JPH0581661B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to a colored hot-dip galvanizing technology on the surface of steel materials, and in particular produces an iridescent color that is a mixture of gold, purple, blue, green, etc., which is not seen in conventional coloring. The present invention relates to a colored hot-dip galvanizing method characterized by: Background of the Invention Hot-dip galvanized steel materials, which are plated using molten zinc, are widely used for corrosion-resistant purposes in a wide range of fields, including components and facilities in sectors such as architecture, civil engineering, agriculture, fisheries, chemical plants, and power transmission. has been done. By the way, in recent years, for facilities such as steel towers, lighting poles, guardrails, temporary stands for various works and exhibitions, and exterior panels, it has become more environmentally friendly than conventional hot-dip galvanized materials that exhibit a metallic color. There is a growing need for colored hot-dip galvanized materials that provide a conforming aesthetic color. As aesthetic awareness increases, demand for colored hot-dip galvanized materials is expected to continue to expand in a wide range of fields, including architecture, civil engineering, plants, power transmission, transportation, agriculture, fisheries, and more. Prior art and its problems The conventional method for coloring hot-dip galvanized steel is to color the galvanized steel by painting, but since Zn in the plating film of hot-dip galvanized steel is active, The fatty acids that make up the oil component of the paint gradually decompose with alkali to form zinc soap. Therefore, there is a drawback that the paint film used for coloring does not adhere to the surface of the plating film and peels off. Therefore, in order to prevent such defects, conventionally, steel is plated using molten zinc, and the plated steel obtained is then exposed to the atmosphere for 1 to 3 weeks to further coat the plated film with Z( OH) ₂ , ZnO,
formation of corrosion products such as ZnCO ₃ and ZnCl ₂ ,
Then, after cleaning the surface of the plated steel, it was necessary to carry out the complicated operation of applying a coating for coloring. Incidentally, in addition to the above-mentioned painting method, a coloring method is known that utilizes the coloring effect of an oxide film during hot-dip galvanizing. for example,
Japanese Patent Publication No. 46-42007 discloses a coloring method using a hot-dip galvanizing bath to which one or more of titanium, manganese, vanadium, etc. are added. However, it was found that the color tone of the colored hot-dip galvanizing obtained according to the technique disclosed herein is generally very pale, the color fades quickly over time, and the coating is likely to peel off. It was not possible to precisely control the color development of the desired color, and the tones often appeared blurry. Under these circumstances, the applicant of the present application has worked to establish a colored hot-dip galvanizing technology that produces vivid colors by increasing the amount of additives, as disclosed in Japanese Patent Application No. 62-81059, and has We have achieved results. Nowadays, it is possible to freely develop a wide variety of hues such as golden yellow, purple, blue, yellow, dark red, and green by combining component control and plating and post-processing conditions. However, if these conventional hues can be made richer and the aesthetics, decoration, and even artistry can be further enhanced, the range of demand for colored hot-dip galvanizing is expected to further expand. For example, highly decorative materials would be appropriate for temporary frames and exterior panels for various exhibition halls and amusement parks. It is thought that decorative features will become important in the future for guardrails and civil engineering and construction sites around the city. SUMMARY OF THE INVENTION In view of these issues, the present inventors went beyond simply coloring the conventional hot-dip galvanized material with a metallic color, and developed a gold, purple, blue, blue,
We conceived of an iridescent colored plating with a mixture of green, and succeeded in creating that color. For iridescent color development, (1) 0.1-0.8wt%Mn or 0.1-0.8wt%Mn.
(2) plating the steel material at a bath temperature of 450-550°C; and (3) using hot water at 40-60°C as a cooling means. It has been found that it is important to use hot water cooling with immersion in water for 3 to 30 seconds. It has been found that cooling with warm water is particularly effective in producing iridescent colors. Based on this knowledge, the present invention provides 0.1 to 0.8 wt%
Mn or 0.1~0.8wt%Mn and 0.05~1.0wt%Cu
using a molten zinc alloy plating bath containing zinc and unavoidable impurities, the bath temperature is 450
After plating steel materials at ~550℃, 40~60
Golden color by soaking in hot water for 3-30 seconds at ℃,
To provide an iridescent hot-dip galvanizing method characterized by developing an iridescent color in which purple, blue, green, etc. are mixed. DETAILED DESCRIPTION OF THE INVENTION Molten zinc alloy plating is carried out by melting the zinc alloy in a plating bath and immersing the steel material to be plated therein. To obtain an iridescent colored plating, it is necessary to perform the plating under specific conditions using a molten zinc alloy bath having a specific composition range. Zinc alloys are prepared by adding certain alloying additives to zinc bullion. In the present invention, the zinc ingot used for the molten zinc alloy is JIS
Mainly distilled zinc bullion type 1 (purity 98.5% or more) and purest zinc bullion (purity 99.99%) specified in H2107
In addition, special zinc ingots can be exemplified, and the impurities unavoidably contained in these zinc ingots are, for example, in one type of distilled zinc ingot, Pb 1.2wt% or less, Cd 0.1wt% or less, Fe 0.020wt% or less However, in the present invention, it is preferable to use a zinc base metal in which the total content of these impurities is less than 1.5 wt%. According to the present invention, the zinc ingot contains (1) 0.1 to 0.8 wt%, preferably 0.2 to 0.8 wt% Mn, or (2) 0.1 to 0.8 wt%, preferably 0.2 to 0.8 wt% Mn and 0.05 to 1.0 A molten zinc alloy bath containing wt% Cu is used.
If the Mn content in the plating bath is less than 0.1 wt%, the oxide film is immature and the color tone will be pale, while if it exceeds 0.8 wt%, it will be difficult to adjust the hue and the wettability to the plating material will deteriorate. Mn
If the content is 0.2wt% or more, the iridescent color will be more stable and easier to develop. Addition of 0.05 to 1.0 wt% Cu improves the dripping of the plating solution and is effective in preventing peeling of the oxide film. Hot-dip plating is performed using the above-mentioned molten zinc alloy bath at a bath temperature of 450 to 550°C. The soaking time is about 1 to 3 minutes. After soaking, the wood is cooled in hot water.
Hot water cooling is performed by immersing in 40 to 60°C hot water for 3 to 30 seconds. If the composition and processing conditions are outside the above specified ranges, the desired iridescent coloring cannot be obtained. If the plating material was too thin, it was difficult to obtain an iridescent color, probably because the cooling rate was faster. It is preferable to use a plated material having a thickness of 1.6 mm or more. Before plating, the material to be plated is subjected to conventional pretreatment. That is, the material to be plated must be degreased using an alkaline bath, scale removed by pickling, etc., and then immersed for a short time in a flux solution such as a ZnCl ₂ -KF solution or a ZnCl ₂ -NH ₄ Cl solution. The flux is processed by With these simple operations, you can obtain an iridescent colored plating with a mixture of gold, purple, blue, and green. This plating material also maintains corrosion resistance and can be widely used in fields that require good appearance and corrosion resistance. Example: Width 50mm x length 100mm x thickness 1.6~6.0mm
An SS41 steel plate was degreased by immersing it in an alkaline bath at 80°C for 30 minutes, then washed with hot water, and then immersed in a 10% hydrochloric acid solution at room temperature for 30 minutes to remove scale. Next, this steel plate was washed with hot water and then soaked in a 35% ZnCl ₂ −NH ₄ Cl solution at 60°C.
Flux treatment was performed by immersing the sample in water for 1 minute. The thus pretreated steel plate was plated by immersing it in a plating bath having the composition shown in the table at a temperature of 450 to 550° C. for 1 minute, and then cooling with hot water. Hot water cooling was performed by immersion in 40°C hot water for 5 seconds. The results are shown in Table 1.

[Table] Peeling of oxide film: ○ No occurrence × Occurrence
Sagging: ○ Good × Bad Effects of the invention Hot-dip galvanized materials with an iridescent color that is different from conventional colored hot-dip galvanized materials can be obtained, so they can be used for materials and facilities where aesthetic and decorative properties are strongly desired. A suitable zinc material is provided and is expected to have applications in a wide range of fields and in fields where it has not been used heretofore.

Claims (1)

[Claims] 1 0.1~0.8wt%Mn or 0.1~0.8wt%Mn
After plating a steel material at a bath temperature of 450 to 550℃ using a molten zinc alloy plating bath containing 0.05 to 1.0wt% Cu and the balance consisting of zinc and unavoidable impurities, An iridescent colored hot-dip galvanizing method characterized by developing an iridescent color in which gold, purple, blue, green, etc. are mixed by immersing in hot water for 3 to 30 seconds and cooling with hot water.