JPS6244563A - Manufacture of hot dip zinc-aluminum alloy coated steel wire - Google Patents

Abstract

PURPOSE:To obtain the titled steel wire having superior corrosion resistance and workability and beautiful surface skin, by entering flux treated steel wire to the former in molten zinc bath vessel and molten zinc-Al alloy bath vessel provided separately, then immediately entering the wire into the latter to coat it. CONSTITUTION:The steel wire 1 treated with connectional flux for hot dip zinc coating and dried is changed into a molten zinc bath 3 in a bath vessel 2 to hot dip zinc coat it, pulled up and squeezed by an apparatus 6 made of asbestos, etc. The wire 1 is charged in a molten zinc-Al alloy bath 5 added with high concn. Al in a bath bessel 4 to hot dip coat it with zinc-Al alloy. The wire 1 is pulled up vertically from the bath 5, thereat, it is extremely lightly squeezed by an apparatus 7 made of asbestos so that adhesion of oxide, etc., at bath surface to the wire 1 surface is prevented. Next, immediately the wire 1 is cooled by an apparatus 8, then entered in a roll dies apparatus 9 to smooth unevenness of the wire 1 surface. The wire 1 subjected to skin pass by the apparatus 9 is passed through a guide roll 13, then cooling after treated and coiled.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention uses the same flux used for hot-dip galvanizing to produce zinc-aluminum alloy coated steel wire with high corrosion resistance, in a simple and easy manner. This relates to a method for accurately applying zinc-aluminum alloy plating to a steel wire, and a method for producing a zinc-aluminum alloy plated steel wire having a smooth surface by performing a skin pass using a roll die after zinc-aluminum plating. It is related to.

(Prior art) In recent years, zinc plating has been developed in a zinc-aluminum alloy bath with an aluminum addition of at least 3 g as hot-dip plating for steel products, which has better corrosion resistance than zinc plating and better workability than aluminum plating. It is well known that methods for aluminum alloy plating have been developed and some have been put into practical use.

When applying zinc-aluminum alloy plating to steel wire, in the pre-treatment stage of the steel wire surface that is carried out prior to the plating process, if this is done using a hydrogen reduction method, the molten zinc-aluminum alloy will be coated directly after the pre-treatment. No problem occurs when the steel wire is immersed in the bath for plating, but the hydrogen reduction method requires expensive equipment.

When this is done using a flux force method, especially when using a dry flux method such as galvanizing steel wire, chlorides such as zinc chloride and ammonium chloride are used as flux, so the aluminum in the zinc bath and 3FeCA2 + 2Aj aFe + 2
AIC! .

As a result, aluminum in the bath is consumed, making bath management difficult, and unplated areas are likely to occur, making it impossible to obtain a good plated surface.

To solve this problem, a molten zinc bath and a molten zinc-aluminum alloy bath containing a high concentration of aluminum were floated on top of a molten lead bath, and the two were separated by a partition, and after the material to be plated was treated with 7 lux, It is charged into a molten zinc bath to perform galvanizing, and then passed through a molten lead bath to bath dipped zinc.
A method has been proposed in which the aluminum alloy is removed from the aluminum alloy bath and subjected to zinc-aluminum alloy plating.

In this method, the flux-treated material to be plated first enters the molten zinc bath, so there is no reaction between the slack and aluminum as described above, and no unplated areas are generated, making it possible to achieve good plating. Become.

However, in this method, lead is dissolved in the molten zinc bath and the molten zinc-aluminum alloy bath to an amount of at least 1%;
The zinc-aluminum alloy plating layer formed on the surface of the material to be plated contains at least 1% lead. Zinc-
The lead content in the aluminum alloy plating layer is 0.1 to 0.
．． It is clear from many documents that when the ratio is 2 or more, the corrosion resistance of zinc-aluminum alloy plated materials is significantly reduced.

On the other hand, in the case of hot-dip galvanized steel wire, when the galvanized steel wire is pulled out of the bath, a squeezing operation is usually performed for the purpose of controlling the N coating and smoothing the surface. In the case of steel plates, air, gas, etc. are used.

However, in the case of hot-dip zinc-aluminum alloy coated steel wire, asbestos and wire are used as the drawing method.

If air or the like is used in the conventional method, a sufficient amount of adhesion cannot be obtained due to the good fluidity of the zinc-aluminum alloy bath.
Furthermore, it is difficult to continuously obtain a satisfactory and beautiful surface texture using charcoal drawing 9 or the like.

It is clear from extensive literature that zinc-aluminum alloy plating has much better corrosion resistance than zinc plating at the same thickness. It has been confirmed through experiments that the thicker the material, the better the corrosion resistance.

Therefore, in the case of zinc-aluminum alloy plating, in order to obtain higher corrosion resistance, it is necessary to increase the amount of coating as in zinc plating.

There is also a method in which the zinc-aluminum alloy coated steel wire is not squeezed when it is pulled up from the bath, but the surface is finished using a hole die or roll die device during or after winding. Drawing in a hole die or roll die causes changes in the mechanical properties of the steel wire, increasing its strength and decreasing its elongation.

(Problems to be Solved by the Invention) The method of the present invention uses 7 lacs, which is exactly the same as 7 lacs used in conventional hot dip galvanizing, to produce hot-dip zinc-aluminum alloy coated steel wire. ,
The object of the present invention is to solve the above problems and provide a zinc-aluminum alloy plated steel wire that has excellent corrosion resistance, a beautiful surface texture, and excellent workability.

(Means for Solving the Problems) In the method of the present invention, the molten zinc bath and the molten zinc-aluminum alloy bath to which a high concentration of aluminum has been added are #lff separately, and the plated @ wire is After going through the same 72x treatment and drying process as galvanized steel wire,
First, it is placed in a hot-dip zinc bath to be galvanized, then immediately charged into a hot-dip zinc-aluminum gold plate containing a high concentration of aluminum and plated with a zinc-aluminum alloy, and then pulled up vertically from the alloy bath. .

When pulling steel wire from a molten zinc bath, squeezing is done with wire or asbestos as in conventional galvanizing, but when pulling a steel wire vertically from a molten zinc-aluminum alloy bath, conventional zinc plating is used. If wire, asbestos, air, etc. similar to plating are used, a sufficient amount of adhesion cannot be obtained, and if charcoal is used, a beautiful surface texture cannot be obtained.

Therefore, in the method of the present invention, when pulling a steel wire vertically from a molten zinc-aluminum alloy bath, a very light squeezing is performed to prevent asbestos and other oxides on the bath surface from adhering to the steel wire. After cooling, the surface of the steel wire, which is not smooth, is finished by performing a skin pass using a roll die device before the zinc-aluminum alloy is completely cooled.

Examples of the method of the present invention will be described in detail below with reference to the drawings.

The drawing shows an example of the manufacturing process of the zinc-aluminum alloy plated steel wire of the present invention.

The steel wire 1, which has been treated with the same flux as in conventional hot-dip galvanizing and has undergone a drying process, is first charged into a hot-dip zinc bath 3 in a hot-dip zinc bath 2 and galvanized. The molten zinc bath 3 contains 0.1 to 0.2% to suppress the development of the alloy layer.
When the steel wire 1 to which aluminum has been added is pulled out of the hot-dip zinc bath 3, it is squeezed by a squeezing device 6 made of asbestos or wire, as in conventional hot-dip galvanizing. The galvanized steel wire 1 is then placed in a hot-dip zinc-aluminum alloy bath 5 containing a high concentration of aluminum in a bath 4, where zinc-aluminum alloy plating is performed.

Since the base metal used for both the molten zinc bath 3 and the molten zinc-aluminum alloy bath 5 has a lead content of 0.1 to 0.2 t or less, the lead content of the plating layer of the steel wire 1 is Also 0
．． It can be suppressed to 1 to 0.2% or less.

The steel wire 1 is vertically pulled up from the molten zinc-aluminum bath 5, and at this time, very light squeezing is performed by a squeezing device 7 made of asbestos or the like to prevent oxides on the bath surface from adhering to the steel wire surface.

It is then immediately cooled down by the cooling device 8.

The main purpose of the cooling performed here is to prevent the zinc-aluminum alloy plated on the surface of the steel wire from sagging and to minimize surface irregularities, making it suitable for the surface finishing process in the next roll die device 9. The objective is to lower the temperature of the zinc-aluminum alloy to a temperature lower than that of the zinc-aluminum alloy.

The cooled steel wire 1 then enters a roll die device y9, where the unevenness of the steel wire surface j is smoothed by the roll die.
The temperature is preferably within a range at which solidification of the zinc-aluminum alloy begins and at which the zinc-aluminum alloy maintains sufficient ductility.

Also, roll dice equipped RF! 9. In order to prevent the zinc-aluminum alloy on the surface of the steel wire from adhering to the roll die, it is necessary to consider the material of the roll, the degree of polishing of the roll surface, the cooling of the roll, etc. The groove diameter of the roll die should be the same as the diameter of the steel wire to be plated, and the roll reduction is adjusted while checking the degree of finish on the surface of the A wire, but the degree of roll reduction is extremely small.
It is not large enough to affect the mechanical properties of the material.

The steel wire 1 that has been skin-passed by the roll die device 9 passes through the guide rolls 13, is subjected to post-cooling treatment, etc., and is wound up by a winding machine.

The amount of adhesion can be freely selected by increasing or decreasing the linear velocity.

Further, in the figure, 10, 11, and 12 are guide rolls.

(Function) According to the method of the present invention, even if the same flux as in conventional hot-dip galvanizing is used, the flux-treated steel wire
Since the molten zinc bath is charged first, good zinc-aluminum alloy plating can be achieved without causing the above-mentioned reaction between the flux and aluminum, and without generating unplated areas.

Note that a small amount of aluminum (approximately 0.1 to 0.2%) is added to the molten zinc bath in order to suppress the development of alloy j-, but this level of aluminum addition may result in non-plating, etc. There will be no adverse effects.

Further, in the method of the present invention, a molten zinc bath and a molten zinc
Since lead is not used in the aluminum bath, it is possible to control the lead content in each bath to 0.1 to 0.2% or less by selecting a zinc base metal or a lead-aluminum alloy base metal. Therefore, the lead content in the zinc-aluminum alloy plating layer on the @ wire surface after plating can be kept low, and a zinc-aluminum alloy plated steel wire with excellent corrosion resistance can be obtained.

Furthermore, in the method of the present invention, when pulling the steel wire from the molten zinc-aluminum alloy bath, only a very light squeezing operation is performed to prevent oxides on the bath surface from adhering to the steel wire. The amount of N deposited is proportional to the rate at which the steel wire is pulled out of the molten zinc-aluminum alloy bath, and it is possible to obtain a greater amount of deposit than if various other drawing operations were performed.

In addition, regarding the surface texture, immediately after pulling the steel wire from the molten zinc-aluminum alloy bath, the surface of the wire was coated with zinc-
In order to prevent the aluminum alloy from sagging and to minimize surface irregularities, it is immediately cooled and then smoothed using a roll die device, making it possible to continuously obtain a beautiful surface texture.

A skin pass using a roll die device does not completely cool down the zinc-aluminum alloy plated on the surface of the steel wire.
The process is carried out in a still soft state, so the strength of the steel wire increases and the elongation decreases, as when the plated gold camphor is surface-finished by drawing with a hole die or roll die machine after it has completely cooled down. No change in mechanical properties occurs.

As mentioned above, the zinc-aluminum alloy plated steel wire obtained by the method of the present invention has no defects such as unplating, the lead content in the plating layer can be controlled to be low, and it has a high coating weight, so it has good corrosion resistance. It can be said that it is a zinc-aluminum alloy plated copper wire that has a beautiful surface texture, is soft and has excellent workability.

(Example) The table shows an example of the manufacturing conditions and performance of the zinc-aluminum alloy plated steel wire manufactured by the method of the present invention.

In the case of surface hot-dip galvanizing, the time required for red rust to develop in a salt spray test is about 200 to 300 hours if the amount of coating is on the surface level, so the corrosion resistance of the zinc-aluminum steel wire obtained by the method of the present invention is far superior. That is clear.

(Effects of the Invention) As described above, the method of the present invention uses 7 lux, which is exactly the same as in conventional hot-dip galvanizing, to coat zinc-aluminum alloy coated steel with a sufficient coating amount and a beautiful surface texture, and excellent corrosion resistance. wire is obtained without compromising its mechanical properties,
It can be said to be a revolutionary method.

[Brief explanation of the drawing]

The drawings are process diagrams for manufacturing the zinc-aluminum alloy plated steel wire of the present invention. 1 is a steel wire, 2 is a molten zinc bath, 3 is a molten zinc bath, 4 is a molten zinc-aluminum alloy bath, 5 is a molten zinc-aluminum alloy bath, 6.7 is a drawing device, 8 is a cooling device, 9 is a roll Dice device, 10, 11. 12 and 13 are guide rolls.・,j,1. ,', ,j;'

Claims (2)

[Claims] (1) When applying hot-dip zinc-aluminum alloy plating to steel wire, use the conventional hot-dip galvanizing flux as is, and perform hot-dip galvanizing as the first stage plating,
A method for producing a zinc-aluminum alloy plated steel wire, which comprises performing molten zinc-aluminum alloy plating in a molten zinc-aluminum alloy bath in which a high concentration of aluminum is added to zinc as the second stage plating. (2) After applying hot-dip zinc-aluminum alloy plating to the steel wire and performing a very light drawing operation, it is cooled, and before the zinc-aluminum alloy on the surface of the steel wire has completely cooled, it is plated with a roll die. Zinc, which is characterized by its skin-passing properties.
Method for producing aluminum alloy plated steel wire.