JPS63247331A - Zinc alloy for colored galvanization - Google Patents

Abstract

PURPOSE:To subject a member to be galvanized to Zn alloy galvanization in which the coloring of yellow, dark red or green is freely capable by immersing the member to be galvanized into a molten Zn alloy galvanizing bath in which specific ratios of Ti, Pb, Cd, Cu, Sn, Bi, Sb, In, etc., are independently or compositely added to high pure Zn and galvanizing said member. CONSTITUTION:An iron steel member, etc., is subjected to the molten alloy galvanization by using the molten galvanizing bath of the Zn alloy contg., by weight, 0.2-0.7% Ti, the Zn alloy contg. 0.2-0.7% Ti and 1.3-5.9% Pb, the Zn alloy contg. 0.2-0.7% Ti, 1.2-1.3% Pb and 0.1-0.2% Cd or the Zn alloy contg. 0.2-0.7% Ti, 1.0-1.2% Pb, 0.05-0.2% Cd and in addition at least one kind among 0.01-0.05% Cu, Sn, Bi, Sb and In as the molten Zn alloy galvanizing bath, and after that, is drew up to regulate the oxidation ratio of the galvanized film. In this way, the colored galvanization in which the coloring of yellow, dark red and green can be freely performed is subjected to the member.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the production of α2 to α7wt% Ti, which is used to generate yellow, dark red, and green colored oxide films when hot-dip galvanizing the surface of steel materials. Contains zinc alloy.

Background of the Invention Hot-dip galvanized steel materials plated using hot-dip zinc are used for corrosion-resistant purposes in a wide range of fields, including components and facilities in sectors such as construction, civil engineering, agriculture, fisheries, chemical plants, and power transmission. It is widely used.

By the way, in recent years, steel towers, lighting poles, guardrails,
For facilities such as temporary stands for various works and exhibitions, and exterior panels, we use colored hot-dip galvanized materials that have an aesthetic color that matches the surrounding environment rather than conventional hot-dip galvanized materials that exhibit a metallic color. is now in demand. As aesthetic awareness increases, demand for colored hot-dip galvanized materials is expected to increase in the future in a wide range of fields including architecture, civil engineering, Plan 1 power transmission, transportation, agriculture, fisheries, and more.

Conventional technology and its problems The conventional method for coloring hot-dip galvanized steel is to color the plated 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 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 peels off.

Therefore, in the past, in order to prevent such defects, iron chains were plated with molten zinc, and the plated steel obtained was then exposed to the atmosphere for 1 to 3 weeks to further coat the plated film. )2, ZnO1CihCO3 and Z11C12, etc., and after cleaning the surface of the plated net, it was necessary to carry out the tedious operation of applying a coating for coloring.

By the way, apart from the above-mentioned painting method, a coloring treatment method is known that utilizes the coloring effect of an oxide film during hot-dip galvanizing. For example, Tokuko Sho 46-4200
No. 7 discloses a coloring treatment method using a hot-dip galvanizing bath to which 181 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 was generally very pale, the color quickly faded over time, and the coating was likely to peel off. It was not possible to accurately control the color development of the desired color, and the tones often became blurred.

Under these circumstances, there is a need for hot-dip galvanized materials with vivid yellow, dark red, and green colors.

Furthermore, surface coloring techniques using molten zinc alloy baths containing specific amounts of T1 and Mn are also known. but,
The zinc ingots used for hot-dip plating are the purest zinc ingots (zinc purity of 99,995% or more) and special zinc ingots (zinc purity of 99,99% or more) specified in JISH2107.
In this case, the rate of formation of an oxide film on the surface of the plating bath is rapid, and the amount of oxide generated on the plating bath is increased, which reduces the dripping property between the plating bath and the material to be plated. It was observed that unplated areas were likely to occur and the hue of the oxide film was likely to be non-uniform.

Therefore, we have developed a zinc alloy for colored hot-dip galvanizing that has good plating wettability, can make the hue of the colored oxide film uniform, and can clearly produce the aforementioned yellow, dark red, and green colors. is awaited.

Summary of the Invention As a result of repeated research in response to the above needs, the present inventors have discovered that by using a zinc alloy containing α2~Q and 7wt% Ti, it is possible to develop vivid hues of yellow, dark red, and green. I got the knowledge that this is the case. Said special public service 1974-4200
No. 7 discloses some Zn-T1 alloy examples, but
The TI content here is much lower than the present invention level. Therefore, the three colors mentioned above cannot be clearly produced in a controlled manner. Yellow, dark red, and green colors were made possible only by increasing the T1 content to a level of 0.2 to Q, 7 wt%.

Thus, the present invention contains α2-α7vt% Ti,
To provide a zinc alloy for colored hot-dip galvanizing, the balance of which is composed of zinc and inevitable impurities, and which can freely develop yellow, dark red, and green colors.

Furthermore, the following alloys with additional components added to the above Tl-Zn alloy were found to be useful for uniform yellow, dark red and green coloration: (a) 12-α7vt% TI and 13-5.9wt. %
A zinc alloy for colored hot-dip galvanizing that can freely develop yellow, dark red and green colors, containing Pb and the remainder consisting of zinc and unavoidable impurities, (b) Q, 2 to α 7
wt %TI and t2 ~ t3vt %P
A zinc alloy for colored hot-dip galvanizing that can freely develop yellow, dark red and green colors, containing 0.1 to α2vt%Cd, and the balance consisting of zinc and inevitable impurities, (c) I12 ~α7vt%Ti and tO~t2vt%
Pb, α05~Q, 2wt%Cd, 0.01~α0
Colored molten zinc containing 5 wt% of at least one of CuSn, Bt, sb, and In, with the remainder consisting of zinc and inevitable impurities, and capable of freely developing yellow, dark red, and green colors. Zinc alloy for plating.

Steel materials are immersed in a molten zinc bath of these alloys for plating, and the resulting plated steel is left to cool in the atmosphere or heated at a specific temperature, and the conditions are controlled to produce yellow, dark red, and green colors. It is possible to freely develop different hues. Zinc ingot (℃99,995)
% or more) and special zinc base metal (99.99% or more), it is possible to plate with a uniform hue with good plating wettability.

DETAILED DESCRIPTION OF THE INVENTION Hot-dip zinc alloy plating is carried out by dissolving a zinc alloy in a plating bath and immersing the material to be plated therein.

Zinc alloys are prepared by adding certain alloying additives to zinc bullion. In the present invention, the zinc ingots used for zinc alloys include the purest zinc ingots (99,995%) specified in JISH2107 and special zinc ingots (
99.99% or more)
degree is used. This is caused by impurities (PbSCd,
This is to prevent a decrease in color-forming powder due to the variable mixing of F., etc.). However, while the use of such high-purity zinc eliminates variations in plating conditions due to impurities, for example, it is possible to immerse the steel material in a plating bath containing specific amounts of T1 and Mn (saturated with Fa). When plating is applied, the hue of the colored oxide film on the plating layer may be partially changed due to the rapid formation rate of the oxide film on the surface of the plating bath or the large amount of oxide generated on the plating bath. This tends to result in uneven hue, such as a mixture of two colors. Unmet areas are also likely to occur.

Under these backgrounds, the present author has decided that α2~(L7wt
It has been found that addition of % T1 is effective in making yellow, dark red and green colors appear clearly without causing unplatedness or color unevenness.

If the Tl content in the above plating bath is less than 1% α2 weight, the formation of a colored oxide film in the plating layer of the plated steel material is immature, and the color tone is thin and uneven, so the commercial value as a colored plated steel is low, and Tl-containing When the amount is higher than 0.7% by weight, the rate of formation of the oxide film becomes faster and the hue of the colored oxide film changes quickly, making this adjustment difficult.

Furthermore, the amount of oxides generated on the plating bath increases, and the wettability between the plated steel material and the plating bath decreases.

In order to further improve plating wettability, Q is 2 to 0.7.
wt% Tl-Zn alloy with Pb-t Cd1sn, Bl.

As a result of examining various types of alloys to which elements such as sb and In are added, it has been found that the zinc alloys (a), (b), and (c) described above are particularly useful. These three types of alloys will be explained: a) Alloy containing t3 to 5.9 wt% Pb in addition to TI: If the Pb content is less than 15%, the wetting improvement effect is small, and in colored plating at a bath temperature of 470 to 500°C. Partial non-plating occurs, and especially at bath temperatures of 470 to 490°C, the proportion of dross adhering to the plating film increases. Also, 50
Plating at 0 to 600° C. similarly causes non-plating and causes color unevenness in the colored oxide film. The effect of adding PB is improved to the extent of dissolution alteration. Since the pb solubility in dissolved zinc at a bath temperature of 600 °C is 5.9 W t%,
This was set as the upper limit.

mouth) Other than Ti, t2~t5vt%Pb and α1~[L2v
Alloy with t%Cd added together: When pb and Cd are added together, the effect can be exerted with a small amount of both. However, if the Pb content is less than t2vt%, even in the presence of CD, partial non-plating occurs in colored plating at a bath temperature of 470 to 600°C, and
At ℃, the rate of dross adhering to the plating film increases.

Even if the Pb content is within the above range, if the Cd content is 0.
A similar problem will occur if it is less than 1vt%. Pb
When t3vt% is exceeded, and when Cd α2wt% is exceeded, more oxides are formed on the plating bath, and the incidence of non-plating increases.

c) In addition to TI, to~t2wt%Pb and α05~(L
Contains 2vt%Cd, and further contains Cu, Sn, Bi, S
α01~(LO5vt%) of one or more of b and In
Added alloy: Cu5Sns Bi % Addition of one or more of Sb and In assists the wettability improvement effect of PB and Cd. When Pb content is less than 0.5vt% and CdQ is less than 0.5vt%, partial non-plating occurs in colored plating at a bath temperature of 470 to 600°C, and especially at a bath temperature of 470 to 490°C, the proportion of dross adhering to the plating film increases. do. On the other hand, Pb
If it exceeds 12 wt% and CdO, 2 wt%, more oxides will be generated on the plating bath. In this case Cu, S! l
, BS, Sb, In at least one type from α01 to α05vt%
By adding it, the rate of oxide film formation on the upper surface of the plating bath is suppressed, and the wetting property with the plating M material is improved.

As a result, non-plating, color unevenness, dross adhesion, etc. can be prevented, and the hue of the colored oxide film can be easily adjusted, and the hue density can be increased.

In hot-dip galvanizing using such zinc alloys,
The material to be plated is degreased using an alkaline bath, scale removed by pickling, and other operations, and then subjected to 7 lux treatment for plating. For example, ZnC1z-KF-based solution, ZlIC12-NH4
This can be carried out by immersion in a C1 solution or other known flux solution for a short period of time.

After the preliminary treatment, the material to be plated is immersed in a plating bath controlled at a specific temperature for 1 to 3 minutes, and then the material to be plated is pulled out of the bath. By controlling the degree of oxidation of the plating film, yellow, dark red, and green colors are produced. Color development can be obtained freely.

For example, after the plating material is pulled out of the plating bath, its cooling rate is controlled by air cooling, water cooling, slow cooling in a hot water cooling furnace, or the like.

Alternatively, the degree of oxidation can be reduced by holding the plating material in an atmosphere at a temperature of 450 to 550° C. for a predetermined period of time after pulling it. The holding temperature, holding time, and subsequent cooling method are selected.

By increasing the oxidation degree of K, yellow, dark red and green M)C colors are developed.

For example, the following is an example of oxidation degree control: Yellow:
After being pulled out from a plating bath with a bath temperature of 590°C, it was held in a temperature atmosphere of 500°C for 15-20 seconds and cooled with water.

Dark red: Increase the bath temperature by 5-10°C, increase the ambient temperature, or extend the holding time by 5-10 seconds.

Green: Increase the bath temperature by an additional 5 to 10°C, raise the ambient temperature, or extend the holding time by an additional 5 to 10 seconds.

Furthermore, (a) Tl-1,3 to 5.9vt%P of the present invention
b-Zn alloy (a) TI-t 2~t 3vt%Pb
-11~0,2 vt%Cd alloy and (c) Ti-1
o ~'L2wt%Pb-α05~α2wt%Cd-α
o1~α05vt% (Cus Sns Bls 8bq
In the case of In) alloys, the development of golden, purple, and blue colors can be controlled.

The colors are golden yellow, purple, blue, yellow, dark red, and green in order of decreasing degree of oxidation.

Example and Comparative Example Width 5011III Length 100 fl and Thickness & 2 strips 5S
41 Steel plate was degreased by immersing it in an alkaline bath at 80°C for 30 minutes, then washed with hot water, and then soaked in a 10% hydrochloric acid solution for 30 minutes at room temperature.
The scale of the steel plate was removed by immersion for 0 minutes. Next, this steel plate was washed with hot water and then immersed in a 35% ZnCl4-NH4Cl solution at 80°C for 1 minute to perform flux treatment. The thus treated steel plate was placed in a plating bath having the composition shown in Table I for 1 hour.
After being immersed for a minute, it was pulled up at a rate of about 6 kg per minute. Each steel plate pulled up from the plating bath was heated in an atmosphere at 500° C. for a predetermined time and cooled with hot water to form a colored oxide film as shown below.

The processing details are as follows: Yellow: Bath temperature 590°C ↓ 500°C holding time 15-20 seconds Dark red: Bath temperature 600°C ↓ 500°C holding time 25-30 seconds Green: Bath temperature 610°C ↓ 500°C holding time Time: 35 to 40 seconds Reference Example Using Alloy Metals 2 to 5 of Examples, golden, purple, and blue colors were successfully developed under the following conditions.

Golden color: Bath temperature 490℃ (1 minute) ↓ Holding time at 500℃ 1-2 seconds Purple: Bath temperature 500℃ (1 minute) ↓ Holding time at 500℃ 10-15 seconds Blue: Bath temperature 520℃ ( 1 minute) ↓ Holding time at 500°C: 15 to 20 seconds In this way, by gradually increasing the oxidation conditions in conjunction with the examples, a variety of colors such as golden yellow → purple → blue → yellow → dark red → green were obtained. In fact, as many as 6 colors can be controlled at will, and no unplated or uneven color will occur.

Effects of the Invention By providing a zinc alloy for colored hot-dip galvanizing that can vividly and controllably develop yellow, dark red, and green colors without causing unplatedness or color unevenness, we have improved the aesthetic appearance of buildings, civil engineering, etc. This makes it possible to manufacture galvanized steel materials that exhibit the following properties.

Claims (1)

[Claims] 1) Zinc for colored hot-dip galvanizing that contains 0.2 to 0.7 wt% Ti, with the balance consisting of zinc and unavoidable impurities, and can freely develop yellow, dark red, and green colors. alloy. 2) 0.2-0.7wt% Ti and 1.3-5.9wt
% Pb, with the remainder consisting of zinc and unavoidable impurities, and is capable of freely developing yellow, dark red and green colors, for colored hot dip galvanizing. 3) 0.2-0.7wt% Ti and 1.2-1.3wt
% Pb and 0.1 to 0.2 wt % Cd, the balance being zinc and unavoidable impurities, a zinc alloy for colored hot-dip galvanizing that can freely develop yellow, dark red, and green colors. 4) 0.2-0.7wt% Ti and 1.0-1.2wt
%Pb, 0.5-0.2wt%Cd, 0.01-0
．． 05 wt% of at least one of Cu, Sn, Bi, Sb, and In, and the remainder is zinc and inevitable impurities, and is capable of freely developing yellow, dark red, and green colors. Zinc alloy for galvanizing.