JP2001232443A - Coating structure for surface treatment of die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treated coating which can prevent seizure and galling of a die cast which can be coped with even in the middle of the casting at a casting site and considerably reduce the use of a releasing agent by forming a simply treated coating to be naturally dried or dried by heating at a low temperature after the coating is performed by brushing or spraying. SOLUTION: A soft and porous coating is formed on a surface of a die, and ceramic particles are added thereto, or the releasing agent or various kinds of organic materials are absorbed in the pores according to the casting condition of a casting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating structure capable of easily performing a surface treatment of a die casting mold.

[0002]

2. Description of the Related Art Conventionally, die-casting die surface treatment has been performed by a dedicated equipment for surface treatment for the purpose of preventing seizure and biting of an aluminum alloy on the die surface and extending the life of the die. . Among the main surface treatment methods applied to die casting dies, general large-area surface treatments include nitriding treatments such as tuftride, gas nitrocarburizing, ion nitriding, I-NIX, Edison hard, etc. under commercial names. Was. In addition, partial surface treatment of a mold with severe seizure includes formation of carbide by TD process, ion plating, PVD, CVD.
-Surface coating of TiC, TiN, etc. by the PVCD method. These surface treatments require dedicated equipment and require a high processing temperature and a long processing time. WC with a spray coating that can be processed over a large area or partially during the repair and maintenance stage of the mold using a relatively small dedicated thermal spray equipment
Etc. had a ceramic surface coating. Tests have been conducted to paint and coat heat-resistant silicone and Teflon. Further, in order to remove the aluminum alloy adhered to the mold and prevent seizure, an anti-seizure agent for brush-coating the part by another method has been used.

A conventional nitriding treatment / surface treatment film by TiC / TiN coating has formed a very hard film of HV1000-3000.
In severe casting conditions that are vulnerable to mechanical shock and differential thermal expansion,
There was a disadvantage that the hard coating (2) was broken at around 500 to 1000 shots. As shown in FIG. 1, the adhered aluminum alloy (3) penetrating into the cracks of the hard coating (2)
As a result of seizure and biting, the adhesion of the aluminum alloy gradually increased and, at the same time, alloying was performed on the mold surface (1) to form an intermetallic compound (4).

[0004] An anti-seizure agent for applying a brush coating to a burn-in portion can be easily applied at the casting site, but has only a durability of about 5 to 20 shots. Was stained black or dark brown. Heat-resistant silicone and Teflon coatings have poor adhesion to the mold surface and are more easily adhered to the higher temperature side. Since the WC film formed by thermal spray coating is a hard film, cracks occur in the same state as in FIG. 1 around 500 to 1000 shots. Since it is a build-up coating by thermal spraying, it was necessary to use it after finishing rough surface skin with a file or a grindstone.

Conventionally, a simple coating that does not require special equipment, such as brush coating or spray coating at a mold repair / maintenance stage or at a casting site, and natural drying or low-temperature heating drying can be used. There was no treated film that was durable against seizure and biting in the forming process.

[0006]

SUMMARY OF THE INVENTION It is practical if the processing can be performed simply and at the casting site without using dedicated equipment or equipment. The method that can be processed at the casting site is to stop the casting in the middle, remove the aluminum alloy baked on the mold with a grindstone or a hard metal spatula, spray it on the mold surface or apply it with a brush, and let it dry naturally It is preferable to use a processing method in which the casting operation can be started by slightly heating and drying with a gas burner, a hair dryer, or the like. At the stage of repairing and repairing a new mold or a mold after casting for a certain period, the oil and release agent film on the mold surface can be removed by washing or a little polishing, and the same processing as above can be performed. Is preferred. In this case, it is possible to employ a dipping treatment in the treatment solution in order to obtain a reliable treatment film with a small mold structure component.

[0007] Conventionally treated coatings are vulnerable to stress deformation, thermal expansion difference, and mechanical impact of the mold and are cracked, so that a coating that is not cracked or hard to crack is produced.

[0008] The conventional treatment film requires a durability as long as possible because of the dedicated equipment. It looks maintenance-free when long durability is obtained, and it seems to be good at first glance, but if you notice a problem by neglecting the mold check, it may become a defect that has been mass-produced. Check is necessary. If a simple construction method capable of processing at the casting site is adopted, if reprocessing is repeated at the end of the casting operation also as a die check, it is sufficient if the durability is at least half a day or one day. Naturally, the durability is as long as one week and one month, but if it can be easily processed, it is not an essential condition. In addition, if it is more than one month, in the normal case, the mold is lowered and repair and maintenance is performed, so it is only necessary to process at that time, and there is no processing work at the casting site, so reasonable production is possible .

In severe casting conditions, the mold release agent film is evaporated, thermally decomposed and oxidized in the high temperature part of the mold, and the aluminum alloy injection port is washed by the flow of the molten metal and the amount of aluminum alloy passing therethrough. I do. As a result, the release agent coating wears and disappears, and seizure occurs even when the molten aluminum alloy comes into direct contact with the mold surface or the treated coating. Even at that part, there is no seizure or bite, and a film that can release the cast product is created.

[0010]

In the casting of die casting, a release agent is sprayed and applied every shot to release the cast product. Since the release agent is mainly composed of lubricating oil, wax and silicone, the strength of the sprayed release agent film is only viscous, and it is lower at the mold temperature. Has become. With the release agent coating, the mold can be released on the surface of the overwhelming area without any problem and casting is performed. In addition, the surface of the overwhelming surface area has a feature that the mold life is long without damage to the mold. This does not have to be a very hard coating like the conventional surface treatment coating. Furthermore, since solidification is completed and the soft aluminum alloy that is still in a high temperature state is released, it is slightly harder than the lowest aluminum alloy and durable on it. Hardness that can be expected will be sufficient. Therefore, the treated film may be softer. In severe casting conditions where there is a problem with seizure and biting, evaporation, thermal decomposition,
A heat treatment higher than the oxidizing temperature and a treatment film stronger than the release agent film for withstanding the washing of the hot water flow are required.

A hard and dense surface-treated coating is liable to crack due to thermal expansion or mechanical impact. However, if the coating has very fine cracks from the beginning, the coating strength is reduced. The mechanical shock can be dispersed and will not be greatly broken. This very fine crack can be replaced by providing pores in the coating. For mechanical shock, compression of pores and stress deformation of mold.For compressive stress, expansion of pores for compressive elongation stress, for expansion of pores, for thermal expansion of mold, dispersion of expansion due to many pores and soft coating. It can follow the expansion. In the thermal shock, not only the expansion and contraction of the pores, but also the thermal shock stress itself on the mold surface can be reduced by the decrease in the thermal conductivity due to the pores. Also, the pressure applied during the filling of the molten aluminum alloy can withstand the expansion and contraction and collapse of the pores, so that a thin film can withstand the stress deformation due to the rigidity of the mold. Although it is a non-dense, soft and porous coating, the coating strength is much stronger than the viscosity of the release agent, and the release agent that penetrates the pores has increased heat resistance, reducing wear and loss of the processed coating. And durability.

[0012] A soft and porous treatment film eliminates the need for a sintering step of performing treatment at a high temperature, for example, to densify the ceramic. Can be formed. (Fig. 2) shows continuous pores (6) and independent pores (7) in the cross section of the coating (5).
Is shown. In order to remove the solvent from the solution to be applied, it is necessary to dry naturally or to heat and dry the solvent to evaporate. However, since the boiling point of the solvent is low, a treated film can be formed at a maximum of 200 ° C. Processing is possible. The method of spraying or brush-coating, performing natural drying to low temperature treatment, and forming a soft and porous film was as follows. A) Sol-gel coating A coating is formed by using an organic metal such as alcoholate, alkoxide, chelate, or acetic acid, and absorbing moisture from the air after the application and heating with a hair dryer for 5 minutes. The organic portion of alcoholate, alkoxide, chelate and acetic acid is decomposed by heating to form pores. The organic metal on which the film was formed was Zr, Zn, Mg, Al, Ti, Si, B, Ca,
Sr, Ba. B) Colloid A film is formed by using a colloid-dispersed solution and heating it with a hair dryer for 5 minutes after application. The colloidal dispersant evaporates to agglomerate the fine colloidal particles to form a porous coating. The colloidal material on which the film could be formed was A
1, Si, Ti, Zr. C) Phosphate In order to obtain adhesion to the mold, an aqueous solution of a phosphate containing excess phosphoric acid is used, and after the application, the film is heated by a hair dryer for 10 minutes to form a film. Hydrogen resulting from evaporation of the solvent or chemical reaction between the mold and phosphoric acid forms a porous film. Phosphoric acid salts on which a film can be formed are Na, Li, K, M
g, Ca, Zn, Sr, B, Ba, Al, Si, Ti,
Zr, Cr, Mo, W, Mn, Fe, Co, Ni. D) Sulfate In order to obtain adhesion to the mold, an aqueous solution of a sulfate containing excess sulfuric acid is used, and after the application, a hair dryer is heated for 5 minutes to form a film. The water in the solvent evaporates or hydrogen is generated by the chemical reaction between the mold and sulfuric acid to form a porous film. The sulfuric acid salts on which the coating was formed are K, Mg, Ca, Zn, S
r, Ba, Al, Ti, Zr, Mn, Fe, Co, N
i. E) Silicate / Titanate / Zirconate / Aluminate An alkali-water-soluble salt is used to obtain adhesion to the mold. After the application, a film is formed by heating with a hair dryer for 10 minutes. Evaporation of the solvent water and its foaming result in a porous film. The alkali salt on which the film was formed was L
i. Na, K, Cs. F) Others Any soft and porous coatings such as carbonates and oxalates that can be applied by brushing or spray coating to form coatings can be used. Nitrate is excluded because nitrous gas is generated during pyrolysis.

[0013] Even if a film can be formed as described above, if the aluminum alloy comes into close contact with the molten aluminum alloy when it comes into direct contact with the molten aluminum alloy, there is a portion where the release agent is worn out or disappears. It will also burn in. In order to confirm this, the above-mentioned materials A to E were brush-coated on an iron plate having a thickness of 1 mm, and heated and dried with a hair dryer for 10 minutes to form a film. This was subjected to an immersion test in which it was immersed in a 700 ° C. molten aluminum alloy for 1 hour, and the state of adhesion between the iron plate and the aluminum alloy when it was taken out was observed. As a result, the aluminum alloy could be taken out without adhering. Sol-gel coating Colloidal coating The peeled aluminum alloy was in intimate contact and could not be peeled off. Phosphates and sulfates of Na, K, Co, and Ni, sodium silicate, and aluminum alloy in a skin state were easily peeled off. Mg, Ca, Zn, Sr, Ba, B, Al, Ti, Z
phosphates and sulfates of r, Cr, Mo, W, Mn, Fe, carbonates of Mg, Ca, Zn, Sr, Ba, K, titanates, zirconates, aluminates

When the thickness of these treated coatings exceeds 100 μm as the film thickness increases, cracks may occur, peeling of the coatings may occur, the treated coatings may become rough, the strength may be reduced, and heat drying may occur. When foaming,
The coating film drips to an uneven film thickness, and the number of defects in the treated film increases. As the film thickness decreases, the strength of the treated film increases and the film becomes good. However, there is a risk that the molten aluminum alloy is eroded easily. 1
A time immersion test was performed. As a result, although the film thickness slightly fluctuated depending on the construction technique, the aluminum alloy soaked and adhered to the roughened film, and the colloidal alumina soaked and adhered to the aluminum alloy side. 118 microns: The aluminum alloy adhered to the skin, but could easily be peeled off. 101 microns: no skin-like adhesion. 48 micron: same as above 11 micron: same as above 5 micron: same as above 1 micron: same as above No data could be obtained due to the size of the colloidal particles and the measurement limit of the film thickness measuring instrument, but the dilution ratio of colloidal alumina was increased. An immersion test was performed with the treated film formed, but there was no adhesion of the skin state. Therefore, the effect can be expected if the treated film was formed. Therefore, the effective coating thickness is
0.1-100 microns.

If the release agent film cannot be easily peeled off in a immersion test in a burn-in portion where the release agent film is worn out or disappears, the aluminum alloy adheres and cannot be used as a treated film. In order to easily peel off the aluminum alloy, immersion tests were performed by adding various ceramics. (Fig. 3)
As described above, the surface area of the aluminum alloy in direct contact is reduced by non-adhering ceramic particles. In the above-mentioned film formation, sodium silicate which was not able to be peeled at all because the aluminum alloy in a skin state adhered closely was used. The material composition to be applied is 10% sodium silicate aqueous solution 5
50 g of powder of about 30 microns of each ceramic material in 0 g
g was added and mixed with stirring. This material was brush-coated on an iron plate, heated and dried with a hair dryer for 10 minutes, and then subjected to a 1 hour immersion test in a molten aluminum alloy at 700 ° C. As a result, similar to the sol-gel or colloid-treated coating, the following ceramics did not adhere to the skin or could be easily peeled off even if they adhered. Oxide: Mg, Ca, Sr, Ba, B, Al, Ti, Z
r, Zn, Cr, Mn, Fe, fluoride: Mg, Ca, Sr, Ba, B, Al, Ti,
Zr, Zn, boride: Ti nitride: Si, B, Ti, carbide: Si, Ti, W carbonate: Mg, Ca, Sr, Ba, Zn, Mn,

Further, in order to confirm the performance of the added ceramic, 5 g of the above ceramic material was added to 95 g of a 10% sodium silicate solution, mixed and stirred, and then brush-coated on an iron plate, followed by heating and drying with a hair dryer for 10 minutes. Did. This test piece was immersed in a molten aluminum alloy at 700 ° C. for 1 hour. As a result, the ceramics to which the aluminum alloy did not adhere or which could easily be peeled off even when they adhered were as follows. Oxide: Mg, Ca, Sr, Ba, B, Al, Ti, C
r, fluoride: Ca, Sr, Ba, Ti, nitride: Si, B, Ti, boride: Ti, carbide: Si, Ti, carbonate: Ca, Sr, Ba, Mn,

Since the state of the coating changes depending on the particle size of the ceramic particles, the effect of the particle size was investigated by selecting various types of alumina which are easy to be uniform. A 10% aqueous solution of silicic acid was mixed with 30% alumina of various particle sizes and stirred.
The iron plate was brush-coated and dried by heating with a hair dryer for 10 minutes. 120 micron: The film thickness was large due to the rough treatment film, and the powder adhered to the hand when rubbed by hand. 100 microns: powder attached to hands was slightly reduced, but otherwise the same as above. 85 μm: particle diameter of 100 μm or less when viewed as a sphere, and a particle diameter that forms a two-layered state by close packing, and even when rubbed by hand, powder did not reach the hand and the film thickness became appropriate . 50 microns: Same as above. The visual roughness of the treated film was not felt. 30 micron: same as above 10 micron: same as above When the film thickness exceeded 100 microns, fine cracks appeared. 5 micron: same as above 2 micron: same as above Less than 2 microns is in the area of colloidal particles and does not result in the addition of powder. As a result, the particle size was preferably in the range of 2 to 85 microns.

In order to see the effect of the amount of the ceramic material, calcium carbonate having a particle diameter of about 20 microns was selected as a representative, and its 1, 3, 5, 10, 30, 50, 7
A 10% aqueous solution of sodium silicate was added to 0, 80, 90, and 95 g to make a total of 100 g, and the iron plate was brush-coated and dried at 200 ° C. by heating. This test piece was
An immersion test was performed for 1 hour in a molten aluminum alloy at 0 ° C., and the state after removal was observed. As a result, it was difficult to peel off due to the adhesion of the ceramic 1% aluminum alloy. Ceramic 80-95% No aluminum alloy adhered, but the strength of the coating was weak and calcium carbonate powder adhered to the aluminum alloy, and the coating side peeled off and became tattered. Therefore, when the compounding amount of the ceramic is 3 to 70%, good aluminum alloy releasability can be obtained.

In the strong casting conditions where the coating of the release agent wears and disappears, the main component of the release agent is oil, wax or silicone. are doing. A commercially available mold release agent (Matsuro E-12, Matsumura Petroleum Institute Co., Ltd., Morsol E-12) was brush-coated on an iron plate, and dried at 130 ° C. where evaporation and change of the mold release agent itself were relatively small to obtain test pieces. This was repeatedly immersed in a molten aluminum alloy at 700 ° C. for 10 seconds and discharged for 5 seconds under conditions similar to a shot cycle of casting. As a result, the first time, the aluminum alloy fell with the generated gas without adhering, and the second time, the aluminum alloy in a slightly leathery state adhered with the generated gas,
The third time, when the aluminum alloy skin adheres and peels off, the aluminum alloy adheres to the iron plate in a dotted manner. The fourth time, the number of the adhered spots increases sharply. Aluminum alloy can no longer be peeled. Just in case,
The test piece under the same conditions was put in a furnace at 400 ° C. for 10 seconds, and then an immersion test was directly performed. As a result, many points of the aluminum alloy were adhered from the first time, and the aluminum alloy in a skin state could not be peeled off the second time. 7
Immediately after being immersed in the molten aluminum alloy at 00 ° C, the release agent evaporates and a large amount of pyrolysis gas is generated, and the gas acts as a boundary to bring the aluminum alloy into a non-contact state, so that the aluminum alloy does not adhere. . As the number of times of immersion increases and decreases, the release agent evaporates and pyrolysis gas is consumed, so the boundary gas gradually disappears and the aluminum alloy comes into direct contact with the iron plate and adheres and alloys. Adhesion prevents peeling. That is, in a severe casting condition portion, the heat resistance is insufficient with only the release agent coating alone, and the coating is broken.

In the immersion test of the soft and porous film,
A 10% aqueous solution thereof was brush-coated on an iron plate using sodium silicate which was not adhered to the aluminum alloy and could not be separated at all, and was heated and dried at 200 ° C. A commercially available mold release agent (Morsol E, Matsumura Petroleum Research Institute, Inc.) is applied to this soft and porous film.
-12) and dried by heating at 130 ° C.
The same immersion as above in a molten aluminum alloy at 0 ° C. was repeated. As a result, the aluminum alloy did not adhere at all until the eighth time, and the aluminum alloy in a leather state started to adhere from the ninth time,
The peeling of the adhered skin was able to be performed at the first time, and no adhesion of the aluminum alloy was found on the substrate. As a precaution, a test piece under the same conditions was placed in a furnace at 400 ° C. for 10 seconds, and then an immersion test was immediately performed. As a result, the aluminum alloy did not adhere until the fourth time, and the peeled aluminum alloy could be peeled off from the 5th to the 12th time, and gradually became difficult to peel off the 13th to the 15th time. At first, the release agent on the outermost surface evaporates and a large amount of pyrolysis gas is generated.However, since the release agent penetrating into the pores is gradually generated thereafter, the aluminum alloy adheres even if the number of times of immersion is increased. No longer. When the number of times of immersion is further increased, the release agent eventually disappears, but since the release agent is spray-coated every shot and is always replenished, it does not disappear. Rather, since the release agent permeated into the pores remains, the spray application amount per shot can be reduced. If there is a soft and porous treatment film on the base,
Since the aluminum alloy does not directly contact the iron plate, the iron plate is not damaged. The soft and porous treatment film can impregnate a release agent or various organic substances into the pores. Since the coating is based on a soft, porous coating, the coating is much stronger than the release agent coating. The strength of the coating is not the viscosity but the rigidity of the undercoat. Also, compared to the resin material alone, the resin containing the filler of the inorganic material has the same heat resistance as the rise, and the heat resistance of the release agent and the organic material soaked in the undercoat is confined in the pores, It evaporates and decomposes only gradually and naturally improves.

This means that if an organic material having higher heat resistance than the release agent is impregnated, durability can be obtained, and the mold release having higher heat resistance even in severe casting conditions where the release agent film is worn out or disappears. If a lubricating material is impregnated, the cast product can be released without seizure, resulting in a durable treated film.
A soft, porous film with aluminum alloy attached 1
The substrate was brush-coated with a 0% aqueous sodium silicate solution and dried by heating for 10 minutes with a hair dryer. Various organic materials were dispersed and dissolved in a solvent to form a 5% solution on the base, and the base was impregnated with the organic material, and dried at 130 ° C. to form test pieces. The test piece was subjected to a repeated immersion test under the same conditions as above to determine the number of immersion repetitions at which the molten aluminum alloy did not adhere at all. The test was repeated up to 31 times, but the test was stopped at 32 times or more because the quality of the organic material could not be determined. 10 or less Mineral oil: Machine oil / Cylinder oil Synthetic oil: Paraffin / Naphthene / Polybutene / Polybutadiene / Polyether Natural fats / oils: Rapeseed oil / Soy oil / Fax seed oil / Castor oil / Palm oil / Large amount of generated gas during first immersion It became smoke and rose. 11 to 20 times Wax: carnauba wax, honey wax, petroleum wax, paraffin wax, beeswax Fatty acid: stearic acid / oleic acid / linoleic acid / erucic acid Synthetic oil: higher alcohol / dodecyl alcohol / polyethylene glycol: glycerin ester / triglyceride resin : Styrene resin / cellulose acetate / polyethylene terephthalate
Some became dark brown. 21 to 30 times Extreme pressure additive: soap (Na, Al, Ca, Li): sulfonate (Ca, Ba, Mg): phosphonate (Ca, Ba, Mg): zinc dibenzodithiocarbamate / dialkyldithiocarbamate tribenzoyl borate resin : Polypropylene, epoxy resin, phenolic resin, polyethylene, high wax, nylon, polycarbonate, methacrylic resin, melamine resin, polyarylate Generates very little gas, gradually turns black from dark brown to black, then slowly to black As it disappeared, the aluminum alloy began to adhere. 31 times or more Resin: Silicone, polyimide, polyamide, Teflon, polyetheretherketone Smoke was slightly emitted, but there was almost no visible change by repetition.

If the organic material is diluted with a solvent, as shown in FIG. 4, the organic material can be impregnated into a portion having pores. When the organic material is immersed in a molten aluminum alloy at 700 ° C., the heat resistance of the organic material is reduced. The speed of evaporation and thermal decomposition changes depending on the nature, and the number of immersions changes. In die casting, a release agent is sprayed and applied for each shot to release the casting from the mold, so it is repeatedly reinforced with a release agent coating.
The impregnated organic material has higher durability than when directly immersed in a molten aluminum alloy. Further, in a severe casting condition where the release agent film is worn or lost, an organic material having higher heat resistance and lubricity may be impregnated. The combination of the base and the organic material corresponding to all casting conditions becomes possible, and all functions required for die casting can be satisfied.

[0023] Forming a film by a process of impregnating a soft and porous film with an organic material is troublesome and troublesome. If this can be done by one coating, it becomes a simpler processing method. The same repeated immersion test as described above was conducted for aluminum chelate, cyclic aluminum, butyl titanate, and acetylacetone tributoxy zirconium, which are thought to produce a structure as shown in FIG. 4 at a finer level. As a result, all of the four types reached 31 times or more. Materials having a structure in which an organic substance is bonded to the skeleton of a metal oxide of an organic metal are effective, but since the materials available at present are limited to the above, other materials cannot be tested.

[0024]

[Function] The mold surface during the casting and at the repair / maintenance stage has an aluminum alloy attached thereto due to the release agent and the dirt and seizure after the casting. The adhered aluminum alloy is shaved with a file or a grindstone, and the dirt on the surface is washed with a surfactant, or the surface of the mold is polished with a grindstone or an abrasive to clean the surface. The base of the clean mold is thinly brush-coated or spray-coated, and air-dried for 5 to 20 minutes. If you want to process quickly, use a gas burner, heater, or hair dryer to keep the surface temperature at around 200 ° C.
Heat and dry for about 10 minutes. When the solvent portion is evaporated by drying due to the characteristics of the inorganic material, the portion where the solvent has evaporated becomes pores. Normally, in the case of ceramics, sintering is performed at a high temperature afterwards to eliminate pores and make it denser, and to give strength.However, this treated coating does not require so high strength, so it can withstand use even with pores. I can do it. The presence of the pores enables a simple treatment method in which the surface treatment can be performed without requiring a dedicated heating equipment at a low heating temperature. An organic material dispersed / dissolved in a solvent is impregnated into the pores obtained by evaporating the solvent of the underlying solvent from the underlying coating film having pores, and is naturally dried or at a temperature at which the solvent of the organic material evaporates for 3 to 10 minutes. Heat and dry with a heater. New molds and mold parts have cutting oil and rust preventives from the manufacturing process adhere to the surface. To remove this, the surface of the mold is cleaned by washing with a surfactant, and then the same treatment as above is performed. If you add a small amount of inorganic base material to the surfactant or abrasive, the surface will be cleaned and the inorganic material will adhere to the mold surface at the same time,
When the above-mentioned undercoating treatment is performed thereon, a treatment film having very good adhesion can be obtained.

Conventionally, a large amount of the release agent has been used by spraying the release agent over the entire surface under severe casting conditions. When a treatment film in which a lubricating material is impregnated into the top coat is formed on a general wide casting area, the release can be performed even if the release agent is not sprayed or hardly applied to the portion. When a release agent is sprayed and applied in a severe casting condition portion, a spray is applied to a general large casting area, and the release can be performed without spraying and applying the release agent over the entire surface. As a result, the amount of the release agent used is greatly reduced, and the working environment is significantly improved.

[0026]

Embodiments of the present invention will be described below. A comparison was made on the same surface or part as the conventional mold surface treatment, which will be described. The treatment method was as follows: the surface of the mold was rubbed with a brush using a surfactant, washed, primed, burner dried, topcoated, heated and dried with a hair dryer for 10 minutes, and then casting was started. (Example 1) Die-casting machine: 350 ton Casting product: Outlet water core Since the gate (entrance of the molten aluminum alloy) is a direct hit to the core, the direct hit portion is seized and bitten, and the core is pulled out and cracked into a cast product. Had occurred. Conventional-1: The core was subjected to a nitriding treatment of tuftride. Result-1: Fine cracks occurred on the die surface from about 350 shots, and cracks occurred in the cast product at 673 shots. Conventional-2: The core was coated with TiN by the PVCD method. Result-2: The gold surface became black at about 530 shots,
One streak bite occurred at the 626 shot, the bite gradually increased, and the cast product cracked when the core was pulled out at the 1019 shot. Treatment film-1 of the present invention: 10% aqueous solution of sodium silicate Result-1: The surface became black at about 120 shots, and 522
One streak bite occurred at the shot, and a crack occurred at the 856 shot. Ti treated by special equipment
Although it was inferior to N coating, the operation up to about 80% was obtained by simply applying and heating and drying. Treatment film-2 of the present invention: 10% of 30 micron MgO added to colloidal silicon Result-2: It seems that the release agent adhered to the surface at about 240 shots was carbonized, but the surface became black and about 1220 shots The burnt product adhered to the cast product, and the cast product cracked at 1346 shots. Treatment film-3 of the present invention: Undercoating-colloidal zircon Topcoating-polyethylene Result-3: The surface became black at about 260 shots, and 188
The one that is scorched at about 0 shot adheres to the casting,
At the 2432 shot, a crack occurred in the casting. Processed film-4 of the present invention: undercoating-Mn phosphate overcoating-polycarbonate Result-4A: The surface became black at about 350 shots, and 31
The burnt one adhered to the cast at about 00 shots, and cracked at the 7329 shot. Result-4B: The same process was repeated by lightly polishing the surface of the mold, and the number of shots before cracking was observed. The second repetition → 9158 shots The third repetition → 12843 shots: The fourth repetition → 13215 shots: The fifth repetition → 13053 shots The number of shots before cracking of the cast increases due to repetition, but is almost constant from the fourth repetition become. (Example 2) Die-casting machine: 650 ton Casting product: Core for punching out a valve body for torque converter (drafting gradient: 30 minutes) An operation of incorporating a pulling-out cylinder into a die, pulling out the core first, and then opening the die. If a bite occurs, the core cannot be polished and must be replaced. The core pin is hidden in the mold on the mold structure, which is a disadvantageous condition that the release agent is hardly applied. Conventional-1: The core was subjected to tuftride processing. Result-1: There were 598 shots of the core being burned out and exchanging the core patiently up to the quality limit allowed for the cast product. Conventional-2: A core was coated with TiN by a CVD method. Result-2: The core could not be released in 7 shots because the release agent was hardly applied, the drawing cylinder was small, and the drawing force was small. Coating -6 of the present invention: undercoat-colloidal silicon overcoat-silicone Result-6: 18 in the same judgment as in the case of the tuftride treatment
It was 59 shots. Coating -7 of the present invention: undercoating-colloidal alumina overcoating-silicone Result -7: After about 620 shots began to burn, up to the same judgment as in the case of the tuftride treatment, 33
There were 48 shots. (Example 3) Die-casting machine: 350 tons * 1 cast Casting: Door closer body Fine cracks are quickly generated at the corners of the square shape. Conventional Example-1: A general solution-treated, precipitation-hardened mold without surface treatment. Result-1: The mold was repeatedly used until the corners were finely cracked at about 500 shots and the cracks could not be filed while being filed with the file. The average mold life in the past was around 42,000 shots. Conventional Example-2: I-NIX nitriding treatment was performed on the mold surface. Result-2: A small crack was formed in the corner at about 1000 shots, and the average mold life under the same treatment as above was 55,000 shots, and 63,000 shots even with the maximum durability. Conventional Example-3: Mold surface treatment was performed on the mold surface by overlaying WC on the mold surface. Result-3: A fine crack was formed in the corner at about 1530 shots, and around about 3800 shots, the crack began to peel around, and the crack itself did not increase.
Since it took too much time to sand the stripped part,
I gave up after 6,000 shots. Processed film of the present invention -8: Undercoat-ferrous phosphate / ferric phosphate Overcoat-silicone: Since cracks did not occur and cracks in the corners began to be generated from 116500 shots, the mold was used without sanding. Life time. Processed film -9 of the present invention: undercoat-aluminum alcoholate Overcoat-phenylsilicone: cracks did not occur, and from 153,700 shots, cracks at the corners began to occur. (Example 4) Die-casting machine: 350 ton * 1 piece casting Cast product: Core of dorcrowser body (draft 10 minutes): Core of Φ30 * 250L, which used to have a draft angle of 5 ° conventionally. The processing allowance at the tip of the slope is 2.8 mm for one meat.
In order to reduce the processing loss, the draft is reduced. Conventional-1: The core surface was subjected to tuftride treatment. : Detachment was observed when the draft angle was 5 °, but seizure / biting occurred from the first shot even at the setting of 30 ′, and did not escape from the third shot. Conventional-2: The core surface was coated with TiN by the PVD method. : The shot could not be missed in the third shot before the burn-in and biting occurred when the draft was set to 30 '. Processed film of the present invention -10: undercoating-sodium aluminate overcoating-phenylsilicone Result -10A: Seizure / biting started from 1513 shots, the release resistance of the biting became large, and it could not be removed at 1530 shots. Result-10B: The above-mentioned seizure / biting portion was polished to remove the adhered aluminum alloy, and then re-application was repeated. No more misses in the second 1682 shots. 3rd repeat 1733 shots Same as above 4th repeat 1742 shots Same as above 5th repeat 1736 shots Same as above Finally, the casting was stopped every 1700 shots, the mold was polished, and the reprocessing was repeated. Processed film of the present invention -11: Undercoat-Colloidal titanium Overcoat-Teflon FEP Result -11A: Seizure / biting began to occur from 6650 shots, but it did not increase, so casting was continued as it was, and it did not come off at 15,682 shots Was. The polishing of the core has been completed once every 10 to 11 days.
When the thickness of the aluminum alloy attached to the core is thin, it can be removed with a stainless steel spatula, and when it is thick, it can be cut with a file or a grindstone. Without, the core of the mold was not damaged at all. Result-11B: The aluminum alloy adhering to the seizure / biting portion was removed by polishing, and the reprocessing was repeated. 15663 shots for the second repetition 15703 shots for the third repetition
The core polishing work has been completed once a day. Processed film of the present invention -12: Undercoating-Phosphoric acid is 1/3 molar excess of 10% Zn phosphate 6
The core was immersed in a 0 ° C. aqueous solution for 7 minutes, and lightly heated with a gas burner. : Topcoat-dipped in a Teflon FEP solution dispersed and dissolved in 5% toluene solvent for 20 seconds, air-dried for 5 minutes and lightly heated with a gas burner. Result -12A: The image was slightly burned in a few shots but did not increase, so the casting was continued as it was, and the shot did not come off in 17833 shots. Result-12B: Since the burned-in portion of the core could be removed with a stainless steel spatula, the surface was rubbed with a brush impregnated with a surfactant and wiped off with a rag, and the top coat was applied with a brush and the burner was applied. After lightly heating and drying with
After casting, it stopped falling after 15238 shots. The re-application of only the top coat was almost equivalent to the coating treatment-11 of the present invention, so that the labor for the treatment could be omitted. (Example 5) Die-casting machine: 1650 ton * 1 cast Casting product: Crank case: The release agent film is washed by the molten aluminum alloy flowing force from the gate opening, making it difficult to release, and stretching the mold. Arrived and the castings were distorted and cracked. Conventional -1: Tuftride treatment: After releasing the release agent containing a large amount of silicone or wax, the release agent was finally released by spraying and applying a large amount. (21) Result-1: The release agent coating has a large area that can be washed from the product shape, and the way it is washed varies depending on the shape position. I was Also, since the amount of the release agent sprayed is large, an extra release agent film adhered to the mold surface is deposited.
The release agent film deposited on every 00 shots had to be removed. Treated film -13 of the present invention: Undercoat-Aluminum phosphate Overcoat-Dissolved monomethylsilicic acid with methyl silicone Result-13A: No need to remove distortion of cast product. When casting was performed under the same conditions as those of the other parts with the concentration of the release agent and the amount of spraying, sometimes it was necessary to remove distortion, but 12,000 shots could be cast without removing the release agent film. . Result -13B: After the above-mentioned casting, reprocessing was performed and casting was repeatedly performed under the same casting conditions. Second repetition 13400 shots The distortion removal after casting disappeared. The third repetition of 15600 shots The above shot had to be removed without removing the mold release agent coating during this period, but the casting was continued by repeatedly reprocessing every 15000 shots. Normally, fine cracks were generated at about 15,000 shots, but no crack was generated even after about 50,000 shots. Processed film of the present invention -14: One coat of butyl titanate Result -14A: 12,300 shots were cast in the same manner as in Result -12A. Result -14B: After the above-mentioned casting, reprocessing was performed and casting was repeatedly performed under the same casting conditions. The second repetition 11900 shots The third repetition 12400 shots The effect was not prolonged by the reprocessing, but a good level could be achieved from the beginning. Die-casting machine: 1650 ton * 1 piece casting Cast product: differential gear case: There is a large core that is pulled out from above, and the release agent that sprays and applies from the split surface of the mold cannot adhere to the back side As a result, it was not possible to stop seizure, and it was troubled by pressure leakage and poor appearance. Conventional-1: I-NIX treatment: Even if something is attempted, no access is available on the back side of the mold, and there is no other means for taking measures. Processed coating film of the present invention -15: Undercoat-1: 1 molar mixture of colloidal zircon / alumina: Overcoat-2: 1 mixture of ethyl acetate aluminum diisopropylate and nylon . Result -15A: Although the release agent may be slightly splashed, it is about 630 under the same casting conditions as before.
Seizure was not recognized until 0 shot, and the seizure became equivalent to the conventional level at about 15,700 shots. Result -15B: The treatment was carried out under the above conditions, and after reaching 6,300 shots, a surfactant was put into a spray gun through a small gap on the back side of the mold, spray-washed, and dried by air blowing. Thereupon, the above-mentioned top coat was sprayed and applied, air-dried for 10 minutes, and then dried by air blowing. After 6,300 shots, burn-in was not recognized until about 4,500 shots.

[0027]

According to the present invention, there are three major defects (burn-in bite, hot wrinkle hot water boundary, burrow) in die-casting, and expensive surface treatment with dedicated equipment has been performed to prevent the burn-in and bite.
The present invention can prevent seizure and biting by simple on-site processing without using special equipment, so that casting can be restarted by stopping only a small amount of casting during processing without removing the mold from the die casting machine. Things. Therefore, there is no need to prepare extra mold parts and keep them in stock. Conventionally, it has become possible to cast and remove a draft that was difficult to release from a cast product and could not be used in the design of the cast product, using a combination of an undercoat and a top coat with lubricating release properties. The removal of a small draft can improve the dimensional accuracy of the cast product. Among the undercoats, there are those in which hot water wrinkles and poor hot water boundaries have disappeared or their area has been reduced, and the undercoating is also effective for the poorness. In the part with burn-in / bite,
Since a large amount of the release agent is sprayed and applied under the casting conditions, the vaporized and thermally decomposed gas of the release agent enters the casting and forms a cavity. The presence of the non-baked treated coating makes it possible to reduce the amount of the release agent sprayed and applied, thereby reducing burrows. Cracks develop from the seizure / biting portion and become severe and unusable, resulting in the life of the mold. The treated film of the present invention can prevent the release agent film from being worn out or lost, and also prevent seizure and biting even in a portion where the release agent is not applied. Is also greatly extended.
In the working environment, the most important factor is the dirt due to the scattered release agent. However, the treatment film of the present invention significantly reduces the amount of the release agent to be sprayed and applied, which is advantageous not only in terms of dirt but also in terms of cost. become.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional coating.

FIG. 2 is a cross-sectional view showing a structure of a treated film of the present invention.

FIG. 3 is a cross-sectional view showing the structure of a ceramic-added treatment film of the present invention.

FIG. 4 is a cross-sectional view showing the structure of a treated film impregnated with the organic material of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mold surface 2 hard coating 3 adhered aluminum alloy 4 intermetallic compound 5 treated coating 6 continuous pore 7 independent pore 8 ceramic 9 pore 10 organic material

Claims (4)

[Claims] 1. A coating structure having pores in a thickness range of 0.1 to 100 microns. 2. The coating structure according to claim 1, wherein oxides, fluorides, nitrides, borides, carbides and carbonates of 2 to 50 microns are added in an amount of 3 to 70%. 3. Mineral oil, synthetic oil, natural fat, fatty acid, wax, silicone, Teflon (registered trademark), extreme pressure additive,
2. A resin / lubricating polymer impregnated into pores.
Film structure. 4. A coating structure formed of an organic metal aluminum chelate, cyclic aluminum, butyl titanate, acetylacetone tributoxy zirconium.