JPWO2008093651A1 - Method for producing rust-proof coated PC strand - Google Patents

Abstract

An object of the present invention is to provide a method for producing a rust-preventing coated PC strand that can be easily and reliably filled with internal voids simultaneously with processing into a PC strand, has a good yield, and can be produced at low cost. A thermoplastic synthetic resin in which at least a core wire of each single strand constituting a steel stranded wire is preheated immediately before the twisting position and heated and melted at the twisting position at the time of the twisting process. The rust preventive material is supplied to fill the gaps between the single strands of the steel stranded wire with the rust preventive material, and then the blueing treatment and / or heat stretching treatment is performed on the PC strand. After heat treatment, the outer periphery of the steel stranded wire is covered with a rust preventive material made of a thermoplastic synthetic resin. [Selection] Figure 1

Description

  In the present invention, an internal void used mainly for stress introduction of prestressed concrete (hereinafter referred to as PC), suspension material such as a cable-stayed bridge, and tension material of a stringed beam is filled with a synthetic resin rust preventive material. The present invention relates to a method for producing a rust-coated PC strand.

  Conventionally, in the manufacture of rust-proof coated PC strands used for tension wires for PC wires and string strings, side wires made of a plurality of single steel wires are placed around a core wire made of a single steel wire. And twist it with a twisting machine to make a steel stranded wire, or twist a single layer or multiple layers of middle layer wire around the core wire into a single layer, and a plurality of single strands on the outside The outer layer wire made from is twisted into a steel stranded wire, which is transferred to another rust-proofing plant and subjected to rust-proof coating treatment.

  In the production of steel stranded wire, after twisting each steel wire, the steel stranded wire is heated to 300 ° C to 350 ° C and subjected to a blueing treatment to obtain the tensile strength, elastic limit, fatigue limit of the steel stranded wire. Etc., or applying a tensile load while heating the steel stranded wire to about 300 ° C. to 350 ° C., and then cooling (so-called heat stretching treatment or hot stretching treatment) ) To reduce relaxation.

On the other hand, in the antirust coating treatment, the steel stranded wire subjected to the above bluing treatment or heat stretching treatment is heated to about 200 ° C. to 300 ° C., and it is passed through a crosshead type synthetic resin extrusion molding machine. While filling the space | gap between each single strand of a steel stranded wire with a thermoplastic synthetic resin material, the outer periphery of a steel stranded wire is coat | covered with a synthetic resin material.
JP-A-57-198211 Japanese Patent No. 2537457

  However, in the conventional technology as described above, since the stranded wire process and the rust-proof coating process are performed at different locations, it is expensive to transport the product, that is, the steel stranded wire, between the two work sites. There is a problem that it is a factor of increase, and there is a problem that a descale (rust removal) treatment of the steel stranded wire must be performed in the work.

  In addition, since the work to fill the rust preventive material in the gap between the single strands after the twisting process, it takes a high level of technology to obtain a sufficient filling state, the yield of the finished product is deteriorated, There was a problem that the cost was inevitably high.

  In view of such conventional problems, the present invention can perform rust prevention simultaneously with processing to PC strands, and can easily and reliably fill the gaps between the single strands, that is, the internal gaps in the PC strands. The purpose of the present invention is to provide a method for producing a rust-proof coated PC strand that can be produced at a low cost with a good yield.

  In order to solve the conventional problems as described above and achieve the initial object, the feature of the invention described in claim 1 is that the side wire is twisted around the outer periphery of the core wire, or one or more layers are twisted around the outer periphery of the core wire. The outer layer wires are joined to the outer side of the combined middle layer wires to form a twisted steel wire, and the steel twisted wires are subjected to heat treatment such as blueing treatment and / or heat stretching treatment, In the method for producing a rust-proof coated PC strand in which a gap between each single wire constituting a wire is filled with a rust-proof material and the outer periphery of the steel stranded wire is coated with a rust-proof material, the twist during the twisting process The thermoplastic synthetic resin in which the center line at the twisting center is heated and melted at the twisting position at the time of twisting by supplying a rust preventive material composed of a thermoplastic synthetic resin heated and melted at the matching position Covered with rust-proof material After filling the gaps between the single strands of the steel stranded wire with the rust preventive material, and after performing the heat treatment on the steel stranded wire, before cooling the steel stranded wire, The outer periphery of the stranded steel wire is covered with a rust preventive material made of a thermoplastic synthetic resin.

  A feature of the invention described in claim 2 is that, in addition to the configuration of claim 1, the center line at the center of twisting in the twisting process is preheated immediately before the twisting position.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, a thermoplastic synthetic resin is supplied to the outer periphery of the twisting position of the single strands in the twisting process. The thermoplastic synthetic resin enclosed in a container and heated and melted in the container is supplied with the thermoplastic synthetic resin to prevent the gap between the single strands from being heated and melted during the twisting process of the steel stranded wire. It is to fill with rust material.

  The feature of the invention described in claim 4 is that the side wire is wound around the outer periphery of the core wire, or one or more layers are twisted around the outer periphery of the core wire, and the outer layer wire is applied outside the middle layer wire to form a steel stranded wire. The steel stranded wire is processed and subjected to a heat treatment such as a blueing treatment and / or a heat stretching treatment, and a gap between each single strand constituting the steel stranded wire is filled with a rust preventive material. And, in the method for producing a rust-proof coated PC strand that coats the outer periphery of the steel stranded wire with a rust-proofing material, the center line at the center of twisting in the twisting process is preheated immediately before the twisting position, The center line is powder-coated with a thermoplastic synthetic resin as the rust preventive material, and the thermoplastic synthetic resin is adhered to the center line and melted, and at the twisting position at the twisting process, Heating and melting a center line The space between the single strands of the steel stranded wire is filled with the rust preventive material in a state covered with the rust preventive material made of the thermoplastic synthetic resin, and then the heat treatment is performed on the steel stranded wire. After being applied, before the steel stranded wire is cooled, the outer periphery of the steel stranded wire is covered with a rust preventive material made of a thermoplastic synthetic resin.

  A feature of the invention described in claim 5 is that the side wire is wound around the outer periphery of the core wire, or one or more layers are twisted around the outer periphery of the core wire, and the outer layer wire is applied outside the middle layer wire to form a steel stranded wire. The steel stranded wire is processed and subjected to a heat treatment such as a blueing treatment and / or a heat stretching treatment, and a gap between each single strand constituting the steel stranded wire is filled with a rust preventive material. In addition, in the method for producing a rust-proof coated PC strand in which the outer periphery of the steel stranded wire is coated with a rust preventive material, the anti-corrosion PC strand is placed on the center line at the center of twisting at the time of twisting immediately before the twisting position. It is sprayed while melting a powder of thermoplastic synthetic resin as a rust material, adheres the thermoplastic synthetic resin to the center line, and the center line at the center of the twist is heated and melted at the twist position at the time of twisting. Said thermoplastic synthetic tree After filling the gaps between the single strands of the steel stranded wire with the rust proofing material in a state covered with a rust proofing material made of fat, and then subjecting the steel stranded wire to the heat treatment, the steel Before cooling the stranded wire, the outer periphery of the stranded steel wire is covered with a rust preventive material made of a thermoplastic synthetic resin.

  The feature of the invention described in claim 6 is that, in addition to the structure of any one of claims 1 to 4 or 5, the heated state of the steel stranded wire by the treatment is maintained after the heat treatment. In the meantime, the steel stranded wire is passed through a crosshead type synthetic resin extruder and the outer periphery thereof is covered with a rust preventive material made of a thermoplastic synthetic resin.

The feature of the invention described in claim 7 is that, in addition to the structure of any one of claims 1 to 5 or 6, the heated state of the steel stranded wire by the treatment is maintained after the heat treatment. In the meantime, the outer periphery of the steel stranded wire is covered by a powder coating method in which the steel stranded wire is passed through the thermoplastic synthetic resin powder layer to deposit the powder on the outer periphery of the steel stranded wire.

  The feature of the invention described in claim 8 is that, in addition to the structure of any one of claims 1 to 6 or 7, the thermoplastic synthetic resin as a rust preventive material is saturated polyester, polyethylene and polyolefin. The use of materials of the system.

  As described above, in the present invention, a rust preventive material made of a thermoplastic synthetic resin heated and melted at a twisting position at the time of twisting of a steel stranded wire is supplied, and each unit of the steel stranded wire is supplied by the rust preventive material. By filling the voids between the strands, and then applying the heat treatment to the steel stranded wire, and then coating the outer periphery of the steel stranded wire with a rust preventive material made of a thermoplastic synthetic resin. Can be rust-proofed simultaneously with processing to steel stranded wire, and can easily and reliably fill the gaps between the single strands, that is, the internal gaps in the steel stranded wire, resulting in good yield and low cost. Can be manufactured.

  Also, by preheating the center line at the center of twisting at the time of twisting immediately before the twisting position, the core wire that is a single strand, and the steel twisted wire in which the middle layer wire is twisted to the core wire The adhesion of the rust preventive material to the center line consisting of is increased.

  Further, each single strand is provided by surrounding the outer periphery of the twisted position of the single strands in the twisting process with a container to which a thermoplastic resin is supplied, and supplying the thermoplastic resin heated and melted in the container. By filling the gap between them with a rust preventive material made of thermoplastic synthetic resin that is heated and melted during the twisting process of the steel stranded wire, the space inside the steel stranded wire can be filled with the rust preventive material easily and accurately. .

  In addition, the center line at the center of twisting in the twisting process is preheated immediately before the twisting position, and the center line is powder-coated with a thermoplastic synthetic resin as a rust preventive material, and the thermoplastic synthetic resin is applied to the center line. By adhering and melting, the thermoplastic synthetic resin can be efficiently attached to the center line.

  Also, just before the twisting position, the thermoplastic synthetic resin is sprayed on the centerline at the center of twisting at the time of twisting while melting the powder of thermoplastic synthetic resin as a rust preventive material, and the thermoplastic synthetic resin is attached to the centerline. Thus, the thermoplastic synthetic resin can be effectively attached to the center line.

  Further, after the heat treatment, while the heated state of the steel stranded wire by the treatment is maintained, the steel stranded wire is passed through a crosshead type synthetic resin extrusion molding machine and the outer periphery thereof is made of a thermoplastic synthetic resin. By coating with a rust material, the heating work as a pretreatment of the conventional coating process becomes unnecessary, and the cost is reduced.

  In addition, after the heat treatment, while the heated state of the steel stranded wire by the heat treatment is maintained, the steel stranded wire is passed through the thermoplastic synthetic resin powder layer so that the powder is placed on the outer periphery of the steel stranded wire. By coating the outer periphery of the steel stranded wire by the powder coating method to be applied, the apparatus for coating is simplified.

Further, as the thermoplastic synthetic resin as a rust preventive material, saturated polyester type, polyethylene type and polyolefin type materials can be used, and more specifically, a partially saponified product of ethylene-vinyl acetate copolymer (EVA) is used as a molecule. By using a polyolefin multi-element polymer (Mersen H: trademark of Tosoh Corporation) containing an acetoxy group and a hydroxyl group in the chain, the follow-up to the deformation of the steel stranded wire is improved after the rust preventive is solidified. It becomes difficult, workability at the time of use is good, and durability is improved.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a first embodiment of the present invention, and more specifically, a steel twist in which side wires 2 which are also single strands are aligned around a core wire 1 which is a single strand by a single arrangement. As shown in FIG. 7, a space between the single strands of the steel stranded wire 3 (hereinafter referred to as an internal space) 4 is internally filled and prevented with respect to the wire 3, for example, a seven-stranded steel stranded wire 3 not subjected to normal rust prevention. An overall schematic configuration for manufacturing a rust-proof coated PC strand 7 which is filled with a rust material 5 and whose outer periphery is coated with an external coating rust-proof material 6 is shown.

  The rust preventive material used in this embodiment is a thermoplastic synthetic resin made of a saturated polyester or polyethylene material for both internal filling and external coating, more specifically, ethylene-vinyl acetate copolymer (EVA). A polyolefin-based multi-element polymer (Mersen H: trademark of Tosoh Corporation) having a partially saponified product and containing an acetoxy group and a hydroxyl group in the molecular chain can be used.

  In FIG. 1, the code | symbol 10 is a steel wire twist processing machine. This processing machine has a rotating disk 13 that is driven to rotate about a horizontal support shaft 12 of a machine base 11, and a stranded wire reel 14 corresponding to the number of twists is provided on the front surface of the rotating disk 13. The side wire 2 is wound beforehand. Further, a through hole is opened at the center of the rotating disk 13, and the core wire 1 is passed through the central portion thereof. The core wire 1 is wound around a core wire reel 15 in advance. Then, the side wire 2 is spirally twisted around the outer periphery of the core wire 1 by turning the rotating disk 13 while moving the core wire 1 as a center line.

  A heater 17 is fixed to the machine base 11 to heat the center line made of the core wire 1. In addition, this heater 17 should just exist in the position where this core wire is pre-heated in the rear part of the feeding position from the reel 15 of the core wire 11. This preheating is for bonding the internally filled anticorrosive material 5 to each single strand, and is heated to about 200 ° C. As the heater 17, a high-frequency induction heater can be used in addition to a heating wire heater.

  The internally filled anticorrosive material 5 is supplied to the twisting position of the side wire 2 with respect to the core wire 1, and the internal voids in the steel twisted wire are filled with the anticorrosive material 5 simultaneously with the twisting process. That is, the container 20 for supplying a rust preventive material is disposed around the twisting position, and the inner filled rust preventive material 5 heated and melted in the container 20 is pressurized and injected to the twisting position. A rust preventive material is filled, and this is wound into the steel stranded wire 3 when the single strands are twisted together to fill the internal gap.

  As shown in FIG. 2, the container 20 has an inner peripheral surface 21 formed in a taper shape in accordance with the feeding angle of the side line 2, and is heated by resin from a rust preventive material supply port 22 opened on the inner peripheral surface. The rust preventive material 5 heated and melted from the melt extruder 23 is pressurized and injected into the container 20. The container 20 is entirely maintained at a predetermined melting temperature of the resin by the electric heater 29.

  The back surface of the container 20 is closed by a rotating lid body 24, and the lid body 24 has opening ports 25 and 26 through which the core wire 1 and the side wire 2 pass, and at the tapered tapered end portion. A stranded wire passage hole 27 through which the twisted steel stranded wire passes is opened. A die 28 corresponding to the outer peripheral shape of the steel stranded wire 3 is rotatably fitted in the passage hole 27, and most of the internally filled rust preventive material 5 attached to the outer periphery of the steel stranded wire 3 is removed. It is like that.

  As shown in FIG. 7, the steel stranded wire 3 twisted in a state in which the internal space is filled with the rust preventive material 5 is then passed through a brewing furnace 30 which is a heat treatment for removing the processing strain. The residual stress due to twisting is removed. An induction heating furnace can be used as the brewing furnace 30. Although not shown in detail in the drawing, an inductor for passing a high-frequency current is provided therein, and the steel stranded wire 3 passes through the center of the inductor. ing.

  The stranded steel wire 3 that has passed through the brewing furnace 30 is then sent to a heat stretching device 31 that is a heat treatment for reducing relaxation. The heat stretching device 31 includes, as an example, a heating furnace 32 and feed mechanisms 33a and 33b that are provided before and after the heating furnace 32 and apply a predetermined tension to the steel stranded wire 3. The relaxation performance is improved by performing the cooling process.

  The steel stranded wire 3 that has been subjected to the heat stretching treatment is subjected to rust removal on the surface by applying to the descaling device 34 as necessary, and then the steel stranded wire temperature is a temperature required for resin deposition (for example, about 250 ° C.) Before becoming lower, a rust-proof coating is applied to the outer periphery of the steel stranded wire 3. This rust-proof coating treatment is to apply a synthetic resin coating to the outer peripheral surface of the steel stranded wire 3 by using the heating by the heating furnace 32 in the heat stretching treatment. As an example, a crosshead type synthesis as shown in FIG. A resin extrusion molding machine 35 is used.

  This molding machine 35 has a rust preventive material supply port 36 for supplying a rust preventive material made of a synthetic resin material heated and melted from the periphery in the middle of a wire passage 36 penetrating in the front-rear direction. When the outer coated anticorrosive material 6 is adhered to the outer periphery of the stranded steel wire 3 passing through the wire passage 36 by being extruded by the rust preventive heating / melting extruder 37, and passes through the die 38 at the tip of the wire passage 36 Then, the die 38 is molded so as to have a desired cross-sectional shape.

  The cross-sectional shape of the outer covering rust preventive material 6 is, for example, if the inner shape of the die 38 is made circular, the valley portion between the single strands on the outer periphery of the steel stranded wire contracts a lot when the rust preventive material 6 is cooled and solidified. As shown in FIG. 8, the outer periphery of the cross-section has a polygonal shape with a rounded apex, and the polygonal shape has the steel strand wire outer peripheral side of the single strand of the outer peripheral side constituting the steel twisted wire as its apex. The outer periphery of the rust preventive material filling the spiral concave portion has a flat surface that connects the vertices with straight lines.

  In addition, the outer covering rust preventive material 6 is applied by using a crosshead type synthetic resin extrusion molding machine as described above, or in a powder container 41 containing a synthetic resin powder 40 as shown in FIG. A so-called powder coating method in which the twisted wire 3 is passed and the resin powder 40 is brought into contact with the surface of the twisted wire 3 to be melted by the heat of the steel twisted wire 3 and deposited on the surface of the steel twisted wire 3 may be employed. In this case, as shown in FIG. 9, the outer surface shape of the externally coated anticorrosive material 6 is a shape that follows the outer shape of the steel stranded wire 3.

  After the outer periphery of the steel stranded wire 3 is thus covered with the externally coated anticorrosive material 6, it is passed through a cooler 42, and the whole is cooled with cold air, and the anticorrosive materials 5 and 6 are solidified to form an anticorrosive coated PC strand. No, take up the take-up reel 43.

In the above-mentioned embodiment, as shown in FIG. 7, the production of the rust-proof coated PC strand composed of the steel stranded wire 3 in which one side wire 2 is twisted around the outer periphery of the core wire 1 has been described. For example, as shown in FIG. The middle layer wire 51 is twisted on the outer side of the core wire 50, and the outer layer wire 52 is twisted on the outer periphery to form a multilayer steel twisted wire as shown in FIG. It is possible to manufacture a rust-preventing coated PC strand that is filled with the rust-preventing material 5 and whose outer periphery is coated with an external covering rust-preventing material. In the manufacture thereof, as shown in FIG. Are sequentially passed through the steel wire twisting machines 60 and 61 for twisting each of the wires and twisting for each layer and filling the internal voids with the anticorrosive material in the same manner as described above, thereby preventing the prevention of multilayer steel twisted wires. Rust coated PC strand can be molded. In the drawings showing the embodiments, the same or equivalent parts are denoted by the same reference numerals, and redundant description is omitted.

  In addition to this, although not shown in the drawing, for the multilayer steel stranded wire in which the core wire 50 and the middle layer wire 51 of the outer layer wire 52 are divided into a plurality of layers, the internal voids are similarly formed during the twisting process for each layer. A multi-layer anticorrosive coated PC strand can be produced by filling with an internally filled anticorrosive material.

  In this case, the steel wire twisting machine 60 has the same structure as that of FIG. 2 described above, and the steel wire twisting machine 61 has an intermediate layer wire on the outer periphery of the twisted steel twisted wire 3 as shown in FIG. 51 and / or the outer layer wire 52 are twisted together, and the structure is the same as that of the twisting machine 60. The twisting machine 61 uses a steel stranded wire 3 in which the middle layer wire 50 is twisted around the outer periphery of the core wire 50, which is a single strand, as the center line, and more closely matches the outer layer wire 52 around the outer periphery. The heater 17 immediately before the alignment position preheats the steel stranded wire 3 composed of the core wire and the middle layer wire.

  In each of the above-described embodiments, the case where the heat stretching process, which is also a heat treatment, is performed after the blueing process, which is a heat treatment, is shown. Heating by a bluing furnace is used, and after the heating, when the temperature drops to a temperature required for resin deposition on the steel wire, coating with an external coating rust preventive material is performed. In addition to the above, the heat treatment includes various heat treatments such as a heat treatment for improving the uniform elongation rate, and a twisted steel wire and a desired quality.

  Further, the rust removal by the descaler 34 is performed when necessary and is not always necessary. In addition to the above, this descaling device may be sandblasting or shot peening. Moreover, it is good to rust down a single strand before twisting.

  In each of the above-described embodiments, a powder coating method may be used when the internal voids in the steel stranded wire are filled with the internal filling rust preventive material 5. In this powder coating method, powder (a rust preventive material made of a thermoplastic synthetic resin) is attached to an object to be coated (center line), and the powder is melted by the heat of the object to be coated that has been heated in advance. Examples of the method include fluid dip coating, electrostatic spray coating, and electrostatic fluid dip coating.

  First, the Example at the time of using a fluid immersion coating method is described. In general, the fluid dip coating method is a method in which a powder is fluidized and a preheated object is immersed in the fluidized powder. In this embodiment, when this fluid dip coating method is used to attach the powder of thermoplastic synthetic resin as the internal rust preventive material 5 to the core wire 1 as the center line, instead of the container 20 in the first embodiment. An immersion tank 70 shown in FIG. 12 is used. In addition, the part similar to the container 20 attaches | subjects the same code | symbol, and abbreviate | omits description.

  Similar to the container 20, the immersion tank 70 has an inner peripheral surface formed in a tapered shape in accordance with the feeding angle of the side line 2. Further, a powder flow supply path 72 is formed at the bottom of the immersion tank 70, and the powder of the thermoplastic synthetic resin as the internal rust preventive material 5 is immersed along with the air through the powder flow supply path 72. It is sent into the tank 70 and flows in the immersion tank 70.

  An exhaust path 73 is provided in the upper part of the immersion tank 70 so as to exhaust. The exhausted air is sent to a powder recovery device (cyclone) 74, and the powder contained in the air is recovered. The collected powder is sent to the powder supply device 71. The powder supply device 71 is connected to a compressor 75, and supplies powder to the immersion tank 70 by compressed air sent from the compressor 75.

  Then, the thermoplastic resin powder is caused to flow in the immersion tank 70, and the core wire 1 serving as the center line heated in advance is passed through the immersion tank 70, whereby the flowing thermoplastic resin powder is obtained. It is fused to the core wire 1. In this way, by covering the center line with a rust preventive material made of a thermoplastic synthetic resin that has been heated and melted, this rust preventive material is wound into the steel stranded wire 3 at the time of single strand twisting, The space between each single strand of the steel stranded wire is filled with the rust preventive material.

  Next, an example using an electrostatic spray coating method will be described. Generally, this electrostatic spray coating method uses a so-called electrostatic gun, and sprays the powder charged from the electrostatic gun onto the object to be coated, thereby attaching the powder to the object to be coated. . The object to be coated is grounded, and the powder adheres to the object to be coated efficiently by Coulomb force. In this embodiment, when the thermoplastic synthetic resin powder is attached as the inner rust preventive material 5 to the core wire 1 as the center line, the electrostatic container shown in FIG. 13 instead of the container 20 in the first embodiment. 76 is used. The core wire 1 is grounded. In addition, the same code | symbol is attached | subjected to the part similar to the container 20 of the electrostatic container 76, and description is abbreviate | omitted.

  The electrostatic container 76 includes electrostatic guns 77 and 77. The electrostatic guns 77 and 77 are for injecting charged powder onto the core wire 1. The electrostatic guns 77 and 77 are of a corona discharge type and include an electrode 78. The electrode 78 is connected to a high voltage applying device 79, and the high voltage applying device 79 applies a high voltage to the electrode 78 to charge the powder. The electrostatic guns 77 and 77 are connected to a powder supply device 80, and the powder is conveyed from the powder supply device 80 by air.

  Similar to the container 20, the electrostatic container 76 has an inner peripheral surface tapered in accordance with the feeding angle of the side line 2, and a pump 82 is provided from a powder recovery port 81 opened on the inner peripheral surface. Thus, the powder is recovered and reused.

  In the electrostatic container constructed as described above, powder of thermoplastic synthetic resin as the internal filling antirust material 5 charged by the electrostatic guns 77 and 77 is sprayed onto the core wire 1. Then, the thermoplastic synthetic resin adheres to the preheated core wire 1 and is melted on the core wire 1. Thus, at the twisting position, the center line is covered with a rust preventive material made of a thermoplastic synthetic resin heated and melted.

  The electrostatic fluidized dip coating method is a method of increasing the deposition efficiency by further charging the powder in the above-described fluidized dip coating method. When this electrostatic fluidized dip coating method is used, a dip tank 70 provided with a voltage applying device for charging powder is used. The center line is grounded in the same way as the electrostatic spraying method.

  Further, when the internal voids in the steel stranded wire are filled with the internal filling rust preventive material 5, a spray coating method may be used. This thermal spray coating method is generally a method in which a thermoplastic resin powder is melted and sprayed onto the object to be coated, and when the powder is sprayed onto the object to be coated, by passing through a flame, The powder is sprayed on the object to be coated in a molten state.

  In this embodiment, when this thermal spray coating method is used to attach the thermoplastic synthetic resin powder as the inner rust preventive material 5 to the core wire 1 as the center line, instead of the container 20 in the first embodiment. A thermal spraying container 83 shown in FIG. 14 is used. In addition, the same part as the container 20 attaches | subjects the same code | symbol, and abbreviate | omits description.

Similar to the container 20, the thermal spraying container 83 has an inner peripheral surface that is tapered in accordance with the feed angle of the side line 2. The thermal spray container 83 has an open rear surface, and thermal spray guns 84 and 84 are inserted from the rear surface so that powder is sprayed to the base position.

  The thermal spray guns 84, 84 eject a flame and inject a powder of thermoplastic synthetic resin, which is the internal filling rust preventive material 5, through the flame. Then, the thermal spray guns 84, 84 spray and weld the powder of the thermoplastic synthetic resin, which is the internal filling rust preventive material 5, to the core wire 1 in a molten state.

  The spray guns 84 and 84 are fixed to the tip of a spray gun support member 85 installed on the machine base 11. The thermal spray gun support member 85 is formed in a horizontally long cylindrical shape, one end of which is installed on the machine base 11 and the other end passes through a through-hole formed in the center of the rotating disk 13 for thermal spraying. It is inserted into the container 83. The spray guns 84, 84 are fixed to the other end side.

  The thermal spray guns 84 and 84 are connected to a gas cylinder 86 so that a gas for injecting a flame is supplied. The spray guns 84 and 84 are connected to a powder flow tank 87, and the powder is conveyed from the powder flow tank 87 by air.

  The powder fluid tank 87 is supplied with powder from a powder tank 88 and is supplied with compressed air from a compressor 89. In the powder flow tank 87, the powder flows in the air, and the powder is sent to the spray guns 84 and 84 in this state. Further, the compressed air sent from the compressor 89 is dried by the dryer 90 and then sent to the powder flow tank 87. Furthermore, combustion air is sent from the compressor 89 to the thermal spray guns 84 and 84. These pipes pass through the inside of a spray gun support member 85 formed in a cylindrical shape and are connected to the spray guns 84 and 84.

  Note that these powder coating method and thermal spray coating method may be used when the outer covering rust preventive material 6 is applied.

It is a processing-process figure of the 1st Example of this invention. It is sectional drawing which shows the twist processing machine part in the process of FIG. It is sectional drawing which shows an example of the same antirust coating apparatus of an outer peripheral surface. It is sectional drawing which shows the other example of the rust prevention coating | coated apparatus of an outer peripheral surface equally. It is a processing-process figure of the 2nd Example of this invention. It is sectional drawing which shows an example of the twist processing apparatus of an intermediate | middle layer wire or an outer layer wire same as the above. FIG. 2 is a cut end view showing a steel stranded wire in a state where an internal void in the example shown in FIG. 1 is filled with a rust preventive material. It is a cut end view showing an example of a rust-preventing coated PC strand after the outer peripheral surface rust-preventing coating step. It is a cutting end figure showing other examples of the antirust coated PC strand after the outer peripheral surface antirust coating process. FIG. 6 is a cut end view of a steel stranded wire in a state in which an intermediate layer wire and an outer layer wire in a second embodiment of the present invention are twisted. It is a cutting | disconnection end elevation which shows an example of the antirust coating PC strand after an outer peripheral surface antirust coating process same as the above. It is explanatory drawing which shows the apparatus at the time of using the fluid dip coating method in this invention. It is explanatory drawing which shows the apparatus at the time of using the electrostatic spray coating method in this invention. It is explanatory drawing which shows the apparatus at the time of using the thermal spray coating method in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core wire 2 Side wire 3 Steel twisted wire 5 Internal filling antirust material 6 Outer covering anticorrosion material 7 Antirust coating PC strand 10 Steel wire twisting machine 11 Machine stand 12 Horizontal support shaft 13 Turntable 14 Strand wire reel 15 Core Wire reel 17 Heater 20 Container 21 Inner peripheral surface 22 Rust preventive material supply port 23 Resin heating / melting extruder 24 Lid 25.26 Inlet 27 Twisted wire passage hole 28 Die 29 Electric heater 30 Brewing furnace 31 Heat stretching Device 32 Heating furnace 33a, 33b Feed mechanism 34 Descale device 35 Crosshead type synthetic resin extrusion molding machine 36 Antirust material supply port 37 Antirust material heating and melting extruder 38 Die 40 Synthetic resin powder 41 Powder container 42 Cooling machine 43 Winding reel 50 Core wire 51 Middle layer wire 52 Outer layer wire 60, 61 Steel wire twisting machine 70 Immersion tank 71 Powder supply device 72 Powder flow supply path 73 Exhaust path 7 4 Powder recovery equipment (cyclone)
75 Compressor 76 Electrostatic container 77 Electrostatic gun 78 Electrode 79 High voltage applying device 80 Powder supply device 81 Powder recovery port 82 Pump 83 Thermal spraying container 84 Thermal spray gun 85 Thermal spray gun support member 86 Gas cylinder 87 Powder flow tank 88 Powder Tank 89 Compressor 90 Dryer

Claims (8)

Twist processing to make a steel stranded wire by placing a side wire on the outer periphery of the core wire or an outer layer wire on the outside of the middle layer wire twisted in one or more layers on the outer periphery of the core wire, Heat treatment such as bluing treatment and / or heat stretching treatment, filling the gaps between the single strands of the steel stranded wire with a rust-proofing material, and preventing the outer periphery of the steel stranded wire. In the manufacturing method of a rust-proof coated PC strand coated with a rust material,
By supplying a rust preventive material made of a thermoplastic synthetic resin heated and melted at the twisting position at the time of twisting, the center line at the twisting center is heated and melted at the twisting position at the time of twisting. In addition, the space between the single strands of the steel stranded wire is filled with the rust preventive material in a state covered with the rust preventive material made of the thermoplastic synthetic resin, and then the heat treatment is performed on the steel stranded wire. Then, before cooling the steel stranded wire, the outer periphery of the steel stranded wire is coated with a rust preventive material made of a thermoplastic synthetic resin.   The method for producing a rust-proof coated PC strand according to claim 1, wherein a center line at the center of twisting in the twisting process is preheated immediately before the twisting position.   Each of the single strands is provided by surrounding the outer periphery of the twisting position of the single strands in the twisting process in a container to which a thermoplastic synthetic resin is supplied, and supplying the thermoplastic synthetic resin that is heated and melted in the container. The method for producing a rust-preventing coated PC strand according to any one of claims 1 and 2, wherein the interstices are filled with a rust-preventing material made of a thermoplastic synthetic resin that is heated and melted during twisting of a steel stranded wire. Twist processing to make a steel stranded wire by laying one side or multiple layers on the outer periphery of the core wire or twisting the outer layer wire on the outer side of the middle layer wire to the outer periphery of the core wire, While performing heat treatment such as blueing treatment and / or heat stretching treatment, the space between each single strand constituting the steel stranded wire is filled with a rust-proofing material, and the outer periphery of the steel stranded wire is rust-proof In the method for producing a rust-proof coated PC strand coated with a material,
The center line at the center of twisting in the twisting process is preheated immediately before the twisting position, and the center line is powder-coated with a thermoplastic synthetic resin as the rust preventive material, and the center line is heated. A plastic synthetic resin is adhered and melted,
At the twisting position at the time of the twisting process, each of the steel stranded wires is covered with the rust preventive material so that the center line at the center of the twist is covered with a rust preventive material made of the thermoplastic synthetic resin that is heated and melted. Rust preventive material which fills the space between the strands, and after the heat treatment is performed on the steel stranded wire, and before the steel stranded wire is cooled, the outer periphery of the steel stranded wire is made of a thermoplastic synthetic resin. A method for producing a rust-proof coated PC strand, characterized in that it is coated with Twist processing to make a steel stranded wire by laying one side or multiple layers on the outer periphery of the core wire or twisting the outer layer wire on the outer side of the middle layer wire to the outer periphery of the core wire, While performing heat treatment such as blueing treatment and / or heat stretching treatment, the space between each single strand constituting the steel stranded wire is filled with a rust-proofing material, and the outer periphery of the steel stranded wire is rust-proof In the method for producing a rust-proof coated PC strand coated with a material,
Immediately before the twisting position, spraying while melting the powder of thermoplastic synthetic resin as the rust preventive material to the centerline at the center of twisting in the twisting process, the thermoplastic synthetic resin to the centerline Attach
At the twisting position at the time of the twisting process, each of the steel stranded wires is covered with the rust preventive material so that the center line at the center of the twist is covered with a rust preventive material made of the thermoplastic synthetic resin that is heated and melted. Rust preventive material which fills the space between the strands, and after the heat treatment is performed on the steel stranded wire, and before the steel stranded wire is cooled, the outer periphery of the steel stranded wire is made of a thermoplastic synthetic resin. A method for producing a rust-proof coated PC strand, characterized in that it is coated with   After the heat treatment, while the heated state of the steel stranded wire by the treatment is maintained, the steel stranded wire is passed through a crosshead type synthetic resin extruder and the outer periphery thereof is made of a thermoplastic synthetic resin. The manufacturing method of the anticorrosion coating PC strand of any one of Claims 1-4 or 5 coat | covered with a material.   After the heat treatment, while the steel stranded wire is heated by the treatment, the steel stranded wire is passed through the thermoplastic synthetic resin powder layer to cover the powder around the steel stranded wire. The manufacturing method of the anticorrosion coating PC strand of any one of Claims 1-5 or 6 which coat | covers the steel twisted wire outer periphery with the powder coating system to make it wear.   The method for producing a rust-proof coated PC strand according to any one of claims 1 to 6 or 7, wherein the thermoplastic synthetic resin as the rust-proof material uses a saturated polyester-based, polyethylene-based, or polyolefin-based material.

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