JP2019198879A - Casting mold made of cast iron and method for producing ingot using the same - Google Patents

Abstract

To provide a casting mold made of cast iron capable of preventing the deposition of an ingot thereto which provide a problem upon ingot removal, and a method for producing an ingot using the same.SOLUTION: A casting mold 1 made of cast iron comprises: a base 10 whose upper face is provided with a graphite layer 12; and a frame body 20 standing from the peripheral section of the base 10 and whose inside face is provided with a release film 23. Regarding a method for producing an ingot using the casting mold 1, the base 10 whose upper face is provided with a plate graphite layer 12 and the frame body 20 whose inside face is provided with a release material are prepared, the base 10 and the frame body 20 are joined while holding the peripheral section of the graphite layer 12 by the upper face of the base 10 and the lower edge face of the frame body 20 to compose the mold 1, a molten metal is made to flow into the mold 1 and solidification is performed by cooling, and thereafter, the mold 1 is tilted to discharge an ingot.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cast iron mold for casting used in a refining process and an ingot manufacturing method using the same.

  In casting methods in which the ingot is molded by cooling the molten metal poured into the mold, a mold release material is generally applied to the mold surface in advance for the purpose of improving the peelability of the ingot from the mold. ing. For example, Patent Document 1 discloses a mold comprising a rectangular bottom plate made of graphite as a casting mold for polycrystalline silicon semiconductor, and four side plates made of graphite provided on each of the four sides thereof. Those adjacent to each other are assembled so as to be separable by screwing.

  The mold of this patent document 1 is described that the inner surface is covered with silicon oxide, nitride, or carbide, thereby preventing the ingot from being fused to the mold. On the other hand, as a casting mold used in a refining process for continuously casting a molten metal such as a Ni / Fe / Cu alloy, an inexpensive cast iron mold is generally used. In this case as well, a release material is applied in advance to the inner surface of the mold.

JP 62-108515 A

  Various materials have been proposed as mold release materials for cast iron casting molds that are used in the molten metal refining process. However, a phenomenon that the release material previously applied to the inner surface of the mold peels off from the inner surface of the mold due to the impact of dropping when the molten metal is poured into the mold from the mouth of the furnace body. This phenomenon occurred remarkably in the place where the molten metal dropped and in the vicinity thereof, and this portion was the starting point for wear of the bottom surface of the cast iron mold.

  Further, when the release material is peeled off, the cast iron mold comes into direct contact with the molten metal, so that the ingot and the mold are welded and it may be difficult to take out the ingot. In particular, in a refining process of a high melting point metal such as a metal whose main component is a Ni / Fe / Cu alloy having a melting point of approximately 1400 to 1450 ° C., even a cast iron mold having a melting point of about 1500 ° C. may be melted and cooled. When solidifying, the ingot and the mold are sometimes welded to each other so that it is difficult to come off. The present invention has been made in view of the problems of the above-described conventional mold, and for cast iron casting capable of preventing the ingot from being welded to the cast iron casting mold, which is a problem when removing the ingot. The object is to provide a mold.

  In order to achieve the above object, a cast iron casting mold according to the present invention includes a pedestal provided with a graphite layer on an upper surface thereof, a frame body provided with a release film on an inner surface thereof standing from the peripheral edge of the pedestal. It is characterized by consisting of.

  The ingot manufacturing method according to the present invention includes a pedestal having a plate-like graphite layer installed on the upper surface, and a frame body coated with a release material on the inner surface and dried, A mold is formed by joining the pedestal and the frame while sandwiching the peripheral edge between the upper surface of the pedestal and the lower end surface of the frame, and after casting the molten metal into the mold and solidifying by cooling, the mold It is characterized by taking out the ingot by tilting.

  According to the present invention, since the solidified ingot is hardly welded to the cast iron casting mold, the ingot can be easily removed.

It is a longitudinal cross-sectional view of one specific example of the cast iron casting mold of the present invention.

  Hereinafter, a specific example of the cast iron casting mold of the present invention will be described with reference to FIG. The mold 1 shown in FIG. 1 is composed of a flat pedestal 10 having a graphite layer on its upper surface, and a frame 20 that is erected from the peripheral edge of the pedestal 10 and has a release film on its inner surface. Then, the molten metal poured into the mold 1 from above is received and cooled and solidified to form the metal. The ingot thus processed can be easily taken out by inclining the mold 1.

  More specifically, the pedestal 10 is made of a relatively inexpensive cast iron generally used as a casting mold, and a concave portion having a substantially uniform depth is formed on the upper surface 11 thereof. A plate-like graphite layer 12 is fitted in the recess. Thereby, the problem which the conventional mold | type which a mold release material peels by the impact of the molten metal falling from the mouth of a furnace body can be eliminated. That is, the graphite layer 12 serves as a barrier wall (barrier) for the molten metal falling from the furnace port at the time of casting, so that it is possible to prevent the cast iron base 10 from being directly affected by the melt and being worn out.

  In particular, by using the graphite layer 12 containing graphite as a main component, even when a high melting point metal having a melting point of about 1400 ° C. is cast, the component constituting the base 10 is excellent in heat resistance against the molten metal. It is also possible to prevent the problem of contamination as an impurity in the ingot. The thickness of the plate-like graphite layer 12 is desirably 10 mm or more since it may be broken by an impact caused by dropping of the molten metal if it is thin like a carbon sheet having a thickness of about 1 mm. However, since the capacity | capacitance of the molten metal received in a casting_mold | template will reduce when too thick, it is preferable that it is 30 mm or less.

  The frame 20 erected from the peripheral edge of the pedestal 10 is coupled to the pedestal 10 by screwing with a plurality of screws 30. The frame 20 may be coupled to the base 10 by using a metal fixing belt 31 instead of or in addition to the above-described screwing. In order to fix the base 10 and the frame 20, the fixing belt 31 is usually fixed so as to be wrapped around two portions at both ends of the mold 1 as shown in FIG. 1. At that time, it is preferable to wind the fixing belt 31 so as not to particularly protrude inside the frame body 20. The frame body 20 has a tapered structure in which the inner side surface 21 is inclined so that the inner side becomes wider toward the upper side, whereby the ingot after solidification can be easily taken out.

  The inner peripheral edge portion of the lower end surface 22 of the frame 20 having the tapered inner surface 21 is located inside the outer peripheral edge portion of the plate-like graphite layer 12. Thus, when the frame body 20 is coupled to the pedestal 10 by screwing or the like, the peripheral portion of the plate-like graphite layer 12 is sandwiched and fixed between the lower end surface 22 of the frame body 20 and the upper surface 11 of the pedestal 10. Is possible. Therefore, even if the mold 1 is tilted when the ingot is taken out, the graphite layer 12 does not fall, and the cast molten metal can be prevented from coming into contact with the cast iron base 10.

  A release film 23 is provided over the entire inner surface 21 of the frame body 20. The release film 23 is coated with a release material mainly composed of silicon resin, boron nitride, barium sulfate, graphite, zirconia / alumina / silica mixed, or tertiary calcium phosphate, and then dried. By doing so, it can be formed. When applying, it is preferable to apply uniformly with a thickness of 2 mm or more, but if it is applied too thick, the cost increases, and there is a possibility of peeling off when solidified, so a thickness of 5 mm or less is preferable. In the case of accepting a molten metal composed of a high melting point raw material having a melting point exceeding 1400 ° C., a material mainly composed of graphite or a zirconia / alumina / silica mixed system is suitable.

  The molten metal was poured into the casting mold 1 made of cast iron as shown in FIG. 1 by tilting a furnace body not shown. This molten metal was prepared by melting a raw material (Fe / Cr / Ni alloy) containing a material having a high melting point exceeding 1400 ° C. in a high frequency induction melting furnace. The concave portion having a substantially rectangular shape in plan view provided on the upper surface 11 of the pedestal 10 having a substantially rectangular shape in plan view constituting the cast iron mold 1 contains 99.9% by mass or more of graphite and 0.1% by mass of ash. A plate-like graphite layer 12 having a substantially rectangular shape in plan view and contained therein was fitted. In addition, a graphite mold release material (model number: Toyokazole WGS-225) manufactured by Oriental Sangyo Co., Ltd. is applied to the four inner side surfaces 21 of the frame 20 with a spatula so as to be uniform with a thickness of about 2 mm. And after application | coating, in order to prevent the explosion which generate | occur | produces with the water | moisture content contained in a mold release material, the excess water | moisture content was removed by heating with a gas burner.

  After the molten metal cast into the cast iron mold 1 was cooled and solidified, the resulting ingot was taken out by tilting the cast iron mold 1. As a result, the ingot was detached from the mold so as to slide down by tilting the cast iron mold 1 about 70 ° from the horizontal plane. The cast metal was cast into cast iron mold 1 under the same conditions as above, cooled and solidified, and the casting process for taking out the ingot was repeated seven times. However, there was a problem that the mold 1 and the cooled ingot were welded. I did not. In addition, the time required to take out the ingot from the mold 1 was within 30 seconds in all cases.

  For comparison, casting was performed in the same manner as described above except that a conventional cast iron casting mold was used. At that time, a mold release material (model number: Toyokazol WGS-225) manufactured by Oriental Sangyo Co., Ltd., the main component of which is made of graphite, is uniformly distributed with a thickness of about 2 mm on the upper surface of the cast iron mold base and the inner surface of the frame Then, it was applied in advance using a spatula and heated with a gas burner in the same manner as described above to remove excess water. In the case of this conventional cast iron mold, since the ingot was welded to the casting mold, the ingot could not be taken out even if the mold was tilted after cooling. To separate and remove the welded ingot from the cast iron mold, the cast iron mold is turned upside down and the bottom of the pedestal is continuously struck with a large hammer and can be finally removed in about 2 hours. It was.

DESCRIPTION OF SYMBOLS 1 Cast iron casting mold 10 Base 11 Upper surface 12 Graphite layer 20 Frame body 21 Inner side surface 22 Lower end surface 23 Mold release film 30 Screw 31 Fixing belt

Claims (4)

  A casting mold made of cast iron, comprising: a pedestal having a graphite layer on the upper surface; and a frame body standing on the periphery of the pedestal and having a release film on the inner surface.   2. The cast iron casting mold according to claim 1, wherein the graphite layer is fixed by being sandwiched between an upper surface of the base and the frame body.   The graphite layer is plate-shaped, is fitted in a recess provided on the upper surface of the pedestal, and the lower end surface of the frame body is in contact with the peripheral portion of the plate-shaped graphite layer. The cast mold made of cast iron according to claim 1 or 2, characterized by the above.   A pedestal having a plate-like graphite layer on the upper surface and a frame body coated with a release material on the inner surface and dried are prepared, and the periphery of the graphite layer is placed on the upper surface of the pedestal and under the frame body A casting is characterized in that these pedestals and the frame body are joined while being sandwiched between end faces to form a mold, and after casting molten metal into the mold and solidifying by cooling, the mold is tilted to take out the ingot. A method of manufacturing a lump.

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