KR100563113B1 - Method of forming corrosion protection coatings on prestressing strand - Google Patents

Abstract

In the prior art, it is possible to improve the tensile fatigue characteristics without damaging the flexibility required for the PC strand and the adhesion strength with concrete, and also due to damage to the coating. In order to prevent the exposure of), a thick film is formed on the surface layer portion (outer peripheral surface).

 Corrosion protection film double bond structure formation processing method of PC strand is the pretreatment process of loosening the PC strand and loosening the repetition side line from the core line, and adjusting the side line to the core line after this pretreatment process. A primary coating step of applying a synthetic resin powder coating to the surface layer except for the spiral grooves by loosening and loosening by kneading, heating, adhering, and then cooling to form a resin film only on the surface layer; After this primary coating step, the side line of the PC strand is loosened from the core wire, and the synthetic resin powder coating is applied to each of the outer peripheral surfaces of the core wire and the side wire in the loosely loosened state through the core wire adjusting means, and heated and evenly attached. Later, it cools and molds each resin film of a single state in which a part becomes double bond film in a side line. After the secondary coating step and the secondary coating step, the step of twisting the side line in the original state with respect to the core wire so that the double bond coating portion is located on the surface layer portion of the stranded wire, A thick double bond coat can be easily formed in order to protect the outer surface where the risk of film damage is revealed as a special structure without impairing the properties.

 PC strands, surface, core, siding and spiral grooves.

Description

How to form rust preventive film of PC strands {METHOD OF FORMING CORROSION PROTECTION COATINGS ON PRESTRESSING STRAND}

1 (a) is a conceptual diagram of a plating processing line in a first step of a method for forming a corrosion protection film of a PC strand according to the present invention, and FIG. 1 (b) shows a bus bar to be processed. ) And element wires.

Fig. 2 (a) is a side view of a wire drawing processing line in the first phase of the same phase, and Fig. 2 (b) is a cross-sectional view of an element wire for stranded wires to be processed.

Fig. 3 (a) is a side view of the stranded wire processing line in the first phase of the same phase, and Fig. 3 (b) is a cross-sectional view of the PC strand strand to be processed.

It is a side view of the rustproof film processing line of the resin film process in a secondary process.

Fig. 5 (a) is a cross-sectional view of the stranded wire for repetitive strands, Fig. 5 (b) is a cross-sectional view of the loosening device, and Fig. 5 (c) is a cross-sectional view of the PC strand in which the rust preventive film is formed.

<Explanation of symbols for the main parts of the drawings>

1, 13, 16, 21: processing line, 2: busbar, 3, 3a, 3b, 3c: roller, 4: uncoiler device, 5: draw roll, 6: primary cleaning treatment, 7: wire drawing Treatment, 8: secondary cleaning treatment, 9: plating treatment, 10: winding device, 11: wire, 12: plated film, 14: strand wire for stranded wire, 15: stranded wire treatment, 17: core wire, 18: side wire, 19: PC Stranded wire, 20: Resin film, 22: Loosen apparatus, 23: Front side wide open keeping apparatus, 24: Core wire adjusting apparatus, 25: Primary heating apparatus, 26: Powder coating apparatus, 27: Secondary heating apparatus, 28: Cooling Apparatus, 29: rear enlarged opening holding apparatus, 30: loose closing apparatus, 31: film thickness measuring apparatus, 32: pinhole detection apparatus, 33: receiving apparatus, 34: blasting apparatus, 35: support arm, 36: Fixed pulley, 37: movable pulley, 38: blasted.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a corrosion protection film of a PC strand used as a tension material of a prestressed concrete method in a building structure and a civil structure.

As a method of forming a double rust preventive layer for preventing corrosion of steel wires in the core wires and the side wires of a steel wire, for example, there is an invention of Japanese Patent Application Laid-Open No. 11 (1999) -120826. . This forms an aluminum zinc coating layer in the outer peripheral surface of a core wire and a side line, and forms a resin film from this coating layer.

However, in the method of forming a double antirust layer as described above, an epoxy resin film is formed by temporarily repeating the strand in which the alumina zinc coating layer is formed, but this epoxy resin film is adhesive due to the oil content of the alumina zinc coating layer. There was a problem that this was bad.

The present invention has been made in view of the above problems, and an object thereof is to provide a method for forming an anticorrosive film of a PC strand having good adhesion of a resin film to repeated core wires and side lines in a method for forming a double antirust layer. It is.

In order to solve the above problems, the anticorrosive coating film forming method of the PC strand of the present invention forms a plated film on the outer circumferential surface of the wire, and wire drawing the wire on which the plated film is formed to perform wire drawing for the stranded wire. And twisting the plurality of strands of the stranded wire together to form a PC strand consisting of core and side lines, and temporarily repeating the PC strands to blast the core and side lines, and then to the blasted core and side lines A resin film is formed on an outer circumferential surface, and the resin film is cooled and then twisted together again. In addition, the soil amount of a blasting process includes the thing of 100-250 kg / hr. In addition, the blasting process uses a mixed iron powder of shot and grit, and has a square of 0.2 to 0.4 mm diameter spherical iron and a grit of 0.3 to 0.8 mm square. It includes iron.

By temporarily repeating the side lines of the PC strands from the core wires and blasting, the plated film surface becomes clean and suitable rough surface, so that the adhesion of the resin film to the core wires and the side wires is increased.

In addition, the soil amount of the blasting treatment is optimally 180kg / hr, and if it is less than 100, there is a problem that the surface oil can not be removed completely; There is a problem of worsening.

In addition, by using the mixed iron powder of shot and grit in the blasting treatment, the zinc coated surface can be made clean and appropriate rough surface.

In addition, when the shot is less than 0.2 mm in diameter, there is a problem in that plane cleaning cannot be performed and surface oils cannot be removed. If the grit is less than 0.3 mm square, there is a problem in the surface roughness. If the grit is greater than 0.8 mm, the surface roughness becomes excessive, the smoothness of the coating resin becomes poor, and the iron is easily cracked. .

EMBODIMENT OF THE INVENTION Hereinafter, the Example of the antirust film formation method (henceforth a film formation method) of the PC strand of this invention is described with reference to drawings. The film formation method of this invention consists of a primary process and a secondary process, and FIGS. 1-3 show the primary process which mainly consists of a wire drawing and a plating process, the wire drawing after a plating, and a stranded wire process, FIG. 4 and FIG. Shows a secondary process of loosening the twisted wire treatment to form an rust preventive film and then returning it to the original twisted wire state. In addition, in each process, the same code | symbol is attached | subjected to the same component, and it demonstrates, and attaches different code | symbol only to a different component.

FIG.1 (a) is a conceptual diagram which shows the processing line 1 which performs the wire drawing and plating process in a primary process. 1 (b) is sectional drawing which shows the process of the bus bar 2 to be processed, and this bus bar 2 is 10-14 mm in diameter. The bus bar 2 is wound around a roller 3 having a predetermined length, and the roller 3 is set to an uncoiler device 4 at one end of the processing line 1.

The bus bar 2 drawn out from the uncoiler 4 by the drawing roll 5 is subjected to the primary cleaning process 6, the wire drawing process 7, the secondary cleaning process 8 and the plating process 9. Is wound around the roller 3a of the winding device 10 of the other end.

The primary washing treatment 6 consists of acid washing and water washing, and firstly, the outer peripheral surface of the busbar 2 is washed with hydrochloric acid solution, and then the hydrochloric acid solution attached to the outer peripheral surface of the busbar 2 is carried out. Wash with water. In addition, the wire drawing process 7 cold-draws the bus | line 2 of the 10-14 mm diameter wash | cleaned process, and sets it as the element wire 11 of 5-9 mm in diameter.

The 5-9 mm diameter element wire 11 formed by the wire drawing process 7 is continued, and the secondary washing process 8 is performed. This secondary cleaning process 8 is performed by immersing the wire 11 in a flux solution tank, but this flux solution tank contains a saturated solution of ammonium chloride or a complex salt solution of ammonium chloride and zinc chloride. have.

Next, the strand 11 which this secondary washing process 8 was performed is dried, and plating process 9 is performed. As the plating process 9 in this case, for example, the plating film 12 by zinc is immersed in the molten zinc tank filled with molten zinc. Then, the element wire 11 on which the plating film 12 is applied is wound around the winding device 10. In addition to the above zinc plating, the plating treatment 9 includes zinc alloy plating, aluminum alloy plating, copper plating or chromium plating.

2 (a) is a conceptual diagram of the wire drawing processing line 13 which shows the wire drawing process 7 of the element wire 11 in a primary process. This processing line is also set to the uncoiler apparatus 4 in the one end part of the processing line 13 by winding the roller 3a by which the wire 11 was wound similarly to the said process, and here it is taken out by the take-out roll 5 The drawn wire 11 is wound by the wire drawing process 7 by cold drawing, and wound around the roller 3b set in the winding device 10 of the other end. By this wire drawing process 7, as shown in FIG.2 (b), the element wire 11 in which the plating film 12 was formed is wire-drawn by the element wire 14 for stranded wires about 4-5 mm in diameter.

3 (a) shows the conceptual diagram of the stranded wire processing line 16 which carries out the stranded wire process 15 of the strand wire 14 for the wire drawn by the primary process. Similarly to the stranded wire processing line, the roller 3b on which the stranded wire 14 is wound is set in the uncoiler device 4 at one end of the stranded wire processing line 16, and a drawing roll ( 5) is drawn out and treated with stranded wire. In this case, since the stranded wire process 15 is performed using the 7 stranded stranded wires 14, in the one end part of the stranded wire processing line 16, the stranded stranded wire 14 to the seven uncoiler apparatus 4, respectively. ) Rolled roller 3b, and these seven stranded wires 14 are drawn out and twisted together by stranded wire processing 15, and the roller 3c of the winding device 10 of the other end is used as the PC stranded wire 19. )

This twisted pair process 15 twists seven stranded stranded wires 14 together, and sets one of the seven stranded wires 17 into a core wire 17, and the stranded wire strands 14 around the core wire 17. It twists together as a side line 18, and forms the PC stranded line 19 as shown in FIG.3 (b). And the antirust film formation process is performed to the core wire 17 and side line 18 of the PC strand 19 which were formed in this primary process in a secondary process.

Fig. 4 shows a conceptual diagram of the rust-preventive coating line 21 in the secondary process, and an uncoiler device 4 on which one end side of the roller 3c wound the PC strand wire 19 formed in the primary process is set. ) Is installed, the drawer roll 5, the loosening device 22, the front expansion opening and holding device 23, the core wire adjusting device 24, and the primary heating device from the uncoiler device 4 toward the other end side. (25), powder coating device 26, secondary heating device 27, cooling device 28, rear enlarged opening and holding device 29, loose closing device 30, film thickness measuring device, pinhole detection device (32), the receiving device 33, and the winding device 10 are provided in the adjoining state in order, and the blasting device 34 is provided between the core wire adjustment device 24 and the primary heating device 25.

As described above, the coil-shaped strand wire 19 set in the uncoiler device 4 is drawn out sequentially from the pull-out roll 5 from here, and the side line 18, which is twisted in a spiral with the core wire 17, loosens the device. It repeats at (22), and this is widened by predetermined space | interval in the front-back expansion holding | maintenance apparatuses 23 and 29, and this state is hold | maintained.

The core wire adjustment device 24 provided on the rear side of the front enlargement opening and closing apparatus 23 winds the excess of the core wire 17 generated by the formation of the resin film 20 on the core wire 17 and the side wire 18. This loosens the PC strand 19 and forms the resin film 20 of the required thickness on the core 17 and the side line 18, and then loosely closes again, that is, returns to the original stranded state, whereby the core 17 and Since the diameter of the side line 18 becomes larger by the thickness of the resinous film 20, and the winding of the side line 18 to the core line 17 is farther away by that thickness, the diameter of the side line 18 is greater than that before the loosening. This is because the length of the side line 18 is insufficient, and the core line 17 gradually becomes redundant.

This core wire adjusting device 24 is composed of a fixed pulley 36 and a movable pulley 37 supported by a support arm 35, which is coiled in a direction to be separated from the fixed pulley 36. Force is always applied by a spring. Then, even in the state where the side line 18 is widened at predetermined intervals by the expansion-and-hold holding devices 23 and 29 before and after being repeated by the loosening device 22, the core wire 17 is already loosened, and the excess state is do. The excess core wire 17 is wound on the movable pulley 37 by winding the side coming from the loosening device 22, and then rolled up on the fixed pulley 36 to be pulled out to the rear side. Therefore, although the fixed pulley 36 and the movable pulley 37 are in a close state, when the surplus gradually increases, the movable pulley 37 moves in a direction to be separated from the fixed pulley 36 so that the excess of the core wire 17 is removed. Adjust it so it doesn't loosen.

The blasting apparatus 34 uses mixed iron for shot and grit, and the surface of the plated film 12 of the core wire 17 and the side line 18 in a loose state of the mixed iron powder. 100 to 250 kg / hr at a time, and cleaning and surface for removing deposits or rust removal of fats and oils adhered to the surface are roughened, for example, for shots of spherical iron having a diameter of about 0.2 to 0.4 mm. And grit is a cube iron powder of 0.3 to 0.8 mm angle.

Thus, as shown in FIG.5 (a), the blasting process 38 by the blasting apparatus 34 is performed before formation of the rustproof film in a secondary process, ie, formation of the resin film 20, The blasting process 38 flushes and cleans the mixed iron for shot and grit on the surfaces of the core wire 17 and the plated film 12 at each side line 18, which are loosened by the PC strand 19, and are loosened. At the same time, by forming the rough surface, the formation of the rust-preventive coating in the secondary process, that is, the adhesion of the resin coating 20 can be improved.

In this case, the blasting treatment 38 is applied in the range of the soil amount 100-250 kg / hr, preferably 180 kg / hr. And when the amount of earth-blasting of blasting process is less than 100, for example, there exists a problem which cannot remove the fats and oils adhered to the surface of the plating film 12 completely, or when it exceeds 250 kg / hr, the plating film 12 is shaved off There is a problem that the efficiency is reduced, or the iron of the blasting cracks.

The core wire 17 and each side line 18 which the blasting process 38 complete | finished remain in a loose | released state, and it transfers to the primary heating apparatus 25, and this primary heating apparatus 25 is carried out to a usable temperature. It heats and it transfers to the powder coating apparatus 26 in the heated state. In this powder coating apparatus 26, a thermosetting resin or a thermoplastic resin is apply | coated substantially uniformly around the core wire 17 and each side line 18 which are in a heating state by electrostatic coating means.

As resin used in this case, it is an epoxy resin, a polyester resin, a fluororesin, a polyethylene resin, etc., for example, As an electrostatic coating means, the electrostatic fluid immersion powder coating technique can be employ | adopted, for example. And the resin apply | coated with powder around the core wire 17 and each side line 18 which are in the pre-heated state melt | dissolves and adhere | attaches in a film form almost the most of the application | coating adhesion surface by the heat heated.

Subsequently, the core wires 17 and the respective side wires 18 coated with the resin are kept in a loosely released state and transferred to the secondary heating device 27, and the resin applied and dissolved by the secondary heating device 27 is dissolved. Is heated from the outside, and the whole melts again and adheres around the core line 17 and each side line 18 as the resin film 20 which shows a substantially uniform film shape.

Thus, after the resin film 20 in a molten state is formed around the core wire 17 and each side line 18, it transfers to the next cooling apparatus 28, and the whole is cooled by this cooling apparatus 28. As a result, the resin film 20 is cured, and the core wire 17 and each side line 18 are individually formed to form the resin film 20 as an antirust film.

When the core wire 17 and each side line 18 in which the resin film 20 was formed are twisted together by the loose closing device 30 shown in FIG. The PC stranded wire 19 in which the double rust preventive film of the film 12 and the resin film 20 is independently performed for each line is completed.

As described above, the PC stranded wire 19 in which the double rust preventive film is formed detects the state (positive or negative) of the rust preventive film by the film thickness measuring device 31 and the pinhole detection device 32 of the film, thereby It is wound by the winding device 10.

The antirust coating film formation method of the PC strand of this invention WHEREIN: The double wire rust prevention film of a plating film and a resin film is formed in a core wire and each side line, and the blasting process is carried out after plating film formation, and the adhesiveness and adhesion of a resin film to a plating film are carried out. The sex becomes good. Moreover, since adhesiveness and adhesiveness are favorable, the antirust performance of a resin film improves.

Claims (3)

A plating film is formed on an outer circumferential surface of an element wire, a wire drawing process of the wire on which the plating film is formed is performed to form a strand for stranded wire, and a plurality of strands of stranded wire are formed. The dog strands are joined together to form a PC strand consisting of a core line and a side line, and the PC strand is temporarily repeated to blast the core and side lines, and the blasted core line And forming a resin film on the outer circumferential surface of the side line, and cooling and then twisting the resin film together to form a corrosion protection film of the PC strand. The method of claim 1, The rust prevention film formation method of the PC strand of the said blasting process is 100-250 kg / hr. The method according to claim 1 or 2, The blasting process uses mixed iron for shot and grit, and for shot, spherical iron having a diameter of 0.2 to 0.4 mm, and for grit 0.3 to 0.8 mm. The anti-corrosive film formation method of PC strands characterized by being cube iron.

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