JPS63317658A - Zinc alloy for hot dipping and method of application thereof - Google Patents

Abstract

PURPOSE:To color a base material of iron and steel into the desired hue by using a molten Zn alloy, by specifying respective contents of Ti, Mn, Cu, Cr, Ni, and Zn in the above Zn alloy. CONSTITUTION:A zinc alloy having a composition consisting of, by weight, 0.3-0.7% Ti and/or 0.1-0.5% Mn, further one kind selected from 0.1-0.5% Cu, 0.01-0.05% Cr, and 0.01-0.05% Ni, and the balance Zn is refined. By using this molten alloy, plating is applied to a base material of iron and steel at 480-530 deg.C bath temp. Then, this plated steel is allowed to stand to be cooled in the air, by which an oxide film can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zinc alloy for hot-dip plating, which is used to apply a plating layer to steel and to generate a colored oxide film, and a zinc alloy using the same to form a colored oxide film. Concerning how to color.

Mitsuho ℃3J "Kuchi: Hot-dip galvanized steel, which is plated using hot-dip zinc, has been used in a wide range of fields ranging from materials and facilities in sectors such as architecture, civil engineering, power communications, transportation, agriculture, and fisheries. Used as a corrosion-resistant material.

On the other hand, in recent years, with the diversification of uses for steel products, especially
Colored hot-dip galvanized steel is used for steel towers, lighting poles, guardrails, various temporary structures, exterior panels, etc., because it matches the surrounding environment better than metal-colored steel such as conventional hot-dip galvanized steel. In the future, a wide range of demand for colored hot-dip galvanized steel is expected not only in architecture, civil engineering, power communications, etc., but also in sectors such as transportation, agriculture, and fisheries.

Therefore, the conventional coloring method for hot-dip galvanized steel is mainly to color the plated steel by painting, but since Zn in the plating film of hot-dip galvanized steel is active, the paint cannot be used. Fatty acids, which are the constituents of oil, gradually decompose with alkaline 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 is separated from ff, l+.

Therefore, in order to prevent such defects, conventionally, steel is plated with molten zinc, and the plated steel obtained is then exposed to the atmosphere for 1 to 3 hours to further coat the plated film with Zn(011). z, ZnO1ZnC0. and Z
It is necessary to form corrosion products such as nC1z, then clean the surface of the plated steel, and then apply a coating for coloring, which is a complicated operation.

In view of the above-mentioned situation regarding the coloring of hot-dip galvanized steel, the inventor of the present invention has investigated a technology that can color steel materials at the same time as plating them.
A plated steel obtained by plating a steel base material by immersing it in a molten zinc bath containing Ti) or manganese (Mn) or both, and a specific amount of one selected from Cu, Cr and Ni. When left to cool in the atmosphere or heated in an atmosphere at a specific temperature, a colored oxide film is generated on the plating layer of the plated steel, and coloring can be applied at the same time as plating, and the oxide film is further promoted. They discovered that, when developed, the hue and tone of yellow, purple, blue, green, etc. can be adjusted, and the present invention has been completed.

Therefore, the present invention provides a zinc alloy for hot-dip plating for obtaining colored hot-dip galvanized steel by simultaneously plating and coloring steel with hot-dip zinc, and using the zinc alloy for plating and coloring steel. The purpose is to provide a method for applying

The present invention will be explained in detail below.

Features of the present invention include: ■ 0.3 to 0.7% by weight of Ti, 0.1 to 0.5% by weight of Mn, or both, and 0.1 to 0.5% by weight of Cu, Cr. Q, Ql
0.05 to 0.05 heavy stirring and Ni 0.01 to 0.05
a zinc alloy for hot-dip plating containing one type selected from % by weight;
Plating a steel base material at a temperature of 0 to 530°C, and allowing the resulting plated steel to cool in the atmosphere to produce a colored oxide film on the plating layer to color it. Method of coloring, and (1) plating a steel base material using the above zinc alloy for hot-dip plating at a bath temperature of 480 to 530°C, and heating the obtained plated steel in an atmosphere of 450 to 550°C to form a plated layer. A method of plating and coloring steel, which involves producing a colored oxide film and coloring the steel.

The zinc ingots used in the molten zinc alloy in the present invention for Y-ing 1- are mainly distilled zinc ingots of type 1 (purity of 98.5% or more) and the purest zinc ingots specified in JIS II 2107. Money(
(purity 99.99%) and special zinc ingots,
For example, in distilled zinc ingots, the undullable substances unavoidably included in these zinc ingots include Pb of 1.2 wt% or less, Cd
0.1 int% or less, Fe 0.020wt% or less, but in the present invention, the total content of these impurities is 1.
．． It is preferable to use 5 wt % ungrooved zinc ingot.

In the present invention, 0.3 to 0.7% by weight of Ti or 0.1 to 0.5% by weight of Mn, or both, are added to the above-mentioned zinc ingot (distilled zinc ingot is mainly used). Furthermore, one of metals selected from Cu, Cr and Nj
The process is carried out using a bath of molten zinc containing seeds in a proportion of 0.1 to 0.5% by weight of Cu and 0.01 to 0.05% by weight of Cr and Ni.

To perform plating using the above molten zinc alloy bath, the steel base material is immersed in the zinc alloy bath at a bath temperature of 480 to 530°C for about 1 to 2 minutes, and then the steel base material is pulled out of the bath. After cooling in the air, cool with water.

Further, in the present invention, the steel base material may be similarly immersed in the above zinc alloy bath, then pulled out of the bath, heated for a short time in an atmosphere of 450 to 550°C, then air cooled, and then water cooled.

Furthermore, if the steel material after plating is left to cool in the atmosphere, the oxidation time will be shortened and the formation of an oxide film on the plating layer will be shortened.
On the other hand, heating the plated steel material prolongs the oxidation time and slows down the formation of the oxide film.

That is, oxidation of the plated layer can be controlled by allowing it to cool or heating after plating.

When a steel base material is immersed in a zinc alloy bath and left to cool in the atmosphere as described above, a plating layer is formed on the base material and an oxide film is formed on the plating layer, and immediately after plating, it is exposed to the atmosphere. When the oxide film is left to cool for 5 to 10 seconds and then cooled with water, the oxide film exhibits a yellow hue.

In addition, when the steel base material is immersed in a zinc metal bath as described above, then heated, and then air-cooled or water-cooled, the hue may be purple, blue, or green depending on the heating time and heating temperature. It begins to show itself.

For example, after plating the steel base material as described above,
When heated in an atmosphere at 0°C for 50 to 60 seconds, air-cooled, and then water-cooled, it exhibits a purple hue, and when heated for 2 minutes, air-cooled, and water-cooled, it exhibits a blue hue.

Therefore, when a steel base material is plated and then heated, it can be colored in a desired hue such as purple, blue or green (light green) by controlling the heating conditions.

Furthermore, in the present invention, the oxide film formed on the plating layer can be reduced by changing the content of Ti and Mn in the zinc alloy bath used for plating, as well as the amount of Cu5Cr or Ni added, within the above-mentioned range. You can also adjust the hue and tone as desired.

Next, the effects of the content of these metals in the zinc alloy used in hot-dip plating in the present invention on the formation of the oxide film and its hue will be explained.

b) Titanium (Ti): If the Ti content in the above plating bath is less than 0.3% by weight, the formation of an oxide film in the plating layer of the plated steel material is immature, so the heating temperature and heating time after plating should be set at the upper limit. However, the color tone of the oxidized steel is pale, and its commercial value as colored plated steel is low.

On the other hand, if the Ti content is higher than 0.7% by weight, the rate of formation of the oxide film becomes faster, so the hue of the formed oxide film changes rapidly, making it difficult to adjust it, and it also becomes difficult to adjust the hue of the formed oxide film. The amount of oxide increases and the wettability of the oxide film to the plating base material deteriorates.

) Manganese (Mn): If the Mn content in the above plating bath is less than 0.1%, T
As in the case of t, the oxide film is not yet fully formed, so the color tone of the oxide film is pale.On the other hand, if it exceeds 0.5% by weight, it is similarly difficult to adjust the hue, and the oxide film is thin on the plating base material. wettability deteriorates.

C) Copper (Cu): When the content of Ti and Mn in the plating bath approaches the above upper limits, as mentioned above, the rate of oxide film formation increases and it becomes difficult to maintain a constant hue;
When the plating bath contains 0.1 to 0.5% by weight of Cu, the rate of oxide film formation is suppressed, and as a result, it becomes possible to adjust the hue and improve the wettability of the oxide film to the plating base material.

Note that if Cu is contained outside the above range, the above effects can be expected.

2) Chromium (Cr) and nickel (Nt): Ti-containing plating bath (Ti-Zn alloy bath) and Mn-containing bath (Mn
-Zn alloy bath), Ti and Mn are easily distributed in the upper layer of the bath (therefore, more oxides are formed on the plating bath, the wettability of the oxide film to the plating base material becomes poor, and in addition, the plating bath Cr or Ni
0. By containing Ol to 0.05% by weight, Ti and Mn in the plating bath can be uniformly distributed,
Moreover, the wettability of the oxide film to the plated steel material and the yield of the plating bath can also be improved. Note that Cr and Ni
If it is contained outside the above range, the above-mentioned effects cannot be obtained.

Furthermore, when the molten zinc alloy used in the present invention contains Cu, Cr or Ni, in addition to the above-mentioned effects,
Since interference colors unique to these metals can be emitted, there is an advantage that the hue of the oxide film can be made very vivid.

As mentioned above, by using a molten zinc alloy containing Ti or Mn or both and a specific amount of one selected from CLISCr and Ni as a plating bath according to the present invention, molten zinc is applied to the steel base material. When applying a plating layer, oxide films of various hues can be generated on the plating layer, and by changing the conditions for generating this oxide film, specific hues can be developed. Therefore, colored hot-dip galvanizing Beneficial for steel acquisition and profit.

and t Below, the present invention and its effects will be specifically explained with reference to Examples.

Example A 5S41 steel plate with dimensions of 50 m5 in width, 10 mm in length, and 3.2 mm in thickness was degreased by immersing it in a Phulkari bath at a temperature of 80°C for 30 minutes, then washed with hot water, and then soaked in 1.5 mm of hydrochloric acid.
The rust was removed by immersing it in a 0% solution for 30 minutes at room temperature.

Next, this steel plate was washed with hot water and then immersed in a ZnC1g-F solution for 30 seconds at room temperature to undergo a flux treatment. Incidentally,
This flux treatment is performed to remove oxides from the surface of the steel sheet and to ensure that the active surface of the base material is well wetted with molten metal.

Each of the thus treated rope plates was immersed in plating baths having various compositions shown in Table 1 at a bath temperature of 480 to 500° C. for 1 to 2 minutes, and then pulled up at a rate of 3 ra/mm.

An oxide film was formed on each steel plate pulled out of the plating bath under the following conditions.

i) After being pulled out of the plating bath, it is air cooled in the atmosphere and then water cooled.

ii) After pulling out from the plating bath, in an atmosphere of 500°C for 10
Heat for ~30 seconds, then air cool, then water cool.

, 1ii) After being pulled out from the plating bath, it is heated in an atmosphere at 500° C. for 1.5 to 2.0 minutes, and then air cooled and then water cooled.

iv) In an atmosphere at 500°C after pulling out from the plating bath2.
After heating for 0 to 3.0 minutes, cool in air and then in water.

As shown in Table 1, when steel plates are immersed in plating baths of various compositions, pulled up and plated, and then air-cooled in the atmosphere and then water-cooled, an oxide film with a yellow hue is formed; When a plated product as described above is heated, then cooled in air and then water, an oxide film with a hue of purple, blue, or light green (thin edge) is formed depending on the heating conditions.

Furthermore, as seen in Na4 in the table, when the content of Mn and Cu in the plating bath reaches its upper limit, a glossy color tone appears.

Claims (3)

[Claims] (1) 0.3 to 0.7% by weight of Ti, 0.1 to 0.5% by weight of Mn, or both, and further Cu0.
1 to 0.5% by weight, Cr0.01 to 0.05% by weight
and one selected from 0.01 to 0.05% by weight of Ni, with the remainder consisting of Zn and impurities,
A zinc alloy for hot-dip plating used to color steel base materials to the desired hue. (2) 0.3 to 0.7% by weight of Ti, 0.1 to 0.5% by weight of Mn, or both, and further Cu0.
1 to 0.5% by weight, Cr0.01 to 0.05% by weight
and one selected from 0.01 to 0.05% by weight of Ni, with the remainder consisting of Zn and impurities, and the steel base material is plated at a bath temperature of 480 to 530°C. , by allowing the obtained plated steel to cool in the atmosphere, a colored oxide film is generated on the plating layer, and the above-mentioned zinc alloy for hot-dip plating is used to plate and color steel. Method. (3) 0.3 to 0.7% by weight of Ti, 0.1 to 0.5% by weight of Mn, or both, and further Cu0.
1 to 0.5% by weight, Cr0.01 to 0.05% by weight
and one selected from 0.01 to 0.05% by weight of Ni, and the remainder is Zn and impurities, and the bath temperature is 480 to 530°C.
The plated steel obtained by plating the steel base material with 450
A method for plating and coloring steel using the above zinc alloy for hot-dip plating, characterized by forming a colored oxide film on the plating layer by heating in an atmosphere of 550°C to 550°C.