JPH01180909A - Manufacture of corrosion resistance zinc alloy coated steel wire - Google Patents

Abstract

PURPOSE:To form alloy layer having high corrosion resistance as thick film at wide ratio of Zn : Al by sintering after sticking mixed powder while passing heated steel wire through the mixed powder of Zn and Al. CONSTITUTION:The steel wire 10a carried out from a pay-off 1 is heated between an electric conducted roll 3 and a drawing die 4 with an electric conducted heating device 2. The mixed powder 10'b of Zn and Al is stuck on the outer circumference of the steel wire 10a by passing through a coating vessel 5 charging Zn-A mixed powder 10' b at 99.1-50.50 mixing ratio of Zn:Al. After forming the mixed powder of Zn and Al stuck by rolling this with forming rolls 6 to the coating layer having uniform thickness round cross sectional shape, this is sent to a sintering furnace 7, and by heating, Zn-Al mixed powder coating layer is melted, to form Zn-Al alloy coating layer 10b having composition corresponding to the mixing ratio on the outer circumference of the steel wire 10a. This is wound to a coiler 8 as Zn-Al alloy coated steel wire 10 having thick thickness, much Al content and extremely excellent corrosion resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a tin alloy coated steel wire that has excellent corrosion resistance in severe atmospheres such as coastal areas.

BACKGROUND ART AND PROBLEMS] It is known that aluminum-coated steel wire has excellent corrosion resistance. The Aβ203 film formed on the surface plays a major role in its corrosion resistance behavior.
This is also something that everyone agrees on.

However, the role of A, 12203 as a protective film is in a normal corrosive atmosphere, and may not necessarily be sufficient in a severe atmosphere such as a coastal area. In other words, if a thick artificial film is formed as in alumite treatment, the ρ203 film formed by natural surface oxidation will have some areas where the film is insufficiently formed, resulting in so-called pitting. It is well known that it causes deep partial corrosion called corrosion. In particular, if the wire is used under conditions such as vinyl-coated wire, where the outside is coated with an insulator and oxygen supply is insufficient, severe pitting corrosion, known as 1g gap corrosion, will occur, causing major damage in a short period of time. There may be progress.

ZN-plated steel wire first appeared in the world as a corrosion-resistant steel wire, and has been widely used in the field of electric wires, such as for overhead ground wires and steel cores of steel-core aluminum stranded wires. This corrosion resistance behavior is due to the so-called self-sacrifice of ZN, and the ZN film that serves as an anode for the steel wire is selectively corroded, acting as what is known as cathodic protection to prevent the internal steel wire itself from corrosion. It is something. Therefore, its corrosion behavior is general corrosion, and its behavior does not change even in severe atmospheres such as coastal areas. Comparing this with the above-mentioned pitting corrosion, pitting corrosion progresses locally, and local corrosion progresses early, causing large damage locally. However, since the ZN-plated steel wire is fully corroded, the corrosion progresses overall and does not progress locally, so as a result, the corrosion becomes slower over time compared to the pitting corrosion. This results in superior corrosion resistance even in extremely harsh environments.

According to recent research by the inventors, the corrosion resistance of Zn in the above atmosphere is as follows:
It was found that the use of the -A and Q alloys further improved the corrosion resistance performance, particularly against the crevice corrosion mentioned above.

However, in the past, coating steel wires relied solely on plating methods, and the coating thickness was only 50 μm at most, and even if there was a demand for a thicker coating, there was no way to form it. Ta.

Furthermore, when using the plating method, the steel wire side during solidification!
There are problems such as the formation of a highly concentrated layer, which accelerates corrosion, and the uniformity of the plating bath composition deteriorates, resulting in uneven composition in the longitudinal direction of the wire. In some cases, there is a problem in that some wires are preferentially corroded due to differences in alloy composition.

Therefore, the inventors previously proposed a method of forming a Zn-A, Q alloy coating with a thickness of several 100 μrn by an extrusion method. However, when using the extrusion method, the appropriate range of extrusion conditions for the alloy is surprisingly narrow, and the extrusion speed may not be sufficiently high, hot embrittlement may occur during extrusion, or the amount of A It has gradually become clear that when the amount increases, the deformation resistance increases and coating becomes impossible. Especially 1. The content of l is 15%
This is extremely difficult to achieve depending on the extrusion method, and there is a need for a method that makes it easier to obtain a Zn-A, 2 alloy coated steel wire with a large wall thickness and a high content of 8ρ.

``Object of the Invention'' The present invention has been made in view of the above-mentioned circumstances, and is intended to be applied to Zn, which has a large coating thickness and can contain Zn over a wide range from a small amount to an extremely high amount. -A, a method for manufacturing an f1 alloy coated steel wire is provided.

[Summary of the Invention] That is, the gist of the present invention is to coat the outer periphery of a steel wire with a mixed powder of Zn and A[in a range where the mixing ratio of Zr3/A, fl is 99/1-50150. and then sintering the coated mixed powder.
As a result, A[Z'n- with high content and large wall thickness]
A, I1 alloy coating layer can be easily formed.

[Example] The present invention will be explained below based on examples.

FIG. 1 is an explanatory diagram showing two specific steps according to the present invention.

The steel wire 10a sent out from the payoff 1 is heated by the energizing heating device 2 between the energizing roll 3 and the drawing die 4, and is made into a uniform mixed powder of zn and Aρ with the required mixing ratio ]0-b. Zn-A, Il mixed powder 10-b is drawn into the powder coating layer 5 and adhered to the outer periphery of the steel wire 10a, and is rolled and formed by forming rolls 6 to form a powder of uniform thickness. Arrange the coating layer into a circular cross-section. In this state, the powder is fed into the sintering furnace 7 and the Zn powder and the A and [l powders are mutually diffused and sintered to form a zinc alloy coating with a Zn-,1 alloy composition corresponding to the mixing ratio of Zn and 8ρ. While forming the layer 10b, the coating layer] Ob and the steel wire 10a are metallurgically strongly adhered, and the winding machine 8 winds up the Zn-A as shown in FIG.
, [) An alloy coated steel wire 10 is obtained.

In the present invention, zn powder and A [powder mixing ratio Zn/
The lower limits of A and Q are kept at 99/1. This is 99/1
This is because below, the content of A becomes dilute and the corrosion resistance against crevice corrosion described above deteriorates. Further, the upper limit is set at 50150. This is no more than Aρ
As the concentration of A increases, the inherent corrosion resistance behavior of Zn weakens, and A
This is because the corrosion resistance behavior of ρ appears and similarly deteriorates the corrosion resistance against crevice corrosion.

However, in the present invention, since the initial state coated on the steel wire 10a is powder, unlike the case of plating or extrusion, it does not matter what the mixing ratio, that is, the composition ratio of A to zn. There is no difference in the degree of difficulty in depositing this onto the steel wire, and whether the mixing ratio is 99/1 or 50150, it can be deposited by the same operation and method. In this case, the coating thickness can be several 100 μm regardless of the mixing ratio. These characteristics are unique attributes of the powder method, and can be said to provide flexibility that cannot be expected with other methods.

After the mixed powder is applied as described above, it is sufficiently compressed before sintering to make it easy to sinter, and it is also shaped into a perfect shape after sintering.

Regarding this compression means, rolling using the rolling forming rolls is suitable from the viewpoint of compressing the powder.

However, compression can also be achieved by drawing by selecting the shape of the die, and in this case, the outer diameter size can be adjusted more favorably. Furthermore, compression by extrusion is also possible using powder extrusion technology, which also has the feature of making it easy to adjust the outer diameter.

Example 3 After degreasing and cleaning, the surface of a steel wire with a diameter of 0 mm was polished, and the wire was preheated to 250°C by electrical heating.
The mixed powder of Zn/Aρ is introduced into the mixed powder of 9515 and has a mesh particle size, and the mixed powder of Zn/Aρ is applied to the surface of the steel wire. Next, the outer diameter was adjusted by compression molding using a roll having an outer diameter of 100 mm and a groove radius of 1.65 mm, and the coated powder layer was passed through a sintering furnace in a reducing atmosphere at 350°C to sinter the coated powder layer. At the same time, the interface with the steel wire was also firmly bonded. As a result, zn -5%
A tin alloy coated steel wire having a coating layer made of one alloy could be manufactured at a line speed of 5 m/min.

The self-diameter winding of this coating layer showed similar or better results in the tests and crushing tests than those obtained by the plating method and the extrusion method.

Furthermore, production was carried out in the same manner as above with the content of Aρ increased by 5%, but there was no particular difference in production depending on the content of l, and no significant difference was observed in terms of product quality. It was found that the excellent characteristics of the law can be demonstrated.

[Effect of the invention] As described above, according to the manufacturing method of the present invention, Zn-,
1 alloy coating can be easily coated on steel wire over a wide composition range of Aβ, and in particular, when it is desired to increase the content of A[=9-], it is extremely difficult to coat the composition range with conventional methods. The present invention is highly significant in that it can be manufactured easily, and the present invention should be highly evaluated as it greatly contributes to improving the corrosion resistance performance in severe atmospheres.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a specific configuration according to the present invention, and FIG. 2 is a sectional view of a zinc alloy coated steel wire manufactured by the method according to the present invention. 2: Electric heating device, 5: Powder coating tank, 6: Forming roll, 7: Sintering furnace, 10: Zinc alloy coated steel wire, 10a: Steel wire, 10b: Zn-A [sintered layer, 10-b: Mixed powder of Zn and Aρ. Agent Patent Attorney Fujio Sato - 10 - Figure 2 ob

Claims (2)

[Claims] (1) Add mixed powder of Zn and Al to the outer periphery of the steel wire.
A method for manufacturing a corrosion-resistant zinc alloy coated steel wire, comprising coating and forming the coated mixed powder at a mixing ratio of /Al in a range of 99/1 to 50/50, and then sintering the coated mixed powder. (2) The manufacturing method according to claim 1, wherein rolling, drawing or extrusion is used as the means for coating and molding the mixed powder.