JP2007056370A5 - - Google Patents

Description

Method for producing copper alloy conductor for train line and copper alloy conductor for train line

  The present invention relates to a method for manufacturing a copper alloy conductor for a train line (trolley wire) that supplies power to a train via a pantograph or the like, and a copper alloy conductor for a train line.

  As the copper alloy conductor for train wires (trolley wires), a hard copper wire having high conductivity or a copper alloy material (copper alloy wire) having wear resistance and heat resistance is used. As a copper alloy material, tin (Sn) is added to a copper base material, and the Sn content is adjusted to 0.3% by weight, which is mainly used for an overhead wire including a Shinkansen.

In recent years, speeding up of trains has been promoted, and it is necessary to increase the overhead wire tension, so the train wire has been changed from a 1.5 t tension overhead wire to a 2.0 t tension overhead wire.
Therefore, there is a demand for a copper alloy conductor for high-strength electric wires that can withstand these high tension overhead wires.

  As high-strength copper alloy conductors for train wires, products using precipitation-strengthened alloys have been commercialized. There are also those using a solid solution strengthened alloy such as a Cu-Sn alloy system.

  As a conventional method for producing a trolley wire using a solid solution strengthened alloy, a copper alloy casting material containing 0.4 to 0.7% by weight of Sn is hot-rolled at a temperature of 700 ° C. or more and rolled. There is a method of producing a trolley wire by finishing and rolling the rolled material at a temperature of 500 ° C. or less to obtain a rough drawn wire, and drawing the rough drawn wire.

JP-A-6-240426 (Table 1)

  However, the use of a precipitation strengthened alloy has disadvantages such as a small material lot and heat treatment in an intermediate process, as well as poor workability and high manufacturing costs. Therefore, it is not suitable for a consumable product having a life span of 5 years such as a train line.

  In addition, in the case of using a solid solution strengthened alloy, the strength can be improved as the Sn content is increased. However, on the other hand, the conductivity is extremely lowered, and the current capacity is not reduced. It is not suitable as a train line because it is not possible. It is very difficult to manufacture a current Sn alloy system having the necessary strength for a high-strength overhead wire without increasing the Sn content and impairing the necessary conductivity.

  In the manufacturing method of the high-strength copper alloy trolley wire described in Patent Document 1, since the additive element is only Sn, the necessary strength is obtained by performing the finish rolling at a rolling temperature of 500 ° C. or less. Is 0.4 to 0.7% by weight, so that the electrical conductivity is low although the strength is high.

  In order to obtain a high-strength and high-conductivity train wire, it is conceivable to add another element together with Sn. In this case, if the finish rolling (final rolling) is performed at a temperature of 500 ° C. or less, cracks of the rolled material increase during rolling, so that the appearance quality of the rough drawn wire is extremely lowered, and the strength of the train line is extremely extreme. There is a problem that it drops.

  Then, the objective of this invention is providing the copper alloy conductor for train wires which solves the said subject and has high electrical conductivity and high intensity | strength.

The present invention was devised to achieve the above object, and the invention according to claim 1 is characterized in that any one or two of Sn, In, and Ag is 0.15 to 0.8% by weight in total. It is a copper alloy conductor for train wires, characterized in that it is contained, the balance is made of Cu and inevitable impurities, the electrical conductivity is 60% IACS or more, and the tensile strength is 420 MPa or more.

The invention according to claim 2 is a copper alloy conductor for train wires according to claim 1, further comprising 0.01 to 0.1% by weight of oxygen. is there.

The invention according to claim 3 is the copper alloy conductor for train lines according to claim 1 or 2, further comprising 2 to 40 ppm of phosphorus.

The invention according to claim 4 is a casting material in which tin is added to a copper base material to be melted, a molten copper alloy is formed, the molten metal is formed, and the molten metal is cast at a predetermined temperature. In a method for producing a copper alloy conductor for a train wire by subjecting the rough drawn wire to cold drawing by performing hot rolling in multiple stages, the casting temperature is set to 800 ° C. to 900 ° C., and the heat It is a method for producing a copper alloy conductor for a train wire, characterized in that the final rolling of the inter-rolling process is performed at a rolling temperature exceeding 500 ° C and not more than 600 ° C.

The invention according to claim 5 is the method for producing a copper alloy conductor for train wires according to claim 4, wherein the copper base material has an oxygen content of 0.01 to 0.1% by weight.

The invention according to claim 6 is the copper alloy conductor for train wires according to claim 4 or 5, wherein phosphorus is further added to the copper base material together with the additive element, and the phosphorus content is adjusted to 2 to 40 ppm. mETHOD der manufacturing Ru.

The invention according to claim 7 is for the train wire according to any one of claims 4 to 6, wherein the copper alloy material is subjected to hot rolling in multiple stages so that the wire diameter of the rough drawn wire is 8 to 30 mm. It is a manufacturing method of a copper alloy conductor.

In the invention according to claim 8, the cold working is performed by cooling the cold working apparatus so that the degree of work is 50% or more and the wire temperature is 100 ° C. or less. It is a manufacturing method of the copper alloy conductor for electric wire of description.

The invention according to claim 9 is a copper alloy conductor for a train wire produced by using the manufacturing method according to any one of claims 4 to 8.

  As is apparent from the above description, according to the present invention, the following excellent effects are exhibited.

(1) Addition of tin to a copper base material to melt, form a molten copper alloy, form a molten metal, and perform hot rolling in multiple stages on a cast material cast at a predetermined temperature. In the method of manufacturing a copper alloy conductor for a train wire by subjecting the rough drawn wire to cold drawing, the casting temperature is set to 800 ° C. to 900 ° C., and the final rolling of the hot rolling process is set to 500 ° C. Is performed at a rolling temperature of less than 600 ° C and is made into a high-strength rough drawn wire by low-temperature casting and low-temperature rolling, and the rough drawn wire is subjected to cold working with reduced processing heat, resulting in a significant decrease in conductivity. A train line having high tensile strength can be obtained without incurring.

(2) Since existing or conventional continuous casting and rolling equipment and cold work equipment with low production costs can be used, high-conductivity and high-strength electric train lines can be produced at low cost.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a flowchart showing the steps of a method for producing a copper alloy conductor for a train line according to a preferred embodiment of the present invention.

  As shown in FIG. 1, the manufacturing method of the copper alloy conductor for train wires (trolley wires) according to the present invention includes a melting step (F1) of adding an additive element to a copper base material and melting it to form a molten copper alloy. A casting step (F2) for casting a molten copper alloy to form a cast material, a hot rolling step (F3) for subjecting the cast material to hot rolling in multiple stages to form a rolled material, and the rolled material Cleaning and winding process (F4) for cleaning and winding into a rough wire, and sending out the rough wire that has been wound, and cold processing the wire into a copper alloy conductor for train lines (drawn) ) Processing step (F5). The copper alloy conductor for the train line is then processed into a desired shape of the train line according to the application.

  From the melting step (F1) to the washing / winding step (F4), the existing or conventional continuous casting and rolling equipment is used. The cold working step (F5) is performed using an existing or conventional cold working apparatus.

  More specifically, in the melting step (F1), one or two of tin (Sn) and indium (In) is added to a copper base material having an oxygen content of 0.01 to 0.1% by weight. In this step, the content of the additive element is adjusted to 0.15 to 0.8% by weight and dissolved to form a molten copper alloy.

  The additive elements In and Ag are elements that improve the strength in the same way as Sn, and are characterized by a lower decrease in conductivity than Sn. Therefore, in this embodiment, the Sn content is less than 0.4% by weight, the In content is increased, and a decrease in conductivity is avoided.

  For example, when the total content of Sn and In is less than 0.15% by weight, the effect of improving the strength is not recognized even if the production conditions are changed. Further, if the total content of Sn and In exceeds 0.8% by weight, the deformation resistance of the material is increased, so that the load in the continuous casting and rolling equipment is increased, and the minimum conductivity as a train line is 60. % Cannot be secured. Therefore, in the present embodiment, by appropriately adjusting the total content of Sn and In within the range of 0.15 to 0.8% by weight, as will be described later in the examples, the strength is improved and the conductivity is increased. Can be freely adjusted in the range of 60% IACS to 90% IACS.

  Moreover, when the content of the additive element increases, the copper wire surface flaws tend to increase during hot rolling. Therefore, when the content of the additive element is large (for example, 0.5% by weight or more), in order to reduce the surface damage of the copper wire during the hot rolling, the additive element (for example, Sn and Further, phosphorus (P) is added together with In), and the content of P is adjusted to 2 to 40 ppm and dissolved to obtain a molten copper alloy. If the content of P is less than 2 ppm, the effect of reducing the surface scratches on the copper wire is not recognized so much, and if the content of P exceeds 40 ppm, the conductivity decreases.

  The casting step (F2) is a step of casting a molten copper alloy at a casting temperature of 800 ° C. to 900 ° C. lower than a normal casting temperature (above 900 ° C. and less than 1100 ° C.) to obtain a cast material.

  In the hot rolling step (F3), the cast material is hot rolled at a rolling temperature of 700 ° C. to 800 ° C. at the initial stage of rolling, and the final rolling is performed at a rolling temperature of over 500 ° C. and 600 ° C. or lower. It is a process of applying to a rolled material. In hot rolling, the degree of work is set to 80% to 90% in order to increase the strength of the rough drawn wire.

  The structure of the rough drawn wire can be refined by casting a molten copper alloy at a low temperature of 800 ° C. to 900 ° C. and hot-rolling the final rolling under a low temperature condition exceeding 500 ° C. and 600 ° C. or less. It is possible to improve the wire strength.

  For example, when the final rolling is performed at a low rolling temperature of 620 ° C. in the low-temperature casting, the structure of the rough drawn wire is not refined, and the mechanical strength is not significantly improved. On the other hand, when the rolling temperature of the final rolling is as low as 500 ° C. or less, the content of Sn and In is large, and when the contained elements are three elements, cracks during rolling increase, and the appearance quality of the rough drawn wire is extremely high. To drop. Therefore, the rolling temperature of the final rolling is optimally over 500 ° C to ≦ 600 ° C.

  The cleaning / winding step (F4) is a step of cleaning and rolling up the rolled material to form a rough drawing line. The wire diameter φ of the wound rough wire is, for example, 8 to 30 mm, more preferably 22 to 25 mm.

  In the cold working step (F5), the wound wire is sent out, the degree of work is set to 50% or more on the wire, and the influence of strength reduction due to processing heat during continuous wire drawing is reduced. This is a step of performing a cold working for cooling a cold working device such as a die so that the temperature becomes 100 ° C. or lower to obtain a copper alloy conductor for a train line.

  In order to improve the strength of the train line, it is necessary to increase the workability in the hot rolling process to improve the strength of the rough drawing line, and it is also necessary to ensure the workability in the cold work to be 50% or more. .

  As described above, the optimum wire diameter φ of the rough drawn wire that satisfies these conditions is 22 to 25 mm. If the wire diameter φ exceeds 25 mm, that is, if the degree of processing in hot rolling is small, it will not be possible to obtain a great improvement in strength when processed into a train wire, and elongation characteristics will deteriorate due to work hardening during cold working. It is to do.

The copper alloy conductor for the train line is then processed into a train line having a desired shape according to the application, for example, a train line 21 as shown in FIG. The train line 21 has ear grooves 23 a and 23 b for attaching hanger ears on both sides of the train line body 22. The lower outer peripheral surface of the train line main body 22 is a large arc surface 24 that is a part on which the pantograph of the train slides. The outer peripheral surface on the upper side of the train line main body 22 is a small arc surface 25. Sectional area of the contact line 21 is 110mm ² ~170mm ^2.

  If the method for manufacturing a copper alloy conductor for a train wire according to the present invention described above is used, as will be apparent from the examples described later, the conductivity is a high conductivity of 60% IACS or more, and a high tension overhead wire is used. A high-strength electric wire with a required tensile strength of 420 MPa or more can be manufactured.

  Thus, in the method for producing a copper alloy conductor for train wires according to the present invention, one or two of Sn, In, and Ag are added to a copper base material, and the content of the additive element is 0.15. It is adjusted to ~ 0.8 wt% to make a copper alloy melt, and the melt is subjected to low temperature casting (casting temperature is 800 to 900 ° C) and low temperature rolling (final rolling temperature is over 500 ° C to 600 ° C or less). Since the rough drawn wire is made into a high-strength drawn wire and the cold-worked with reduced processing heat is applied to the rough drawn wire, a train wire having a high tensile strength can be obtained without causing a significant decrease in conductivity.

  In addition, since the production method according to the present invention can use existing or conventional continuous casting and rolling equipment and cold working equipment with low production costs, a high-conductivity and high-strength train line can be produced at low cost.

  One of the features of the production method according to the present invention is that the content of Sn added to the copper base material is the same as the current state or the high-strength copper alloy trolley wire described in Patent Document 1, as will be described later in Examples. Despite being adjusted to a value (0.3% by weight) less than that of the manufacturing method, the structure of the rough drawn wire is refined by low-temperature casting and low-temperature rolling, so that it has high conductivity and high strength. The purpose is to produce a copper alloy conductor at a low cost. This is because when the content of Sn added to the copper base material is increased, the strength is increased, but the electrical conductivity is decreased and the cost is increased.

In order to verify the effect of the present invention, the content of the additive element was changed in various ways to produce several types of electric wires 21 described with reference to FIG. 2, and the tensile strength (MPa), conductivity (% IACS) The three characteristics of appearance and appearance were examined. The wire diameter φ of the rough wire before being processed into the train line 21 was 23 mm, and the cross-sectional area of the train line 21 was 170 mm ² (170SQ). The target conductivity was 60% IACS or higher, and the tensile strength was 420 MPa or higher.

(Samples 1-12)
In Samples 1 to 12, the Sn content added to the copper base material was fixed at 0.3% by weight. This is the same as a train line using the current Cu—Sn alloy.

In each of Samples 1 to 4, the In content added to the copper base material was 0.1% by weight, and the oxygen (O ₂ ) content of the copper base material was 10, 50, 340, and 1000 ppm, respectively. The weight percentage is approximately 1/10000 ppm. Samples 5 and 6 each have an In content of 0.2% by weight, a P content added to the copper base material together with Sn and In is 0.2 ppm, respectively, and an oxygen content of the copper base material is 400, respectively. 320 ppm. Sample 7 had an In content of 0.3% by weight, a P content of 10 ppm, and an O ₂ content of 380 ppm. Sample 8 had an In content of 0.4 wt%, a P content of 21 ppm, and an O ₂ content of 380 ppm. Samples 9 to 11 all had an In content of 0.5% by weight, a P content of 38,51 ppm, 1 ppm or less, and an O ₂ content of 400,387,410 ppm, respectively. Sample 12 had an In content of 0.6% by weight. The characteristic results are shown in Table 1.

  As shown in Table 1, Samples 1 to 11 have an In content of 0.1 to 0.5% by weight. Therefore, the higher the In content, the higher the tensile strength (438 to 507 MPa), and the higher the conductivity (84 to 62). % IACS) is low. In particular, Samples 8 to 11 have an Sn content of 0.3% by weight and an In content of 0.4% by weight or more, and thus are 500 MPa or more, which is optimal as a high tension overhead wire. Samples 9 to 11 have a total content of Sn and In of 0.8% by weight, but have a conductivity of 60% IACS or more. Therefore, it can be seen that when In is added to the copper base material together with Sn, the strength can be improved while suppressing a decrease in conductivity. Sample 12 had a total content of Sn and In of 0.9% by weight, so that the load on the continuous casting and rolling equipment was large, and it was difficult or impossible to produce rough wires and train wires.

In Samples 1 and 2, since the O ₂ content of the copper base material was 50 ppm or less, which was the same as that of the low oxygen copper base, fine scratches were observed on the appearance of the rough wire and the train wire. On the other hand, in Sample 4, the O ₂ content of the copper base material was as high as 1000 ppm, but slight scratches were observed on the appearance of the rough wire and the train wire. Therefore, it is preferable to use a copper base material having an O ₂ content of 100 to 1000 ppm (0.01 to 0.1% by weight).

  Further, when comparing the sample 5 and the sample 6, the appearance of the sample 5 having a P content of 0 ppm was good, whereas the sample 6 having a P content of 2 ppm was good. It can be seen that the appearance can be improved by adding P together with In. On the other hand, Sample 10 having a P content of 50 ppm had a good decrease in conductivity, although the appearance was good. Therefore, when adding P together with Sn and In to the copper base material, the P content may be adjusted to 2 to 40 ppm.

Next, by changing the casting temperature and the final rolling temperature in various ways, rough drawn wires having different wire diameters are produced, and the tensile strength (MPa) and elongation (%) of the train wire 21 produced by cold working the rough drawn wire. The characteristics of were investigated. The cross-sectional area of the train line 21 was 170 mm ² (170SQ). The target tensile strength was 420 MPa or more.

(Examples 1-3)
In each of Examples 1 to 3, the Sn content added to the copper base material was fixed at 0.3% by weight, the casting temperature was fixed at 880 ° C., which was lower than usual, and the final rolling temperature was fixed at 560 ° C. In Examples 1 to 3, rough wire diameters were 23, 25, and 30 mm, respectively, and O ₂ contents were 320, 380, and 410 ppm, respectively.

(Comparative Examples 1-4)
In Comparative Examples 1 to 4, the Sn content added to the copper base material was 0.3% by weight. In Comparative Examples 1 to 4, the rough wire diameters were 23, 23, 25, and 30 mm, respectively, and the O ₂ contents were 400, 380, 380, and 400 ppm, respectively. In Comparative Example 2, the casting temperature was 880 ° C., and the final rolling temperature was 380 ° C. In Comparative Examples 1, 3 and 4, the casting temperature was 920 ° C., the normal temperature, and the final rolling temperature was 620 ° C.

  The characteristic results of Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Table 2.

  As shown in Table 2, when Example 1 with a rough wire diameter of 23 mm is compared with Comparative Example 1, Example 1 has a casting temperature of 880 ° C., which is lower than usual, and the final rolling temperature exceeds 500 ° C. and 600 It can be seen that the tensile strength of the train line is improved by 15 MPa compared to Comparative Example 1 in which the casting temperature is 920 ° C., which is the normal temperature, and the final rolling temperature is 600 ° C., which is 560 ° C., which is 560 ° C. or less. The elongation of the train line is almost the same in Example 1 and Comparative Example 1.

  Similarly, when Example 2 and Comparative Example 3 having the same rough wire diameter and Example 3 and Comparative Example 4 are compared with each other, Examples 2 and 3 have a tensile strength of 18 and 18 compared to Comparative Examples 3 and 4, respectively. It turns out that it improved by 15 MPa. The extension of the train line is almost the same in Example 2 and Comparative Example 3, and in Example 3 and Comparative Example 4.

  Further, as can be seen from the comparison of the tensile strengths of Examples 1 to 3, when the rough drawing wire diameter is increased from 23 mm to 25 mm and 30 mm, the tensile strength and elongation gradually increase even if the degree of drawing is increased. It tends to decrease. This is because, as described above, if the diameter of the rough wire exceeds 25 mm, the degree of processing in the hot rolling process is small, so that a large strength improvement when processed into a train line cannot be obtained, and at the time of cold processing This is because the elongation characteristics are reduced by the work hardening of the material. Accordingly, the wire diameter of the rough drawn wire is optimally 22 to 25 mm.

  Since Comparative Example 2 has a casting temperature of 880 ° C. and a final rolling temperature of 380 ° C., which is 500 ° C. or less, the load during casting and rolling of the continuous casting and rolling equipment is large, and it becomes impossible to manufacture a train line.

  As clarified in the examples, the method for producing a copper alloy conductor for a train wire according to the present invention is mainly composed of a Cu-Sn alloy used in a current train wire, and a copper base material together with Sn. It is characterized in that a copper alloy conductor for a train wire having a high tensile strength can be manufactured at a low cost while keeping the conductivity high by appropriately adding In having a strength equivalent to Sn.

  Since the Cu-Sn alloy as a train wire has high wear resistance, the Sn content added to the copper base material is at least 0.15% by weight as in the current state in order not to impair the performance. The above is necessary.

  The tensile strength that is indispensable for high-strength overhead wires is 420 MPa or more, more preferably 500 MPa or more, considering the wear limit of train wires. Therefore, the optimum content of In added to the copper base material together with Sn is 0.4% by weight or more. It is. However, since In is a rare metal, it is expensive, and in order to obtain cost merit, it is necessary to minimize its content.

  Moreover, if the total content of Sn and In added to the copper base material exceeds 0.8% by weight, the hardness of the continuous casting material increases, and the load on the rolling roll of the continuous casting rolling equipment becomes extremely large. , Making it difficult to commercialize.

  Therefore, in order to produce a high-conductivity and high-strength electric wire, the Sn content is 0.3% by weight and the In content is 0.4% by weight as in the samples 8 and 9 in the examples. Alternatively, 0.5% by weight is optimal.

  In the continuous casting and rolling process, the structure of the rough drawn wire can be refined by performing low temperature casting and low temperature rolling. However, when the temperature is lowered extremely at the time of casting and rolling, the deformation resistance of the material increases, so that the load on the equipment increases and mass production becomes difficult.

  Therefore, in the example, the low temperature casting at 880 ° C. and the final rolling temperature of 560 ° C. are optimal as in Examples 1 and 2.

  In the above-described embodiment, the example in which Sn and In are added to the copper base material has been described. However, the same effect can be obtained even if Sn and Ag are added to the copper base material.

  In addition, when added to a copper base material, examples of additive elements that can improve strength while maintaining high conductivity like In and Ag include magnesium (Mg) and boron (B). For example, as a copper alloy material, one or two of Sn, In, Mg, and B are added to a copper base material having an oxygen content of 0.01 to 0.1% by weight, and the content of the added element You may use what adjusted 0.15 to 0.8 weight%. When In is replaced with Mg in the above-described embodiment, since Mg is less expensive than In, almost the same effect can be obtained and the manufacturing cost can be further reduced.

  In the above embodiment, the casting temperature is set lower than the normal temperature. However, if the casting temperature is extremely lowered, the casting material is more likely to be damaged. Therefore, the casting temperature is set to the normal temperature. It may be.

It is a flowchart which shows suitable embodiment of this invention. It is sectional drawing which shows an example of the train line produced using the manufacturing method of the copper alloy conductor for train lines which concerns on this invention.

Claims (8)

One or two of Sn, In and Ag are contained in a total of 0.15 to 0.8% by weight, the balance is composed of Cu and inevitable impurities, the conductivity is 60% IACS or more, and the tensile strength A copper alloy conductor for train wires, characterized in that the length is 420 MPa or more. In the copper alloy conductor for train lines according to claim 1,
Furthermore, the copper alloy conductor for train wires characterized by containing 0.01 to 0.1% by weight of oxygen. In the copper alloy conductor for train lines according to claim 1 or 2,
Furthermore, the copper alloy conductor for train wires characterized by containing 2-40 ppm of phosphorus. The copper base material is melted by adding tin, forming a molten copper alloy, forming the molten metal, and subjecting the cast material obtained by casting the molten metal to a predetermined temperature in multiple stages. In the method of producing a copper alloy conductor for a train line by making a rough drawn wire and cold-working the rough drawn wire,
A method for producing a copper alloy conductor for train wires, wherein the casting temperature is set to 800 ° C to 900 ° C, and the final rolling of the hot rolling process is performed at a rolling temperature of more than 500 ° C and not more than 600 ° C. The said copper base material is a manufacturing method of the copper alloy conductor for train wires of Claim 4 whose oxygen content is 0.01 to 0.1 weight%. The method for producing a copper alloy conductor for a train wire according to claim 4 or 5, wherein phosphorus is further added to the copper base material together with the additive element, and the phosphorus content is adjusted to 2 to 40 ppm. The method for producing a copper alloy conductor for a train wire according to any one of claims 4 to 6 , wherein the cast material is subjected to hot rolling in multiple stages so that a wire diameter of the rough drawn wire is 8 to 30 mm. Processing between the cold is a working ratio of 50% or more, and the wire temperature of the copper alloy conductor catenary according to any one of claims 4-7 for cooling the cold working device such that the 100 ° C. or less Production method.