JP5162627B2 - Method for producing filter for molten metal and filter for molten metal - Google Patents

Description

  The present invention relates to a method for producing a filtering material for a molten metal such as a filter used for removing foreign matters contained in a molten metal obtained by melting a material such as a casting and purifying the molten metal, and a filtering material for a molten metal.

  For casting products that use metals such as aluminum, the molten metal (melted metal) such as aluminum is poured from the mold spout, passed through the runner, and poured into the product cavity. It is obtained by solidifying the molten metal in the cavity. However, if solid impurities such as metal oxides or shards of refractory contained in the molten metal are mixed into the mold as they are, pinholes and surface defects may occur in the process of manufacturing the cast product. In addition, if the molten metal entrains air during pouring, a “nest” is generated in the cast product. In order to prevent this, it is necessary to remove solid impurities from the molten metal and ensure a rectifying action. Therefore, conventionally, a metal melt filter material is used to remove the solid impurities by filtering the molten metal, Methods have been proposed to ensure rectification. As such a filtering material for molten metal, for example, as disclosed in Patent Document 1, a metal wire mesh, a SUS mesh, or the like has been used conventionally.

  However, when a metal wire mesh is used as a filter material for a metal melt that is easy to be alloyed with other metals such as aluminum, when the metal melt passes through the wire mesh, the iron content of the wire mesh melts into the metal melt, There was a problem that iron or the like was mixed in the cast product, which caused rust or deterioration in the cast product.

  Further, the filter medium is used for a sprue part, a runner part, etc., such as mold casting, and the molten metal solidified integrally with the cast product at these portions is cut out from the cast product after solidifying. It is desired that the melted solidified material that has been excised is remelted and reused. However, the solidified metal that has been cut off is attached in a state in which the metal mesh cannot be removed, and when it is remelted as it is, the iron content of the metal mesh melts and the iron content ratio increases, so the purity of the molten metal decreases. There was a problem. Furthermore, since the specific gravity of the wire mesh is heavy, it sinks to the bottom of the melting furnace or the crucible melting furnace, and it is difficult to scoop out from the molten metal at a high temperature. Under these circumstances, it has been difficult to redissolve and recycle the excised metal with filter material, and it has been forced to sell it as a recycled material at a scrap price, which has been a major factor in yield reduction.

  Furthermore, in a metal wire mesh or the like, the iron wire easily falls off from the end. The dropped iron wire is mixed with the molten metal in the mold, causing the cast product to have insufficient strength and causing rust, leading to a decrease in quality.

  In order to compensate for the drawbacks of such a wire mesh, a filter medium based on glass fibers impregnated with a phenol resin is used. However, the filter material of the glass fiber base emits smoke from the phenol resin at the time of use, and the casting is colored, and the phenol resin contains formaldehyde, so that a bad smell is generated due to generation of pyrolysis gas of the phenol resin. was there.

JP 2008-200833 A

  The present invention has been made in view of the above-described circumstances, and the object of the present invention is to prevent a metal such as iron from being melted into a molten metal in a cast product, and rust is generated or deteriorated in the cast product. In addition, the metal with filter media after use can be re-melted and reused as a molten metal, greatly contributing to product yield improvement, cost reduction, and energy saving. Another object of the present invention is to provide a method for producing a metal melt filter medium and a metal melt filter medium capable of suppressing the off-flavor associated with the generation of pyrolysis gas of phenol resin containing formaldehyde.

The object of the present invention comprises at least a resin impregnation step of impregnating a woven fabric made of heat-resistant fibers with a thermosetting resin, a thermoforming step, and a firing step, and each step is processed in this order , are achieved by providing a method for producing a molten metal for the filtering material, characterized that you molded three-dimensionally by the thermoforming process.

  Further, the object of the present invention is to produce a filter material for molten metal, characterized in that, in the thermoforming step, an end portion of the woven fabric made of the heat-resistant fibers is strongly compression-molded and the heat-resistant fibers are pressure-bonded to each other. This is achieved more effectively by providing a method.

  In addition, the object of the present invention is to provide a crevice treatment process between the resin impregnation process and the thermoforming process, and between the resin impregnation process and the baking process when the thermoforming process is not provided. This is achieved more effectively by providing a method for producing a filtering material for molten metal, characterized in that

  Moreover, the said objective of this invention is achieved more effectively by providing the manufacturing method of the filter material for molten metal characterized by the said heat-resistant fiber being glass fiber.

  Moreover, the said objective of this invention is achieved more effectively by providing the manufacturing method of the filter material for molten metal characterized by the said thermosetting resin being a phenol resin.

  Further, the above object of the present invention is characterized in that the thermoforming step is performed at 160 to 300 ° C. for 15 to 90 seconds, and the firing step is performed at 550 to 750 ° C. until the phenol resin is carbonized. This is achieved more effectively by providing a method for producing a melt filter material.

  The object of the present invention is to provide a method for producing a filter material for molten metal, wherein the phenol resin is impregnated by 15% or more with respect to the weight of the woven fabric composed of the heat-resistant fibers. Is achieved more effectively.

  Furthermore, the object of the present invention is more effectively provided by providing a method for producing a filtering material for molten metal, which comprises a step of impregnating and drying a coating agent after the firing step. Achieved.

  According to the method for producing a filter material for molten metal according to the present invention, the method comprises at least a resin impregnation step of impregnating a woven fabric made of heat-resistant fibers with a thermosetting resin, and a firing step. Therefore, the thermosetting resin can be carbonized, whereby the fibers can be hardened to produce a flat plate-shaped filter material for molten metal. Moreover, according to the manufacturing method of the filter material for molten metal which concerns on this invention, after making a thermosetting resin gelatinize by comprising a thermoforming process between a resin impregnation process and a baking process, carbonization is carried out. By doing so, the fiber can be solidified and the metal melt filter can be three-dimensionally molded. In this way, by carbonizing the thermosetting resin in the firing step, smoke generation can be suppressed when using the filter material for molten metal, and coloring of the casting can be prevented and generation of off-flavors can be prevented. . In other words, without using a metal mesh or the like having a metal component, a filter material for molten metal that has the same appropriate strength and elasticity as a metal mesh or the like, does not drop off fibers, and does not impair the quality of a cast product. Can be obtained.

  Moreover, the manufacturing method of the filter material for molten metal according to the present invention strongly compresses and molds the ends of the woven fabric made of heat-resistant fibers in the thermoforming process and presses the fibers together. Fibers fall off from the end and do not enter the mold.

  Moreover, the manufacturing method of the filter material for molten metal which concerns on this invention has a rectification | straightening effect higher by providing a crevice treatment process between a resin impregnation process and a thermoforming process, and lets a molten metal pass more smoothly. The filter material for metal melts which can be manufactured can be manufactured.

  Further, according to the filter material for molten metal according to the present invention, the heat-resistant fiber woven fabric is impregnated with the thermosetting resin, that is, the heat-resistant fiber containing no metal component is used as the base material. Iron is not mixed into the molten metal. Therefore, it is possible to prevent rust from occurring in the cast product and obtain a high-quality cast product.

It is a perspective view of the filter material for molten metal which concerns on this invention. It is a top view of the filter material for molten metal which concerns on this invention shown in FIG.

  Hereinafter, the manufacturing method of the filter material for molten metal and the filter material for molten metal according to the present invention will be described in detail with reference to the drawings. In addition, the manufacturing method of the molten metal filter material and the molten metal filter material according to the present invention are not limited to the following embodiments, and the configuration is appropriately changed within the scope of the claims. Needless to say, it can be done.

  The method for producing a filter material for molten metal according to the present invention (hereinafter referred to as “the present production method”) includes at least a resin impregnation step of impregnating a thermosetting resin into a woven fabric made of heat-resistant fibers, and a firing step. And each of these steps is processed in this order. That is, by heating and carbonizing the woven fabric that has undergone the resin impregnation step in a firing step, a flat plate-shaped filter material for molten metal using a heat-resistant fiber not containing a metal component as a base material can be produced. Even such a filtering material for molten metal has the same strength and elasticity as a filtering material using a conventional wire mesh or the like.

  Furthermore, in this manufacturing method, by providing a thermoforming step between the resin impregnation step and the firing step, that is, the woven fabric that has undergone the resin impregnation step is heated in the thermoforming step to gel the thermosetting resin. Three-dimensional molten metal based on heat-resistant fibers that do not contain a metal component by forming a filter material for molten metal and then heating it again in the firing step to carbonize the thermosetting resin Filter material can be molded. Even such a three-dimensional filter material for molten metal has the same strength and elasticity as a conventional filter material using a metal mesh or the like.

  As described above, the molten metal filter material manufactured by the present manufacturing method carbonizes the thermosetting resin impregnated in the woven fabric in the firing step, so that smoke generation during use of the molten metal filter material is suppressed. And coloration of the casting can be prevented. In addition to this, it is possible to prevent the generation of off-flavors associated with the generation of pyrolysis gas of the thermosetting resin.

  Here, the resin impregnation step is a step of impregnating a woven fabric made of heat-resistant fibers with a thermosetting resin.

  In addition, as the woven fabric made of heat-resistant fiber used in this production method, a woven fabric made of glass fiber, a woven fabric made of phenol resin fiber, a woven fabric made of silica fiber, or the like, which does not contain metal components. Is used. The filter material for molten metal produced by this production method can be used for molten metal such as copper, aluminum, zinc, etc. Among these, particularly in the case of molten aluminum, a woven fabric made of glass fiber is used. It is particularly preferred. As described above, the filter material for molten metal manufactured by the present manufacturing method is based on a woven fabric made of fibers that does not contain metal components such as iron like a conventional filter material made of wire mesh. When the filter material for molten metal is used (at the time of pouring), the metal component that generates rust in the cast product such as iron is not dissolved in the molten metal, which can greatly contribute to the quality improvement of the cast product.

  Moreover, as thermosetting resin, various well-known things, such as a phenol resin and an amino resin, can be used. When the filter material for molten metal manufactured by this manufacturing method is used as a filter material for molten aluminum, the molten aluminum has a high temperature of about 700 ° C. Therefore, a phenol resin that is easy to stabilize in shape as a filter material for molten metal manufactured by the present manufacturing method and has a property of withstanding high temperatures by carbonization is most preferable among various thermosetting resins.

  Here, when a phenol resin is used as the thermosetting resin, the impregnation amount of the thermosetting resin (impregnation amount of the phenol resin) is desirably 15% or more with respect to the weight of the woven fabric of the heat-resistant fiber, Preferably it is 15 to 40%, More preferably, it is 25 to 35%. If the amount of impregnation of the thermosetting resin is less than 15%, if there is a thermoforming process in the subsequent process, the thermosetting resin cannot be gelled and the heat resistant fiber cannot be hardened and molded in the thermoforming process. Even after the firing step, the strength as a filter material for molten metal is insufficient, making it difficult to use as a filter material for molten metal.

  The firing step is a step of producing a filter material for molten metal by carbonizing a thermosetting resin to solidify the heat-resistant fibers. In this way, by carbonizing the thermosetting resin, it is possible to generate smoke during use of the filter material for molten metal, generation of a strange odor due to generation of pyrolysis gas of the thermosetting resin, and coloring of the casting. Can be prevented.

  In addition, when this manufacturing method has a thermoforming process, a baking process is the process of heating again and carbonizing a thermosetting resin, after passing through the thermoforming process which gels and solidifies and molds a thermosetting resin. It becomes. If the thermosetting resin is kept gelled in the thermoforming process, the problem of odor and fuming generated at high temperatures, which is a drawback of thermosetting resin, can be solved when using the filter material for molten metal. Smoke and off-flavor are generated. However, like this manufacturing method, after passing through the thermoforming process, by heating again in the baking process to carbonize the thermosetting resin, it is possible to prevent the generation of off-flavors and smoke, and also prevent the casting from being colored. Can do.

  Here, in the baking step, when a phenol resin is used as a thermosetting resin at a temperature higher than the thermoforming step described later, baking is performed until the phenol resin is carbonized in an oxygen-free atmosphere at 550 to 750 ° C. In addition, when the heating in the baking process is insufficient, the thermosetting resin is not sufficiently carbonized, and smoke and off-flavor are generated when the obtained molten metal filter material is used.

  Next, the thermoforming process is the above-mentioned resin impregnation process, the heat-resistant fiber impregnated with the thermosetting resin is heated, the thermosetting resin is gelled, and the heat-resistant fiber is solidified to form a metal melt filter material. This is a three-dimensional molding process. In this way, the thermosetting resin can be gelled so that it can be molded into a filter medium, and at the same time, the intersection of the mesh of the woven fabric made of heat-resistant fibers (where the fibers intersect) can be bonded and sealed. it can. Thereby, it can prevent that a fiber falls out from the intersection of the mesh | network of the woven fabric of a heat resistant fiber. As a result, the fibers are not mixed into the mold together with the molten metal, so that the quality of the cast product is not impaired.

  Furthermore, it is preferable that the end of the woven fabric made of heat-resistant fibers is strongly compression-molded in this thermoforming process. As a result, it is possible to prevent the fibers from dropping off from the end of the filter for the molten metal, so that it is possible to more effectively prevent the fibers from being mixed into the mold, and the intersection of the woven fabric of the heat-resistant fibers described above. The quality of the cast product can be further improved by a synergistic effect with the effect of preventing the fibers from falling off.

  When a phenol resin is used as the thermosetting resin, the thermoforming process is performed at 160 to 300 ° C. for 15 to 90 seconds. When the heating temperature in the thermoforming process is less than 160 ° C., that is, about 100 ° C., it is difficult to completely gel the thermosetting resin even though it can be molded. It becomes difficult to ensure desired strength and elasticity. In addition, when the heating time is less than 15 seconds, particularly when the heating temperature is 160 ° C., it is difficult to completely gel the thermosetting resin even though it can be molded. It becomes difficult to secure desired strength and elasticity as a material. On the other hand, if the heating time is longer than necessary, for example, the heating time exceeds 90 seconds, work efficiency is reduced.

  Furthermore, it is more preferable that the manufacturing method is provided between the resin impregnation step and the thermoforming step, and in the case where the thermoforming step is not provided, an opening treatment step is provided between the resin impregnation step and the firing step. . In addition to removing foreign substances such as oxides contained in the molten metal and refractories in the furnace when the molten metal filter material is used, that is, when pouring, prevent the molten metal from entraining air. It also plays a role of ensuring a rectifying action that passes smoothly. For this reason, it is necessary for the filter material for molten metal to have an appropriate opening that can filter out foreign substances. However, the heat-resistant fiber woven fabric is impregnated with the thermosetting resin in the resin impregnation step, and the thermosetting resin is adhered to the mesh of the woven fabric and sent to the subsequent thermoforming step or firing step, heated and dried. If this is done, the mesh of the woven fabric may be blocked, and the rectifying effect described above may not be obtained. Therefore, it is preferable to provide an opening treatment step between the resin impregnation step and the thermoforming step in this way to drop the thermosetting resin adhering to the mesh of the woven fabric. In addition, as the opening treatment process, various methods capable of dropping the thermosetting resin, such as blowing air or vibrating, can be used.

  As mentioned above, although the manufacturing method of the filter material for molten metal which concerns on this invention was demonstrated about the case where it comprises at least a resin impregnation process and a baking process, this manufacturing method is the cutting process of a heat-resistant fiber, thermoforming in addition to this. It goes without saying that various processes such as a deburring process after the process, a thermoforming process, and an impregnation / drying process with a coating agent after the baking process may be included. In particular, if a coating agent impregnation and drying step is provided after the firing step, the generation of smoke and off-flavor can be further suppressed.

  Next, the filter material for molten metal (hereinafter referred to as “the present filter material”) according to the present invention will be described. FIG. 1 shows a perspective view of the filter medium 1, and FIG. 2 shows a top view of the filter medium 1. The filter medium 1 is formed as shown in FIGS. 1 and 2 by impregnating a woven fabric of heat-resistant fibers with a thermosetting resin, and is formed from a molten metal such as copper, aluminum, zinc, or the like in an oxide or furnace. In order to filter out foreign matters such as refractory refractories, it is used in a sprue part, runner part, etc., such as mold casting. Since the filter medium 1 is made of a heat-resistant fiber that does not contain a metal component as a base material, it is possible to produce a high-quality cast product without causing deterioration such as rust generation in the cast product. it can. That is, unlike a conventional filtering material such as a wire mesh, metal components such as iron of the wire mesh do not melt into the molten metal. Accordingly, there is no generation of rust or the like derived from this iron, and the cast product is not deteriorated, so that a high quality stable cast product can be manufactured. In addition, since the base material is formed by impregnating the thermosetting resin, the intersection of the fibers of the mesh of the base material (the portion where the fibers intersect) is sealed, and the fiber does not fall off from this portion. Therefore, the fibers are not mixed into the mold together with the molten metal, and the quality of the cast product is not impaired.

  Moreover, as shown in FIG.1 and FIG.2, as for the edge part 2 of the woven fabric of the heat resistant fiber used as a base material of this filter material 1, fibers are crimped | bonded. As a result, it is possible to prevent the fibers from falling off from the end portion 2 of the filter medium 1, and the synergistic effect of preventing the fibers from dropping from the intersection of the above-described base mesh fibers, the fibers are cast together with the molten metal. Can be more effectively prevented from being mixed into the casting, and the quality of the casting can be further improved.

  Moreover, the filter medium 1 is made of a heat-resistant fiber woven fabric that does not contain a metal component, so that the metal with the filter medium can be dissolved again and used as a molten metal. That is, when a conventional metal with a filter material including a metal component such as a wire mesh is redissolved, the metal such as the wire mesh sinks into the molten metal due to its high specific gravity, and it is difficult to scoop off the metal such as the wire mesh that is a foreign object. . However, since the filter medium 1 is made of fibers having a low specific gravity, when the metal with the filter medium is remelted, the fibers float on the surface of the molten metal. Therefore, since the fibers can be easily removed from the molten metal, the used metal with a filter medium can be remelted and reused as a molten metal without being sold as a recycled material at a scrap price. .

  As the heat-resistant fiber woven fabric used in the filter medium 1, various woven fabrics that do not contain metal components, such as glass fiber woven fabric, silica fiber woven fabric, and phenol resin woven fabric, are used. be able to. Among these, glass fiber woven fabric is preferable because it is inexpensive.

  Moreover, it is preferable that the woven fabric of the heat-resistant fiber used for this filter material 1 is 6-19 in the mesh | network opening number between 25 mm. The mesh of the woven fabric is appropriately selected according to the structure of the melting furnace or the crucible melting furnace, the type of refractory, the filtration method, the viscosity of the molten metal, and the like. That is, in the case of a furnace in which foreign matters such as refractory bricks are likely to be mixed, in the case of a filtration method in which the molten metal passes through the filter medium quickly, or when the viscosity of the molten metal is high, a material having a large mesh, that is, a coarse mesh is used. Etc., as appropriate. If the mesh is too fine, the molten metal adheres to the filter medium as the molten metal is filtered, resulting in clogging, and the filtration rate is gradually reduced, making it impractical. On the other hand, if the mesh is too rough, the filtration rate of the molten metal is improved, but foreign substances such as oxides and refractory refractories in the furnace cannot be sufficiently separated.

  In addition, the weaving method of the heat-resistant fiber woven fabric is not particularly limited, and various types such as a plain weave, a leno weave, and a leopard weave can be used.

As mentioned above, as shown in FIG.1 and FIG.2, the case where the filter material for this molten metal was shape | molded three-dimensionally through the resin impregnation process, the thermoforming process, and the baking process was demonstrated. However, although not shown in the drawings, the metal melt filtering material may be formed into a flat plate shape through a resin impregnation step and a firing step.

1 Filtration material for molten metal 2 Edge of woven fabric of heat-resistant fiber

Claims (8)

It comprises at least a resin impregnation step of impregnating a woven fabric made of heat-resistant fibers with a thermosetting resin, a thermoforming step, and a firing step, and each step is processed in this order, and is three-dimensional by the thermoforming step. molding to the production method of the molten metal for the filtering material, characterized in Rukoto to. The method for producing a filtering material for molten metal according to claim 1 , wherein in the thermoforming step, an end portion of the woven fabric made of the heat-resistant fibers is strongly compression-molded, and the heat-resistant fibers are pressure-bonded to each other. The method for producing a filter material for molten metal according to claim 1 or 2 , further comprising an opening process step between the resin impregnation step and the thermoforming step. The said heat-resistant fiber is a glass fiber, The manufacturing method of the filter material for molten metal in any one of Claim 1 thru | or 3 characterized by the above-mentioned. The said thermosetting resin is a phenol resin, The manufacturing method of the filter material for molten metal in any one of Claim 1 thru | or 4 characterized by the above-mentioned. The molten metal filtration according to claim 5 , wherein the thermoforming step is performed at 160 to 300 ° C. for 15 to 90 seconds, and the baking step is performed at 550 to 750 ° C. until the phenol resin is carbonized. A method of manufacturing the material. The said phenol resin is impregnated 15% or more with respect to the weight of the woven fabric which consists of the said heat resistant fiber, The manufacturing method of the filter material for molten metal of Claim 5 or Claim 6 characterized by the above-mentioned. The method for producing a filtering material for molten metal according to any one of claims 1 to 7 , further comprising an impregnation and drying step of a coating agent after the firing step.

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