WO2001098005A1

WO2001098005A1 - Filter wire net for aluminum or aluminum type alloy castings

Info

Publication number: WO2001098005A1
Application number: PCT/JP2001/000392
Authority: WO
Inventors: Hiroshi Hashizume; Yasuo Iwaki; Yoshio Okamoto
Original assignee: Yamato Wire Netting Co., Ltd.
Priority date: 2000-06-20
Filing date: 2001-01-22
Publication date: 2001-12-27

Abstract

A filter wire net which, when Al (aluminum) or Al type alloy castings are to be made, is disposed on the sprue or gate of a mold to remove impurities in the molten metal, wherein the shape of the wire net is retained from the start of pouring of molten metal in a casting operation till completion of solidification, and when the sprue piece containing the filter wire net is cut off after the casting operation and the Al or Al type alloy left in the sprue piece is heated and melted, for reuse, in a furnace, the filter wire net can also be melted and mixed in the molten metal of Al or Al type alloy. This saves the labor and time for removal of the filter wire net, making it possible to achieve drastic cost reduction and improvement in operational efficiency. Further, since the filter wire net itself can be reused as a component of the Al type alloy, it contributes largely to resource saving and eradication of industrial waste.

Description

Description Filters for aluminum or aluminum alloys

The present invention relates to a filter wire mesh for AI or AI-based alloy material, which is used for removing AI or various inclusions in a molten metal when producing AI (aluminum) or AI-based alloy material. Background art

AI or AI alloys are excellent in light weight, and AI alloys are also good in strength, making them the main materials for transportation machinery parts. In order to improve product quality, it is necessary to prevent the inclusion of inclusions and to suppress blowholes, shrinkage, and occurrence of hot water wrinkles.

In particular, if the structure is formed without removing inclusions made of other non-metallic particles such as metal particles, intermetallic compounds, metal oxides, or brick debris, the inclusions will accompany the particles, and This may cause internal defects in the object or surface defects. In particular, in the case of an AI alloy material having higher strength and higher susceptibility to cracking than pure AI, it is necessary to reduce as much as possible the internal defects that are the starting points for the occurrence of internal cracks. Therefore, it is necessary to prevent the inclusion of these inclusions regardless of the size of the parts or the complexity of the shape.

Conventionally, as a means for preventing the mixing of these impurities into the molten metal, a woven wire mesh (hereinafter referred to as “iron filter wire mesh”) using a wire material such as mild steel has been provided at a gate or a weir, and the iron filter wire mesh has been used. There is known a technology that traps inclusions and prevents the inclusions from flowing into the product side.

Here, in the actual production work, a large amount of AI-based alloy remaining on the gate In order to use it, the sprue piece containing the iron filter wire mesh is cut off after fabrication and refined in a melting furnace. Considering this situation, the disadvantage of the prior art is that the molten metal re-melted in the melting furnace contains an iron filter wire mesh and impurities, and a great deal of time and effort are required to separate and remove these. . On the other hand, the iron filter wire mesh left at the bottom of the melting furnace, which cannot be separated and removed, reacts with the AI component by heating at a high temperature to produce a hard and brittle F e— AI intermetallic compound, and the F e— It was also pointed out that AI intermetallic compounds had an adverse effect on the product quality of recycled products. Another problem was that once used iron filter wire mesh could not be reused and had to be discarded.

The present invention has been made in order to solve such a problem, and when producing AI or AI-based alloy material, melting is performed in a filter wire mesh which is disposed in a mold gate or cough to remove impurities in the molten metal. An object of the present invention is to provide a filter wire mesh for AI or AI-based alloy material, which can omit the separation and removal work in the furnace. Disclosure of the invention

The present inventors have conducted intensive studies to solve the above-mentioned problems.As a result, the wire mesh shape was maintained during the construction work and the filter functioned as one.When the wire mesh was heated and melted in the melting furnace, the filter wire mesh also became AI or We have found that the use of a filter wire mesh that can be dissolved and mixed into the molten AI alloy makes it possible to completely omit the separation and disposal work in the melting furnace described above.

Atmospheric pressure is achieved by forming an appropriate surface treatment film on Cu (copper) or Cu alloy, which is easy to process into wire mesh and does not degrade the quality of the AI alloy even if it elutes into the molten metal. In both the normal normal pressure forming and the low pressure forming for the purpose of improving the yield, elution of the 1 or 0 alloy into the molten metal is suppressed during the forming time. When reheated in AI alloy melt melting furnace after granulation time, the surface treatment film is eroded by prolonged immersion in C _U or C _U alloy base coercive It was found that the function as a protective coating was lost, and as a result, the filter wire mesh dissolved and mixed into the AI or AI-based alloy melt.

In particular, a Ni (nickel) or Ni alloy coating, a carbon-based coating, or an oxide coating is effective as the surface treatment coating, and the thickness of each coating suitable for suppressing wire mesh dissolution during the manufacturing time The range and formation conditions can also be found, and among them, it has been found that pretreatment, particularly shot blasting, is effective in improving the characteristics of the oxide film, and the present invention has been accomplished.

In the normal-pressure production, the production time is the time from the start of molten metal injection to the completion of solidification, and in the low-pressure production, it is the time from the start of molten metal injection to the completion of pressurization and holding.

Specifically, in the production of AI or AI-based alloy products, a filter mesh placed in a mold gate and cough to remove impurities in the molten metal solidifies from the start of molten metal injection in the production operation. Until completion, the shape of the wire mesh is retained, and after the assembling work, when the sprue piece containing the filter wire mesh is cut off and heated and melted in a melting furnace to reuse the AI or AI-based alloy remaining in the sprue piece, The filter wire mesh is also mixed and dissolved in the molten AI or AI alloy. As a result, the labor and time required for removing the filter wire mesh can be omitted, and a significant cost reduction and improvement in work efficiency can be achieved. Furthermore, the filter wire mesh itself can be reused as a component of the AI alloy, greatly contributing to resource saving and the eradication of industrial waste.

Alternatively, when manufacturing AI or AI-based alloy products, pressurize from the start of molten metal injection in low-pressure manufacturing work with a filter mesh placed in a metal gate or cough to remove impurities in the molten metal. The wire mesh shape is retained until the holding is completed.When the gate piece including the filter wire mesh is cut off after the assembling work, and the AI or AI-based alloy remaining in the gate piece is heated and melted in a melting furnace to reuse it, Made the filter wire mesh dissolved and mixed in the molten AI or AI alloy. As a result, not only can the production yield be improved by applying a low-pressure structure, but also the The labor and time required for removing the lubricating wire mesh can be omitted, greatly reducing costs and improving work efficiency.Furthermore, since the filter wire mesh itself can be reused as a component of the AI alloy, saving It can greatly contribute to the eradication of resources and industrial waste.

In addition, Cu or a Cu alloy was covered with a surface-treated film to constitute the above-described filter net. This makes it possible to obtain a filter wire netting that can be melted and melted into the molten metal during reheating in a melting furnace by a simple process that does not melt during the manufacturing operation.

Further, the surface treatment film was a Ni or Ni alloy film, a carbon-based film, or an oxide film. This makes it possible to limit the dissolution of the filter wire net to only within the manufacturing time with a simple process.

Further, the film thickness of the N 合金 or Ni alloy film was set at 20 / im to 60〃m, or the film thickness of the carbon-based film was set at 5 m to 20 m. This makes it possible to suppress the dissolution of the filter wire net even in a long-time manufacturing operation.

Further, the oxide film is formed by heating the alloy No. 1 or No. 1_1 at 150 ° C. to 500 ° C. in the air for 20 minutes to 720 minutes. Also according to this, it is possible to suppress the dissolution of the filter wire mesh even in a long-time manufacturing operation.

In addition, shot blast was applied as a pretreatment of the oxide film. As a result, the adhesion of the oxide film is improved, the peeling of the oxide film during packing, transport, use, etc. of the filter wire mesh after the film formation can be prevented, and the dissolution resistance of the oxide film is also improved. However, even if the manufacturing time exceeds the general manufacturing time due to an operation error or the like, it is possible to reliably prevent the filter mesh from melting. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows the effect of the substrate and surface treatment on the solubility of the filter mesh.

Figure 2 shows the effect of the pretreatment on the adhesion of the oxide film in a table. Figure 3 shows the effect of the pretreatment on the dissolution resistance of the oxide film in a table. BEST MODE FOR CARRYING OUT THE INVENTION

As a constituent material of the filter wire mesh according to the present invention, a wire made of Cu or a Cu alloy is used. This is because Cu is an alloy element that is generally contained in the largest amount in AI alloy materials, and does not significantly degrade the product quality even when dissolved in the molten AI alloy. This is a force that is easy to use and is suitable as a constituent material of a wire mesh.

The alloy elements in the Cu alloy include Ni, Sί (gay element), etc., but the material strength and elution resistance are improved to suppress the melting of the wire mesh to some extent. The chemical component may be any chemical component that does not disturb the predetermined quality of the product even if it is eluted into the product.

As the surface treatment film according to the present invention, an Nί or Nί alloy film, a carbon-based film, or an oxide film is preferable.

Among them, the Ni or Ni alloy film has excellent elution resistance, and can sufficiently prevent the dissolution of Cu or Cu alloy during the injection of molten metal. The thickness of the Ni or Ni alloy film is not particularly limited, but is preferably from 20 to 60 jm. When the film thickness is less than 20 m, the elution resistance is insufficient, and the wire mesh shape is quickly broken and the filter function cannot be sufficiently exhibited. When the film thickness exceeds 60 j «m, the adhesion to the Cu substrate is insufficient. It is easy to peel off due to a decrease in cost, and it is also expensive.

The method for coating the Ni or Ni alloy film is not particularly limited as long as it is a method of forming a uniform film such as electroplating and electroless plating. The alloying elements of the Ni alloy include Co (cobalt) and Si. However, as in the case of the Cu alloy, the strength and elution resistance of the Ni alloy film are improved to improve the wire mesh. Suppresses melting appropriately, or even if eluted into molten AI or AI alloy, specified product Any chemical component that does not inhibit the quality may be used, and is not particularly limited.

Carbon-based coatings have poor wettability of molten metal, in other words, excellent repellency of molten metal, so that AI or AI alloy molten metal is prevented from getting wet on Cu or Cu alloy surface, and wire mesh is dissolved in molten metal Can be effectively prevented. The thickness of the carbon-based film is not particularly limited, but is preferably 5 m or more and 20 m or less. If the film thickness is less than 5 μm, the repelling property is insufficient, and if it exceeds 2 O jum, the adhesion of the film is poor, and the molten metal flowing during pouring tends to fall off.

As a method of coating a carbon-based film, there are a method of simply immersing in an aqueous solution in which carbon powder is dispersed, pulling up and drying, and a method of mechanically pressing the carbon powder. The method is not particularly limited as long as it is a method capable of forming a film and obtaining a film having such adhesion that the film does not fall off during the fabrication operation.

Carbon-based coatings include C—Sί, C—Ti (titanium), and C-organic substances, but they have excellent repellency. They protect the wire mesh during fabrication and must be re-melted in a melting furnace. What is necessary is just one having resistance to dissolution that is sufficient to dissolve when heated.

The oxide film, like the carbon-based film, has an effect of preventing the Al or AI alloy molten metal from getting wet on the Cu or Cu alloy surface because the molten metal has excellent repellency.

Thus, the present inventors have studied in detail the temperature range and the heating range suitable for forming an oxide film. As a result, from the viewpoint of forming an oxide film having good quality and a sufficient film thickness in a short time, 3 It has been found that high-temperature / short-time heating at 200 ° C. to 500 ° C. for 20 minutes to 90 minutes is preferable.

In addition, a detailed investigation was conducted on the handling and structural strength of the filter wire mesh in assembling into the mold in the actual construction work, and under the conditions of high temperature and short-time heating, Cu or Cu alloy was Since it is annealed and softened by high temperature, it can be used for large-sized parts that filter a large amount of molten metal in a short time with a large-diameter filter wire mesh. It was clarified that the structural strength of the filter was insufficient, and the filter mesh could be deformed at the time of installation or at the start of injection. And to prevent this softening,

Low-temperature heating of 150 ° C to 300 ° C is effective, and long-term heating of 90 minutes to 720 minutes is necessary to obtain a sufficient film thickness even with the low-temperature heating. There was found.

From the above examination results, it can be said that it is preferable that the heating temperature in the air is 150 ° C. or more and 500 ° C. or less, and the heating time is 20 minutes or more and 720 minutes or less. However, as described above, the appropriate heating temperature and heating time need to be determined according to various conditions such as the manufacturing conditions, the size of the filter mesh, and the installation position.

If the heating temperature is lower than 150 ° C, the oxidation of Cu is insufficient, so the growth of the oxide film is small no matter how long the heating is performed, and if it exceeds 500 ° C, the oxide film formed Becomes porous, and the elution resistance deteriorates. In addition, if the heating time is less than 20 minutes, the thickness of the oxide film is not sufficient and the surface of the wire mesh cannot be uniformly coated, and if the heating time exceeds 720 minutes, it takes too much time to form the oxide film. The efficiency becomes extremely poor.

In forming such Ni or Ni alloy film, carbon-based film, oxide film, etc. on the surface, degreasing, chemical etching, shot blasting, etc. are performed as pre-treatment, and furthermore, the adhesion of the film etc. Various characteristics can be improved.

In particular, it was found that various properties were significantly improved when shot blasting was performed before forming the oxide film.

Hereinafter, examples of the present invention will be described.

First, the effects of the substrate and surface treatment on the solubility of the filter wire mesh are described.

First, the method of manufacturing the filter wire mesh sample used in this experiment will be described. A 0.5 mm diameter Cu element wire is alternately knitted to form a wire mesh with a 14 mesh of 1.0 mm thick, and this wire mesh is cut into a width of 10 mm to form a coil. u Make wire mesh. The Cu wire mesh cut into a length of 5 Omm with a slitter is used as a Cu wire mesh sample.

Then, the Cu wire netting was plated in an electroless Nί plating bath and then cut to a length of 5 Omm to obtain a Ni-coated wire netting sample. Further, the Cu wire mesh is immersed in an aqueous solution in which carbon powder is dispersed, pulled up, dried, and cut into a length of 5 Omm to obtain a carbon-coated wire mesh sample. Further, the Cu wire mesh is heated in a heat treatment furnace, pulled out of the furnace, cooled, and then cut to a length of 50 mm to obtain an oxide film-coated wire mesh sample for investigating the influence of the surface treatment.

As a comparative material, a conventional iron filter mesh was also used as an Fe mesh sample in the experiment.

Next, the experimental method will be described.

In a bath in which the molten AI alloy was maintained at a constant operating temperature of 650 ° C, a plurality of the above wire mesh samples of 50 mm x 100 mm in size were immersed. The presence or absence of dissolution was investigated. Regarding the presence or absence of this dissolution, the weight of the wire mesh sample after removing the attached AI alloy with acid is compared with the weight of the wire mesh sample before immersion, and the difference in weight, that is, the weight reduction, is the wire mesh sample before immersion. Was determined to be dissolved when the weight was 5% or more of the weight.

In addition, the results when various wire mesh samples were used for actual fabrication work and reheated together with the sprue pieces in the melting furnace are also shown.

The AI alloy used in this experiment was equivalent to JIS AC2B (Cu:

2-4%, Si: 5-7%, Mg: 0.5% or less, Ni: 0.35% or less, Zn: 1% or less, Fe: 1% or less, balance AI) used.

Figure 1 shows the survey results. As can be seen from the diagram, the conventional Fe wire mesh sample can exhibit the filter function without dissolving during the manufacturing operation, but does not dissolve as it is in the melting furnace.

On the other hand, the Cu wire mesh sample without surface treatment has a typical fabrication time (100 Seconds to 300 seconds) Before immersion, it is already dissolved and loses its filter function. However, by forming a surface treatment film according to the present invention, particularly a Ni film, a carbon-based film, and an oxide film on the surface, It can be seen that the wire mesh shape is maintained during the sintering time, and is mixed into the melt during remelting in the melting furnace.

In other words, under the film thickness / heating conditions of the present invention, the wire mesh shape can be maintained and a sufficient filter function can be exhibited even in the fabrication process on the long-time side (250 seconds to 300 seconds). I understand.

The immersion test was performed under low pressure, but similar results were obtained under normal pressure.

Second, the effect of pretreatment on the adhesion and dissolution resistance of the oxide film is described.

As pretreatment methods in this experiment, we investigated four types: no pretreatment, degreasing, chemical etching, and shot blasting.

Among them, “no pretreatment” means that 0.5 mm diameter Cu strands are alternately knitted to form a wire mesh of 14 Om with a thickness of 1.0 mm. It is in a state where it is cut into mm and remains as a coiled Cu wire net.

“Defatting” is a process of rocking the Cu wire net in methanol for 2 minutes. “Chemical etching” is a treatment in which a Cu wire mesh is immersed in a 10% hydrochloric acid / 100/0 ferric oxide aqueous solution (bath temperature: 50 ° C.) for 5 minutes.

“Shot blast j is a process of spraying alumina particles through a Cu wire net with an air pressure of 0.4 MPa.

The Cu wire mesh without any pretreatment as described above and the Cu wire mesh subjected to the various pretreatments described above were heated in a heat treatment furnace at a heating temperature of 400 ° C. and a heating time of 50 minutes. After cooling it out, cut it to a length of 5 O mm and use it as an oxide-coated wire mesh sample for investigating the effects of pretreatment. The oxide films shown in the table of FIG. 1 were all formed without “pretreatment”. Next, the experimental method will be described.

The adhesion of the oxide film can be measured using the sample of the wire mesh coated with the oxide film

5 O mm x 10 O mm) was bent at a constant bending angle (inner angle) with a bending radius of 2 mm at the approximate center in the longitudinal direction of the oxide film-coated wire mesh sample, and the bent inner oxide film was peeled off. The presence or absence was visually evaluated, and peeling was judged to have occurred when peeling occurred.

Regarding the dissolution resistance of the oxide film, as described above, a sample of an oxide film-coated wire mesh of size 5 Omm X 10 Omm was placed in a bath with the molten AI alloy kept at a constant operating temperature of 65 ° C. Were immersed, and pulled up one by one at regular intervals, to examine whether or not the oxide-coated wire mesh sample was dissolved in the molten metal.

The presence or absence of this dissolution is determined by comparing the weight of the oxide-coated wire mesh sample after removing the adhering AI alloy with acid to the weight of the wire mesh sample before immersion. The case where the weight was 5% or more of the sample weight was regarded as dissolution.

In addition, in order to clarify the effect of the pretreatment, the solubility in the immersion time of 300 seconds to 600 seconds, which shifts from non-dissolution to dissolution, was investigated in detail.

Next, the survey results are shown in tables in Figs. 2 and 3, respectively.

The results of the adhesion of the oxide film are shown in the table of Fig. 2. "Without pretreatment j, when the bending angle reached 90 degrees, the oxide film was peeled off inside the oxide-coated wire mesh sample. On the other hand, in the case of the metal mesh sample coated with the oxide film, which had been subjected to “degreasing j” “chemical etching” and “shot blasting” before the oxide film formation, no peeling of the oxide film was observed at the same bending angle of 90 °.

In particular, when the shot blast j was applied, the oxide film did not peel even at a bending angle of 45 degrees, and peeling occurred for the first time at a bending angle of 30 degrees, which significantly improved the adhesion of the oxide film. You can see that.

The results of the dissolution resistance of the oxide film are shown in the table of Fig. 3 General manufacturing time (100 seconds to 300 seconds) During immersion, the wire mesh shape of the oxide film-coated wire mesh sample is maintained and a sufficient filter function can be achieved. Dissolved in 50 seconds, whereas an oxide-coated wire mesh sample that had been degreased, chemically etched, and shot-blasted before the oxide film was formed, dissolved in the same fabrication time of 350 seconds Is not recognized.

In particular, "When the shot blast j is applied, the shape of the oxide film-coated wire mesh sample is maintained even with the immersion time of 450 seconds, and the dissolution resistance of the oxide film is remarkably improved. Industrial applicability

INDUSTRIAL APPLICABILITY As described above, the filter metal mesh for animals according to the present invention is useful as a metal wire mesh used for removing oxidized AI and various inclusions in molten metal when producing AI or AI-based alloy articles. It is.

Claims

The scope of the claims

1. When manufacturing aluminum or aluminum-based alloy products, a filter mesh that is placed in a mold gate and removes impurities in the molten metal has a metal mesh shape from the start of molten metal injection to solidification completion in the fabrication operation. When the sluice piece containing the filter wire mesh is cut off after the assembling work and the aluminum or aluminum alloy remaining on the sluice piece is reused by heating and melting in a melting furnace, the filter wire mesh is also made of aluminum. A filter wire mesh for aluminum or aluminum-based alloys, which is dissolved and mixed in a molten aluminum-based alloy.

2. In the case of aluminum or aluminum-based alloy products, the filter wire mesh that is placed in the mold gate and removes impurities in the molten metal is completely pressurized and maintained from the start of molten metal injection in low-pressure production. The wire mesh shape is retained until after. 錶 After the fabrication operation, the sprue piece including the filter wire mesh is cut off and heated and melted in a melting furnace to reuse the remaining aluminum or aluminum alloy in the sprue piece. In this case, the filter wire mesh is also dissolved and mixed in the molten aluminum or aluminum-based alloy.

3. The aluminum or aluminum alloy according to claim 1 or 2, wherein the filter wire mesh is made of copper or a copper alloy, and is coated with a surface treatment film. Filter for wire mesh.

4. The filter wire mesh according to claim 3, wherein the surface treatment film is a Nigel or nickel alloy film, a carbon-based film, or an oxide film.

5. The aluminum or aluminum-based alloy according to claim 4, wherein the surface treatment film is the nickel or nickel alloy film, and the film thickness is 20 m to 60 m. Filter wire mesh for goods.

6. The filter according to claim 4, wherein the surface-treated film is the carbon-based film, and the film thickness is 5 im to 20 m. Wire mesh.

7. The surface treatment film is the oxide film, and the oxide film is formed by heating copper or copper alloy at 150 to 500 ° C for 20 to 720 minutes in the air. 5. The filter or metal mesh for aluminum or aluminum-based alloy material according to claim 4, wherein:

8. The filter wire mesh for aluminum or aluminum-based alloy according to claim 4, wherein shot blasting is applied as a pre-treatment of the oxide film.