JPS59159977A - Galvanized ferrous metallic product and its production - Google Patents

Abstract

PURPOSE:To obtain a galvanized ferrous metallic product having good toughness of a plating layer by subjecting the outside circumference of an iron material to hot dipping of a Zn-Al alloy and subjecting the outside circumference thereof to pure Zn hot dipping by passing the same through a pure Zn bath on the surface of which is applied with a flame. CONSTITUTION:An iron or steel wire 1 is subjected to degreasing 3 and pickling 4 and after the wire is passed through a flux tank 5 and a dryer 6, the wire is dipped in a Zn-Al alloy plating bath 9 contg. >=0.2% Al. The plated wire is pulled up through a squeezer 11 and a cooler 12 and is further passed through a flux tnak 7 and a dryer 8 and thereafter the wire is dipped in a pure Zn plating cell 13 and is pulled through a squeezer 15 and a cooler 16, by which a galvanized ferrous wire 17 is obtd. A flame 26 of a burner, etc. is directly applied on the surface of the pure Zn plating bath in this stage to heat the bath surface so that the Al intruded in the bath is preferentially oxidized and removed and the contamination of the pure Zn by Al is prevented. The galvanized metallic product is stably produced by the above-mentioned method.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to ferrous metals (hereinafter referred to as
The present invention relates to a galvanized iron-based metal product in which two layers of hot-dip zinc-based plating are applied to a material (simply referred to as iron-based), and a method for manufacturing the same.

(Background technology) In recent years, heat-resistant steel core aluminum stranded wire (hereinafter referred to as , AC3R) are used. The iron wire used in such heat-resistant AC8R is usually a steel wire for AC8R that is coated and galvanized.

However, although Aβ coating has excellent corrosion resistance and heat resistance, it is expensive, and zinc plating, although inferior to Aβ coating, has been reported to improve the corrosion resistance of AC8R and be cheaper. As shown in FIG.
E-interface diffusion progresses and Kirkendall voids are formed, leading to peeling of the plating. Miura et al., Journal of the Institute of Metals,
39 (1975) 903), which deteriorates heat resistance.

In order to improve this heat resistance, it was found that applying hot-dip Zn-A4 alloy plating suppressed the growth of the Zn-Fe alloy layer at the interface. It also had the disadvantage of poor workability.

(Disclosure of the Invention) The present invention has been made to solve the above-mentioned problems, and improves heat resistance by suppressing the growth of the Zn-Fe alloy layer at the interface, and also improves the toughness of the plating layer. The purpose of the present invention is to provide galvanized iron products and methods for producing the same.

A first aspect of the present invention is that on the outer periphery of iron, steel or iron alloy material,
This is a galvanized iron-based metal product characterized by being made by hot-dipping a Zn-Aβ alloy containing 2% or more of Zn and pure Zn on top of the Zn-Aβ alloy.

A second aspect of the present invention is that the outer periphery of iron, steel, or iron alloy material is
After hot-dipping a Zn-A1 alloy containing 102% or more, pure Zn is added to the outer periphery of the Zn-A1 alloy, and pure Zn is applied to the plating bath surface to prevent contamination of Al by directly applying a flame to the surface of the plating bath.
This is a method for producing galvanized iron-based metal products, which is characterized by hot-dip plating using an n-bath.

The iron, steel or iron alloy material used in the present invention has a linear shape,
The material may be a strip, tape, tube, plate, or other shape, and the material may be iron, carbon steel, special steel containing other elements, or an iron alloy (eg, Fe-35 to 42% Ni alloy).

Hereinafter, the present invention will be explained by examples using the drawings.

Hereinafter, a line will be explained as an example, but the present invention is not limited thereto.

FIG. 1 is a sectional view showing an embodiment of the plated product of the present invention. In the figure, 31 is an iron or steel wire, with A and 9 on its outer periphery.
Hot-dip Zn-Aβ alloy plating layer 32 containing 0.2% or more,
A molten pure Zn plating layer 33 is applied thereon.

In the present invention, the reason why Zn-AJ7 alloy plating is first applied to the core material is as follows.

Generally, iron-based materials and Zn produce three types of compound layers (γ (gamma), δ (delta), and ζ (zeta)) when heated during or after hot-dip plating of Zn. Such Fe-Zn compounds cause deterioration in toughness, and for example, vibration fatigue strength decreases when heated at 300° C. for 100 hours. Furthermore, when heated at 300°C for 100 hours, the torsion value decreased significantly, and in extreme cases, peeling occurred at the interface of the grown alloy layer.

In order to suppress the growth of this compound layer, in the present invention, Zn
(Add 2% or more of /CA1O. This is to suppress the growth of a compound layer of Fe and Zn during hot-dip plating or heating during subsequent use. If the Al amount is less than 02%, the compound layer will be suppressed. It has no effect and has no effect on improving heat resistance.Is there any particular restriction on the upper limit of A11 ratio? Considering the ease of hot-dip plating, 14% or more is desirable.1
When the number exceeds 496, it becomes important and difficult to manage the plating bath and method, but it is not impossible.

The Zn-Aβ alloy plating layer remaining on the product after pure Zn plating has no particular restrictions on the thickness or amount of coating. In extreme terms, it is sufficient to have a thin Fe-Aβ alloy layer (formed preferentially over the Fe-Zn alloy layer) with a thin interface that is generated during Zn-Aβ alloy plating of iron-based materials. Therefore, molten Zn-
The distance and time of immersion in the Aβ alloy plating bath is extremely short.
Even a short period of time is fine.

Next, a method for manufacturing the plated product of the present invention will be explained. FIGS. 2(a) and 2(b) are block diagrams showing examples of apparatuses used in embodiments of the method of the present invention, respectively. In the figure, 3 is a lead bath for degreasing, 4 is a hydrochloric pickling tank, 5 and 7 are flux tanks, and 6 and 8 are drying devices.

(a) In the diagram shown, the iron wire 1 continuously drawn out from the supply device 2 is pretreated by each processing device 3, 4, 5° 6, and then Zn-A7 alloy plated. It is immersed in a bath 9 with a non-curing roll 10, pulled up through a squeezing device 11 and a cooling device 12, and then is passed through a flux tank 7,
After being subjected to flux treatment in a drying device 8, it is immersed in a pure Zn plating bath 13 with a sinker roll 14, and pulled up through a rocking device 15 and a cooling device 16 to form a galvanized iron wire 17.

(b) In the case shown in the figure, one plating tank 18 is used,
A Pb bath 19 is accommodated at the bottom, and the upper part is divided into front and rear parts by a partition 20, with a Zn-Aβ alloy plating bath 21 at the front and a pure Zn plating bath 22 at the rear floating above the Pb bath 19.

The wire 1 continuously combed out from the sagrai device 2 is pretreated in the same manner as in FIG.
The wire 1 is sequentially immersed in a Zn-A/alloy bath 21, p
The wire is passed through a b-bath 19 and a pure Zn bath 22, and then pulled up through a throttling device 15 and a cooling device 16 to form a galvanized iron wire 25.

In this case, the Pb bath 19 has the effect of removing the flux reaction residue adhering to the wire surface by relative friction LS and preventing non-adherence.

In these inventive methods, the wire 1 is first made of Zn-Al
After plating the alloy, it enters the pure Zn plating bath 13.22, so the Zn-A1 alloy is dissolved in the pure Zn bath, and p and (l) as impurities in the pure Zn bath increase, so the pure Zn bath 13° As the method 22, a method is used in which a flame 26 of a burner or the like is directly applied to the bath surface to heat it, and Al in the bath is preferentially oxidized and removed, thereby preventing contamination of pure Zn with Al. It is desirable to control the amount of Al in the pure Zn plating bath to 0.01% or less.

When performing hot-dip plating in this way, first, Zn-A,
Il? Alloy plating creates a thin Fe-A1 alloy layer at the interface to suppress the growth of the Fe-Zn alloy layer, and then pure Zn is plated on the surface with toughness, improving heat resistance. Galvanized iron products with excellent toughness and workability can be obtained.

The hot-dip plated iron wire is drawn to the final size if necessary.

(Example) Using the apparatus shown in FIG. 2(a), a 2.6 mi soft iron wire was hot-dipped.

A Zn-0.4% Ad alloy was used in the Zn-AjJ alloy plating bath 9, and plating was carried out while applying vibration to the wire at the plating inlet to prevent the plating from sticking.

As the flux, ZnCβ2. NH4Cβ mixture, pure Zn bath 13 NH4Cβ was used before immersion. Zn' as a linear velocity of 20 mi
- Cooled after immersed in A4 alloy bath 9 for 10 seconds, then pure Zn
Hot-dip plating was performed by immersing the sample in Bath 13 (for the immersion time shown in Table 1).

Regarding the obtained galvanized soft iron wire, total coating amount, cracks in Zn layer after winding and unwinding test, 10% at 300°C
Table 1 shows the results of investigating the state of peeling of the Zn layer due to bending after heating for 0 hours.

The winding and unwinding test was performed by winding the wire around a rod having the same diameter d as the wire, unwinding it, and winding it again. After heating, the wire was bent by 90° with the bending radius being 1 minus the wire diameter d.

Table 1 From Table 1, it can be seen that flats 1 to 6 according to the present invention have a sufficient amount of plating, have toughness that does not cause cranking in the Zri layer even when wound and unwound, and have the Zn layer even when bent after heating. It can be seen that it has excellent heat resistance without peeling.

On the other hand, in flat plate 7, which only has Zn-A and 5 alloy plating, many cracks occur on the surface of the plating layer during winding and unwinding, and in flat plate 8, which has only pure Zn plating, the Zn layer peels off when bent after heating. However, heat resistance is poor.

Further, when wire drawing with an area reduction rate of 90% or more was performed after the flattened 1 to Ifa 6 f plating according to the present invention, no defects were produced in the plating layer, and the wire drawing could be performed without any trouble.

(Effects of the Invention) The galvanized iron-based metal product of the present invention configured as described above has the following effects.

Since the outer periphery of iron, steel, or iron alloy material is first hot-dipped with Zn-Al alloy containing 02% or more Al, a thin Fe-AC alloy layer is generated at the interface to suppress the growth of the Fe-Zn alloy layer. However, during hot-dip plating, the plating layer does not peel off due to heating during use, and has excellent heat resistance.Since hot-dip plating of pure Zn is then applied on top of it, pure Zn has a tough surface.
Since the galvanized iron products are plated, they have good toughness as galvanized products and provide galvanized iron products with excellent workability.

After the Zn-Al alloy is hot-dipped, pure Zn is further hot-dipped on the outer periphery of the Zn-Al alloy by using a pure Zn plating bath that prevents Al contamination in the bath by directly applying flame to the surface of the plating bath. Zn-A plated in pure Zn bath
Even if the β-alloy melts and the AC in pure Zn increases, the flame preferentially oxidizes and removes the AC, so the pure Zn plating bath is always kept at a low Al content and the plating surface has toughness. Since pure Zn can be plated, the plated product of the first invention described above can be reliably and stably manufactured, and a manufacturing method suitable therefor is provided.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the plated product of the present invention. FIGS. 2(a) and 2(b) are block diagrams showing examples of apparatuses used in embodiments of the method of the present invention, respectively. 1. Iron-based metal wire, 2. Supply device, 3. Lead bath, 4.
Hydrochloric acid pickling tank, 5, 7... Flux tank, 6, 8... Drying device, 9, 21 ・Zn-A# gold alloy plating bath, 10
．． 14゜23, 24... sinker roll, 11.15
... Throttling device, 12, 16・Cooling device, 1! , 22
Pure Zn plating bath, 17.25・galvanized iron wire, 1
8... Plating tank, 19. Pb bath, 26 Flame, 31
・・Iron or steel wire, 32.Z n -Aβ alloy plating layer,
33. Pure Zn plating layer. ””fpe

Claims (3)

[Claims] (1) A galvanized iron-based metal product characterized in that it is formed by hot-dipping a Zn-A1 alloy containing 02% or more of Aβ and further pure Zn on the outer periphery of iron, steel, or an iron alloy material. (2) After hot-dipping Zn-A4 alloy containing A#0.296 or more on the outer periphery of iron, steel, or iron alloy material, pure Z'n is further applied to the outer periphery and flame is applied directly to the plating bath surface. A method for producing galvanized iron-based metal products, characterized in that hot-dip plating is carried out using a pure Zn plating bath that prevents contamination of g (in the bath). (3) The method for manufacturing a galvanized iron-based metal product according to claim 2, wherein the iron, steel, or iron alloy material is a wire, and the wire is drawn after hot-dip plating.