JPH01180771A - Iron casting formed different kind of metal film and production thereof - Google Patents

Abstract

PURPOSE:To produce an iron casting having excellent durability, outview and touch feel at simple process by forming an alloy of iron and the different kind of metal on the surface of the iron casting at the step of pouring the molten iron into a mold. CONSTITUTION:At first, in a first preparing process, surface roughening agent is coated on recessed part 5 and flat face part 6 in a cope B and drag B', respectively by mixing molding sand with suitable quantity of thermosetting resin to form the surface roughening agent layer 7. The prescribed copper alloy is thermal-sprayed at low temp. on the layer 7 surface to form the thermal sprayed metal film 8. The cope and drag are assembled after completing the preparing process and the molten iron is poured into the mold from a sprue 10. When the poured molten iron is brought into contact with the thermal sprayed metal film 8, the film is melted and made to alloy. By this method, the iron casting having alloyed copper series metal film 2 on the surface is obtd.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a special cast product in which the surface of an iron casting is alloyed with a dissimilar metal, and a method for manufacturing the same. Then, this is injected into a mold to make a casting, but when the injection is finished, the surface of the casting is coated with dissimilar metals, such as nonferrous metals such as copper alloys and nickel, or iron alloys such as stainless steel and iron alloys. The present invention relates to obtaining an iron casting whose surface layer is covered with a thin alloy film, and to a method for producing the same.

Specifically, the desired non-ferrous metal is sprayed on the inner surface of the mold by so-called low-temperature spraying to form a sprayed metal film, and then molten iron is poured into this. The temperature of the thus injected iron is 1400°C to 1450°C.
Because of the high temperature, this molten iron and the sprayed metal coating come into contact and form an alloy. Therefore, when the iron is formed, its surface is completely coated with the alloy.

This method is very simple and highly effective.

The present invention breaks away from the current situation in which iron products are inexpensive, but their uses are severely restricted due to the fact that they produce mold, and instead of cast iron products such as copper and stainless steel, they are used in fields such as interior design, efsteria, etc. It was developed with the aim of obtaining a new iron casting that could be widely used in the field of building materials and parts, and it was successful.

Since ancient times, iron products and copper products have been widely used as utensils necessary for human life, but copper-based metals have a beautiful appearance and do not emit mackerel, so they have been widely used in everyday furniture and utensils for eating and drinking. In contrast, iron products are widely used in the fields of art and ornaments, but iron products need to be processed to prevent rust, and if they are not rust-prevented, their uses will be limited, and the price will be high. There is a desire to use it more because it is cheap, but this point has been an obstacle. If this drawback could be resolved through some kind of processing method, it would be considered a great contribution to society, and the emergence of new processing and processing methods was eagerly awaited. In the past, methods such as applying paint or plating were known, but as is well known, the durability, color tone, and feel of the paint itself affect the value of the entire product. , there is no paint that fully satisfies these factors, and if it is used outdoors,
It is a common experience that it takes a lot of effort to repaint every year, and even for indoor items, if the paint peels off for some reason, it can cause problems. Metsuki is expensive, so its use is limited. On the other hand,
Bronze, nickel, and aluminum castings have been used in a wide range of fields because they do not have the above-mentioned drawbacks.

[Conventional technology]

Metals generally undergo some kind of change when combined with oxygen and moisture in the air, but while non-ferrous metals generally have oxides that have the effect of stopping subsequent corrosion, iron is subject to severe corrosion, so iron products are There have been attempts to advance into the field of application of non-ferrous metal products by applying some kind of surface treatment to the surface. (black dyeing method), surface coating with organic substances, that is, painting, various synthetic resins such as vinyl chloride, vinylidene chloride,
This method uses paints made of polyethylene, polystyrene, epoxy resins, fluororesins, etc., and paints mixed with pigments. However, in order to perform these surface coating treatments, it is necessary to polish the surface of the object to be treated as a pretreatment process, which is a very labor-intensive process, whether it is mechanical or scientific. It is.

[Problem that the invention seeks to solve]

Since the surface of iron castings and iron products is prone to rust, there are many known methods of coating the surface with metals, inorganic substances, or organic substances to form an anticast film or coating layer, but all of them have drawbacks. 0 For example, when creating a metal film such as the plating method, it is inevitable that the equipment will be severely damaged and will be expensive. However, there has been a need for a simpler, more durable means for surface coating with metal that has a more beautiful appearance.

Means for solving problem C].

The present invention was completed as a result of many years of testing and research in order to solve the above-mentioned problems. First, to explain the basics of the technical idea, Fig. 1 is an explanatory diagram of the product according to the present invention. The iron casting 1 has a coating layer 2 on its surface made of an alloy of different metals, for example, bronze and iron, and is no different from a bronze product in terms of its appearance, texture, By explaining the manufacturing method of Oji, which can be evaluated as having the same feel as bronze,
The manufacturing method will be explained below so that you can understand the characteristics of the product itself. Regarding sand casting, which is commonly carried out, a roughening agent is applied to the concave surface 5 of the sand mold and the overlapping flat part 6 of the upper and lower molds as a preparatory step to an upper mold made by a conventional method using casting sand. , a roughened layer 7 is formed. A roughening agent is used when performing so-called low-temperature metal spraying.
This is to ensure the adhesion of sprayed metal, and its outline is to mix fine ceramic particles into a suitable resin.
It can be used in any form such as a water-soluble system, a solvent system, or a water or solvent dispersion system, and detailed examples will be described later. Form a roughened layer. The thickness of the surface roughening agent layer is generally sufficient to form a film of Ion to 30p. Next, as a second preparatory step, a desired metal, for example bronze, is low temperature sprayed onto the roughening agent coating 7. The amount of metal sprayed is normally sufficient to form a sprayed metal coating 8 with a thickness of about 0.05W to 0.5N.The upper and lower sand molds B and B' on which the metal sprayed coatings have been formed are stacked as shown in Figure 3. Molten iron water is poured into the sand mold recess space 9 through a sprue 10. The temperature of the hot water in this case is 1400°C to 1450°C. When the hot iron is poured into the sand mold, the sprayed bronze comes into contact with the hot iron, melting the bronze and forming an alloy of iron and bronze. This alloy eventually forms over the entire surface of the casting. However, only the sprue part was removed later, and since the alloy was missing there, the cast iron was later welded with a bronze welding rod so that there was no exposed part of the cast iron. As is generally known, the above-mentioned bronze thermal spray coating is formed by spraying bronze melted by an arc with high-speed air.
! Since they become fine particles of 5 to 150 u and fly at high speed, some of them may form an oxide film or a nitride film on their surfaces, which may inhibit alloying. Therefore, a reducing agent, such as sodium sulfite, is applied to the surface of the metal spray coating in advance.
Preferable results can be obtained by allowing carbon or the like to exist. Note that borax or the like may be used as a shoulder to promote melting of the metal sprayed coating, and thus an iron casting whose surface is coated with an alloy coating of iron and bronze can be obtained.

The cast product thus obtained, that is, the surface coated with an alloy of iron and bronze, does not simply coat iron with a thin film of bronze, so the potential difference between the two metals that normally occurs between the two metals is eliminated. No electric current is generated and no electrolytic corrosion phenomenon occurs, so its application can be widely used in the field of bronze products, which are surface metals.

As for the casting sand used in the present invention, conventionally used ones can be widely used.For example, sand mixed with phenol-urethane resin used as a self-hardening binder, or 1.2% to 1.8% After coating the surface of the sand mold with phenolic resin, the sand mold was
These are those that are thermally cured by heating at about ℃.

Regarding the surface roughening agent, the ceramic particles contained in the resin have a particle size of 201 Is to 150 p-,
Most materials commonly referred to as ceramics can be used for the particles, such as metals or alloys such as aluminum, zinc, and silicon, or oxides, nitrides, and carbides.
Specifically, there are aluminum oxide, silicon oxide, iron oxide, etc. In addition, particles of resin can also be used in relation to the solvent; for example, acrylic resin, styrene resin, epoxy resin, etc.

These particles can be used not only alone, but also as a mixture of two or more. Among these, silica sand, f-lumina, silicon carbide, etc. are particularly preferred from the viewpoint of chemical stability, hardness, and resistance to precipitation. The amount of particles mixed into the resin used may be determined depending on the situation within the range of 30 to 300% by volume. These requirements regarding the particles were selected from the viewpoint of improving the size of the sprayed metal particles and their adhesion.

Next, regarding the resin used as the surface roughening agent, there are no particular limitations as long as it has a certain level of drying properties, hardness, adhesion, water resistance, and durability. Plastic acrylic resins, vinyl resins, chlorinated rubber, alkyd resins, unsaturated polyester resins that are two-component curing resins, acrylic-urethane resins, polyester-urethane resins, engineered boxy resins, melamine-alkyd resins that are thermosetting resins, Examples include melamine-acrylic resin, melamine-polyester resin, acrylic resin, and acrylic-urethane resin.

These can be used alone or as a mixture of two or more.

Particularly preferred are epoxy resins (combined with curing agents such as polyamide resins and amine adducts), acrylic-urethane resins, acrylic resins, etc., which are thermoplastic during metal spraying and allow the sprayed metal particles to enter the coating and harden after the spraying. .

In addition to the particles and resin, an organic solvent, water, etc. for dissolving or dispersing the resin may be added to the composition used in the present invention, if necessary.

Furthermore, additives such as dyes, pigments, dispersants, anti-foaming agents, and anti-sagging agents can also be used in combination.

In addition, as for the form of actual use, any form such as a solvent system, a water-soluble system, an aqueous dispersion system, a solvent dispersion system, etc. can be taken.

In the present invention, various casting methods can be widely used, and in order to obtain castings with complex shapes, it is necessary to divide the mold into several parts. In the preparatory step, a roughening layer is first formed using a roughening agent, and a desired metal is low-temperature sprayed thereon to form a metal spray coating. Molten iron is poured into the completed mold formed by combining the molds thus made, and an iron casting having an alloyed dissimilar metal coating on the surface is obtained in the same manner as described above.

The alloyed film formed on the surface of the iron casting of the present invention is not limited to one type of dissimilar metal, but can be made of two or more types of metal to produce different pattern effects such as color and gloss. To obtain such an effect, when spraying metal onto the inner surface of the recess of the mold, the first metal is first partially sprayed. This can be easily done by masking the other parts and spraying the first metal.

Next, the second metal is sprayed onto other parts, or the second metal is sprayed onto the entire surface including the first metal. When molten iron is poured into the prepared mold, a film of the second metal is formed entirely on the surface of the casting, and a film of the first metal is further formed in a pattern on the upper surface of the film of the second metal. It forms.

For example, a bronze film is formed on the surface of an iron casting, and a white nickel silver film is formed in a pattern on top of this bronze film.

[Effect]

In the present invention, an alloy of iron and dissimilar metals is formed on the surface of an iron casting by the above-mentioned means, at the step of pouring hot water into a mold, so the manufacturing process is extremely simple and the cost of the product can be kept low. can. This involves two preparatory steps: applying a roughening agent to the inner surface of the mold to form a roughening agent layer;
This is because by performing a simple process of spraying a desired metal different from iron using low-temperature spraying means to form a sprayed metal coating, all that is required is to pour hot water into the mold. (By doing this, it is possible to obtain iron castings with new properties, but since the surface of this product is coated with an alloyed dissimilar metal, it does not cause electrolytic corrosion and is similar to the cast iron castings of the dissimilar metal. Since it can be used as a cast product with a similar appearance, texture, and feel, it opens up a completely new dimension for iron castings.

〔Example〕

Examples of the present invention will be described below. In Figure 2, B, B''
Upper mold B is made by mixing casting sand and an appropriate amount of thermosetting resin.
As a first preparation step, a roughening agent is first applied to each of the recessed portions 5 and flat portions 6 using a lower mold B' to form a roughening agent layer 7. The roughening agent is 100 g of epoxy resin, 80 g of xylene, 60 g of methyl ethyl ketone, and 25 g of butanol.
was added and dissolved, and then 10 g of polyamide resin was added thereto to form a resin component and silicon carbide with an average particle size of 50 nm 22/
This product was obtained by thoroughly stirring the above ingredients, and a film having an average thickness of about 20 pm was formed. 8 is a thermal sprayed metal coating formed on the top surface of this surface roughening agent layer by low-temperature spraying a copper alloy containing 485% w, 10% tin, 3% nickel, and 2% zinc, and has an average thickness of about 15011- After completing the above preparation steps, the upper and lower molds are assembled as shown in FIG. 3, and molten iron is poured into the molds from the sprue lO. The temperature of the water at this time is 14
00°C to 1450°C. As soon as the injected hot water comes into contact with the sprayed metal coating 8, it melts and alloys it. In this way, an iron casting having the alloyed copper-based metal film 2 on its surface was obtained as shown in FIG. Note that the iron remaining in the sprue lO remains in the form of a protrusion on the casting, and although this is removed, an exposed portion of iron remains after removal. This part is sealed by welding with a welding rod made of the copper alloy mentioned above. The newly obtained iron castings can be further processed, such as by polishing the surface. At first glance, this iron casting has the same appearance, texture, and feel as a copper alloy casting.

Next, if the mold has a core, a roughening agent layer and a sprayed metal coating are also formed on the surface of the core by the first and second preparation steps described above.

This may be omitted in some cases. Figure 3 shows core 1
Fig. 1 schematically shows a mold having the following structure.

What is shown in Figure 4 is a device that instantly spreads the hot water to every corner of the mold by reducing the pressure in the mold interior space 9 when pouring hot water into the mold, and also sucks out the gas generated. , 12 is a film, 13 is an air suction table, 14 is a reverse tank, and 15 is a vacuum pump.The vacuum pump is operated in advance to reduce the pressure inside the reverse tank 14, and at the same time hot water is poured, the pulp 16 is opened and molded. The inner space 9 is brought into a reduced pressure state. The iron casting of the present invention can be obtained by subjecting the same first and second preparation steps to the mold used in the manufacturing method of such a casting.

Figure 5 shows the completion of the second preparation process for the upper mold, in which two types of metals are thermally sprayed in the second preparation process to create patterns of different hues on the surface of the casting. That is, after forming the surface roughening agent layer, the area other than the patterned area is covered by masking, and the patterned area is coated with Sokel 20 on nickel silver.
%, W460%, tin 20%) to form a nickel silver metal film 17, and then red copper (!M85%, tin 5%) was sprayed on the entire surface.
%, 4% nickel, 6% zinc) to form a sprayed metal coating 8. The lower mold has a sprayed metal coating of only red copper (reli, not shown). By overlapping the molds and pouring iron hot water in the same manner as described above, an iron casting was obtained whose surface was covered with a red copper alloy film and further had a white nickel silver portion 17 thereon.

〔Effect of the invention〕

The present invention is an iron casting having an alloyed film of different metals formed on its surface, and the production of this by an extremely simple method. Since it is no different from cast iron castings made of other dissimilar metals, it greatly expands the range of applications for iron castings, and has the great advantage that the cost is not so high. It is also expected to be used.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway view showing the structure of the iron casting of the present invention, and Figs. Figure 3 is a cross-sectional view showing the mold with a core, Figure 4 is an explanatory diagram of the pressure reducing device and mold, and Figure 5 is an explanatory diagram after adding the second preparation step. FIG. A: Casting product, B: Upper mold, B゛: Lower mold, l: Iron, 2-alloy coating, 5: Concave surface of mold, 6: Horizontal surface of mold, 7: Roughening agent, 8: Sprayed metal coating, 9: Mold space, lO: Sprue, l
lz core, 12: film, 13: stand, 14: reverse tank, 15: vacuum pump, 16: pulp, 17: nickel silver section.

Claims (5)

[Claims] (1) A dissimilar metal characterized in that the surface of an iron casting forms a film of a dissimilar metal that is alloyed with a dissimilar metal when the molten iron is cast into a mold. Iron castings with a coating formed on them. (2) An iron casting formed with a dissimilar metal coating according to claim 1, wherein the coating is made of two or more dissimilar metals and has a pattern. (3) A roughening layer 7 is formed in advance using a roughening agent on the concave portions 5 and flat portions 6 of the mold made from casting sand, and a metal different from iron is further thermally sprayed on the upper surface by means of low-temperature spraying. After forming the sprayed metal coating 8, the molds are combined and molten iron is injected into the mold to form an alloyed dissimilar metal coating on the surface of the iron casting. A manufacturing method for iron castings. (4) A method for manufacturing an iron casting having a dissimilar metal coating as claimed in claim 3, wherein the dissimilar metal sprayed metal coating is formed of two or more metals. (5) Thermal sprayed metal coatings of different metals are composed of two or more metals, where a certain metal is formed into a partial or patterned thermal sprayed coating, and the base metal is formed into a thermal sprayed coating over the entire inner surface of the mold. A method for manufacturing an iron casting on which a dissimilar metal coating is formed as claimed in claim 3.