JPS6025501B2 - Manufacturing method for wire rod for zinc-aluminum thermal spray coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for manufacturing wire rods for zinc-aluminum thermal spray coating.

Zinc-aluminum alloy wire as a thermal spray coated wire is widely used for corrosion protection of steel towers, bridges, etc. due to its excellent corrosion resistance.

By the way, this type of alloy wire is made by hot extruding or rolling the alloy, but as the aluminum concentration increases, high temperature brittleness tends to occur and processing becomes difficult.

Therefore, it is not possible to increase the degree of processing at one time, and the thinning process becomes an extremely inefficient operation. Furthermore, when the degree of working is lowered to avoid high-temperature embrittlement, the deformation resistance of this alloy system increases rapidly, making it difficult to work in the same way as described above. Further, depending on the diameter of the product, thin wire processing may be required after extrusion or rolling, but for the same reasons as mentioned above, the work is difficult and requires a large amount of means to thin the wire.

Even if it could be processed into a wire for thermal spraying, the wire is extremely hard, so it would be difficult to feed the material with the thermal spray gun normally used for zinc lacquer spraying, and special thermal spraying equipment would be required.

With conventional zinc-aluminum alloy wire, the melting process is performed twice before the zinc-aluminum alloy is thermally sprayed to form the required spray amount.

The first time is when an alloy ingot, which is the raw material for manufacturing the thermal spray wire, is cast, and the second time is when the thermal spray wire is atomized during thermal spraying.

However, the rust and corrosion prevention method by thermal spraying involves spraying an atomized zinc-aluminum alloy onto the steel surface to form the necessary thermal spray coating, and there is no need to alloy zinc and aluminum from the beginning. Since zinc and aluminum are alloyed from the beginning, processing of the spray wire becomes difficult, and special thermal spray equipment different from that used for zinc spraying is required during thermal spraying.

It is not difficult to process zinc or aluminum alone, so instead of alloying the sprayed wire from the beginning, we separate it into zinc and aluminum, which are easy to process, and form a combination of these, which makes processing easier and makes the product more flexible. It becomes easy to handle. The present invention was made based on this idea in order to eliminate the drawbacks of the prior art.
The object of the present invention is to provide an advantageous manufacturing method in which a composite wire is produced by separating the necessary components of an aluminum thermal sprayed wire.

That is, the gist of the present invention is to continuously supply a zinc wire as a core wire, to lay an aluminum tape to be a coating on the circumference of the zinc wire vertically while bending it in the width direction, and to extend the green portions on both sides of the aluminum tape. The present invention provides a method for manufacturing a wire rod for zinc-aluminum thermal spray coating, which is characterized in that the wire rods are stacked one on top of the other and sealed.

The thermal spray coating wire village according to the above method is made of a composite wire in which zinc is used as a core material and aluminum is used as a coating.

Since the thermal spray coating must be a uniform alloy, when the composite wire is heated in the thermal spraying device, it is necessary for each component to come out of the thermal spraying device in a uniformly melted state. The core material is zinc, which has a low melting point, and the coating is aluminum, which has a high melting point and high thermal conductivity.The thermal conductivity of aluminum is very good when heated by flame in the blasting device, so it is still completely sealed. Zinc, which has a lower melting point than aluminum, rapidly melts inside the unmelted aluminum coating, and in this way, the zinc and aluminum come out of the thermal spraying equipment in an almost uniformly molten state. It is possible to obtain a sprayed film with a uniform alloy composition in the same way as when using the alloy wire. Making each component independent is also extremely advantageous in adjusting the component ratio.

Of course, it is desirable that each material used in this case be a single metal, but it is also possible to use an alloy mainly composed of these metals.

FIG. 1 shows a wire rod according to the present invention, in which 21 is a core made of zinc, 22 is a coating made of aluminum, and has lap joints on the longitudinal sides.

FIG. 2 and FIG. 3 each show an example in which the above-mentioned wire rod is obtained industrially.

FIG. 2 shows a suitable means for obtaining the wire shown in FIG. 1, in which a zinc wire 521 is used as the core 21 material, and an aluminum tape 522 having a width wider than the outer circumference of the wire 521 is used as the coating 22. The wire rod 521 is completely surrounded by a tape 522 which is bent in its width direction by the covering forming device 51, and which is tightly formed until the side edges thereof overlap each other.

Note that FIG. 3 shows another means, which is the same as the case of FIG. 2 except that zinc chips or granules 621 are used as the material for the core 21.

In this case, the zinc granules 621 that are continuously supplied before the side edges of the aluminum tape 522 overlap and close are compressed as the overlap of the side edges of the tape 522 increases, and are tightly integrated with the tape 522. Ru.

As a result, the core does not collapse and slip out from the edge.
It can be used in the same machine with a solid core material in advance.

However, the zinc filling rate is lower than that in the case of FIG. 2 using wire, and the spraying efficiency is correspondingly lower. After making it into a composite wire, it is of course possible to perform area reduction processing to make the wire thinner, as with other examples of wire rods, but because zinc particles are used, the area reduction processing is more difficult than in the case shown in Figure 2. is difficult, and there is a problem in particular with rapid surface reduction machining.

The thermal sprayed wire rod obtained in this way is a composite body in which the necessary components are separated, so the component ratio can be easily adjusted, the thermal spraying properties are the same as alloy wire rods, and the thermal spraying layer has the same corrosion resistance as that of alloy wire rods. have.

Furthermore, by using zinc wire and aluminum tape as raw materials, the forming process can be easily performed in the cold, and surface cutting and bending processes are also extremely easy. Therefore, workability and productivity can be significantly improved, which in turn can significantly contribute to reducing cost. Regarding the thermal spray performance of the zinc-aluminum thermal spray wire according to the present invention, one Zn-26%N composite wire manufactured by the method shown in Figure 2 was prepared, and a thermal spraying experiment was conducted under the conditions shown in the following table. . Tests were conducted on the settings of the spray wire in the spray gun, the feeding status of the spray wire, the spray speed, etc., and it was found that the example had workability equivalent to that of the conventional zinc wire and alloy wire shown in the comparative example. I found out that it can be done.

When looking at the X-ray brightness distribution of zinc and aluminum in the sprayed cross section using an X-ray microanalyzer, the distribution of zinc and aluminum is similar in both the composite wire of the example and the alloy wire of the comparative example, indicating that zinc and aluminum coexist well. I found out that

This means that in thermal spraying by composite wire thermal spraying, zinc and aluminum are thermally sprayed in an alloy state, similar to thermal spraying by alloy thermal spraying, and the thermal sprayed layer is a zinc-aluminum alloy.
This was also confirmed by stopping the thermal spraying of the composite wire midway through and analyzing its tip with an X-ray microanalyzer, which revealed that zinc and aluminum coexisted. In addition, in adhesion tests, tensile tests, and corrosion resistance tests, the examples showed similar results to the thermal sprayed wires of the comparative examples.

A particularly advantageous point of the present invention is that the AI concentration is 20 to 40%.
It is possible to manufacture composite wires without difficulty.

It has been recognized from salt water fin fog tests that the AI concentration is related to the corrosion resistance of zinc-aluminum sprayed wires, but the limit for the conventional manufacturing method was an AI concentration of 15%.
According to the above test, the AI concentration is preferably 20 to 40%, and in this respect, the present invention can easily produce a zinc-aluminum sprayed wire with a high peak concentration, which was previously considered impossible.

As described above, the present invention is significantly improved in ease of manufacture and comparable in characteristics.
The effect on industry is extremely large.

[Brief Description of the Drawings] Fig. 1 is a cross-sectional view showing an embodiment of the wire rod according to the present invention, Fig. 2 is an explanatory view showing a method for manufacturing the wire rod according to the present invention, and Fig. 3 is a cross-sectional view showing an embodiment of the wire rod according to the present invention. It is an explanatory view showing a manufacturing method of a wire rod. 21: Zinc core, 22: Aluminum coating, 521: Zinc wire, 621: Zinc granules, 522: Aluminum tape, 51, 61: Covering forming device, 52 and 62: Closer device. O figure 2 figure O 3 figure

Claims (1)

[Claims] 1. A zinc wire is continuously supplied as a core wire, and an aluminum tape to be a coating is placed vertically on the circumference of the zinc wire while being curved in the axial direction, and both side edges of the aluminum tape are overlapped and sealed. A method for manufacturing a wire rod for zinc-aluminum thermal spray coating, characterized by the following.