Method for manufacturing oxygen-free copper castings

Abstract

The present invention provides a method for producing oxygen-free copper castings that have a low impurity content. [Solution] The method for manufacturing oxygen-free copper castings is a method for manufacturing oxygen-free copper castings using an upcasting apparatus. The upcasting apparatus comprises a die configured in a cylindrical shape and a start bar inserted inside the die. The start bar is made of copper.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an oxygen-free copper casting material.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a copper wire material, which includes a step of preparing an upcast material produced by an up-drawing casting method, and a step of producing a drawn wire material by drawing the upcast material. The upcast material is formed of oxygen-free copper.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desired to manufacture an oxygen-free copper casting material with a low impurity content.

[0005] One of the objectives of the present disclosure is to provide a method for manufacturing an oxygen-free copper casting material that can manufacture an oxygen-free copper casting material with a low impurity content.

Means for Solving the Problems

[0006] The method for manufacturing an oxygen-free copper casting material of the present disclosure is a method for manufacturing an oxygen-free copper casting material using an upcast casting apparatus. The upcast casting apparatus includes a die configured in a cylindrical shape and a start bar inserted inside the die. The start bar is formed of copper.

Effects of the Invention

[0007] The method for manufacturing an oxygen-free copper casting material of the present disclosure can manufacture an oxygen-free copper casting material with a low impurity content. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a first cross-sectional view showing a schematic of an upcasting apparatus used in the method for manufacturing oxygen-free copper castings according to the embodiment. [Figure 2] Figure 2 is a second cross-sectional view showing a schematic of the upcasting apparatus used in the method for manufacturing oxygen-free copper castings according to the embodiment. [Figure 3] Figure 3 is a third cross-sectional view showing a schematic of the upcasting apparatus used in the method for manufacturing oxygen-free copper castings according to the embodiment. [Figure 4] Figure 4 is a fourth cross-sectional view showing a schematic of the upcasting apparatus used in the method for manufacturing oxygen-free copper castings according to the embodiment. [Figure 5] Figure 5 is a cross-sectional view showing the procedure for adjusting the distance between the die and the cylindrical member in an upcasting apparatus used in the manufacturing method of oxygen-free copper castings according to the embodiment. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described.

[0010] (1) A method for manufacturing an oxygen-free copper casting according to one aspect of the present disclosure is a method for manufacturing an oxygen-free copper casting using an upcasting apparatus. The upcasting apparatus comprises a die configured in a cylindrical shape and a start bar inserted inside the die. The start bar is made of copper.

[0011] The start bar is inserted inside the die before casting begins and pushes the cap attached to the bottom of the die into the molten metal when casting starts. After dropping the cap into the molten metal, the start bar is pulled upward as the molten metal rises and discharged from the top of the die.

[0012] Conventional start bars are made of iron-based materials. When the molten metal pulled upward contacts the lower end of the start bar, there is a risk that the components of the start bar will mix into the molten metal. Alternatively, when the start bar drops the cap, the start bar itself may fall into the molten metal. In this case, the components of the start bar mix into the molten metal.

[0013] Since the start bar is made of copper, an oxygen-free copper casting material with a low impurity content ratio can be produced even if the components of the start bar mix into the molten metal, as compared with the case where the start bar is made of an iron-based material. [[ID=�]]

[0014] (2) In the method for manufacturing the oxygen-free copper casting material according to (1) above, the copper forming the start bar may be oxygen-free copper.

[0015] The method for manufacturing the oxygen-free copper casting material according to (2) above can produce an oxygen-free copper casting material with an even lower impurity content ratio.

[0016] (3) In the method for manufacturing the oxygen-free copper casting material according to (2) above, the oxygen-free copper forming the start bar may contain 99.99 mass% or more of copper and 0.0002 mass% or less of oxygen, with the balance being inevitable impurities.

[0017] The method for manufacturing the oxygen-free copper casting material according to (3) above can produce an oxygen-free copper casting material with an even lower impurity content ratio.

[0018] [Details of Embodiments of the Present Disclosure] Hereinafter, a specific example of the method for manufacturing the oxygen-free copper casting material of the present disclosure will be described based on the drawings. The same reference numerals in the drawings denote the same objects. The shapes, sizes, positional relationships, etc. shown in each drawing are presented for the purpose of clarifying the description and do not necessarily represent the actual shapes, sizes, positional relationships, etc.

[0019] [Embodiment] <Method for Manufacturing Oxygen-Free Copper Casting Material> Referring to FIGS. 1 to 5, a method for manufacturing an oxygen-free copper casting material according to an embodiment will be described. The method for manufacturing an oxygen-free copper casting material according to the embodiment uses an up-cast casting apparatus 1 shown in FIG. 1. One of the features of the method for manufacturing an oxygen-free copper casting material according to the embodiment is that the up-cast casting apparatus 1 includes a start bar 5 formed of a specific material.

[0020] ≪Up-cast casting apparatus≫ The up-cast casting apparatus 1 manufactures an oxygen-free copper casting material 100 (FIG. 4) by pulling up the molten metal 10 upward and passing it through the die 2 to solidify it. The up-cast casting apparatus 1 includes a die 2, a cap 25, a cylindrical member 3, a cooler 4, a start bar 5, a rod-shaped member 6, a refractory member 7, a tundish 81, and a pinch roll 9.

[0021] 〔Die〕 The die 2 solidifies the molten metal 10. The material of the die 2 is, for example, graphite. The shape of the die 2 is cylindrical. That is, the shape of the oxygen-free copper casting material 100 to be produced is cylindrical. The inner diameter of the die 2 is uniform along the axis of the die 2. That is, the outer diameter of the oxygen-free copper casting material 100 to be produced is uniform along the axis of the oxygen-free copper casting material 100. The outer diameter of the die 2 gradually decreases from the lower end of the die 2 located below in FIG. 1 toward the upper end of the die 2 located above in FIG. 1. That is, the outer peripheral surface of the die 2 tapers from the lower end to the upper end. The die 2 has, in order from the lower end to the upper end, a first portion 21 protruding downward from the cooler 4 and the refractory member 7, and a second portion 22 fitted into the inner peripheral surface of the cooler 4. The lower end of the die 2 is disposed in the molten metal 10. Before the start of casting, a cap 25 is attached to the opening at the lower end of the die 2.

[0022] 〔Cylindrical member〕 The cylindrical member 3 cools the oxygen-free copper casting material 100 that has passed through the die 2. The material of the cylindrical member 3 is, for example, graphite. The shape of the cylindrical member 3 is cylindrical. The inner and outer diameters of the cylindrical member 3 are uniform along the axis of the cylindrical member 3. The inner diameter of the cylindrical member 3 is the same as the inner diameter of the die 2. The cylindrical member 3 is positioned above the die 2 along the axis of the die 2 inside the cooler 4. The cylindrical member 3 is fixed inside the cooler 4.

[0023] In this example, a gap C is provided between the die 2 and the cylindrical member 3. The gap C is, for example, 1.0 mm or more and 5.0 mm or less. When the distance between the lower end of the cooler 4 and the lower end of the cylindrical member 3 is uniform and the length of the die 2 is uniform, the upcasting apparatus 1 with a gap C of 1.0 mm or more and 5.0 mm or less is more likely to produce high-quality oxygen-free copper casting material 100 with fewer and smaller defects compared to upcasting apparatuses with a gap C of less than 1.0 mm or more than 5.0 mm. The reason is as follows: The die 2, in contact with the molten metal 10, expands upward and downward due to thermal expansion. When the upper end of the die 2, which is expanding upward, comes into contact with the lower end of the cylindrical member 3, the die 2 stops expanding upward. There is no member that restricts the downward expansion of the die 2. Therefore, when the upper end of the die 2, which extends upward, comes into contact with the lower end of the cylindrical member 3, the die 2 extends downward by the amount by which it can no longer extend upward. When the spacing C is 1.0 mm or more, the spacing C is wider compared to when the spacing C is less than 1.0 mm, so the length of the die 2 extending upward becomes longer and the length of the die 2 extending downward becomes shorter. As a result, when the spacing C is 1.0 mm or more, the ratio of the contact area with the cooler 4 to the outer surface area of ​​the die 2 tends to be larger compared to when the spacing C is less than 1.0 mm. Similarly, when the spacing C is 5.0 mm or less, the ratio of the contact area with the cooler 4 to the outer surface area of ​​the die 2 tends to be larger compared to when the spacing C is greater than 5.0 mm. Therefore, when the spacing C is 1.0 mm or more and 5.0 mm or less, the cooling performance of the die 2 is higher compared to when the spacing C is less than 1.0 mm or greater than 5.0 mm, so the molten metal 10 is more easily cooled appropriately. The spacing C may be 1.5 mm or more and 4.5 mm or less, or 2.0 mm or more and 4.0 mm or less.

[0024] 〔cooler〕 The cooler 4 cools the die 2 and the cylindrical member 3. The cooler 4 surrounds the outer circumferential surfaces of the second portion 22 of the die 2 and the cylindrical member 3 so as to be in contact with them. The shape of the cooler 4 is cylindrical. The cooler 4 has, in order from the bottom end to the top end, a first portion 41 into which the second portion 22 of the die 2 is fitted, and a second portion 42 to which the cylindrical member 3 is fixed. The inner diameter of the first portion 41 of the cooler 4 gradually narrows towards the top. The inner diameter of the second portion 42 of the cooler 4 is uniform along the axis of the cooler 4. The material of the cooler 4 is a metal such as copper or a copper alloy. The cooler 4 has a flow path 45 through which cooling water 46 flows between the inner and outer circumferential surfaces. The flow path 45 is provided in the region of the cooler 4 except near the top and bottom ends. The cooler 4 itself is cooled by the cooling water 46 flowing through the channel 45, and the die 2 and cylindrical member 3 in contact with the inner circumferential surface of the cooler 4 are cooled.

[0025] [Start bar] As shown in Figure 1, the start bar 5 is inserted inside the die 2 or the cylindrical member 3 before casting begins, and is pushed down by the rod-shaped member 6 at the start of casting, pushing the cap 25 into the molten metal 10 as shown in Figure 2. The start bar 5 and the rod-shaped member 6 are separate and independent components. After dropping the cap 25 into the molten metal 10, the start bar 5 is pushed upward to the position of the pinch roll 9 as the molten metal 10 rises, as shown in Figure 3, and is further pulled upward by the pinch roll 9. The start bar 5 is discharged upward from the cylindrical member 3 as shown in Figure 4. The lower end of the start bar 5 is connected to the oxygen-free copper casting material 100, which has come into contact with the molten metal 10 and solidified. That is, the start bar 5 and the oxygen-free copper casting material 100 are discharged upward together. The shape of the start bar 5 is cylindrical. The outer diameter of the start bar 5 is smaller than the inner diameter of the die 2.

[0026] The start bar 5 is made of copper. When the start bar 5 comes into contact with the molten metal 10, there is a risk that components of the start bar 5 may be mixed into the molten metal 10. Alternatively, when the start bar 5 drops the cap 25, there is a risk that the rod-shaped member 6 may push the start bar 5 too hard, causing the start bar 5 itself to fall into the molten metal 10. In this case, components of the start bar 5 will be mixed into the molten metal 10. Conventional start bars 5 are made of iron-based materials. By making the start bar 5 out of copper, it is possible to manufacture an oxygen-free copper casting material 100 with a lower impurity content, even if components of the start bar 5 are mixed into the molten metal 10, compared to when the start bar 5 is made out of iron-based materials. In other words, by making the start bar 5 out of copper, it is possible to manufacture an oxygen-free copper casting material 100 with high conductivity.

[0027] The copper forming the start bar 5 may be oxygen-free copper. Oxygen-free copper is pure copper containing 99.96% by mass or more of copper. If the start bar 5 is formed from oxygen-free copper containing 99.96% by mass or more of copper, an oxygen-free copper casting material 100 with an even lower impurity content can be manufactured. That is, if the start bar 5 is formed from oxygen-free copper containing 99.96% by mass or more of copper, an oxygen-free copper casting material 100 with an even higher conductivity can be manufactured. The oxygen-free copper forming the start bar 5 may contain 99.99% by mass or more of copper and 0.0002% by mass or less of oxygen, with the remainder being unavoidable impurities. If the start bar 5 is formed from oxygen-free copper containing 99.99% by mass or more of copper, an oxygen-free copper casting material 100 with an even lower impurity content can be manufactured. In other words, if the start bar 5 is made of oxygen-free copper containing 99.99% by mass or more of copper, an oxygen-free copper casting material 100 with even higher conductivity can be manufactured. The proportion of copper and oxygen in oxygen-free copper is a ratio based on the total mass of oxygen-free copper being 100% by mass.

[0028] [Tandish] The tundish 81 is a container for temporarily storing molten metal 10 supplied from a melting furnace (not shown). The tundish 81 is covered with a cover 82 or the like to prevent the molten metal 10 inside from being exposed to the atmosphere. The cover 82 is provided with a through hole into which a refractory member 7 is fitted. A refractory seal (not shown) is provided between the inner circumferential surface of the through hole in the cover 82 and the outer circumferential surface of the refractory member 7 to prevent the molten metal 10 from passing through.

[0029] <Molten metal> The molten metal 10 is formed from oxygen-free copper. The oxygen-free copper forming the molten metal 10 is pure copper containing 99.96% by mass or more of copper. The oxygen-free copper forming the molten metal 10 contains 99.99% by mass or more of copper and 0.0002% by mass or less of oxygen, with the remainder being unavoidable impurities. The ratio of copper and oxygen content in the oxygen-free copper is calculated by taking the total mass of the oxygen-free copper as 100% by mass.

[0030] [Pinch roll] A pair of pinch rolls 9 transport the oxygen-free copper casting material 100 by gripping it. In the initial stages of lifting, the pair of pinch rolls 9 sequentially transport the rod-shaped member 6 and the start bar 5 by gripping them. The pair of pinch rolls 9 are positioned above the cooler 4.

[0031] [Fire-resistant materials] The refractory member 7 protects the cooler 4 from the molten metal 10. The refractory member 7 can prevent the temperature of the cooler 4 from rising due to the heat of the molten metal 10, and can prevent the temperature of the molten metal 10 from decreasing due to the cooling from the cooler 4. The material of the refractory member 7 is, for example, graphite. The refractory member 7 covers the outer circumference of the lower part of the cooler 4 from the lower end. The refractory member 7 has a bottom and a side wall. A through hole is provided in the center of the bottom. The second part 22 of the die 2 is inserted through this through hole. A refractory seal (not shown) is provided between the inner surface of the through hole and the outer surface of the second part 22 of the die 2 to prevent the molten metal 10 from passing through. The side wall is positioned between the inner surface of the through hole in the cover 82 and the outer surface of the cooler 4. The side wall is connected to the periphery of the bottom. The side wall protrudes upward from the periphery of the bottom.

[0032] ≪Process for producing oxygen-free copper castings≫ The method for manufacturing an oxygen-free copper casting of the embodiment comprises the step of producing an oxygen-free copper casting 100 using an upcasting apparatus 1. This step includes the step a1 of preparing the upcasting apparatus 1 and the step a2 of removing the cap 25 using a start bar 5.

[0033] [Step a1] In step a1, the upcasting apparatus 1 is prepared in the following procedure. A first assembly is prepared in which a cylindrical member 3 is fixed inside the cooler 4. A second assembly is produced in which the die 2 is press-fitted into the first part 41 of the cooler 4 by pushing the die 2 into the first part 41 of the cooler 4 from the opening at the lower end of the cooler 4 in the first assembly. The die 2 is pushed in so that the distance C between the die 2 and the cylindrical member 3 is a predetermined length. The die 2 is pushed in, for example, by striking the lower end of the die 2 inserted into the first part 41 of the cooler 4 with a hammer. As described above, the outer surface of the die 2 tapers from the lower end to the upper end, and as described above, the inner surface of the first part 41 of the cooler 4 tapers from the bottom to the top. Therefore, by pushing the die 2 into the first part 41 of the cooler 4, the die 2 can be press-fitted into the first part 41 of the cooler 4. After the die 2 is press-fitted, the distance C is measured.

[0034] In this example, the jig 200 shown in Figure 5 is used to measure the interval C. Figure 5 shows the second set of components arranged horizontally. The jig 200 has a rod-shaped portion 201 and a tip portion 202. The rod-shaped portion 201 is cylindrical in shape. The outer diameter of the rod-shaped portion 201 is smaller than the inner diameter of the die 2. A scale (not shown) is provided on the outer surface of the rod-shaped portion 201. The tip portion 202 is located at the tip of the rod-shaped portion 201. The tip portion 202 is disc-shaped. The outer diameter of the tip portion 202 is larger than the outer diameter of the rod-shaped portion 201 and smaller than the inner diameter of the die 2. The thickness of the tip portion 202 is, for example, 0.5 mm or more and 1.0 mm or less. The thickness of the tip portion 202 is the length along the axis of the rod-shaped portion 201. The tip portion 202 has a thickness of 0.5 mm or more, which makes it less likely for the tip portion 202 to be damaged when it comes into contact with the lower end of the cylindrical member 3, as will be described later. The tip portion 202 has a thickness of 1.0 mm or less, which allows the tip portion 202 to be positioned between the die 2 and the cylindrical member 3 when the gap C is 1.0 mm or more, making it easier to measure that the gap C is of a predetermined length. The gap C is measured using this jig 200 as follows.

[0035] As shown in the upper part of Figure 5, the tip portion 202 is inserted into the inside of the die 2. As shown in the center part of Figure 5, the rod-shaped portion 201 is moved toward the cylindrical member 3, thereby moving the tip portion 202 toward the cylindrical member 3 and dropping it between the die 2 and the cylindrical member 3. The rod-shaped portion 201 is moved toward the end face of the die 2, by bringing the tip portion 202 into contact with the end face of the die 2. The end face of the die 2 is the face facing the cylindrical member 3, which is the left end face in Figure 5. As shown in the lower part of Figure 5, the rod-shaped portion 201 is moved toward the end face of the cylindrical member 3, by bringing the tip portion 202 into contact with the end face of the cylindrical member 3. The end face of the cylindrical member 3 is the face facing the end face of the die 2, which is the right end face in Figure 5. The distance from the point where the tip 202 contacts the end face of the die 2 to the point where it contacts the end face of the cylindrical member 3 is calculated as the sum of the distance and the thickness of the tip 202. This sum is the interval C. The distance from the point where the tip 202 contacts the end face of the die 2 to the point where it contacts the end face of the cylindrical member 3 is determined by the difference between the first scale and the second scale. The first scale is the scale of the rod-shaped portion 201 that overlaps with the lower end of the die 2 when the tip 202 contacts the end face of the die 2. The second scale is the scale of the rod-shaped portion 201 that overlaps with the lower end of the die 2 when the tip 202 contacts the end face of the cylindrical member 3.

[0036] Unlike this example, a microscope may be used to measure the interval C. Insert the microscope into the die 2. Capture an image using the microscope that includes the upper end of the die 2 and the lower end of the cylindrical member 3 within the same field of view. The interval C can be determined by analyzing the captured image.

[0037] Unlike this example, the spacing C may also be determined by distance L1 - (total length L2 - length L3). Distance L1 is the distance between the end face of the cylindrical member 3 and the lower end of the cooler 4 before the die 2 is pressed into the cooler 4. Total length L2 is the total length of the die 2. Length L3 is the length of the die 2 that is exposed from the end face of the cooler 4 after the die 2 has been pressed in.

[0038] If the interval C is within a predetermined length range, the cap 25 is fitted to the opening at the lower end of the die 2. The first part 21 of the die 2 is inserted into the through hole at the bottom of the fire-resistant member 7 attached to the cover 82 of the tundish 81.

[0039] If the gap C is longer than a predetermined length, die 2 may be pushed in further. Then, the gap C is measured. The process of pushing die 2 in further and measuring the gap C is repeated until the gap C is the predetermined length. Alternatively, if the gap C is longer than a predetermined length, die 2 may be pulled out from inside the first part 41 of the cooler 4, and the pulled-out die 2 or a new die 2 may be pushed into the first part 41 of the cooler 4. Then, the gap C is measured. The process of pushing die 2 in further and measuring the gap C is repeated until the gap C is the predetermined length.

[0040] If the gap C is shorter than a predetermined length, the die 2 is withdrawn from inside the first part 41 of the cooler 4, and the withdrawn die 2 or a new die 2 is pushed into the first part 41 of the cooler 4. Then, the gap C is measured. The process of pushing in the die 2 and measuring the gap C is repeated until the gap C reaches the predetermined length.

[0041] Unlike this example, resin may be used to measure the gap C. Specifically, resin is poured between the upper end of die 2 and the lower end of cylindrical member 3 and allowed to solidify. Die 2 is withdrawn, and the solidified resin is also withdrawn. The thickness of the solidified resin at the portion corresponding to the space between the upper end of die 2 and the lower end of cylindrical member 3 is measured. Then, the withdrawn die 2 or a new die 2 is pushed in so that the gap C becomes a predetermined length.

[0042] [Step a2] In step a2, the rod-shaped member 6 is lowered. The rod-shaped member 6 may also be lowered by rotating a pair of pinch rolls 9. The lowered rod-shaped member 6 pushes the start bar 5 downward, causing the start bar 5 to push the cap 25 and drop it into the molten metal 10. Once the cap 25 falls into the molten metal 10, the molten metal 10 is drawn up into the die 2 by the liquid pressure corresponding to the distance from the liquid surface of the molten metal 10. The molten metal 10 is cooled and solidified as it passes through the die 2 and the cylindrical member 3 in sequence. This solidification produces the oxygen-free copper casting material 100. The produced oxygen-free copper casting material 100 is pulled up by a pair of pinch rolls 9. The pulled-up oxygen-free copper casting material 100 is wound onto a roll (not shown).

[0043] [Example Test] In the test example, we investigated the differences in the composition of the casting material due to differences in the material of the start bar in an upcasting machine.

[0044] <Sample No. 1 to Sample No. 3> The castings for Samples No. 1 to No. 3 were manufactured using the oxygen-free copper casting method described above. Specifically, the castings for Samples No. 1 to No. 3 were manufactured using the upcasting apparatus 1 shown in Figure 1. The start bar 5 in the upcasting apparatus 1 was made of oxygen-free copper. The oxygen-free copper forming the start bar 5 contained 99.99% by mass or more of copper and 0.0002% by mass or less of oxygen, with the remainder being unavoidable impurities. The molten metal was formed from oxygen-free copper.

[0045] <Sample No. 101 and Sample No. 102> The castings for sample No. 101 and sample No. 102 were manufactured in the same manner as sample No. 1, except that the starting bar was made of iron.

[0046] <Composition analysis> The composition of each casting sample was determined by ICP emission spectroscopy (Inductively Coupled Plasma Optical Emission Spectrometry). A Thermo Fisher Scientific ARL iSpark 8860 was used for ICP emission spectroscopy. Table 1 shows the percentage (mass ppm) of impurities contained in each casting sample. Table 1 shows the percentage of Fe (iron) impurities, the percentage of other impurities, and the total percentage of these impurities. The impurity percentages shown in Table 1 are based on 100% mass of the total casting mass.

[0047] <Electrical conductivity measurement> The electrical conductivity (%IACS) of the casting material for each sample was measured using the bridge method. The results are shown in Table 1.

[0048] [Table 1]

[0049] As shown in Table 1, the Fe content of the castings from Sample No. 1 to Sample No. 3 was between 0.5 ppm by mass and 5.0 ppm by mass. The conductivity of the castings from Sample No. 1 to Sample No. 3 was 99.5% IACS or higher, and the conductivity of the castings from Sample No. 1 and Sample No. 3 was 100% IACS.

[0050] On the other hand, the Fe content of the castings for sample No. 101 and sample No. 102 was 15 ppm by mass or more. The electrical conductivity of the castings for sample No. 101 and sample No. 102 was 99.0% IACS or less.

[0051] The total impurity content in the casting material of sample No. 1 is equivalent to that of the casting material of sample No. 101, but the Fe content in the casting material of sample No. 1 is lower than that of the casting material of sample No. 101. The total impurity content in the casting material of sample No. 3 is equivalent to that of the casting material of sample No. 102, but the Fe content in the casting material of sample No. 3 is lower than that of the casting material of sample No. 102. The conductivity of the casting materials of sample No. 1 and sample No. 3 is higher than that of the casting materials of sample No. 101 and sample No. 102. From these results, it was found that even if the total impurity content is the same, the lower the Fe content, the higher the conductivity.

[0052] These results show that using a start bar made of oxygen-free copper allows for the production of a casting material with a lower Fe content and higher conductivity compared to using a start bar made of iron.

[0053] The present invention is not limited to the configurations shown in the embodiments, but is intended to include all modifications within the meaning and scope of the claims as indicated by the claims. [Explanation of symbols]

[0054] 1 Upcasting apparatus 2 dice 21 Part 1 22 Part 2 25 caps 3. Cylindrical member 4. Cooler 41 Part 1 42 Part 2 45 flow channels 46 Cooling water 5 Start bar 6. Rod-shaped member 7. Fire-resistant materials 81 Tan Dish 82 Cover 9 Pinch roll 10 Molten metal 100 Oxygen-free copper casting material 200 jigs 201 Rod-shaped part 202 Tip C interval

Claims

1. A method for manufacturing oxygen-free copper castings using an upcasting apparatus, The upcasting apparatus described above is A die constructed in a cylindrical shape, The die comprises a start bar inserted inside the die, The start bar is made of copper. A method for manufacturing oxygen-free copper castings.

2. The method for producing an oxygen-free copper casting material according to claim 1, wherein the copper forming the start bar is oxygen-free copper.

3. The method for producing an oxygen-free copper casting material according to claim 2, wherein the oxygen-free copper forming the start bar contains 99.99% by mass or more of copper and 0.0002% by mass or less of oxygen, with the remainder being unavoidable impurities.

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