Method for producing cast material and casting apparatus

Abstract

To provide a method for producing a cast material with which the cast material having little and small surface defect and high quality can accurately be produced.SOLUTION: A method for producing a cast material includes a step of pouring molten metal from a tundish into a mold space formed by a left block group and a right block group, and an upper belt and a lower belt sandwiching the left block group and the right block group. The step of pouring the molten metal includes a step of bringing the tundish into contact with the lower belt by lowering the tundish while measuring an amplitude of vibration of the tundish at a specific frequency.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a casting material and a casting apparatus. [Background technology]

[0002] Patent Document 1 discloses a method for producing cast material using a casting machine. The casting machine is a twin-belt continuous casting machine. The casting machine includes a left block group and a right block group, upper and lower belts that sandwich the left and right block groups, and a tundish for storing molten metal. The method for producing cast material includes a step of pouring molten metal from the tundish into a mold space defined by the left block group, the right block group, the upper belt, and the lower belt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-157351 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desired to produce high-quality casting materials with few and small surface defects such as scratches and cracks with high precision.

[0005] An object of the present disclosure is to provide a method for manufacturing a casting material that can accurately produce a high-quality casting material with few and small surface defects. [Means for solving the problem]

[0006] The method for producing a casting material according to the present disclosure includes a step of pouring molten metal from a tundish into a mold space defined by a left block group, a right block group, and an upper belt and a lower belt sandwiching the left block group and the right block group. The pouring step includes a step of lowering the tundish to bring the tundish into contact with the lower belt while measuring the amplitude of vibration of the tundish at a specific frequency. [Effects of the Invention]

[0007] The method for manufacturing a casting material according to the present disclosure can accurately manufacture a high-quality casting material with few and small surface defects. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a partial cross-sectional view showing an outline of a casting apparatus according to an embodiment. [Figure 2] FIG. 2 is a perspective view showing the outline of the positions of a tundish and a lower belt provided in the casting apparatus of the embodiment. [Figure 3] FIG. 3 is a top view showing the outline of the positions of the tundish and the lower belt provided in the casting apparatus of the embodiment. [Figure 4] FIG. 4 is a graph showing the vibration frequency of the tundish provided in the casting apparatus of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) A method for producing a casting material according to one embodiment of the present disclosure includes a step of pouring molten metal from a tundish into a mold space defined by a left block group, a right block group, and an upper belt and a lower belt sandwiching the left block group and the right block group. The pouring step includes a step of lowering the tundish to bring the tundish into contact with the lower belt while measuring the amplitude of vibration of the tundish at a specific frequency.

[0011] The amplitude of a specific frequency increases with the vibration of the tundish caused by contact of the tundish with the lower belt. Therefore, the method for producing a cast material described in (1) above can accurately detect contact of the tundish with the lower belt by measuring the amplitude at the specific frequency. In the method for producing a cast material described in (1) above, the molten metal is poured into the mold space while the tundish is in contact with the lower belt. The molten metal flows out of the tundish and immediately contacts the upper surface of the lower belt and flows along the upper surface of the lower belt. On the other hand, when a gap is formed between the tundish and the lower belt, the molten metal flows out of the tundish and drips downward by the gap before contacting the upper surface of the lower belt and flowing along the upper surface of the lower belt. In other words, the method for producing a cast material described in (1) above is less likely to cause turbulence in the flow of the molten metal than when the gap is formed. Therefore, the method for producing a cast material described in (1) above facilitates proper solidification of the molten metal. Therefore, the above-mentioned method (1) for producing a casting material makes it easy to produce a high-quality casting material with few and small surface defects such as scratches and cracks with high precision.

[0012] (2) In the method for producing a casting material according to (1) above, the step of bringing the tundish into contact with the lower belt may be carried out so that the amplitude falls within a specific range.

[0013] By bringing the tundish into contact with the lower belt so that the amplitude falls within a specific range, the tundish can be kept in appropriate contact with the lower belt. In other words, the tundish can be prevented from being pressed excessively against the lower belt. Therefore, the tundish and the lower belt are less likely to be scraped by the sliding between the tundish and the traveling lower belt, which makes it easier to prevent components of the tundish and the lower belt from being mixed into the molten metal. Therefore, the manufacturing method for cast material described in (2) above can produce cast material with fewer impurities. Furthermore, the manufacturing method for cast material described in (2) above can extend the life of the tundish and the lower belt.

[0014] (3) In the method for producing a casting material according to (1) or (2), the frequency may be 5 kHz or more and 60 kHz or less.

[0015] This frequency is a frequency that is not detected during the descent of the tundish before the tundish contacts the lower belt, or a frequency that is detected but has a small amplitude, and is detected when the tundish contacts the lower belt, or a frequency whose amplitude increases. Therefore, the manufacturing method (3) above can accurately detect that the tundish has contacted the lower belt.

[0016] (4) In any one of the methods for producing a casting material described in (1) to (3), the tundish may include a main body that is a container for storing the molten metal, and a pouring part through which the molten metal flows from the main body toward the mold space. The frequency is measured by a vibration measuring device that includes a vibration sensor and a waveguide. The waveguide has a first end that contacts the outer surface of the pouring part and a second end where the vibration sensor is provided.

[0017] The vibration measuring device can detect vibrations in the pouring part, which becomes very hot.

[0018] (5) In the method for producing a casting material according to (4) above, the cross section of the pouring part may be U-shaped, and the outer surface may be the outer surface of a side or bottom of the pouring part.

[0019] In the method for producing a cast material described in (5) above, the amplitude can be easily detected, and therefore it is easy to accurately detect that the tundish has come into contact with the lower belt.

[0020] (6) In the manufacturing method of the casting material described above in (5), the first end portion may be in contact with a portion of the outer surface that is 50 mm or more and 2100 mm or less away from the pouring port of the pouring portion in a direction opposite to the flow direction of the molten metal.

[0021] The pouring spout is positioned close to the left block group, the right block group, the upper belt, and the lower belt. Therefore, by having the first end contact a location 50 mm or more away from the pouring spout in the direction opposite to the flow of molten metal, it is easy to obtain an appropriate contact area of ​​the first end with the outer surface. By having the first end contact a location 2,100 mm or less away from the pouring spout in the direction opposite to the flow of molten metal, it is easy to reliably transmit vibrations of the pouring part caused by its contact with the lower belt to the vibration sensor, making it easy to detect changes in the amplitude.

[0022] (7) In any one of the methods for producing a casting material according to (1) to (6), the tundish may be lowered by a fluid cylinder and a motor-driven jack.

[0023] The hydraulic cylinder can significantly change the vertical position of the tundish. This allows the hydraulic cylinder to quickly move the tundish closer to or further away from the lower belt. The motor-driven jack can finely adjust the vertical position of the tundish. This allows the tundish to be reliably brought into contact with the lower belt and also prevents the tundish from excessively pressing against the lower belt.

[0024] (8) A casting apparatus according to one embodiment of the present disclosure includes a left block group and a right block group, an upper belt and a lower belt sandwiching the left block group and the right block group, a tundish for storing molten metal to be poured into a mold space formed by the left block group, the right block group, and the upper belt and the lower belt, a drive device for raising and lowering the tundish, and a measuring device for measuring the amplitude at a specific frequency of vibrations of the tundish that occur due to contact between the tundish and the lower belt.

[0025] The casting apparatus (8) can easily produce high-quality castings with few and small surface defects with high precision.

[0026] [Details of the embodiments of the present disclosure] Specific examples of the casting material manufacturing method and casting apparatus of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same items. The shapes, sizes, and positional relationships shown in the drawings are depicted for the purpose of clarifying the description and do not necessarily represent the actual shapes, sizes, and positional relationships.

[0027] [Embodiment] <Casting material manufacturing method> A method for producing a cast material according to an embodiment will be described with reference to FIGS. 1 to 4. In the method for producing a cast material according to the embodiment, a cast material 200 is produced using a casting apparatus 1 shown in FIG. 1. The casting apparatus 1 is a twin-belt continuous casting apparatus. The casting apparatus 1 includes a left block group 21 and a right block group 22 (FIG. 2), an upper belt 41 and a lower belt 42 that sandwich the left block group 21 and the right block group 22, and a tundish 5. The method for producing a cast material according to the embodiment includes a step of pouring molten metal 100 from the tundish 5 into a mold space. The mold space is a space surrounded by the left block group 21, the right block group 22, the upper belt 41, and the lower belt 42. The step of pouring the molten metal 100 includes a step of lowering the tundish 5 to bring the tundish 5 into contact with the lower belt 42. One feature of the method for producing a cast material according to the embodiment is that the step of bringing the tundish 5 into contact with the lower belt 42 is performed while measuring the amplitude of vibration of the tundish 5 at a specific frequency. The following description will be given in the order of the casting apparatus 1 of the embodiment used in the method for producing a cast material of the embodiment, and the method for producing a cast material of the embodiment.

[0028] <Casting equipment> The casting apparatus 1 of this example includes a left block group 21, a right block group 22 (FIG. 2), a cooling tank 3, an upper belt 41, a lower belt 42, a tundish 5, a drive unit 6, and a measuring device 7. The "left" and "right" of the left block group 21 and the right block group 22 refer to the "left" and "right" when viewed from upstream to downstream of the molten metal 100. The casting apparatus 1 has a mold space, which is a rectangular space surrounded by the left block group 21, the right block group 22, the upper belt 41, and the lower belt 42. The casting apparatus 1 continuously produces a casting material 200 by solidifying the molten metal 100 continuously poured into the mold space.

[0029] [Left Block Group, Right Block Group] The left block group 21 forms the left side of the mold, and the right block group 22 forms the right side of the mold. Each of the left block group 21 and the right block group 22 includes multiple dam blocks 23 and endless straps 24 connecting the multiple dam blocks 23. The left block group 21 and the right block group 22 form the left and right sides of the endless track-shaped mold. Each dam block 23 is made of, for example, copper or a copper alloy. Each strap 24 is made of, for example, stainless steel. The left block group 21 and the right block group 22 are arranged facing each other on the left and right sides. The left block group 21 and the right block group 22 rotate in synchronization with the rotation of the upper belt 41 and the lower belt 42. The portions of the left block group 21 and the right block group 22 sandwiched between the upper belt 41 and the lower belt 42 are restricted in vertical movement by the upper belt 41 and the lower belt 42. Guides (not shown) are provided on the left and right outer sides of the left block group 21 and the right block group 22. This guide portion restricts the left and right movement of the left block group 21 and the right block group 22. In each of the left block group 21 and the right block group 22, the total length of the multiple dam blocks 23 is shorter than the circumferential length of the strap 24. The total length is the total length in a state without thermal expansion. The difference between the total length and the circumferential length prevents the molten metal 100 from leaking from the gaps between adjacent dam blocks 23 while enabling the left block group 21 and the right block group 22 to move in an orbit.

[0030] [Cooling tank] The cooling tank 3 cools a portion of each of the left block group 21 and the right block group 22 that is not sandwiched between the upper belt 41 and the lower belt 42. The cooling tank 3 is disposed near the outlet of the casting material 200, and a portion of each of the left block group 21 and the right block group 22 is continuously introduced into the cooling tank 3. The cooling tank 3 can effectively cool the dam block 23 that has been heated by contact with the molten metal 100 and the casting material 200.

[0031] [Upper belt / lower belt] The upper belt 41 forms the upper surface of the mold, and the lower belt 42 forms the lower surface of the mold. Each of the upper belt 41 and the lower belt 42 is an endless belt stretched over multiple pulleys 43. Each of the upper belt 41 and the lower belt 42 is made of, for example, stainless steel. Each of the upper belt 41 and the lower belt 42 moves by the rotation of the pulleys 43. The upper belt 41 and the lower belt 42 are arranged so as to face each other vertically. The upper belt 41 and the lower belt 42 sandwich the left block group 21 and the right block group 22 from above and below. A plurality of backup rolls 44 are arranged between the pulleys 43 of each of the upper belt 41 and the lower belt 42. The backup rolls 44 regulate the vertical movement of the upper belt 41 and the lower belt 42. The upper belt 41 and the lower belt 42 are arranged so that their opposing surfaces are parallel to each other, and are also arranged at an angle relative to the horizontal direction so that the entrance of the casting space, through which the molten metal 100 is poured from the tundish 5, is higher than the exit of the casting space, through which the cast material 200 is discharged. Each of the upper belt 41 and the lower belt 42 is cooled by a cooling mechanism (not shown).

[0032] [Tundish] The tundish 5 comprises a main body 51 and a pouring section 52. The main body 51 is a container that temporarily stores the molten metal 100 supplied from a melting furnace (not shown). The main body 51 is covered with a cover (not shown) or the like so that the molten metal 100 inside is not exposed to the atmosphere. The pouring section 52 allows the molten metal 100 to flow from the main body 51 toward the mold space. The pouring section 52 extends from the main body 51 toward the mold space. The pouring section 52 has a pouring spout 520 (FIG. 2) which is an outlet for the molten metal 100. The pouring spout 520 is provided at an end of the pouring section 52. The pouring spout 520 is located near the mold space.

[0033] In this example, the cross section of the pouring section 52 is U-shaped. The cross section is perpendicular to the direction of flow of the molten metal 100. The pouring section 52 has a bottom 521, a left side 522, and a right side 523. The "left" and "right" of the left side 522 and the right side 523 refer to the "left" and "right" when viewed from upstream to downstream of the molten metal 100. The pouring section 52 in this example does not have a ceiling. Therefore, the molten metal surface 110 can be observed from outside. Unlike this example, the cross section of the pouring section 52 may be rectangular. The rectangular pouring section 52 has a bottom, a left side, a right side, and a ceiling. With a rectangular pouring section 52, the molten metal surface 110 is less likely to be exposed to the atmosphere, making the molten metal 100 less likely to oxidize.

[0034] <Molten metal> The molten metal 100 is made of copper or a copper alloy. The copper is pure copper containing 99.90% by mass or more of copper (Cu). A specific example of pure copper is tough pitch copper. The copper content is the percentage where the total mass of copper is 100% by mass. A copper alloy contains 50% by mass or more, or even 90% by mass or more of Cu and additional elements other than Cu. The additional elements of the copper alloy are, for example, tin (Sn) or silver (Ag). When Sn is contained as an additional element, the Sn content is 0.05% by mass or more and 1.0% by mass or less, 0.2% by mass or more and 0.8% by mass or less, or 0.3% by mass or more and 0.7% by mass or less. When Ag is contained as an additional element, the Ag content is 0.05% by mass or more and 0.5% by mass or less, or 0.1% by mass or more and 0.4% by mass or less. The copper content and the content of the additional elements are percentages based on the total mass of the copper alloy being 100 mass %.

[0035] [Driver] The drive unit 6 raises and lowers the tundish 5. The drive unit 6 moves the tundish 5 up and down freely between a standby position indicated by a two-dot chain line and a contact position indicated by a solid line. The contact position is a position where the molten metal pouring section 52 contacts the lower belt 42. The drive unit 6 is not particularly limited as long as it is a device that can raise and lower the tundish 5.

[0036] The drive unit 6 of this example includes a fluid cylinder 61 and a motor-driven jack 62. The fluid cylinder 61 can significantly change the vertical position of the tundish 5. The fluid cylinder 61 can, for example, raise and lower the tundish 5 in centimeter increments. Therefore, the fluid cylinder 61 can quickly move the molten metal pouring unit 52 closer to or farther from the lower belt 42. The fluid cylinder 61 raises and lowers the molten metal pouring unit 52 between the standby position and the contact position. The fluid cylinder 61 is, for example, provided in the center between the front and rear of the underside of the main body 51. Here, the side of the main body 51 closer to the molten metal pouring unit 52 is referred to as the front, and the side farther from the molten metal pouring unit 52 is referred to as the rear. The fluid cylinder 61 is, for example, a hydraulic cylinder or an air cylinder. The fluid cylinder 61 of this example is a hydraulic cylinder. The motor-driven jack 62 can accurately and finely adjust the vertical position of the tundish 5. The motor-driven jack 62 is, for example, provided at the rear of the underside of the main body 51. This motor-driven jack 62 can raise and lower the tundish 5, for example, in millimeter increments. Therefore, the motor-driven jack 62 can reliably bring the molten metal pouring section 52 into contact with the lower belt 42, and also makes it difficult for the molten metal pouring section 52 to press the lower belt 42 excessively. For example, when the motor-driven jack 62 is raised, the molten metal pouring section 52 is lowered. The motor-driven jack 62 is powered by, for example, a servo motor.

[0037] [Measuring instrument] The measuring device 7 measures the amplitude at a specific frequency of the vibration of the tundish 5. The measuring device 7 is not particularly limited as long as it is a measuring device 7 that can measure the above amplitude.

[0038] In this example, the measuring instrument 7 is a vibration measuring instrument. The measuring instrument 7 includes a vibration sensor 71 and a waveguide 72. The vibration sensor 71 is, for example, an acceleration sensor or an acoustic emission (AE) sensor. The vibration sensor 71 in this example is an acceleration sensor. As shown in FIG. 2 , the waveguide 72 has a first end that contacts the outer surface of the pouring part 52 and a second end where the vibration sensor 71 is provided. The waveguide 72 transmits vibrations of the pouring part 52 to the vibration sensor 71. The temperature of the pouring part 52 increases with the temperature of the molten metal 100. Therefore, the material of the waveguide 72 is not particularly limited as long as it can withstand the temperature of the pouring part 52. In this example, the first end contacts the outer surface of the right side part 523 of the pouring part 52. Unlike this example, the first end may contact the outer surface of the left side part 522 or the outer surface of the bottom part 521 of the pouring part 52. If pouring part 52 has the above-mentioned ceiling part, unlike this example, the first end may be in contact with the outer surface of the ceiling part of pouring part 52.

[0039] The first end may be in contact with the outer surface at a location 50 mm to 2100 mm away from the pouring port 520 of the pouring unit 52 in the direction opposite to the flow of the molten metal 100. That is, as shown in FIG. 3, the distance L between the first end and the pouring port 520 may be 50 mm to 2100 mm. In FIG. 3, the flow direction of the molten metal 100 is the rightward direction, and the direction opposite to the flow direction of the molten metal 100 is the leftward direction. For ease of explanation, the left block group 21, the right block group 22, the upper belt 41, and the lower belt 42 are not shown in FIG. 3, and only the pouring unit 52 and the measuring device 7 are shown. By setting the distance L to 50 mm or more, it is easy to obtain an appropriate contact area of ​​the first end with the outer surface. By setting the distance L to 2100 mm or less, vibrations of pouring part 52 caused by contact of pouring part 52 with lower belt 42 can be easily transmitted to vibration sensor 71, making it easier to detect changes in the amplitude of the vibrations. The distance L may be 330 mm or more and 700 mm or less.

[0040] <Casting material manufacturing procedure> When producing the casting material 200, the tundish 5 is lowered by the fluid cylinder 61 from the standby position indicated by the two-dot chain line in Fig. 1 to the contact position indicated by the solid line in Fig. 1. Thereafter, the position of the tundish 5 is adjusted by the motor-driven jack 62 so that the state in which the underside of the bottom 521 of the molten metal pouring section 52 and the lower belt 42 are in contact, i.e., the gap H (Fig. 2) is maintained at 0 (zero) mm, is maintained. Specifically, the following procedure is performed.

[0041] As shown by the two-dot chain line in Figure 1, after the tundish 5 is raised to the standby position by the fluid cylinder 61, the pouring section 52 is preheated with a burner to prevent the molten metal 100 from solidifying in the pouring section 52. At the same time, the molten metal 100 begins to be poured into the tundish 5. While the tundish 5 is in the standby position, the molten metal 100 flows down the rear of the tundish 5 and does not flow into the mold space.

[0042] After the molten metal pouring section 52 has been sufficiently preheated, the tundish 5 is lowered to the contact position by the fluid cylinder 61, as shown by the solid line in Figure 1. At this time, the distance H (Figure 2) between the underside of the bottom 521 of the molten metal pouring section 52 and the lower belt 42 has become approximately 0 (zero) mm as a result of thermal expansion of the molten metal pouring section 52 due to preheating.

[0043] When the tundish 5 reaches the contact position, the molten metal 100 begins to flow into the mold space. The molten metal 100 is continuously solidified in the mold space, continuously producing the casting material 200. The temperature of the molten metal 100 in the tundish 5 exceeds 1,000°C, depending on the material of the molten metal 100. The heat of the molten metal 100 raises the temperatures of the bottom 521, left side 522, and right side 523 of the pouring section 52, but the temperatures of the left side 522 and right side 523 are lower than the temperature of the bottom 521 of the pouring section 52. This is because the entire bottom 521 is in contact with the molten metal 100, while only the lower parts of the left side 522 and right side 523 are in contact with the molten metal 100, and the upper parts are in contact with the air. As a result, the pouring section 52 warps upward, and the gap H between the pouring section 52 and the lower belt 42 gradually increases. Therefore, the pouring part 52 is lowered by the motor-driven jack 62 so that the gap H between the pouring part 52 and the lower belt 42 becomes 0 (zero) mm. At this time, the molten metal 100 is flowing within the pouring part 52, so the gap H cannot be measured directly. During the process of lowering the pouring part 52, the amplitude of the vibration frequency of the pouring part 52 is measured. A specific frequency is detected in association with the vibration of the pouring part 52 caused by the pouring part 52 coming into contact with the running lower belt 42. Therefore, it is possible to accurately detect that the pouring part 52 has come into contact with the lower belt 42.

[0044] The measured frequency varies depending on factors such as the size of the pouring section 52. The frequency is, for example, between 5 kHz and 60 kHz. Vibrations in this frequency range are called AE waves. As shown in Figure 4, this frequency is a frequency that is not detected while the pouring section 52 is descending before contacting the lower belt 42, or a frequency that is detected but has a small amplitude. It is a frequency that is detected when the pouring section 52 contacts the lower belt 42, or a frequency whose amplitude increases. The horizontal axis of Figure 4 represents time (s), and the vertical axis represents frequency (Hz). For ease of explanation, Figure 4 shows the detected frequencies whose amplitude is equal to or greater than a predetermined value. The vertical dashed lines in Figure 4 indicate the times when amplitudes equal to or greater than the predetermined value were detected at 15 kHz, 22 kHz, and 50 kHz. To the left of the vertical dashed line, amplitudes equal to or greater than the predetermined value were detected at 30 kHz, but not at 15 kHz, 22 kHz, and 50 kHz. To the right of the vertical dashed line, in addition to the amplitude at 30 kHz exceeding the predetermined value, amplitudes at 15 kHz, 22 kHz, and 50 kHz exceeding the predetermined value were detected. Therefore, by measuring the amplitudes at 15 kHz, 22 kHz, and 50 kHz, it is possible to accurately detect that pouring part 52 has come into contact with lower belt 42.

[0045] The pouring part 52 is lowered so that the amplitude falls within a predetermined range. Contact of the pouring part 52 with the lower belt 42 can be determined by the amplitude being equal to or greater than the lower limit of the predetermined range. Therefore, contact of the pouring part 52 with the lower belt 42 can be accurately detected. Contact of the pouring part 52 with the lower belt 42 can be determined by the amplitude being equal to or less than the upper limit of the predetermined range. Therefore, the pouring part 52 and the lower belt 42 are less likely to be worn down by the sliding between the pouring part 52 and the running lower belt 42, which makes it easier to prevent components of the pouring part 52 and the lower belt 42 from being mixed into the molten metal 100. This facilitates the production of a casting material 200 with fewer impurities. Furthermore, the life of the pouring part 52 and the lower belt 42 can be extended. The motor-driven jack 62 is controlled to maintain the position of the pouring part 52 when the amplitude is equal to or greater than the lower limit and equal to or less than the upper limit of the predetermined range.

[0046] In the manufacturing method for a casting material according to the present embodiment, the molten metal 100 is poured into the mold cavity while the pouring part 52 is in contact with the lower belt 42. The molten metal 100 flowing out of the pouring port 520 of the pouring part 52 immediately contacts the upper surface of the lower belt 42 and flows along the upper surface of the lower belt 42. On the other hand, if the molten metal 100 is poured into the mold cavity while a gap is formed between the pouring part 52 and the lower belt 42, the molten metal 100 flowing out of the pouring part 52 sags downward by the gap before contacting the upper surface of the lower belt 42 and flowing along the upper surface of the lower belt 42. In other words, the manufacturing method for a casting material according to the present embodiment is less likely to cause turbulence in the melt flow than when the gap is formed. Therefore, the manufacturing method for a casting material according to the present embodiment allows the molten metal 100 to solidify more appropriately than when the gap is formed. Therefore, the manufacturing method of the casting material of this example makes it easier to accurately manufacture a high-quality casting material 200 with fewer and smaller surface defects such as scratches and cracks, compared to when the gaps are formed.

[0047] [Test example] In the test example, we investigated the difference in the number of scratches that occurred on the surface of the cast material depending on the distance H (Figure 2) between the pouring part 52 and the lower belt 42 in the casting device 1. Since the distance H cannot be measured during casting, the thickness of the copper that solidified and remained between the pouring part 52 and the lower belt 42 after the production of the cast material was considered to be the distance H.

[0048] <Sample No. 1> For Sample No. 1, a cast material was produced using the casting apparatus 1 described in the embodiment. The cast material was then repeatedly rolled using a multi-stage rolling mill (not shown) to produce a copper wire rod having a diameter of 8 mm and a circular cross section. The rolling process was performed consecutively with the casting. During the casting process, as described in the embodiment, the amplitude of the vibration of the tundish 5 at a specific frequency was measured using a measuring device 7. The tundish 5 was lowered to the contact position using a fluid cylinder 61, and the position of the tundish 5 was adjusted using a motor-driven jack 62 so that the molten metal pouring section 52 was maintained in contact with the lower belt 42. No solidified copper remained between the molten metal pouring section 52 and the lower belt 42. In other words, the gap H in Sample No. 1 was 0 (zero) mm.

[0049] <Sample No. 101> For Sample No. 101, copper wire rod was produced in the same manner as Sample No. 1, except that the amplitude was not measured during the casting process, i.e., the position of the tundish 5 was not adjusted by the motor-driven jack 62. After production, the thickness of the copper that solidified and remained between the pouring part 52 and the lower belt 42 was measured. The thickness was 7 mm. That is, the gap H for Sample No. 101 was 7 mm.

[0050] <Damage evaluation> The number of scratches on the surface of the copper wire of each sample was measured. The number of scratches on the surface of the copper wire was measured using an eddy current flaw detector. The detection results were divided into four categories based on the size of the scratches detected: large scratches, medium scratches, small scratches, and minute scratches, and are shown in Table 1 as the number of scratches per 1000 kg of copper wire. Large scratches are 3.0 mm or larger. 2 The damage was 1.5mm. 2 Over 3.0mm 2A minor scratch is less than 0.5mm. 2 More than 1.5mm 2 The smallest scratches are less than 0.3 mm. 2 More than 0.5mm 2 The size of each flaw is the area of ​​the opening of the flaw when the flaw on the surface of the copper wire is viewed in plan.

[0051] [Table 1]

[0052] As shown in Table 1, the copper wire of Sample No. 1, where the distance H was 0 (zero) mm, had fewer large, medium, small, and small scratches on its surface than the copper wire of Sample No. 101. In particular, the copper wire of Sample No. 1 had no large or medium scratches on its surface. Furthermore, the copper wire of Sample No. 1 had very few small scratches, less than 1,000 scratches / 1000 kg, and fewer small scratches, less than 2,000 scratches / 1000 kg. That is, since Sample No. 1 had fewer scratches on its surface than Sample No. 101, it is believed that the cast material itself had fewer scratches. From these results, measuring the vibration of the tundish 5 with the measuring instrument 7 and setting the distance H between the underside of the bottom 521 and the lower belt 42 to 0 mm is considered to be very effective in reducing surface defects in the cast material and, ultimately, in reducing surface defects in the copper wire.

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

[0054] 1 Casting equipment 21 Left Block Group 22 Right Block Group 23 Dam Block 24 Straps 3 Cooling tank 41 Upper Belt 42 Lower Belt 43 Pulley 44 Backup Roll 5 Tundish 51 Main body 52 Pouring section 520 Pouring spout 521 Bottom 522 left side 523 Right side 6. Drive unit 61 Fluid Cylinder 62 Motor-driven jack 7 Measuring instruments 71 Vibration Sensor 72 Waveguide 100 molten metal 110 Water surface 200 Casting material H interval L distance

Claims

1. A method for producing a casting material, comprising a step of pouring molten metal from a tundish into a mold space formed by a left block group, a right block group, and an upper belt and a lower belt sandwiching the left block group and the right block group, The step of pouring the molten metal includes a step of lowering the tundish to bring the tundish into contact with the lower belt while measuring the amplitude of vibration of the tundish at a specific frequency. Manufacturing method of casting material.

2. The method for producing a casting material according to claim 1 , wherein the step of bringing the tundish into contact with the lower belt is performed so that the amplitude falls within a specific range.

3. The method for producing a casting material according to claim 1 or 2, wherein the frequency is 5 kHz or more and 60 kHz or less.

4. The tundish is a main body portion that is a container for storing the molten metal; a pouring section through which the molten metal is poured from the main body section toward the mold space, the frequency is measured by a vibration measuring device including a vibration sensor and a waveguide; The waveguide is a first end portion contacting an outer surface of the pouring portion; The method for manufacturing a casting material according to claim 3 , further comprising: a second end portion on which the vibration sensor is provided.

5. The cross-sectional shape of the pouring part is U-shaped, The method for producing a casting material according to claim 4, wherein the outer surface is an outer surface of a side or bottom of the pouring part.

6. 6. The method for manufacturing a casting material according to claim 5, wherein the first end is brought into contact with a location on the outer surface that is 50 mm to 2100 mm away from the pouring spout of the pouring part in a direction opposite to the flow direction of the molten metal.

7. 3. The method for producing a casting material according to claim 1, wherein the tundish is lowered by a fluid cylinder and a motor-driven jack.

8. a left block group and a right block group; an upper belt and a lower belt sandwiching the left block group and the right block group; a tundish for storing molten metal to be poured into a mold space defined by the left block group, the right block group, the upper belt, and the lower belt; a drive device for raising and lowering the tundish; a measuring device for measuring the amplitude at a specific frequency of vibration of the tundish generated by contact between the tundish and the lower belt, Casting equipment.

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