature lower than the melting temperature.
3. The method for producing a multilayer plated metal material according to item 1.