JP2006028664A - Method for producing rustproof-coated steel strand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing rustproof-coated steel strand of low relaxation at low cost. <P>SOLUTION: The method comprises the following process: Steel strand A formed by laying up a plurality of steel wires 1, 1... is threaded through synthetic resin extruders 4 and 5 to subject the strand A to rustproof-coating treatment and fill a thermoplastic synthetic resin material in the voids formed among the respective steel wires along with coating the outer circumference of the strand A with the thermoplastic synthetic resin material. In this process, after forming the strand A by laying up the plurality of steel wires 1, 1..., the strand A is subjected to blueing treatment, and the strand A heated by the blueing treatment is threaded through the synthetic resin extruders 4 and 5 to subject the strand A to the rustproof-coating treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a rust-proof coated steel stranded wire mainly used for a PC wire, a tension string for a string string, and the like.

  Conventionally, in the production of rust-proof coated steel stranded wires used for tension wires for PC wires and string strings, side wires made of a plurality of steel wires are arranged around a core wire made of steel wires, They are twisted together by a twisting machine to form a steel stranded wire, which is transferred to another rustproofing plant and subjected to rustproof coating treatment.

  In the production of steel stranded wire, after twisting each steel strand, 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. Reducing relaxation by applying a permanent load by applying a tensile load while heating the steel stranded wire to about 300 ° C to 350 ° C and then cooling (so-called hot stretching treatment) I am trying.

On the other hand, in the antirust coating treatment, the steel stranded wire subjected to the above blueing treatment or hot stretching treatment is heated to about 200 ° C. to 300 ° C., and it is passed through a crosshead type synthetic resin extrusion molding machine, The space between the steel strands of the steel stranded wire is filled with a thermoplastic synthetic resin material, and the outer periphery of the steel stranded wire is covered with the 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 it is necessary to descale (rust removal) of the stranded steel wire in working.

  In addition, when performing rust prevention processing, because the steel stranded wire that has been subjected to the blueing treatment or the hot stretching treatment is heated again, there is a problem that the effect of the hot stretching treatment is impaired, such as an increase in relaxation. In addition, since an expensive heating device is required for heating again, there is a problem that the operation cost increases.

  In view of the above-described problems of the prior art, an object of the present invention is to provide a method for producing a rust-proof coated steel stranded wire that can obtain a low-relaxation rust-proof coated steel stranded wire at low cost.

  In order to solve the conventional problems as described above and achieve the intended purpose, the invention according to claim 1 is to heat a steel stranded wire obtained by twisting a plurality of steel strands and to bring the heated state into the heated state. A steel stranded wire is passed through a crosshead type synthetic resin extrusion molding machine, and a thermoplastic synthetic resin material is filled in the gap formed between the steel strands, and then the steel filled with the synthetic resin material It is a method for producing a rust-proof coated steel stranded wire in which the outer periphery of the stranded wire is coated with a thermoplastic synthetic resin material.

  In addition to the structure of claim 1, the invention according to claim 2 forms a steel stranded wire by twisting each steel wire, and then performs a blueing treatment on the steel stranded wire and heats by the blueing treatment. The steel stranded wire in the formed state is passed through a crosshead type synthetic resin extrusion molding machine, and after filling the gap formed between the steel strands with the thermoplastic synthetic resin material, the synthetic resin material is The outer periphery of the filled steel stranded wire is covered with a thermoplastic synthetic resin material.

  In addition to the structure of claim 1 or 2, the invention described in claim 3 applies a constant permanent strain to the steel twisted wire while being heat-treated, and the steel twisted wire heated by the heat treatment is crossheaded. After passing through a mold synthetic resin extrusion machine and filling the gap formed between the steel strands with thermoplastic synthetic resin material, the outer periphery of the steel stranded wire filled with the synthetic resin material is thermoplastic The synthetic resin material is then covered, and then the steel stranded wire is cooled.

  The invention described in claim 4 is characterized in that, in addition to the structure of claim 1, 2, or 3, the steel stranded wire is further heated by an induction heating device before passing through the synthetic resin extrusion molding machine.

  The invention according to claim 5 is characterized in that, in addition to the configuration of claims 1 to 3 or 4, the thermoplastic synthetic resin material is a polyethylene-based or polypropylene-based synthetic resin material.

  In addition to the structure of Claim 1, the invention of Claim 6 is characterized by heating a steel stranded wire at 250 ° C. or lower.

  The method for producing a rust-proof coated steel stranded wire according to the present invention comprises heating a steel stranded wire obtained by twisting a plurality of steel strands, and forming the heated steel stranded wire into a crosshead type synthetic resin extrusion molding. After passing through the machine, filling the gap formed between each steel wire with the thermoplastic synthetic resin material, and then coating the outer periphery of the steel stranded wire filled with the synthetic resin material with the thermoplastic synthetic resin material By doing so, a synthetic resin material is suitably filled in the internal space, and a high antirust effect can be obtained.

  After twisting each steel wire to form a steel stranded wire, the steel stranded wire is subjected to a blueing treatment, and the steel stranded wire heated by the blueing treatment is extruded with a crosshead type synthetic resin. After passing through the machine, filling the gap formed between each steel wire with the thermoplastic synthetic resin material, and then coating the outer periphery of the steel stranded wire filled with the synthetic resin material with the thermoplastic synthetic resin material By doing so, the stranded wire process and the rust prevention coating process can be performed on the same line, so the transportation cost between each conventional workplace can be reduced, and the heat in the brewing process is used for heating when performing the rust prevention coating. Since the heating device can be removed, the entire process can be reduced and the cost can be reduced.

  A certain amount of permanent distortion is applied to the steel stranded wire while being heat-treated, and the steel stranded wire heated by the heat treatment is passed through a crosshead type synthetic resin extrusion molding machine to form between the steel strands. After filling the gap with the thermoplastic synthetic resin material, the outer periphery of the steel stranded wire filled with the synthetic resin material is covered with a thermoplastic synthetic resin material, and then the steel stranded wire is cooled, The relaxation is prevented from increasing by the rust-proof coating treatment, and a low-relaxation rust-coated steel stranded wire can be obtained.

  A stable heating state can be obtained by heating the steel stranded wire with an induction heating device before passing it through the synthetic resin extrusion molding machine.

  When the thermoplastic synthetic resin material is a polyethylene-based or polypropylene-based synthetic resin material, it can be suitably filled and coated without losing fluidity.

  By heating steel stranded wire at 250 ° C or lower, the quality of steel stranded wire can be used even when working on other rust prevention processing lines without using the temperature of bluing or hot stretching treatment. In particular, the degradation of relaxation can be suppressed.

  FIG. 1 shows an outline of an apparatus for producing a rust-proof coated steel stranded wire used in the method of the present invention.

  This rust-proof coated steel stranded wire manufacturing apparatus includes a stranded wire machine 2 that twists a plurality of steel strands 1, 1... Into a steel stranded wire A, and a blue for performing a brewing treatment on the steel stranded wire A. Ing heater 3, crosshead type synthetic resin extruder 4 that fills the gap between the steel strands 1, 1 of the steel stranded wire A with a thermoplastic synthetic resin material, and the outer periphery of the steel stranded wire A Is provided with a crosshead type synthetic resin extrusion molding machine 5 that coats a synthetic resin material and a cooling device 6, and a rust prevention coating is performed by sequentially performing a stranded wire process, a brewing treatment process, a rust prevention coating process, and a cooling process. Steel stranded wire B is manufactured.

  The stranded wire machine 2 collects the reels 7, 7... Around which the steel strands 1, 1... Are wound up, and the steel strands 1, 1. The steel wires 1, 1... Fed from the reels 7, 7... Are twisted around the core wire 1 a and the side wires 1 b, 1 b. Are bundled in a state where they are arranged, and twisted in a spiral shape to form a steel stranded wire A.

  The heating machine 3 for bluing heats the fed steel stranded wire A in an oxidizing medium at 300 ° C. to 350 ° C. by a high-frequency induction heating coil or a direct energizing mechanism, and the surface of the steel stranded wire A is a blue oxide film. It is supposed to be covered.

  The synthetic resin molding machine 4 for primary treatment uses a crosshead type synthetic resin extrusion molding machine as shown in FIG. The molding machine 4 is joined with an auxiliary pressure head 10 in the direction of extension of the tip of the crosshead portion 9 and is provided with a molding die 11 at the tip thereof.

  The forming die 11 uses a circular die whose inner periphery is larger than the outer shape of the steel stranded wire A by the thickness of the resin coating. In the figure, reference numeral 12 denotes a heater.

  The synthetic resin molding machine 5 for outer periphery coating uses the crosshead type synthetic resin extrusion molding machine shown in FIG. A molding die 14 is attached to the tip of the crosshead portion 13 of the molding machine 5.

  The molding die 14 is formed into a shape that is larger than the outer surface shape of the primary coating treated steel stranded wire that has been subjected to the primary coating treatment by the synthetic resin molding machine 4 for the primary treatment.

  Next, a method for producing a rust-proof coated steel stranded wire will be described.

  First, the steel strands 1, 1... Are twisted together by the twisting machine 2, and a plurality of side wires 1b, 1b... Are arranged around the core wire 1a as shown in FIG. Line A is formed.

  Next, this steel twisted wire A is passed through the bluing heater 3 and heated at 300 ° C. to 350 ° C. to perform bluing treatment.

  The surface of the steel stranded wire A subjected to the blueing treatment is covered with a blue oxide film.

  Then, the steel stranded wire A in a state of being heated after being subjected to the bluing treatment is passed through the synthetic resin molding machine 4 for primary treatment, and the steel stranded wire is centered on the cross head portion 9 and the auxiliary pressure head 10. The thermoplastic synthetic resin material is continuously fed through A, melted and extruded into the cross head portion 9 during this time, and while passing through the auxiliary pressure head 10, the synthetic resin material is fed from the outer periphery of the steel stranded wire A to the steel element. The pressure is injected into the internal cavities 15, 15... Through the gaps between the lines 1, 1.

  At the same time, the outer peripheral surface of the steel stranded wire A is covered with a synthetic resin material. As a result, as shown in FIG. 5, a primary coating 17 is formed on the inner filling 16 and the outer periphery.

  At this time, since the steel stranded wire A is heated by the brewing treatment, the fluidity of the synthetic resin material is not impaired even if it is not reheated, and the gap 15 and the outer peripheral portion (primary clothing portion) are not damaged. A synthetic resin material can be suitably filled, and the effect of the bluing process is not impaired.

  The synthetic resin material used for internal filling and primary coating can be a high-hardness thermoplastic synthetic resin material such as polyethylene or a thermoplastic synthetic resin material such as a saturated polyester synthetic resin material.

  Next, the outer periphery coating synthetic resin molding machine 5 is passed, and the outer periphery of the steel stranded wire A is coated with the outer periphery coating 18 with a thermoplastic synthetic resin material. At that time, the steel stranded wire A can be suitably coated on the outer periphery of the steel stranded wire A without losing the fluidity of the thermoplastic synthetic resin material due to the residual heat due to the blueing treatment and the internal filling treatment. Yes.

  In addition, a polyethylene, saturated polyester, or nylon hard thermoplastic synthetic resin material is used as the synthetic resin material for outer periphery coating.

  Thereby, the outer peripheral coating 18 is integrated with the outer peripheral surface of the coating in a fused state, and this is fed into the cooling device 6. By cooling with the cooling device 6, the primary coating 17 and the outer coating 18 are solidified almost simultaneously. During this cooling, each synthetic resin material is shrunk, but since there are spiral irregularities on the outer periphery of the steel stranded wire A, there can be a difference in the thickness of the coating between the concave and convex portions, so that the resin cools. When shrinking, a phenomenon called “shrinkage” occurs, and a portion with a large coating thickness can be drawn greatly, and the cross-sectional shape of the rust-proof coated steel stranded wire B does not become circular, but is rounded as shown in FIG. Shape.

  In the above-described embodiment, the outer periphery of the steel stranded wire A is provided with the outer periphery coating 18 (primary coating 17) as shown in FIGS. 5 and 6, but as shown in FIG. The outer periphery coating 18 may be applied in accordance with the shape, that is, in a shape maintaining the spiral irregularities on the outer periphery of the steel stranded wire A.

  Finally, the rust-proof coated steel stranded wire B is wound around the reel 19 and completed.

  As shown in FIG. 8, a constant speed feeding device 20 with a brake and a hot stretching heater 21 are installed between the brewing heater 3 and the primary processing synthetic resin molding machine 4. The tension device 22 is disposed after the cooling device 6 and the steel stranded wire A subjected to the brewing treatment is fed to the constant speed feeding device 20, the hot stretching heater 21, the synthetic resin extrusion molding machines 4 and 5, and the cooling device 6. And it may be made to pass through the tensioning device 22 in order and a low relaxation treatment may be performed. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The constant speed feeding device 20 includes a pair of crawlers 23, 23, and the steel stranded wire A is sandwiched and moved between the crawlers 23, 23. The steel stranded wire A subjected to the brewing process is constant. It is sent at a speed.

  The hot-stretching heater 21 heats the steel stranded wire A to 300 ° C. to 350 ° C. by a high-frequency induction heating coil or a direct energization mechanism.

  The tensioning device 22 is composed of a pair of crawlers 24 and 24 as in the case of the constant-speed feeding device 20, and the rust-proof coated steel stranded wire B after the rust-proof coating treatment is sandwiched and pulled by both the crawlers 24 and 24, so The steel stranded wire A that is braked by the feeding device 20 and fed at a constant speed is pulled by applying a tensile force of about 70% of its maximum tensile strength. The tensile force is applied by a torque converter or the like. What is controlled is preferred.

  The steel stranded wire A is pulled between the constant-speed feeding device 20 and the tensioning device 22 under this heating condition, so that a fixed permanent strain is applied.

  In this manufacturing apparatus, the steel stranded wire A subjected to the brewing treatment is heated by the hot stretching heater 21 while being fed at a constant speed by the constant speed feeding device 20, and is in a heated state. Is passed through the synthetic resin molding machine 4 for primary treatment and the synthetic resin molding machine 5 for outer periphery coating, and the synthetic resin material is filled in the gaps between the steel strands 1, 1,. An outer periphery coating 18 is formed from the material.

  At this time, since the steel stranded wire A is also heated by the hot stretching heater 21 in addition to the heating by the brewing treatment, the synthetic resin material is suitably filled in the gap without losing its fluidity. In addition, a coating can be formed on the outer periphery.

  Then, the rust-proof coated steel stranded wire B that has been subjected to the rust-proof coating treatment is cooled by the cooling device 6, whereby a low relaxation treatment is performed.

  In addition, although the above-mentioned Example demonstrated the example which uses the 7 twisted steel twisted wire A, in addition to this, the 19 twisted steel twisted wire shown in FIGS. Lines may be used.

  The rust-proof coated steel stranded wire shown in FIGS. 9 and 10 has a plurality of side wires 1b, 1b... Smaller in diameter than the core wire 1a around a core wire 1a made of a steel wire, and further outside the side wires 1b, 1b. A plurality of outer wires 1c, 1c,... Having substantially the same diameter as the core wire 1a are disposed on the steel wire C, and a steel stranded wire C formed by spirally twisting the wires is used. Similarly to the rust-proof coated steel stranded wire B shown in FIG. 6 described above, a primary coating 17 is applied together with the internal filling 16, and an outer peripheral coating 18 is applied to the outer periphery thereof.

  On the other hand, the rust-proof coated steel stranded wire E shown in FIG. 10 is subjected to the internal filling 16 and in accordance with the outer peripheral shape of the steel stranded wire C on the outer periphery of the steel stranded wire C. An outer periphery coating 18 is applied, and small protrusions 30, 30... Continuous in the spiral direction are integrally formed on the outer periphery of the outer periphery coating 18.

  Further, the rust-proof coated steel stranded wires shown in FIGS. 11 and 12 are arranged with side wires 1b, 1b,... Having the same diameter as the core wire 1a around the core wire 1a made of steel strands. A steel stranded wire F formed by alternately arranging outer wires 1c, 1c,... Having a diameter larger than the core wire 1a and outer wires 1d, 1d, having a smaller diameter in the circumferential direction on the outside and twisting them. The rust-proof coated steel stranded wire G shown in FIG. 11 is provided with a primary coating 17 together with the internal filling 16 in the same manner as the rust-proof coated steel stranded wire B shown in FIG. It has been subjected.

  On the other hand, the rust-proof coated steel stranded wire H shown in FIG. 12 is subjected to the inner filling 16 and the outer periphery of the steel stranded wire in accordance with the outer peripheral shape of the steel stranded wire F, that is, in a state where the spiral irregularities are maintained. A coating 18 is applied, and on the outer periphery of the outer coating 18, small ridges 30, 30... Continuous in a spiral direction are integrally formed.

  Moreover, although the above-mentioned Example demonstrated the example which performs a twisting process, a brewing process process, a hot stretching process, and a rust prevention coating process continuously on one line, the twisting process is performed on another line. You may do it.

  Furthermore, although the above-mentioned Example demonstrated the example which has arrange | positioned the synthetic resin molding machine 4 for primary processing after the heating machine 3 for blueing or the heater 12 for hot-stretching, the heating machine 3 for blueing or hot stretch An induction heating device is installed between the heating heater 21 and the primary treatment synthetic resin molding machine 4, and the steel stranded wire A is further heated by the induction heating device before passing through the primary treatment synthetic resin molding machine 4. You may do it.

  In this way, the steel stranded wire A can be heated to a predetermined temperature with a small amount of heat, which is economical and eliminates unevenness in temperature, improving accuracy.

  Moreover, although the above-mentioned Example demonstrated the example in which the anticorrosion coating steel twisted wire was provided with the outer periphery coating | cover 18, as shown in FIG. It is good also as composition only of primary covering.

  In addition, if you do not use the temperature of the bluing or hot stretching process and work in other rust prevention processing line, before passing through the synthetic resin extrusion molding machine, the steel stranded wire is 250 ℃ or less By heating with, the quality of the steel stranded wire, in particular, the degradation of relaxation can be suppressed.

It is a schematic diagram which shows the outline of the manufacturing apparatus used for the manufacturing method of the rustproof coating steel twisted wire which concerns on this invention. It is sectional drawing which shows the synthetic resin molding machine for primary processing same as the above. It is sectional drawing which shows the synthetic resin molding machine for outer periphery covering same as the above. It is sectional drawing which shows an example of the steel stranded wire used with this invention method. It is sectional drawing which shows the steel twisted wire which performed the internal filling and primary coating process same as the above. It is sectional drawing which shows a rustproof covering steel twisted wire same as the above. It is sectional drawing which shows another example of the antirust coating steel twisted wire manufactured by the method of this invention. It is a schematic diagram which shows the outline of another example of the manufacturing apparatus used for the manufacturing method of the rustproof coating steel twisted wire which concerns on this invention. It is sectional drawing which shows another example of the antirust coating steel twisted wire manufactured by the method of this invention. It is sectional drawing which shows another example of a rustproof coating steel twisted wire same as the above. It is sectional drawing which shows another example of a rustproof coating steel twisted wire same as the above. It is sectional drawing which shows another example of a rustproof coating steel twisted wire same as the above.

Explanation of symbols

A Steel twisted wire B Anticorrosion coated steel twisted wire C Steel twisted wire D, E Anticorrosion coated steel twisted wire F Steel twisted wire G, H Antirust coated steel twisted wire 1 Steel element wire 2 Twisted wire machine 3 Heating for blueing Machine 4 Primary processing synthetic resin molding machine 5 Perimeter coating synthetic resin molding machine 6 Cooling device 7 Reel 8 Twisted section 9 Cross head section 10 Auxiliary pressure head 11 Molding die 12 Heating machine 13 Cross head section 14 Molding die 15 Gap 16 Inner filling 17 Primary coating 18 Outer coating 19 Reel 20 Constant speed feeder 21 Hot stretcher heater 22 Tension device 23 Crawler 24 Crawler

Claims (6)

  A steel stranded wire formed by twisting a plurality of steel strands is heated, and the heated steel stranded wire is passed through a crosshead type synthetic resin extrusion molding machine to form voids formed between the steel strands. A method for producing a rust-proof coated steel stranded wire, wherein the outer periphery of a steel stranded wire filled with the synthetic resin material is covered with a thermoplastic synthetic resin material after filling the inside with a thermoplastic synthetic resin material .   After twisting each steel wire to form a steel stranded wire, the steel stranded wire is subjected to a blueing treatment, and the steel stranded wire heated by the blueing treatment is extruded with a crosshead type synthetic resin. After passing through the machine, filling the gap formed between each steel wire with the thermoplastic synthetic resin material, and then coating the outer periphery of the steel stranded wire filled with the synthetic resin material with the thermoplastic synthetic resin material The manufacturing method of the rust prevention coating steel twisted wire of Claim 1 to do.   A certain amount of permanent distortion is applied to the steel stranded wire while being heat-treated, and the steel stranded wire heated by the heat treatment is passed through a crosshead type synthetic resin extrusion molding machine to form between the steel strands. A thermoplastic synthetic resin material is filled into the voids, and then the outer periphery of a steel stranded wire filled with the synthetic resin material is covered with a thermoplastic synthetic resin material, and then the steel stranded wire is cooled. Or a method for producing a rust-proof coated steel stranded wire according to 2;   The method for producing a rust-proof coated steel stranded wire according to claim 1, 2 or 3, wherein the steel stranded wire is further heated by an induction heating device before passing through the synthetic resin extrusion molding machine.   The method for producing a rust-proof coated steel stranded wire according to claim 1, wherein the thermoplastic synthetic resin material is a polyethylene-based or polypropylene-based synthetic resin material.   The manufacturing method of the rust-proof steel twisted wire of Claim 1 which heats a steel twisted wire at 250 degrees C or less.

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