JP4092581B2 - Frozen sand mold repair method and surface protection method - Google Patents

Description

  The present invention repairs a frozen sand mold formed by a freeze casting method in which a casting sand mixed with a predetermined amount of water is filled around a model built in a mold to make a mold, and the obtained mold is hardened by freezing. And a surface protection method.

  In the freeze casting method, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 11-138235), low temperature air cooled by a refrigerator is circulated in a mold made of foundry sand to freeze the mold. Further, the frozen mold is stored in a freezer cooled to 0 ° C. or lower by a freezer, and a casting is manufactured by pouring the mold into the mold at the time of casting, which is a relatively simple means of freezing. This is a casting method in which a strong mold can be obtained and a cast product with a good casting surface can be obtained.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-34042) provides an appropriate additive to cinnabar to increase bubbles generated by entrained air during kneading and maintain the generated bubbles in a stable state. And forming a fluidized sand that enables fluidization of the foundry sand, and freezing the fluidized mold formed by using the fluidized sand, thereby giving the foundry sand high fluidity, formability, and uniformity. A method for making a frozen mold is disclosed.

JP 11-138235 A JP 2004-34042 A

However, when a sand mold created using the conventional freeze casting method is damaged, the effect of ordinary repair materials is low, repair is difficult, and the sand mold surface cannot be stored for a long time with the surface condition maintained. There is.
When repairing a frozen sand mold, even when repairing at room temperature, the repair target is a frozen sand mold with cold heat, so the effect of normal repair adhesive etc. is low, extending the curing time and decreasing the bonding time .

  Moreover, when it preserve | saves at low temperature before actual pouring (work which pours the molten metal into a sand mold) is implemented, the water | moisture content of a sand mold surface reduces and the problem that the sand mold surface becomes rough has generate | occur | produced. As a result, the product shape / surface becomes dirty, so that the product value of the product is lowered and the sand mold cannot be stored for a long time, resulting in a problem that the production amount of the frozen sand mold is reduced.

  In other words, the current sand mold repair materials are manufactured on the premise that they are used at room temperature, so the frozen sand mold that is subject to repair has a longer curing time and lower strength, which can be used to repair frozen molds. Is unsuitable. As a result, a sand mold having inferior shape and strength is remanufactured, and defects and defects are likely to occur in the cast product cast by the sand mold.

  In addition, the current freeze casting method takes a form in which a certain amount of hot water (melted metal) is produced, a sand mold corresponding to that amount is preliminarily prepared, and hot water is poured at a time to produce a casting. As a result of pursuing rationalization and cost reduction, this production form is generally performed at present, and it is considered that the freeze casting method does not change. In the case of this production mode, a sand mold having a rough surface is produced by long-term storage at a low temperature by making a sand mold. As a result, there is a problem that a cast product having a rough surface with a low commercial value is produced.

  In view of the problems of the prior art, the present invention can be stored for a long time while maintaining the surface state of the sand mold, and does not cause a prolonged hardening time and a decrease in strength, and thus a damaged portion can be quickly removed. An object of the present invention is to provide a frozen sand mold repair method and surface protection method that can be repaired.

  The present invention achieves such an object, and a first method for repairing a frozen sand mold is to form a sand mold by filling casting sand mixed with a predetermined amount of water around a model built in a mold. When repairing a frozen sand mold formed by a freeze casting method in which the sand mold is hardened by freezing, water is applied to the damaged portion of the frozen mold and rapidly frozen.

  The second frozen sand mold repair method of the present invention is a freeze casting method in which a sand mold is mixed by filling a molding sand mixed with a predetermined amount of water around a model built in a mold, and the sand mold is hardened by freezing. When repairing a frozen sand mold that has been made in accordance with the above, if there is a major damage such as missing part of the frozen sand mold, prepare a frozen sand mold block in advance, and the frozen sand mold block corresponds to the damaged part during repair. Then, the frozen sand mold block is filled in the damaged portion, and the gap between the frozen sand mold and the frozen sand mold block is filled with water-containing sand and water and frozen.

  The surface protection method for a frozen sand mold according to the present invention is based on a freeze casting method in which casting sand mixed with a predetermined amount of water is filled around a model built in a mold to form a sand mold, and the sand mold is hardened by freezing. A thin ice layer is formed by applying water to the surface of the molded frozen sand mold.

  The first frozen sand mold repair method of the present invention is a repair method mainly when damage such as cracks is small. Since the frozen sand mold body itself usually has cold heat and the working atmosphere is low temperature, The water applied to the damaged part freezes rapidly and can be repaired instantly.

  Further, the second frozen sand mold repair method of the present invention is a repair method in the case where there is a major damage such as a part of the sand mold missing. A frozen sand mold block is prepared in advance, and this block is fixed at the time of repair. Repaired with sand and water containing water. Since the frozen sand mold body itself normally has cold heat, the working atmosphere is low temperature, and the frozen sand mold block itself also has cold heat, so instantaneous repair is possible.

  The surface protection method for a frozen sand mold according to the present invention forms a thin ice layer by applying water to the sand mold surface in order to prevent a decrease in moisture present on the surface of the frozen sand mold.

According to the first frozen sand mold repair method of the present invention, water is applied to the broken portion of the frozen sand mold and rapidly frozen, which is effective for repair mainly when damage such as cracks is small. Since the sand mold body itself normally has cold heat, the water applied to the broken part of the frozen sand mold freezes rapidly, and instant repair is possible.
As described above, the curing time is not prolonged and the strength is not lowered, and the damaged portion can be repaired promptly. Accordingly, a frozen sand mold that is not inferior in shape and strength is remanufactured in the same way as at the time of initial production, and there is no occurrence of defects or defects in the cast product cast with this sand mold.

The second frozen sand mold repair method of the present invention is effective mainly when there is a large damage such as a part of the frozen sand mold being missing. A frozen sand mold block is prepared in advance and the frozen sand mold is frozen during repair. After forming the sand mold block to a size corresponding to the damaged portion, the frozen sand mold block is filled in the damaged portion, and the gap between the frozen sand mold and the frozen sand mold block is filled with water-containing sand and water. By freezing, the frozen sand mold body itself usually has cold heat, and in addition, the frozen sand mold block itself also has cold heat, making it possible to repair instantaneously and prevent prolonged hardening time and reduced strength, etc. it can. Therefore, the same effect as the first frozen sand mold repair method of the present invention is exhibited.
If the method of the present invention is carried out in a low temperature atmosphere, better results can be obtained, but it is not an essential requirement to carry out in a low temperature atmosphere.

  Further, according to the surface protection method of the frozen sand mold of the present invention, the applied sand freezes instantaneously because the frozen sand mold itself has cold heat by applying water to the surface of the frozen sand mold to form a thin ice layer. The contact between the external air and the sand mold surface can be cut off, and the subsequent evaporation of moisture from the sand mold surface can be prevented. Thereby, the sand mold surface shape can be stored for a long time. Therefore, the commercial value of the product cast with the frozen sand mold does not decrease, and the problem that the production volume of the frozen sand mold decreases does not occur.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.
FIG. 1 is a perspective view of a frozen sand mold according to a first embodiment to which the first frozen sand mold repair method of the present invention is applied.

  In FIG. 1, reference numeral 1 denotes a frozen sand mold formed by a freeze casting method in which casting sand mixed with a predetermined amount of water is filled around a model built in a mold to form a sand mold, and the sand mold is hardened by freezing. is there. The frozen sand mold has a damaged portion 1b in which the crack 1a and the chipped part 1c are chipped. When repairing these, the working atmosphere is set to a low temperature, and water is supplied to the crack 1a and the damaged portion 1b in the water containers 2 and 3. Apply and freeze quickly.

According to the repair method of the first embodiment, by applying water to the broken part of the frozen mold in a low-temperature atmosphere and rapidly freezing it, it is effective for repair mainly when damage such as cracks is small. Since the frozen sand mold 1 itself has cold heat and the working atmosphere is low temperature, the water applied to the damaged part of the frozen sand mold freezes rapidly, and instant repair is possible.
In this way, prolonged curing time and reduced strength are not caused at low temperatures, and damaged parts can be repaired quickly. Accordingly, a frozen sand mold that is not inferior in shape and strength is remanufactured in the same way as at the time of initial production, and there is no occurrence of defects or defects in the cast product cast with this sand mold.

Next, an embodiment to which the second frozen sand mold repair method of the present invention is applied will be described with reference to the drawings. FIG. 2 is a perspective view of a frozen sand mold according to the second embodiment.
In FIG. 2, 11 is a frozen sand mold formed by a freezing casting method in which a molding sand mixed with a predetermined amount of water is filled around a model built in a mold to form a sand mold, and the sand mold is hardened by freezing. is there. The frozen sand mold 11 has a large damaged portion 11a. When repairing the frozen sand mold 11, the frozen sand mold block 12 is formed into a size corresponding to the damaged portion 11a, and then filled in the damaged portion. The gap with the block 12 is filled with water-containing sand 13 and water and frozen.

  According to the second embodiment, the frozen sand mold 11 itself has cold heat, the working atmosphere is low temperature, and the frozen sand mold block 12 itself also has cold heat. Thus, it is possible to prevent the curing time from being prolonged and the strength from being lowered. Accordingly, the same operational effects as those of the first embodiment can be obtained.

Next, an embodiment to which the frozen sand surface protection method of the present invention is applied will be described with reference to the drawings. 3 and 4 are a perspective view and a sectional view of a frozen sand mold according to the second embodiment.
In order to prevent a decrease in moisture existing on the surface of the frozen sand mold 21, water 23 is applied to the surface of the frozen sand mold by the spray 22, thereby forming a thin ice layer 24 on the surface of the frozen sand mold as shown in FIG.

According to the third embodiment, since the water applied at a low temperature freezes instantaneously, the contact between the external air and the sand mold surface is cut off, and the subsequent water evaporation from the sand mold surface can be prevented. Thereby, the sand mold surface shape can be stored for a long time.
Therefore, the problem that the amount of frozen sand mold produced decreases due to the inability to store for a long period of time does not arise, and the problem that a cast product with a rough surface having a low commercial value does not occur.

  According to the present invention, it can be stored for a long time in a state where the surface state of the sand mold is maintained, and the damaged portion can be repaired quickly without causing a prolonged curing time and a decrease in strength at low temperatures. A frozen sand mold repair method and surface protection method can be provided, so that a frozen sand mold that is not inferior in shape and strength is remanufactured as in the initial production, and there is a defect or defect in the cast product cast with this sand mold. It does not occur and cannot be stored for a period of time, so that there is no problem that the production volume of the frozen sand mold is reduced, and there is no problem that a casting product with a rough surface having a low commercial value is produced.

It is a perspective view of the frozen sand type | mold which concerns on 1st Example to which the repair method of the 1st frozen sand type | mold of this invention is applied. It is a perspective view of the frozen sand type | mold which concerns on 2nd Example to which the 2nd frozen sand type | mold repair method of this invention is applied. It is a perspective view of the frozen sand type | mold which concerns on 3rd Example to which the surface protection method of the frozen sand type | mold of this invention is applied. It is sectional drawing concerning the said 3rd Example.

Explanation of symbols

1,11,21 Frozen sand mold 1a Crack 1b, 11a Damaged part 1c Chipped part 2, 3 Water container 12 Frozen sand block 13 Sand containing water 22 Spray 23 Water 24 Ice layer

Claims (3)

  When the frozen sand mold made by the freezing casting method, in which a sand mold is formed by filling the molding sand mixed with a predetermined amount of water around the model built in the mold to create a sand mold, the sand mold is hardened by freezing. A method for repairing a frozen sand mold characterized in that water is applied to the damaged part of the shell and frozen rapidly.   When casting sand mixed with a predetermined amount of water is filled around the model built in the mold to create a sand mold, and when the frozen sand mold formed by the freezing casting method in which the sand mold is hardened by freezing, the frozen sand mold is repaired. If there is a large amount of damage such as missing part, prepare a frozen sand mold block in advance, and after repairing the frozen sand mold block to a size corresponding to the damaged part, repair the frozen sand mold block. A method for repairing a frozen sand mold, wherein the damaged portion is filled, and the gap between the frozen sand mold and the frozen sand mold block is filled with water-containing sand and water and frozen.   Casting sand mixed with a predetermined amount of water is filled around the model built in the mold to create a sand mold, and water is applied to the surface of the frozen sand mold formed by the freezing casting method in which the sand mold is hardened by freezing. A frozen sand type surface protection method characterized by forming an ice layer.

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