JPH0211460B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a copper-coated steel trolley wire in which a steel wire is used as a core material and the core material is coated with copper or a copper alloy. The present invention relates to a method of manufacturing a tensile copper coated steel trolley wire. [Prior Art] Copper wire or copper alloy wire is usually used for railway trolley wires. Incidentally, recently there has been a strong demand for high-speed train operation, and for this reason, it is required to further increase the strength of trolley wires. In other words, in order to increase the operating speed of trains, it is necessary to increase the wave propagation speed of the trolley wire. In this case, the wave propagation speed C is expressed by the following formula. C=√ However, T is the overhead wire tension, and ρ is the linear density (weight per unit length) of the trolley wire. As is clear from this equation, in order to increase the wave propagation speed C, it is necessary to increase the tension T or decrease the linear density ρ. Therefore, as a technique to reduce the linear density ρ and increase the propagation speed C, an aluminum composite trolley wire in which a steel wire is coated with aluminum and crimped is proposed. In addition, by increasing the strength of the trolley wire,
As a technology to increase the propagation speed C by setting the overhead wire tension T higher than usual, a composite trolley wire made of iron-based materials and copper-based materials, which are stronger than copper, has been proposed (Japanese Patent Publication No. 53-122786 (see issue). [Problems to be solved by the invention] However, these conventional trolley wires
It has the following drawbacks. First, in aluminum composite trolley wires, since the attachment fittings of the trolley wire are made of copper alloy, there is a problem in that the copper alloy of the attachment fittings comes into contact with the aluminum coating layer of the trolley wire, resulting in contact corrosion. In order to avoid this corrosion, it is necessary to change all the currently popular mounting brackets to materials that do not cause contact corrosion with aluminum, which is not practical in terms of cost. Further, in a composite trolley wire made of iron-based materials and copper-based materials, corrosion occurs between the iron-based material and the copper-based material, which causes many practical problems. Furthermore, a technique has been proposed in which a layer of lead or tin is interposed between the iron-based material and the copper-based material to prevent corrosion.
The presence of such an intermediate layer is not preferable because it poses a problem in terms of the strength of the trolley wire and also complicates the manufacturing process. Furthermore, conventional trolley wires do not have satisfactory wear resistance, and for lines that are frequently operated, there is a demand for the development of trolley wires with excellent wear resistance that can extend their service life. The present invention has been made in view of the above circumstances, and provides a method for producing a copper-coated steel trolley wire that can produce a copper-coated steel trolley wire with high strength and excellent wear resistance at a low cost. The purpose is to [Means for Solving the Problems] The method for manufacturing a copper-coated steel trolley wire according to the present invention involves continuously immersing a steel wire in a molten metal of copper or copper alloy, and coating the periphery of the steel wire with copper or copper alloy. After solidifying and adhering the steel wire, the copper or copper alloy coated wire is rolled at a rolling ratio of 10 at a temperature range of 750 to 850°C.
It is characterized by hot rolling in the range of 40% to 40%. [Function] In the present invention, a steel wire as a seed wire is immersed in a molten copper or copper alloy to solidify and adhere the copper or copper alloy around the steel wire. This results in
A copper-coated steel wire strand coated with copper or copper alloy is obtained. Next, when this copper-clad steel wire is hot-rolled under predetermined conditions, the steel wire of the core material and the copper or copper alloy region of the sheathing material are metallically bonded, so that the core material and the sheathing material are firmly bonded. be done. Therefore, the bonding strength between the core material and the covering material is high, and corrosion is prevented from progressing at the boundary between the core material and the covering material. In addition, in the present invention, since the steel wire is immersed in molten copper or molten copper alloy and coated with copper or copper alloy, it has a large diameter like a trolley wire.
A wire having a thick copper coating layer can be manufactured at a lower cost than by electroplating or the like. [Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, a so-called dip forming device used in an embodiment of the present invention will be explained based on FIG. In this dip forming device, a copper or copper alloy coating device 20 is disposed above a steel wire supply device 10. The airtight housing 11 of the supply device 10 has an exhaust port 15 connected to a suitable vacuum evacuation device.
is provided, and the inside of the housing 11 is evacuated to a predetermined degree of vacuum through this exhaust port 15.
A stripping die 12 is disposed at a steel wire inlet on the side of the housing 11, and the surface layer of the steel wire 1 fed into the housing 11 from this inlet is cut by the stripping die 12. A capstan 13 is installed in the housing 11, and the steel wire 1 is wound around the capstan 13 to change its traveling direction upward.
Two pairs of pinch rolls 16 are disposed at the upper part of the housing 11, and the steel wire 1 is pulled out and driven by the pinch rolls 16 and supplied from the housing 11 to the coating device 20. A straightening device 14 for straightening the bent steel wire 1 is disposed within the housing 11 between the pinch roll 16 and the capstan 13. This straightening device 14 includes two rollers 14a and 14c that roll inside the steel wire bent by the capstan 13.
and a roller 14b that rolls toward the outside of the steel wire between the rollers 14a and 14c. capstan 1
The steel wire 1 sent from the rollers 14a, 14b,
14c in this order, the bending caused when it is wound around the capstan 13 is corrected. In addition, the rollers 14a, 14b, 14
c may be rotated by itself by an appropriate drive device (not shown), or may be simply driven by the steel wire 1 in an idler type. In addition, rollers 14a, 14b,
The distance between the wires 14c can be adjusted depending on the type of steel wire and the strength of the bend. The coating device 20 has a crucible 22 in which a molten metal 21 of copper or copper alloy is stored. This crucible 22 is made of a refractory material such as graphite, and is connected to the housing 11 with its outer bottom surface airtightly closing the upper end outlet of the housing 11 of the supply device 10. An insertion hole 23 having substantially the same diameter as the steel wire 1 is formed at the bottom of the crucible 22, and the steel wire 1 is introduced into the crucible 22 through the insertion hole 23 in a liquid-tight manner. . A molten metal supply port 24 connected to a copper or copper alloy melting device 30 is provided on the side of the crucible 22, and the molten metal 21 is supplied into the crucible 22 through this supply port 24. A wire drawing device (not shown) is installed above the coating device 20, and the composite wire 2, which is a steel wire 1 coated with copper or a copper alloy, is drawn upward by the drawing device. This composite wire is fed from the coating device 20 to a subsequent hot rolling device (not shown). In the embodiment of the present invention, after coating a steel wire with copper or a copper alloy using a dip forming apparatus configured as described above, the composite wire is hot rolled. First, as shown in FIG. 1, a steel wire 1 is introduced into an evacuated housing 11 while its surface layer is continuously ground by a peeling die 12. The steel wire 1 having a clean surface is wound around a capstan 13 to change its traveling direction upward.
In this case, the steel wire 1 is bent by the capstan 13, but the steel wire 1 is bent by the straightening device 14.
It is straightened by each roller 14a, 14b, 14c. Next, the steel wire 1 is pulled upward by the pinch rolls 16 and introduced into the crucible 22 from the insertion port 23 provided at the bottom of the crucible 22 of the coating device 20 . Then, the steel wire 1 is drawn upward through the crucible 22, and during this time, the molten metal 21 in the crucible 22 adheres to the steel wire 1. Then, the adhered molten metal 21 solidifies, and a composite wire 2 in which copper or copper alloy is adhered to the circumferential surface of the steel wire 1 is obtained. The composite wire 2 is then processed by a hot rolling machine.
It is hot rolled at a temperature range of 750 to 850°C and a rolling ratio of 10 to 40%. As a result, the core steel wire and
The copper or copper alloy region of the sheathing material forms a metallic bond, and the sheathing material is firmly adhered to the core material. The reason why the rolling ratio is 10% or more is because if it is less than that, the steel wire and the copper or copper alloy region cannot be sufficiently metallically bonded. Further, the reason why the rolling ratio is 40% or less is because if it exceeds the rolling ratio, the degree of processing becomes too high and the thickness of the copper or copper alloy coating material will not be uniform. For this reason, in the present invention, the rolling ratio is set to 10 to 40%. Further, the reason why the rolling temperature is 750° C. or higher is because if it is lower than that, it is impossible to achieve a sufficient metallic bond between the copper or copper alloy region and the steel wire within the above-mentioned rolling ratio range. On the other hand, when the rolling temperature is 850℃ or less,
If it exceeds this range, wear and tear of the rolling rolls and jigs, copper condensation on the guide rollers and roll surfaces, etc. will occur, and rolling will not be carried out smoothly. Next, this hot-worked composite wire is grooved, and as shown in the cross-sectional view of FIG.
A character-shaped groove 5 is formed. In this way, a trolley wire is manufactured. The trolley wire is installed by gripping it with a copper fitting through this groove 5. In the composite wire having a metallic bond produced according to this example, atomic diffusion occurs at the interface between the steel wire and the copper or copper alloy region, resulting in extremely strong bonding. Therefore, for example, even when a compressive load is applied to this composite wire in its diametrical direction, no separation occurs between the steel wire and the copper or copper alloy region. This also applies when the composite wire is tensilely broken or subjected to bending deformation. Therefore, even if the trolley wire is worn out and the core material 3 of the steel wire is exposed, water or the like will not enter the boundary between the copper or copper alloy covering material 4 and the core material 3. Therefore, this boundary portion is not preferentially corroded. The coverage ratio of the sheathing material 4 made of copper or copper alloy is preferably set to 45 to 75% in terms of cross-sectional area ratio (ratio of the area of the sheathing material to the cross-sectional area of the entire trolley wire). If the coverage rate of the sheathing material 4 is less than 45%, when grooving the composite wire to form the grooves 5 of a predetermined depth, the thickness of the copper sheathing material 4 may be less than the depth of the grooves 5. There is a risk that the steel wire core material 3 may become thin and exposed in this groove 5. On the other hand, when the coverage rate of the covering material 4 exceeds 75%, the steel wire core portion inevitably becomes insufficient and the effect of improving wear resistance is reduced. Therefore, the coverage of the covering material 4 is preferably 45 to 75% in terms of cross-sectional area ratio. In addition, in order to use this copper-coated steel composite wire as a trolley wire, it is necessary that the conductivity is 50% IACS or more (value when the conductivity of pure copper annealed material is set to 100). Therefore, various conditions such as the type of copper or copper or copper alloy and the coverage rate should be
It is necessary to select it so that it is 50% or more. The copper-clad steel trolley wire constructed in this way is
Since it is coated with a coating material 4 of copper or copper alloy at a predetermined coverage rate, this coating material 4 comes into contact with the mounting bracket for suspending the trolley wire. Therefore, contact corrosion will not occur with the copper alloy mounting fittings. Furthermore, since steel wire is used as the core material 3, the trolley wire has high strength and excellent wear resistance. Since the strength of the trolley wire is thus high, the overhead wire tension T can be set high.
Therefore, as described above, the wave propagation speed C can be increased, making it possible to increase the speed of the train. Any steel type can be used for the steel wire, but if the strength of the steel wire is too high, it will be inconvenient to handle during the manufacturing process or trolley wire overhead line work. For this reason, it is preferable to use a steel wire material with a carbon content of 0.35% by weight or less. When the carbon content exceeds 0.35% by weight,
If the strength of the steel wire becomes too high, the life of the stripping die 12 will be shortened, for example, in the composite wire manufacturing process using the above-mentioned dip forming method. In this embodiment, since the steel wire is coated with copper or copper alloy by the so-called dip forming method, a copper-coated steel trolley wire can be manufactured at low cost. Trolley wire is mainly a thick wire with a diameter of 10 mm or more, and a covering material (copper or copper alloy).
Since it is necessary to form the installation groove thickly, the cost becomes extremely high if copper-coated steel wire is manufactured by electroplating or the like. On the other hand, by coating copper or copper alloy by the dip forming method as in this embodiment, a composite wire for a trolley wire can be manufactured at low cost. In this embodiment, the steel wire 1 which has passed through the capstan 13 and is bent is straightened by the rollers 14a, 14b and 14c of the straightening device 14. Conventionally, such a straightening device has not been installed in a deep forming device for copper wire. However, when deep forming a steel wire as in this embodiment, the straightening device 14
If this is not provided, it will be difficult to smoothly introduce the steel wire into the crucible 22. That is, since the steel wire 1 is harder than the copper wire, it becomes bent when it is wound around the capstan 13. This crookedness cannot be corrected simply by pulling it with the pinch rolls 16, and there is a risk that the steel wire 1 will become caught in the insertion hole 23 of the crucible 22, resulting in a shutdown of the operation. However, as in this embodiment, for example, three rollers 14
By straightening the steel wire 1 using a, 14b, and 14c, the steel wire 1 becomes straight, so the steel wire 1 can be stably fed into the crucible 22 through the insertion hole 23 without clogging or jamming. can do. Next, the results (examples) of manufacturing a copper-coated steel trolley wire by the method of the present invention will be described together with the results of manufacturing a trolley wire according to a conventional example. In the method of the present invention, as the core steel wire,
JISG3505, SWRM10 mild steel wire rod (diameter 14 mm) was used. This mild steel wire rod was stripped to a diameter of 12.7 mm using a stripping die 12, straightened using a straightening device 14, and then fed to a coating device 20. In this case, as a result of appropriately adjusting the intervals between the rollers 14a, 14b, and 14c, the amount of bending could be suppressed to about 3 to 10 mm in a 1000 mm long portion. On the other hand, if the straightening device 14 is not used, the 1000 mm length will be bent by about 40 to 60 mm.
It is not possible to stably pass the steel wire through the insertion hole 23. In the coating device 20, a copper-coated cast steel wire is manufactured by coating the circumferential surface of the steel wire 1 with copper or copper alloy, and then this cast wire is hot-rolled (rolling ratio: 30%) to form a composite with a diameter of 16 mm. Got the line. Through this hot rolling,
The steel wire and the copper or copper alloy region were firmly joined. Next, normal wire drawing and grooving processing is performed,
A trolley wire having the cross-sectional shape shown in FIG. 2 and a cross-sectional area of 110 mm ² was manufactured. In this way, trolley wires of Examples 1, 2, and 3 having different coverage ratios of copper or copper alloy were manufactured. Note that the coverage ratio of copper or copper alloy can be changed in various ways by adjusting the immersion time of the steel wire in the crucible 22, etc., thereby forming a coating layer of copper or copper alloy with a desired thickness. can do. The conductivity and tensile strength of this trolley wire were measured, and the presence or absence of exposed steel in the grooves, the quality of fittings, and the abrasion resistance were tested. The results are shown in Table 1 below, along with the test results for conventional trolley wires.

[Table] However, in the columns of metal fittings mountability and wear resistance,
○ indicates good, △ indicates slightly bad, and × indicates bad. Further, the unit of electrical conductivity is %IACS, and the unit of tensile strength is Kgf/ ^mm2 . Examples 4 and 5 were manufactured in the same manner as Examples 1 to 3, but the copper (alloy) ratio (coverage) of Example 4 was 40.
%, and the coverage of Example 5 is as high as 80%. Further, Conventional Example 1 is a copper trolley wire, Conventional Example 2 is a copper alloy trolley wire, and Conventional Example 3 is an aluminum-coated steel trolley wire. Note that only Conventional Example 3 has a cross-sectional area of 200 mm ² , and the other trolley wires have a cross-sectional area of 110 mm ² . As shown in Table 1, in Examples 1 to 5, the tensile strength is high, and the steel wire core material and the copper or copper alloy covering material are firmly joined. Therefore, it has excellent corrosion resistance. In addition, Examples 1 to 3
and 5 have electrical conductivity of 50% IACS or higher, and Examples 1 to 4 have excellent wear resistance, and when the coating material made of copper or copper alloy wears away and the core steel wire begins to be exposed, , it was confirmed that further abrasion of the trolley wire becomes difficult to progress. In addition, since the trolley wire can be installed using the current mounting hardware,
Easy to attach to metal fittings. In addition, in Example 4, the coverage rate is low at 40%, so in addition to the conductivity being low at 45% IACS, the steel wire is exposed in the groove and there is a risk of contact corrosion, making it slightly difficult to attach the metal fittings. . In addition, in Example 5, the coverage rate was
Since it is high at 80%, the steel wire portion is small and the wear resistance improvement effect of the steel wire is insufficient. Therefore, the wear resistance is rather poor. Further, since Conventional Example 1 and Conventional Example 2 are copper trolley wires and copper alloy trolley wires, respectively, they have high strength and poor wear resistance. Furthermore, since Conventional Example 3 uses an aluminum-coated steel trolley wire, its strength is low, and contact corrosion occurs between the wire and copper alloy fittings, making it difficult to mount the wire to the metal fittings. Note that the above example is for a trolley wire with a cross-sectional area of 110 ^mm2 , but a trolley wire with a cross-sectional area of 170 ^mm2 , etc.
Of course, the present invention can be applied to other types of trolley wires. Next, the results of an investigation into the relationship between the steel type of the steel wire and the life of the stripping die will be explained. Table 2 below shows the relationship between the steel type of the steel wire, the carbon concentration, the evaluation results of peelability, and the steel wire strength (strength after normalizing).

[Table] However, for the evaluation of peelability, cases where the lifespan of the peeling die 12 was less than 3 hours were indicated by an x mark, and cases where the lifespan was 3 hours or more were indicated by an ○ mark. As is clear from Table 2, when the carbon concentration exceeds 0.35% by weight (SWRH42A), the strength of the steel wire becomes too high and the life of the stripping die 12 is shortened, causing the operation to be suspended for replacement. Since the number of rotations increases, it is disadvantageous in terms of cost. Therefore, it is preferable to use a steel wire with a carbon concentration of 0.35% by weight or less. Note that instead of the steel wire with a carbon concentration of 0.35% by weight or less, an alloy or the like may be used as long as the strength after normalization is equivalent to that of the steel wire. [Effects of the Invention] According to the present invention, a steel wire and a copper or copper alloy region can be metallically bonded, thereby obtaining a copper-coated steel trolley wire in which a coating material portion and a core material portion are firmly bonded. be able to. This trolley wire has high strength and excellent wear resistance, and even if the boundary between the copper or copper alloy and the steel wire is exposed, water etc. will not enter this boundary and cause corrosion. do not have. According to the present invention, a copper-coated steel trolley wire having such excellent properties can be stably manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a dip forming device used in an embodiment of the present invention, and FIG. 2 is a sectional view of a copper-coated steel trolley wire. 1; Steel wire, 2; Composite wire, 3; Core material, 4; Covering material, 12; Stripping die, 13; Capstan, 1
4; straightening device, 22; crucible.

Claims (1)

[Claims] 1 A steel wire is continuously immersed in a molten metal of copper or a copper alloy to solidify and adhere the copper or copper alloy around the steel wire, and then the steel wire is coated with copper or a copper alloy. The wire coated with
A method for producing a copper-coated steel trolley wire, characterized by hot rolling in a range of 40% to 40%. 2. The method for manufacturing a copper-coated steel trolley wire according to claim 1, wherein the steel wire has a carbon content of 0.35% by weight or less. 3. The molten copper or copper alloy is stored in a container, and the steel wire is straightened into a straight line and then enters the container from the bottom of the container, and while being drawn upward through the container, the steel wire is stretched around the steel wire. 2. The method of manufacturing a copper-coated steel trolley wire according to claim 1, wherein the molten metal adheres to the copper-coated steel trolley wire.