JPH0696828B2 - Anticorrosion PC steel stranded wire manufacturing method - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] Among PC steel materials, PC steel stranded wire has a structure that allows water to flow through the gap between the strands from the end if water stopping at the end is not sufficient. There is a problem that water permeates to the central portion of the steel wire due to the capillary phenomenon and corrosion deterioration of the steel wire is accelerated.

Regarding the rust prevention of the parallel part except the both ends, the method of covering the outer circumference with the anticorrosion tube has already been sufficiently successful, but it is not possible to stop the flooding from the end only by the covering construction with the anticorrosion tube. For this reason, after covering the outer circumference with an anticorrosion tube, the tube is filled with an anticorrosion material such as grease to eliminate the gap that serves as a passageway for water between the wires. In this case, no matter where the PC strand is cut, water does not penetrate through the gap from the end.

[Problems to be Solved by the Invention]

The method of covering the anticorrosion tube and filling the anticorrosive material from one end of the tube is disadvantageous in terms of cost and manufacturing labor since the filling step is added after the twisted wire step.

Since the outer strands of this PC steel strand are densely arranged, they are immersed in a liquid phase protective material before winding the twisted wire, or rust-proof on the outer circumference of the twisted wire. It cannot be expected to fill the rust preventive material by the method of extruding the material.

Here, Japanese Patent Publication No. 4334/1975 describes that when the strands are twisted, the anticorrosion compound is filled in the gap between the strands at the twisting ports, but when filling at the twisting ports, the outer circumference is filled. Since we had to take the method of pouring the rust preventive material into the interior through the gap between the strands before the strands were in close contact with each other, it was difficult to expect reliable and uniform filling. And so on.

Therefore, the present invention provides a method for producing a rust-proof PC steel stranded wire, which can easily perform quantitative quantitative rust-preventive material filling in a normal twisted wire process to completely fill the gap between the strands. The task is to do.

[Means and Actions for Solving the Problems]

In order to solve the above problems, in the present invention, a coating layer of a rust-preventive material having viscosity or elasticity is provided on the outer periphery of the center line, after which the outer strands are twisted on the outer side of the center line, As shown in Fig. 1 or Fig. 2, PC stranded wire 1
A method of completely filling the gaps between the element wires 2 constituting the rustproof material 3 with the rust preventive material 3 is adopted.

For example, in the case of the seven strands shown in FIG. 1, as shown in FIG. 3, a coating layer 3a is formed by extruding or applying a rust preventive material having an appropriate viscosity or elasticity on the outer periphery of the central wire 2a. After this, as shown in FIG. 4, the outer peripheral wire is placed outside the central wire.
Obtained by twisting 2b. The coating layer 3a is viscously or elastically deformed by the pressure when the outer peripheral wire 2b is wound, and therefore, if the thickness before the deformation of the layer 3a is sufficiently secured, as shown in FIG. The rust preventive material is densely filled in the gap between the wires.

According to this method, the central strand can be passed through a rust preventive material coating tank or an extruder before reaching the twisting opening of the twisting machine, so that a normal stranding process can be applied as it is. Also,
Since quantitative coating can be performed, reliable filling and uniform filling can be achieved, and high-quality PC steel strands can be obtained at low cost.

FIG. 2 shows a 19-stranded wire in which a middle layer wire layer is present. Even in such a stranded wire, the middle layer wires are twisted by the steps of FIGS. 3 and 4, and then the twisted wire is regarded as the central wire of FIG. 3 and subjected to the same treatment again. The gap between the lines can be completely filled.

The rust preventive material 3 is preferably grease, polyethylene or the like, but is not particularly limited thereto.

〔The invention's effect〕

As described above, in the manufacturing method of the present invention, the coating layer of the rust preventive material is provided on the outer circumference of the center line, and the outer strands are twisted together to push the gap between the outer strands to the outer strands. As it is filled with a deformable rust preventive material, it has excellent rust preventive ability.
PC steel stranded wire can be easily manufactured at low cost without complicating the process and equipment, and is effective in improving the reliability of the product and reducing the cost.

In addition, the PC steel strand obtained by the method of the present invention, when provided with an anticorrosion coating such as a tube on the outer periphery of the parallel portion, exhibits excellent anticorrosion properties over the entire length and is further improved.

[Brief description of drawings]

1 and 2 are both PCs manufactured by the method of the present invention.
A cross-sectional view showing an example of a steel strand, FIG. 3 and FIG. 4 are process drawings of the manufacturing method. 1 ... PC steel stranded wire, 2 ... strand, 3 ... rustproof material.

Claims (1)

[Claims] 1. A coating layer of a rust preventive material having viscosity or elasticity is provided on the outer periphery of a center line, and then outer strands are twisted on the outside of the center line so that a gap between the strands is completely filled with the material. A method for producing rustproof PC steel stranded wire, which is characterized in that