JP2013103262A - Water tank for cooling ingots, cooling apparatus in casting machine, and method for cooling ingots - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water tank for cooling ingots and a method for cooling ingots to control the ingot cooling condition in the water tank to be used for cooling a casting apparatus.SOLUTION: A third cooling apparatus for cooling an ingot C drawn from molds 11, 12 includes a water tank 20 for making cooling water overflow in order to control the cooling condition by adjusting the temperature of the cooling water. Thus, the amount of water in the water tank can be changed by forming the bulkhead of the water tank to be a bellows capable of expanding/contracting a variable gate 22, and the cooling capacity of the ingot can be changed by adjusting the water level of the cooling water in the water tank.

Description

  The present invention relates to a cooling device in a metal casting machine and a cooling method in the casting machine.

  In continuous casting of metal, a continuous casting machine equipped with a water-cooled mold is generally used. A molten metal heated to a melting point or higher is poured into a mold and cooled to continuously cast an ingot. In such continuous casting of metal, three stages of cooling are performed. Specifically, the mold into which the molten metal has been poured is cooled, primary cooling that forms the shape of the ingot at the initial solidification stage, cooling water is blown directly onto the ingot at the bottom of the mold, and cooling is performed. Secondary cooling that determines the size and direction of crystal grains, and tertiary cooling that lowers the surface temperature of the ingot to near room temperature by passing the ingot through cooling water.

  By the way, the quality of the ingot is evaluated by the presence or absence of defects in appearance and the soundness of the internal structure. The presence or absence of defects in appearance and the soundness of the internal structure are greatly affected by the balance of cooling during solidification of metal and the uniformity of cooling. In particular, in copper alloys, the effect of cooling conditions becomes more prominent as the type and concentration of elements to be mixed increases. The quality of the ingot is determined by the cooling balance and the uniformity in the cooling conditions from the initial solidification to the solidification end point.

  In the primary cooling, the mold is directly cooled. Therefore, when the mold itself uses a material having high thermal conductivity, the metal is rapidly cooled, and it is difficult to keep the crystal grain growth direction continuously uniform. In addition, rapid cooling causes an air gap between the inner surface of the mold and the ingot surface due to shrinkage during solidification, thereby reducing thermal conductivity. This decrease in heat conduction causes remelting of the solidified metal in some cases, making the crystal grain growth non-uniform and generating undulations on the ingot surface.

  The water-cooled mold for continuous casting of Patent Document 1 is primarily cooled by cooling water passing through a water channel provided in a protector that holds the outer peripheral surface of a graphite mold (mold), and cooled to an ingot drawn from the mold. Secondary cooling is performed by an ingot cooling water channel having an outlet through which water is ejected. In the mold of Patent Document 1, the outer peripheral corner of the mold is chamfered, and a gap is formed between the outer peripheral corner of the mold and the inner peripheral corner of the protector, so that an air gap is generated when the metal is solidified. To prevent the crystal grains from becoming uniform.

JP 2010-227994 A

  The above-mentioned patent document 1 pays attention to the material and structure of the mold, and while uniforming the crystal grains of the ingot, it is also possible to control the cooling conditions by adjusting the cooling water. . For example, the cooling conditions can be controlled by changing the amount of cooling water supplied to the mold or adjusting the amount of cooling water sprayed to the ingot drawn from the mold. Further, the cooling condition can be controlled by changing the temperature of the cooling water.

  By the way, when solidifying a metal having high thermal conductivity by a continuous casting method, it is important to consider the effect of tertiary cooling. In conventional tertiary cooling, cooling water is poured into a water tank, and the water level in the water tank is kept constant in an overflowed (drained) state. Since the cooling water is replaced by overflowing the cooling water in the water tank, the water temperature does not rise and the cooling condition is kept constant, which is suitable for cooling an ingot that solidifies the metal at a constant temperature.

  In such tertiary cooling, it is possible to control the cooling conditions by adjusting the temperature of the cooling water stored in the storage tank. However, to control the cooling conditions by adjusting the temperature of the cooling water in the tertiary cooling, it is necessary to provide a water temperature measuring device, a heating device or a cooling device for adjusting the water temperature, installation of the device, fuel cost, etc. Cost. For this reason, there is still room for improvement in controlling the cooling conditions in the tertiary cooling.

  Then, in view of said subject, this invention aims at controlling the cooling conditions of the ingot in a water tank.

  The ingot cooling water tank of the present invention for solving this problem includes a water tank for overflowing cooling water for cooling the ingot drawn out from the mold, and is characterized in that the amount of water in the water tank can be changed. According to this configuration, the ability to cool the ingot can be changed by changing the amount of water in the water tank. Thereby, the cooling condition of the ingot in a water tank is controllable.

  In the ingot cooling water tank, the water level at the time of overflow of the water tank can be changed. The amount of water in the aquarium can be changed by changing the water level. By changing the water level in the water tank in the continuous casting machine, the cooling time of the ingot can be controlled by adjusting the time until the ingot drawn from the mold is immersed in the cooling water.

  In the ingot cooling water tank, the height of the partition wall of the water tank can be changed. Moreover, in said ingot cooling water tank, the partition of the said water tank can be made into a variable gate.

  In the ingot cooling water tank, the variable gate may include a fixed plate fixed below the water tank and a movable plate movable in the vertical direction along the fixed plate.

  In said ingot cooling water tank, the partition of the said water tank can be made into a bellows. According to this structure, the water level of the cooling water in the water tank can be adjusted by expanding and contracting the bellows. Thereby, the cooling conditions of the ingot can be controlled.

  Said ingot cooling water tank WHEREIN: The said water tank can be set as the structure provided with the 1 or more drain port from which the position of a depth direction differs, and the on-off valve which each opens and closes the said drain port. According to this structure, the water level of the cooling water in the water tank can be adjusted by selecting the drain outlet for draining the cooling water. Thereby, the cooling conditions of the ingot can be controlled.

  The ingot cooling water tank can cool the ingot in a continuous casting machine. Moreover, said ingot cooling water tank may cool the said ingot in a semi-continuous casting machine.

  In addition, the cooling device in the casting machine of the present invention for solving the above-described problems includes a mold for cooling a molten metal heated to a melting point or higher to form an ingot, and the ingot drawn from the mold A cooling spray that blows cooling water, and the ingot that has been blown with cooling water may be immersed in the water tank.

  In addition, the ingot cooling method of the present invention for solving the above-described problems is characterized in that the amount of water in the water tank in which the cooling water for cooling the ingot drawn from the mold overflows can be changed. Thereby, the water quantity in a water tank can be changed and the cooling conditions of the ingot in a water tank can be controlled.

  According to the cooling device in the casting machine of the present invention, the ability to cool the ingot can be changed by changing the amount of water in the water tank, and the cooling condition of the ingot in the water tank can be controlled.

It is a top view of a casting machine. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is explanatory drawing which expanded and showed the water tank 20 of FIG. (A) shows the case where the movable plate of the variable gate is lowered, and (b) is an explanatory view showing the case where the movable plate of the variable gate is raised. It is the perspective view which showed one of the internal peripheral corner parts of a water tank. It is sectional drawing of the cooling device of Example 2. It is explanatory drawing which showed the cross section of the water tank in other embodiment. (A) shows the case where the water level is set low, and (b) is an explanatory diagram showing the case where the water level is set high. It is explanatory drawing which showed the cross section of the water tank in other embodiment.

  Hereinafter, an embodiment of a cooling device in an ingot cooling water tank and a casting machine according to the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view of a casting machine 1 according to the present embodiment. 2 is a cross-sectional view taken along the line AA in FIG. 3 is a cross-sectional view taken along the line BB of FIG. The casting machine 1 is a device that realizes continuous casting. Since the casting machine 1 is subjected to continuous casting, the cooling device 2 in the casting machine 1 is configured integrally with the casting machine 1. The casting machine 1 includes a forming unit 10, an ingot cooling water tank (hereinafter referred to as “water tank”) 20, and a cooling water supply device 30.

  The molding unit 10 includes molds 11 and 12 arranged to face each other. Passages 13 and 14 through which cooling water flows are formed in the molds 11 and 12, respectively. Cooling water is supplied to the passages 13 and 14 from the cooling water supply device 30 via the pipe 15. A cooling spray 16 for injecting cooling water is provided below the molds 11 and 12. Cooling water to the cooling spray 16 is also supplied from the cooling water supply device 30. The cooling spray 16 can be cooled by spraying cooling water onto the ingot formed by the molds 11 and 12.

  The water tank 20 is located below the molding unit 10. The water tank 20 includes a water tank body 21 located on the outer periphery and a variable gate 22 disposed in the water tank body 21. The water tank body 21 has a rectangular bottom surface, and an opening 23 through which the ingot passes is provided at the center of the bottom surface. During the operation of the casting machine 1, the ingot c passes through the opening 23, but the gap between the ingot c and the bottom surface of the water tank body 21 is sealed so that cooling water can be stored in the water tank 20.

  The variable gate 22 is disposed in parallel to the side surface 21 a along the longitudinal direction of the water tank body 21. The variable gate 22 is provided on both sides of the side surface 21a along the longitudinal direction. The variable gate 22 functions as a partition wall for the water tank 20. This will be described in more detail with reference to FIGS.

  FIG. 4 is an explanatory view showing the water tank 20 of FIG. 3 in an enlarged manner. 4A shows a case where the movable plate 222 of the variable gate 22 is lowered, and FIG. 4B shows a case where the movable plate 222 of the variable gate 22 is raised. FIG. 5 is a perspective view showing one of the inner peripheral corners of the water tank 20. The variable gate 22 includes a fixed plate 221 and a movable plate 222. Both the fixed plate 221 and the movable plate 222 are made of steel. The fixing plate 221 is joined to the bottom surface of the water tank body 21 without a gap and is fixed below the water tank 20. The fixing plate 221 is joined to the side surface 21a of the water tank body 21 with a predetermined interval. The movable plate 222 is disposed on the inner side of the fixed plate 221 and can move in the vertical direction.

The screw bolt 24 is supported by a fixed nut 25, and the screw bolt 24 itself moves up and down when the screw shaft of the screw bolt 24 moves relative to the fixed nut 25. In addition, bearing portions 27 having through holes 271 through which the screw bolts 24 pass are welded to the movable plate 222 at both corners of the upper portion of the movable plate 222. Further, an engagement portion 243 having a diameter larger than that of the through hole 271 of the bearing portion 27 is attached to the lower end portion of the screw bolt 24, and the movable plate 222 is supported in a state of being suspended by the engagement portion 243, and the screw When the screw bolt 24 moves up and down due to the rotation of the bolt 24, the engaging portion 243 supports the bearing portion 27 so that the movable plate 222 moves up and down.
Further, the upper end of the screw bolt 24 has a grip 242, and the upper end thereof has a wrench hole for rotating the screw bolt. When the worker rotates the grip portion 242, the screw portion 241 rotates and the movable plate 222 can be moved in the vertical direction. For the rotation of the screw portion 241, a driving motor (not shown) may be installed to rotate the screw bolt 24.
Further, a plurality of guide portions 26 are provided on the fixed portion 221. The guide unit 26 guides the movable plate 222 so that the movable plate 222 is located at an equal distance from the side surface 21a of the water tank body 21 when the movable plate 222 moves. The guide portions 26 are provided at equal intervals along the side surface 21 a of the water tank body 21. By providing this guide portion 26, a predetermined interval is provided between the movable plate 222 and the side surface 21 a of the water tank body 21.

  Water is poured into the water tank 20 by the cooling water supply device 30. Alternatively, the cooling water sprayed on the ingot by the cooling spray 16 is supplied into the water tank 20. As shown in FIGS. 4A and 4B, the cooling water poured into the water tank 20 is stored in an area surrounded by the water tank body 21 and the variable gate 22. While casting is being performed, the cooling water is poured into the water tank 20. Although a sealing mechanism is not provided between the fixed plate 221 and the movable plate 222 of the variable gate 22, the movable plate 222 is pressed against the fixed plate 221 by water pressure when cooling water is injected, and the leakage of cooling water is reduced. Further, since the cooling water is injected more than the leakage, a sealing mechanism is not necessary. When the water level of the cooling water exceeds the height of the variable gate 22, the cooling water overflows beyond the variable gate 22. Therefore, by changing the height of the variable gate 22, the level of the cooling water in the water tank 20 can be changed, and the amount of cooling water stored in the water tank 20 can be changed.

  The cooling water overflowing beyond the variable gate 22 flows down between the variable gate 22 and the side surface 21a of the water tank main body 21 (indicated by arrows in FIGS. 4A and 4B). A drain port (not shown) is provided at the bottom of the water tank body 21 to discharge the overflowed cooling water. The discharged cooling water is collected in a recovery tank 40 disposed in the lower part of the water tank 20 and then sent to a cooling tower (not shown). Then, after cooling water is cooled at 35-36 degreeC in a cooling tower, it is again sent to the molds 11 and 12 and the water tank 20 by the cooling water supply apparatus 30, and is utilized for cooling of an ingot.

  Next, an example of continuous casting by the casting machine 1 will be described. Here, copper casting will be described. In the continuous casting of copper, the molten copper heated to a melting point (about 1083 ° C.) or higher is continuously solidified in a short time. In the continuous casting of copper, the molten copper heated to the melting point or more is poured into the molds 11 and 12 from the upper side of the molding part 10. The molten copper poured into the molds 11 and 12 releases heat to the cooling water in the molds 11 and 12 and solidifies (primary cooling). The copper metal (ingot c) whose surface has solidified is drawn out to the lower part of the molds 11 and 12 and further cooled by cooling water blown from the cooling spray 16 (secondary cooling). Subsequently, the ingot c is further cooled by immersing it in cooling water stored in a water tank 20 provided at the lower part of the molding unit 10 (third cooling).

In the above cooling device and method, the cooling rate of the cast metal is fast, and in the case where defects such as oscillation marks and center cracks occur on the surface of the ingot due to rapid cooling, the cooling rate is reduced. In addition, the variable gate is lowered so as to lower the water level in the water tank 20 of the tertiary cooling section, and the cooling rate is lowered by reducing the amount of cooling water, thereby preventing the occurrence of defects such as oscillation marks and center cracks.
In addition, when the cooling rate of the metal to be cast is slow and the temperature of the metal to be cast is too high, the meniscus of the metal solution is lowered downward in the molds 11 and 12 of the primary cooling part, and the carbon of the mold part and the like. Impurities are involved, and the purity of the casting deteriorates. Further, when the solution temperature is high, the metal being cast does not solidify from the middle, but flows out as a solution, and casting stops. To prevent this, the water level in the tertiary cooling section is adjusted and the water level is increased, so that the cooling rate can be increased, and contamination of impurities and stop of casting can be avoided.
Furthermore, it is possible to produce a high-quality casting having a uniform crystal grain size by controlling the cooling rate of the metal casting to the optimum condition by adjusting the water level of the tertiary cooling section.

  Further, in some cases, slow cooling is required in continuous casting or, conversely, rapid cooling is required in accordance with the type of metal to be cast and the characteristics of the product itself. The cooling device 2 in the casting machine 1 can control the cooling condition of the ingot c by changing the amount of cooling water in the water tank 20, particularly the water level. That is, when it is desired to slowly cool the ingot c, the movable plate 222 is moved downward, and the variable gate 22 is lowered to lower the cooling water level in the water tank 20 (state shown in FIG. 4A). . As a result, the cooling capacity is reduced by the amount of water cooling for the tertiary cooling, and the time until the ingot c is immersed in the cooling water is extended, so that the ingot c can be gradually cooled. On the other hand, when rapid cooling of the ingot c is necessary, the movable plate 222 is moved upward and the variable gate 22 is raised to raise the level of the cooling water in the water tank 20 (FIG. 4B). State). As a result, the cooling capacity is improved by the depth of the water tank for the third cooling, and the ingot c drawn from the molds 11 and 12 is immediately immersed in the cooling water. Can be cooled. Thus, the cooling device 2 in the casting machine 1 changes the capacity of cooling the ingot c by changing the amount of water in the water tank 20, particularly the water level, and controls the cooling condition of the ingot c in the water tank 20. . Since the cooling conditions can be controlled in accordance with the characteristics of the metal product to be cast in this way, it is possible to suppress problems such as defects on the surface of the ingot caused by rapid cooling, oscillation marks, center cracks, etc. Can be manufactured. Further, since the water level in the water tank 20 can be easily changed by changing the height of the variable gate 22, the cooling condition of the ingot c in the water tank 20 can be controlled without cost.

  In this embodiment, the variable gate 22 is composed of two steel plates, a fixed plate 221 and a movable plate 222. However, the movable gate 222 can be doubled and tripled so that the variable gate 22 can be changed. It is good also as a structure which sets this in detail.

Next, Example 2 will be described. In Example 2, semi-continuous casting by the casting machine 1 is performed. FIG. 6 is a cross-sectional view of the cooling device 100 of the present embodiment. The ingot cooling water tank (hereinafter referred to as “water tank”) 120 in the present embodiment is deeper than the water tank 20 of the above-described form shown in FIG. Furthermore, since the depth of the water tank 120 is deep, the length of the fixed plate 1221 and the movable plate 1222 of the variable gate 22 in the depth direction is also increased. In addition, since the other structure is the same as said form, it attaches | subjects the same number in a figure and abbreviate | omits detailed description. Further, the mechanism for changing the water level is the same as that in the above embodiment. According to the cooling device 100 shown in the present embodiment, the cooling rate can be adjusted by adjusting the water level of the water tank in the semi-continuous casting machine.
(Other embodiments)

  Next, an embodiment of the present invention different from the above embodiment will be described. In the present embodiment, the variable gate 22 composed of the fixed plate 221 and the movable plate 222 in the embodiment shown in FIG. 3 is changed to a variable gate 51 composed of a bellows. FIG. 7 is an explanatory diagram showing an embodiment described here. FIG. 7A shows a case where the water level is set low, and FIG. 7B shows a case where the water level is set high. The aquarium 50 of this embodiment is different from the aquarium 20 in the above embodiment in that the configuration of the variable gate is different. As shown in FIGS. 7A and 7B, the cooling water is stored in a region surrounded by the water tank body 21 and the variable gate 51 made of a bellows. The variable gate 51 is suspended by a wire 52 from above. By rotating the wheel 53 around which the wire 52 is wound to loosen the wire 52, the bellows is bent and the variable gate 51 is lowered. On the contrary, when the wheel 53 is wound up, the bellows is extended and the variable gate 51 is raised. By extending and contracting the bellows in this manner, the height of the variable gate 51 is continuously changed, the water level in the water tank 50 is changed, and the cooling condition of the ingot in the water tank 50 is controlled. In addition, since the other structure is the same as the cooling device in the casting machine demonstrated above, detailed description is abbreviate | omitted.

  Next, an embodiment of the present invention different from the above embodiment will be described. FIG. 8 is an explanatory view showing a cross section of the water tank 60 in another embodiment. The aquarium 60 of this embodiment is different from the aquarium 60 in the above embodiment in that the means for changing the water level of the cooling water in the aquarium 60 is different. That is, the water tank 60 of the present embodiment does not include the variable gate 22, but a plurality (four) of drain ports 61, 62, 63, 64 and drain ports 61, 62, 63 having different positions in the depth direction. , 64 are provided with a plurality (four) of on-off valves 65, 66, 67, 68.

  The cooling water is stored in the water tank 60, and the water level of the cooling water in the water tank 60 is controlled by the open / close state of the on-off valves 65, 66, 67, 68. One of the on-off valves 65, 66, 67, 68 is opened and the rest is used in a closed state. Cooling water is discharged to the recovery tank 69 from the drain port opened by the on-off valve. For example, FIG. 8 shows a state in which cooling water overflows from the drain port 63 with the on-off valve 67 opened. Since each drain outlet provided in four places differs in the depth direction position in the water tank 60, the water level of the cooling water in the water tank 60 changes depending on the position of the drain outlet from which the cooling water is discharged. Therefore, it is possible to change the water level of the cooling water in the water tank 60 and control the cooling condition of the ingot by setting an open / close valve that opens in accordance with the required cooling conditions. In addition, since the other structure is the same as the cooling device in the casting machine demonstrated above, detailed description is abbreviate | omitted. Moreover, if the objective of changing the water level in a water tank is considered, the number of the drain outlets should just be one or more places.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

DESCRIPTION OF SYMBOLS 1 Casting machine 2,100 Cooling device 10 Molding part 11,12 Mold 20,50,60,120 Water tank 21 Water tank main body 22 Variable gate 221,1221 Fixed plate 222,1222 Movable plate 24 Screw bolt 25 Fixed nut 26 Guide part 30 Cooling Water supply device 40 Recovery tank 51 Variable gate (bellows)
61, 62, 63, 64 Drain port 65, 66, 67, 68 On-off valve

Claims (17)

  An ingot cooling water tank, characterized in that the amount of water in the water tank for overflowing cooling water for cooling the ingot drawn from the mold can be changed.   The ingot cooling water tank according to claim 1, wherein the water level at the time of overflow of the water tank can be changed.   The ingot cooling water tank according to claim 2, wherein the height of the partition wall of the water tank can be changed.   The ingot cooling water tank according to claim 2, wherein a partition wall of the water tank is a variable gate.   5. The ingot cooling water tank according to claim 4, wherein the variable gate includes a fixed plate fixed below the water tank and a movable plate movable in the vertical direction along the fixed plate. .   The ingot cooling water tank according to claim 2, wherein a partition wall of the water tank is a bellows.   3. The ingot cooling water tank according to claim 2, wherein the water tank includes one or more drainage ports whose positions in the depth direction are different from each other, and an opening / closing valve that opens and closes each of the drainage ports.   The ingot cooling water tank according to any one of claims 1 to 7, wherein the ingot is cooled in a continuous casting machine.   The ingot cooling water tank according to any one of claims 1 to 7, wherein the ingot is cooled in a semi-continuous casting machine. A mold that heats above the melting point and cools the molten metal to form an ingot;
A cooling spray for blowing cooling water to the ingot drawn from the mold;
The cooling device in the casting machine provided with the ingot cooling water tank as described in any one of Claims 1 thru | or 9 which immerses the said ingot which sprayed the cooling water in the said water tank.   A method for cooling an ingot, characterized in that the amount of water in a water tank for allowing overflow of cooling water for cooling the ingot drawn from a mold can be changed.   The ingot cooling method according to claim 10, wherein the water level at the time of overflow of the water tank can be changed.   The ingot cooling method according to claim 11, wherein the height of the partition wall of the water tank can be changed.   12. The ingot cooling method according to claim 11, wherein the water tank can be drained from different positions in the water depth direction.   The ingot cooling method according to any one of claims 10 to 13, wherein the ingot is cooled in a continuous casting machine.   The ingot cooling method according to any one of claims 10 to 13, wherein the ingot is cooled in a semi-continuous casting machine. Cooling the mold poured with molten metal heated above the melting point to form an ingot,
The method for cooling an ingot according to any one of claims 11 to 16, wherein after cooling water is sprayed on the ingot drawn out from the mold, the ingot is immersed in the water tank.

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