DE2223263A1 - Process for the production of basic components for casting molds - Google Patents

Description

The invention relates to improvements in casting molds and methods of these heart parts, and more particularly relates to improved basic parts of such molds
directed and on methods to produce this su, aIneη introducing refractory insert in its upper surface.

All-metallic ingots are made from molds
cast. ”A common form is the so-called“ big et. The chairs are large, usually rectangular, flat-

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before metal plate !!, usually made of cast iron are and are used al ο support for the sides of the form and also of course the boöeti part represent the shape. The strings of the shape taper generally of diameter from bottom to tip. Other types of shapes are among the; Came "big end up" forms known. You put pouring pan-like containers for the molten metal, the electrode part of which is an integral, non-removable part of the overall form »

Various problems usually arise with the use of these shapes, in particular im With regard to the surface of their basic components. The unprotected metal surface is melted in the presence of Metals that are sprayed onto their surface are quickly pitted and bulged. In the basic components large bumps are caused by the force and high temperature caused by the flowing, molten metal is developed which comes into contact with the surface of the chair. Since many melts in the generally about 1.5 to 3.0 meters (5 to 3 10 feet) high the metal must be at least from this height and fairly often poured from even greater heights. This creates a considerable amount of pressure. By a such force and at a temperature which is at least the liquefaction temperature of the molten metal is, the hot molten metal causes hole-like depressions in the basic components. Furthermore becomes the problem of the formation of pits or holes in the basic parts of the molds created by the above Factors caused are aggravated by the fact that the molten metal, particular in the vicinity of the bottom of the mold, in its eroding, hot, liquid state for a considerable time after pouring remains.

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The molten metal has after solidification into a metal billet, a _T Bodenforra the unwanted, eroded OberfIache reconfiguration of the chair or the basic component of the mold corresponding. A significant part of metal ingots therefore goes through cutting off the irregularly shaped end pieces of the metal plate !! lost when the castings are withdrawn from the mold and anschlie3enö to plates or V / alzen further ^blocks: are processed. Die3 is of course highly undesirable as it causes an undesirable loss of usable metal and an increase in scrap metal ₉ which must then be reworked.

Another extremely serious and costly problem arises when the casting has solidified in the mold to such an extent that it can be removed from both the sides of the mold and its base or chair. In many cases, when the surface of the chair is unprotected or inadequately protected, erosion occurs, as described above, and the ingot has a greater tendency to adhere firmly to the chair. Thus, in order after the sides of the mold from the ingot are removed _t which can effectively reach by a minimum coating film of coating materials normally rean, the ingot will be dissolved under application of force of the chair. This usually vvird 'achieved in that the ingot 2 is lifted with the adhering chair and is thrown against another larger object, is losgestoßen whereby the ingot. In many cases, the chair and guibblock are simply dropped onto the floor from a suitable height. In such situations, the chair is often broken into two or more smaller pieces and can no longer be used to cast other blocks. Again, the replacement costs for these chairs are high, which makes this aspect of the

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Casting process makes unfavorable. The same problem also exists with regard to the so-called "big end" up "Forms / in which the ingots stick, especially to their base. New forms of this type are special Sensitive to sticking, which is due to its smooth surface, which is not protected by a metal oxide layer or hammer impact. Then arises a strong metal bond between the lower part of the mold and the metal blocks.

The cracking of the molds, especially their bases, which was due to the rough treatment discussed above is, however, by gluing the Basic parts required with the ingots will also be affected by the heat shock during the formation of the ingots enlarged. Unprotected or insufficiently protected mold base surfaces are particularly sensitive to such destructive shock effects.

The prior art includes many solutions to the problems described above in connection with with the erosion of the basic components of the cast foils to mitigate. A number of refractory coatings have been suggested, but these are not total satisfactory. A previous solution to eroding the mold chairs suggested using refractory inserts in to bring in the bottom of the mold, this refractory insert to reduce erosion. Ceramic inserts could not be used with commercial success. Their main disadvantage is that as a result of Capillary action the molten metal enters the space between the insert and the mold and tends to to force the ceramic insert out of its cavity. When this occurs, the ceramic insert is located above the top surface of the chair and has

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the tendency to become trapped in the ingot. This causes metallic inclusions in the ingot, which in turn requires the expensive "end-cutting" operation power. · '■

The possibility of improved basic components of Making molds, or the ability to repair eroded chairs, thereby increasing the lifespan would result in a significant step in the port compared to the state of the art.

The present invention further relates to a method of making refractory inserts that are incorporated into the introduced upper surface of a basic component of a mold wherein the component originally contains a cavity in the surface, or in which the surface in the form of a cavity, and at least two irregularly shaped metal anchor elements in the cavity are firmly attached, the cavity is filled with thermally recycled, plastic, refractory material is heat-hardened, this plastic, refractory material and then on the upper surface a slurry made of refractory material that is in a binder is suspended, is applied to produce a coating of sufficient thickness to erode and the To prevent sticking and this pulp is dried, creating a protective, firm coating on the base component is formed, wherein the slurry is at least one of the refractory materials silicate glass, crystalline silicate, Aluminum silicate, aluminum graphite, zirconium silicate,

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Magnesium silicate and clay, suspended in at least one of the binders , such as aqueous alkali sulfate, colloidal silica sol, liquid acidic aluminum phosphate and ethyl silicate, the binder binding the refractory particles and thereby forming a firmly adhering "coating" which is bound to the surface is.

Further features and advantages of the invention will become apparent from the following description, along with the accompanying drawings, apparently:

Figure 1 is a horizontal cross-sectional side view an eroded form that has been repaired using the method according to the invention:

Fig. 2 is a top plan view of an eroded base member of a mold;

Fig. 3 shows a horizontal view of a cavity and shows Z-shaped metal core elements, which are shown in attached to the cavity.

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In the drawings, in which like parts are denoted by like numbers, "a base component of a mold 10 is shown of substantially rectangular shape." This base component or chair is normally of large size and is made of cast iron. Typical of such chairs may have a thickness of 3o cm or more and a length of 1 _t 2o m up to 1 "8o m (4 to 6 feet) reach" Stark eroded chairs can have a diameter of about 9o cm (3 feet) and a depth of about 25 cm (1o inc lien) can be eroded. In the event of such erosion, such chairs are normally discarded as no longer usable.

As shown in Figs. 1 and 2, - has Chair 1o has a cavity 12 formed on top of the chair 14.

The drawings show 2 or more irregularly shaped anchor elements 18 in their preferred Z-shape Configuration which is attached to the side walls 16 of the cavity 12 are attached. The Z screws in the drawing are attached to the Side walls 16 of the cavity 12 by means of threaded screws 2o, which are shown in greater detail in Fig. 3, anchored. A convenient method of anchoring the irregularly shaped Z-elements is to use them Uagel impact tools operated by ignition cartridges, which allow the Z-elements to be anchored quickly within the cavity.

Although the metal anchor elements are shown in a Z-shape, they can also be more irregular in other shapes Form snake-shaped are present. For example, corkscrew-like shapes, L-shapes, V-shapes and the like can be

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be turned.

It is preferred to anchor the irregularly shaped anchor elements in such a way that their base part, which is the The cavity of the chair touches "more in the plane of the surface than is perpendicular to it. In. in other words, it is undesirable; to use threaded screws to fix their pointed linden tree in the basic component, there the end of the screw transfers the heat in a punctiform manner, causing a hot spot or a burning effect when the top of such a screw comes into contact with the molten metal. V / ie from As can be seen in the drawings, the base part of the Z-element touches the edge of the cavity, creating a larger one Heat transfer surface is generated to provide a localized, point heating of the mold to a minimum to press down.

After the irregularly shaped metal anchor elements 18 are attached in the cavity of the casting / orra, the cavity is filled with ceramic material, which is numbered 22 in the drawing. This plastic, refractory material is said to be heat resistant and hardenable to form a dense ceramic surface capable of receiving cast, molten metal such as liquid steel.

As already indicated, the irregularly shaped metal anchor elements 18 preferably have a Z-shape. They can be mounted within cavity 12 in a variety of configurations. Your number should be large enough to have a good anchoring effect between the surface of the cavity 12 and the plastic, refractory material 22 to achieve.

The plastic, refractory materials made from

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exceptional results in using the invention are mainly composed of aluminum oxide and can include other ingredients such as inorganic phosphates, minor amounts of water, clay and the like contain. These so-called aluminum oxide ramming mixtures are described in US Pat. No. 3,547,664, and some of the counter-references are also discussed here are. A preferred type of starch mix like him in this patent specification has the following composition:

% By weight

Tabular aluminum oxide 3 »33 now (■ 6 mesh) 60 Calcined alumina -o, o44 mrn (~ 325 mesh) 28 Cyanite 0.295 mm (48 mesh). 5

Kaolin clay. 3

Phosphoric acid (85 # ig) Η-, ΡΟ, 4

ceramic fiber 0.12

Water 4

Compositions of the above type are pneumatic Means or the like pulped into the cavity of the mold, previously with the irregularly shaped Kotall anchor elements had been provided. In addition to the ceramic materials of the above kind In the context of the invention, other ceramic materials can also be used, provided they are thermally resistant in this way are to come into contact with the molten metal,

After the cavity has been filled 12 _f dns plfistiache refractory 'Oa is te rial treated with 22 heat the material fouorfeate to un in a uniform Fora. tie. Forms treated in this way have been put back into the Dinnr.t and in many cases have a

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-lo

ne achieved a much longer service life than is achieved with the use of new cast iron chairs.

It is apparent that the methods described for repairing eroded chairs can be used to make new chairs. For the production of new chairs, a cast iron chair is made, with a suitable cavity in its upper part, similar to the aforementioned cavity 12 _? contains. The irregularly shaped metal anchor elements 18 are fastened within the cavity and then the plastic, refractory material 22 is introduced into the cavity. If suitable casting devices are available, the irregularly shaped Me ta Hankerelemente can unite into the pre-formed cavity by the original casting process, rather than through use; subsequent Verenkerungsprozessesr.es are introduced. In accordance with the present invention, the ability of the chairs made in accordance with the methods described above to resist erosion can be further enhanced by the application of certain chair cover materials. These refractory materials are described in the following U.S. Patents, which are incorporated herein U.S. Pat. No. 3,104,815, U.S. Pat. No. 3,509,936, and U.S. Pat. No. 3,184,813 These materials are all known substances and are commercially available. Typical aluminum silicates are, for example, mica, an aluminum silicate with a layered structure, and mull it, an orthorombic aluminum from the island of Mull, which is also artificially produced by heating Can be made from andalunite, silimanite or cyanite. Excellent uiagneöiunisili ask kate

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ForsterΙΐ or talc, while zircon is useful Represents zirconium silicate. A. typical crystalline Silicate is quartz. The most preferred refractory material, which is described in more detail below is, represents silicate glass * The binder that comes with any one or more of the above refractory materials can be used, e.g. colloidal silica oil, aluminum phosphate, liquid acid Aluminum phosphates, ethyl silicate or alkali metal silicate represent. One of the preferred suspending agents for the foregoing refractories is colloidal Silicate sol, which is also described in detail in a later part.

The Schlarrm is used in such a tightness that that a coating of sufficient thickness is formed to prevent the aforementioned sticking and erosion su. To successful drying of the Sc II air ms with or without application by Warne, resulting in expulsion of the liquid phase from the surface of the basic component, leaving a thin film of solid, refractory coating behind, the molten metal is then placed in the mold and onto the upper part of the now coated base component poured.

After solidification has taken place, the liquid metal becomes an ingot from the coated basic component and the sides of the shape removed.

The liquid acidic aluminum phosphate binders represent materials that are normally produced by the chemical reaction of aluminum oxide with phosphoric acid will. The resulting products can take a variety of molecular forms, depending on the proportions

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ness of the respective reaction participants. Therefore the aluminum phosphates are best made by a ratio of PpO ₁ -: AIpO.? Are defined. Liquid aluminum phosphates, which are advantageously used in the application of the invention, have a ratio of ΡρΟ _Γ ί AIpO-, from 1: 1 to 5 * 1 ·

The aluminum phosphates are all acidic in nature and they must be kept in the acidic form if they are to be preserved as liquids. In general, aluminum phosphates which are suitable as binders in the process have a pH of less than 3.o. in one percent aqueous solution. The aluminum phosphate binder is usually in the form of an aqueous solution when mixed with one or more of the solid refractory materials listed above to result in a slug. Preferred binder solutions contain 10-65 percent by weight of aluminum phosphate solids based on total weight an aqueous solution containing dissolved aluminum phosphate.

Liquid aluminum phosphates suitable as binders are available under the name VALKOPIlOS ". Typical materials are e.g. "ALKOPHOS C" and "ALKOPHOS CE" the clear or pale colored aqueous solutions of Represent mixtures of mono- and di-aluminum orthophosphate. Analytical values of representative samples from these two materials are given in Table I below:

Table I.

ALKOPHOS C ALKO PHOS C E

Molecular weight 318 1110

P ₂ O ₅ 33.1 $ 36, o #

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ALKOPHOS C - ALKOPHOS GB

0, 8.6 j » 11, ο io

Viscosity at 25 ° C, cps 55-90 500-2000

Specific weight, 25 / 15.5 ° C 1.47 t, 60

pH, 1 $ solution '2.6 276

Free acid content

(as H ₃ PO ₄ ) 6.8 io o, o3 ⁰ I *

Percentage weight loss

at 110 ⁰ G 48, ο $ * 52.0 io

Estimated solubility 50-70 # 50-70 ° / o Melting point of the solids content

150-180O ⁰ C 1500-1800 ⁰ C

Alkali metal silicates represent another class of binders. Preferred binders are: sodium silicate and potassium silicate. Among these, sodium silicate is easier to obtain and at a lower price. As stated above, silicate material is preferably used in IPorir of sodium silicate. Commercially available material normally contains, usually in aqueous form, about 25 to about 40 wt.% Of solid sodium silicate. Typical products contain 3o to 4o Ge \ v .- $ of pesticide. These commercially available silicates can focus 7> \ x jeuem desired solids content or diluted. Alkali metal silicate binders preferred for use in accordance with the invention contain 5 to 45% by weight of alkali metal silicate in aqueous solution.

Just like water as a solvent for alkali metal silicone Can be used to form the liquid binders according to the invention, a binder also contain other solvents of a polar nature. It is necessary that the organic solvents are compatible with water, and not in

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have a harmful effect on the alkali metal silicate, for example by initiating its polymerization to a solid, unusable, glass-like mass. Particularly preferred organic substances which are used in combination with water as solvents for the alkali metal silicate compounds are those which lower the freezing point of pure aqueous alkali metal silicates by mixing them with aqueous silicate solutions. Such products are particularly useful during the colder months of the year when they must be stored and / or used at a relatively low temperature. Amines such as morpholine, diethylamine, etc. and organic polyhydroxy compounds such as ethylene glycol, glycerine, etc. are preferred substances for preparing solutions of alkali metal silicate binders.

Preferred "winterproof", non-freezing binders contain 5 to 45% by weight of alkali metal silicate, 1o to 95% by weight of water and 5 to 50% by weight of organic, hydrophilic polyhydroxy compound.

Regardless of whether the binder is a relatively rsine aqueous solution of alkali metal silicate or a combined one Solvent syatem that is both water and water compatible contains organic solvents of the above type, is the ratio of refractory Material to binders that form the sleep products according to the invention, 2: 1 to 1: 50. The preferred Sleeves contain refractory material, preferably crystalline silicate or silicate glass, which is in a or more of the binders described above is suspended, in a ratio of 2: 1 to 1:25

Another preferred binder is colloidal silica oil to make the slurries according to the invention form. The3 ainrl known materials? which in the trade

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Available silica oils which are used in the practice of the invention are sold under the name "Nalcoag". Silicate sols of this type are described below
described in Table II.

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Table II

Silicate Gol I, II III IV V VI

Percentage of colloidal

Silicate SiO ₂ 15 3o 35 - 36 21 - 22 49 - 5o 35

pH 8.6 10.2 6.6 3.7 9.0 3.5

Viscosity at 25 ⁰ C cps. less less less less ro - than than than than

ο 5 5 5 1o2o-3o6 _? 5

co specific gravity

cn at 2o ° C 1.09 1.2o5 1.255 1.06 1.385 1.255

- ^ Average surface

o before c * per g SiO ₉ 33o-43o 19o-27o 135-19o 135-19o 12o-15o 135-190

~ j ~

¹ ^ average! .Particle size

⁰⁰ in millimicrons 7.9 11-16 16-22 16-22 2o-25 16-22

Density (pounds / gallon)

at 2o C "9.1 I0.0 1o.5 8.8 11.6 I0.5

Percent Ka ₅ O o, o4 o, 4o o, 1o o.o5 0.30 c.o1

NJ N-) CO NJ CD CO

Other silica sols in addition to the above may be represented using known conventional techniques. In a preferred application of the invention, the silicate sols with a suitable base are either at the time their preparation or just before their use treated to a pH of at least 11.ο or preferably to get at least 11.5. These alkaline sols tend to stick to the covers of the chairs cause. Perhaps the most convenient method of making aqueous colloidal silicate sols is described in US Pat. No. 2,244,355, in which a dilute solution of an alkali metal silicate with a cation exchange resin is brought into contact in hydrogen form, whereby that silicate is converted into a dilute aqueous, colloidal silicate sol. The diluted SaI can become solid Conglomerations are concentrated, the more economical are usable from the standpoint of shipping costs and ultimate process usage in which the procedures outlined in ÜS-PSs 2 574 9o2, 2 68p and 2 6o1 23 * 3 are mentioned.

Another type of silicate sol made according to the invention Can find use, is described in US Pat. No. 2,856,3o2, love aqueous colloidal silicate other forms of colloidal silicate can be used, such as sols that contain a large amount of polar organic solvent. Such brine can generally referred to as a3 organo-sols and are of the brine type described in US Pat. No. 2,386,247 are. Rs iat only required that the used Silicate particles are colloidally distributed in a hydrophilic substance, such as water or lower alkyl alcohols or other organic compounds, relatively high dielectric constant,

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In some cases, mixtures of water with organic substances that are compatible with water can be used as Suspending medium used for the colloidal silicate particles will. Particularly preferred organic substances are those that reduce the freezing point of the pure aqueous brine by adding them to these aqueous silicate sols, reduce. Brine produced in this way are particularly cheap during the colder months of the year, if they have to be stored and / or used at a relatively low temperature. Amines such as ivloropholine, diethyl " amine, etc. and polyhydroxyorgano compounds such as ethylene glycol, glycerine, etc. are preferred materials for Formation of silicate sols that contain these substances as a sol-silicate suspending medium or as part of a Mixture to which additional water has been added. A preferred sol treated to protect against freezing contains 5 - 50 parts by weight of polyhydroxy compound such as ethylene glycol, 2o - 85 parts by weight of water and 1o to 6o parts by weight of silicate.

Regardless of the method used to produce colloidal silicate sol, the water, polar organic Contains liquids or mixtures of these substances as a continuous suspension phase, it is desirable that the brine contain silicate particles that are dense and are arorphous and have an average particle diameter that is Does not exceed 15o millimicrons, beoixzen. As can be seen from Table II, all silicate sols used as raw materials, an average Particle diameter less than 15o millimicron. The starting asilicate sols preferably have an average Particle diameter from 1o to 5o milliir.icron. The silica concentration in the brines can range between o.1 and 60% by weight of silicate, not restricted to silicon dioxide. Particularly inexpensive brines contain l.o bi3 6o Gow .-, ί

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of silicate and preferably 10 to 60 wt .- ^.

Other brine used as a binder for the refractory Silicate materials that can be used are called "salt-free" Known as silica brine. These are particularly preferred when the suspension is limited to the silicate particles of the binder consists only of a polar, organic liquid, or a 'mixture of' »Yasser and polar organic liquid Represents liquid. Since many of the aforementioned sols are normally used as stabilizers, alkali metal compounds contained, they are generally not comparable to organic systems, what with the fact related to the salts that are in the aqueous Sol, cause gel formation or precipitation of the silicate particles, if the aqueous phases through polar organic solvents are replaced. This can be achieved by using "salt-free" aqueous silicate sols as starting materials for the production of pure organosols or mixtures of aqueous and organic silicate carriers will. U.N; To prevent this gelling effect, it is necessary to remove the cations that cause this effect d, from the surface of the colloidally dispersed silica particles and remove from the liquid phase of the sol. This can easily be achieved if you are typical Silicate sols of the type of US Pat. No. 2,574,9o2 with a cation exchange resin in the hormone and a strong one Base anion exchange resin treated in the OH form. These Treatment results in an aqueous sol in which both the continuous aqueous phase of the sol and the silicate particles can be regarded as "salt-free". Typical, commercially available silicate sols used for manufacture "Salt-free" silicate sols that can be deionized are described in Table II above. These Aqueous "salt-free" silicate brine can either be used as such in combination with one or more of the named,.

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Refractory materials used to prevent an over-ζugs3Chlamrr! manufacture, or these "salt-free" silica sols may be found in use in modifiziei'ter Fo] ¹ * wherein the aqueous phase is wholly or partly by a hydrophilic polar liquid such as an alcohol is TZT ers ", or wherein DER alcohol with the aqueous Sol is mixed in the desired proportions. The "salt-free" pure alcoholic or aqueous alcoholic silicate sols can easily be combined with refractory material and the resulting hose is used to cover the chairs.

If the particle size of the above-described silicate sols is within the specified range, the silicate particles which are located within the aqueous or organic sol have specific surfaces, of Kunrü / uGrst 20 m "/ g and usually more than 100 m / g the deionized brine used as a binder, they generally have a salt content, expressed as NapSU., of less ice o.o1 ^l / l,

The sludge is used in an amount such that a coating of sufficient thickness is formed to prevent the aforementioned sticking and to prevent erosion. After the sludge has dried with or without the application of heat _t which leads to the expulsion of the liquid phase from the surface of the base unit and which leaves a thin film of solid, refractory coating, the molten metal is then poured into the mold and onto the upper part of the now covered basic structure ils poured. The liquid wet all "is removed from the coated base component and the sides of the mold after it has solidified into an ingot.

The cover sludge can be on or on the chair

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the base of the mold can be easily applied by a variety of methods. For example, the Schlamir. be applied by flowing it over the chairs, by spraying, or by covering the chair with the help of instruments, etc. The spraying method seems to be the most effective and practical method of applying schi arania. It is best to apply the mud to the part of the chair of the "big end down ^11" mold before placing the metal mold sides on top.

Effective removal of the liquid phase of the sludge The solid refractory material can likewise be made by a variety of methods. E.g. the Base part of the mold to be coated with the mud and gradually dry. Another method, a thin one Applying a protective coating consists of placing the mud on an already heated chair or on a Form that has oinen integral base to apply. This is particularly preferred when the chairs or their metallic molded sides or the "big end up" Molds are generally already cold before the molten metal is introduced, which is due to the residual heat from the foregoing, since in such a method the drying time is very short.

Another method of applying the protective file, consists in coating the base component and then heating it up, either quickly or slowly as desired to drive off the liquid portion of the sludge. In any case, it is necessary that the Coating in a V / ice is formed after the base member has come into contact with the sludge.

The most preferred method is the coating slurry Applied to chairs or Foringrunübauteile that a temperature of skin temperature up to 54o ° C is preferred

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from 9o ° to 43o ° C. The best adhesion of the solid cover to the chair is achieved by applying mud to chairs at a temperature of 9o to 26o G. Y / it has been determined that the best results were obtained with films of a thickness of o.o25 (o.oi inch) to 7.62 cm (3 inch), preferably from o.o25 (o.oi inch) to 0.318 (1/8 inch).

It is believed that the excellent coating success by using the slurry described above is achieved by their ability to produce a solid ceramic Coating to form even if this is on the basic components of the fora at relatively low temperatures of e.g. 26o ° C or even lower, at least below the casting temperatures. The coating will completely resistant to the influence of water and remains firmly adhered to the bases of the mold even when washing is done.

Once the coating has been formed, the preparation for casting is complete, except when "big end down" forms are used. In such cases, the sides of the form should - if not already during of the coating »available - can only be applied to the basic component after coating.

After the coating operation, the material is melted Metal poured into the mold, and after it has solidified into a cast block this separated from the sides of the mold. The invention does not require specific? pages the mold or bottom parts of the mold made of certain metal or the use of a certain casting metal and is therefore not restricted. As stated above two refractory materials are extremely suitable for coatings. Both materials are known and require deodorant

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half little further explanation. One of them is crystalline, refractory silicate material. Representative representatives are sand, crystalline silicate flour, crystalline silicate grains U3W.

Preferred refractory materials are silicate glasses. These are glass modifications of silicon dioxide which are recovered from selected low-temperature crystal modifications by melting and are often referred to as quartz glass or Siliciuniglaa. The specific silicon glasses also include those made of fused quartz glasses, silicate glasses, silicon dioxide glasses such as the well-known Vycor (registered trademark). The coefficient of thermal expansion of these above-mentioned materials is relatively small in relation to other refractory materials such as, for example, ICron glass and lead glass sotj'pan. ! In allger.einen they have Wärmeausdehnungskooffizionten smaller than 5 χ 1 o "crc / ° C are also the Siliciumdioxydgehalt this granular silicon containing refractory materials is high in general than 96;. 'F ° Silioiuttdioxyd expressed as SiO _r? and moves in a range of a height of about 99 «S fs SiOp. Thus, the term" silica glass "is used to denote a refractory material which contains silica glass with a coefficient of thermal expansion and a SiOp content within the range given above.

Bs has been found to give the best results when covering chairs when the refractory material used in the silicate sludge is obtained is able to withstand significant thermal shocks. ' Due to the extremely hot temperature of the molten Metal compared to the temperature of the chair, even when the latter is heated, occurs an extremely abrupt one Temperature changes when the metal is in contact with the chair

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emotion comes. The coating itself must be able to
to withstand this thermal shock in order to give the chair the necessary protection. It has been theorized that the failure of some more closely related materials
at least partially due to their U nf H hi jrl'e it
is to this sudden increase in warmth \ vi - the ~
stand, whereby a hot of the coating and thus an exposure of the metal surface to the sprayed, molten metal, which is poured into the mold.

In view of the foregoing, it is generally believed that the most preferred refractory materials
such ho) α evenness boi are at the same time the lowest coefficient of thermal expansion. These properties reside in particular in the silicon dioxide glass type, in particular those of the fused silicon dioxide type. The last-mentioned materials have a silicon dioxide content greater than 95 $, preferably greater than 97 $, expressed as SiO ₉ , and a V ^; ari; ift ^ usehnungöl «) u: fj ^. ^ ienten, who does not
is greater than about G χ 1 ο "em / cm / C.

A typical fused silica of the above described type, which is extremely useful in the practice of the invention, has a Ymrmeauadehnungskoef-

ty

efficient. from about b χ 1o cro / cn - / 'C, and the following type isc lie η Λ na Iy κ e η- \ ι erte:

Table III iI £ Lk- ¹ JIiLlLiT 11 ':

Δ 1 0 17

other Si 1iciumoxde 1.o

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_ 25 -

The above type of silica products will easily by grinding very pure, melted sill Obtain cium dioxide glasses. Likewise, can be used to manufacture borosilicate glasses and vyeoroilicate glasses are ground from extremely valuable refractory materials.

Another preferred refractory material represents aluminum oxide. It is a well-known material which is explained a little by its characterization shall be. For example, tabular, milled aluminas can be used with great success. An .excellent Alumina source makes calcined, fine ground aluminum oxide with low soda content and one Particle size of o.o44jim {- '325 menh).

The particle size of the refractories can vary over a wide range, but Ks is preferably, the particles of refractory material are sufficient are small to allow uniform distribution of refractory and binder. The smaller the particle size is, that's how long a sludge remains, which consists of a binder and refractory material is manufactured * in a homogeneous state. F. a it has been found that particles of 0.14 mm (15o meoh) down to a fraction of a micron be, can. Have the preferred refractories an average particle diameter of 20 to 100 microns, with particles whose diameter is the The lower limit is closer, are particularly preferred. Specific Silicon dioxide glasses, which are sold under the name "NaI-cast" · (registered trademark) fall within the preferred particle size range given above and have been used with great success ur; i erosion of the basic parts of castings and daa adherence to prevent the same from the cast blocks formed.

20 98 BO / 072-8 _f BAD ORIGINAL

The binder which is einon part of Üborzugsschlannrn, must in a sufficiently large amount present, may be to form m> the particles of the refractory material to bind, and thereby a tightly adherent, continuous and unbroken coating which is firmly connected to the surface of the stool . ' Without the required amount of binder relative to the refractory. After application and drying of the sludge, the resulting coating exhibits a so-called "pancake" effect, with numerous undesirable holes appearing in the coating and thereby releasing parts of the chair or the base surface of the casting mold. Preferred sludges therefore contain 10 to 70% by weight of refractory material and 3o to 90% by weight of binder. Particularly favorable Schlatnmzusäume NAET tongue η contain 2o to 60 percent. -Fo on. refractory material and 40 to 80 wt .- ^ binder.

The following examples show typical embodiments of the invention. These examples are only intended to illustrate the invention, but not to limit it. The following examples show typical slurries that can be created to form a uniform coating surface on the chair. The sodium silicate, which is part of the binder, contained 37.5 / 0 pesticides, the remainder being water. The examples serve to illustrate the invention. However, the invention is on. not limited to them. The percentages given are wt .- #.

Sodium silicate
crystalline silicate powder

Example II Sodium Silicate
WaEj 30 r
Crystalline Silikr-Itinehl

- 27 2Q98S0 / Q728

BATH ORIGINAL

.27 -

Belspiel III Sodium α3licate # Water

crystalline silicate flour

Sodium silicate water
θ / ζ crystalline silicate flour

$ liatric silicate

Vi'assor
^ crintalline silicate tie

Hatriuinr silicate

WHsanr

kr is' j 11 i no e Silikatir, «hl

The following example illustrates the effectiveness of the Schutaes according to the inventions "lower part of the chair against Erosion and subsequent sticking of the cast tube formed.

Example YlI

iiin about ^ .Ui-; Gschlan: m was in your following. Relationship formed:

Pound (e ngl. C

37.5> 3 aqueous solution of sodium

si'Jikat ""

. '. Vans he Ethylene glycol

kri 31 η 1 llii «a Sillkat flour 1 4ο bentonite

319.5 209850/0728

BATH ORIGINAL

The bentonite used as a dispersant was made with about three parts of the crystalline silica powder mixed and slowly added to the sodium silicate, which had been further diluted with water. After stirring for 15 minutes, ethylene glycol was added. The leftover crystalline silica powder was then rapidly stirred until a uniform suspension was obtained became *

Silicate gloss can be used in combination with sodium silicate to form a sludge that is exactly the same good or better oversight properties ί'εη ala the one just now has described mud. I'm an excellent mud combination contains "lialcast" material and Hatriura silicate.

The procedure cleared? The invention for the 'repair of eroded basic components of metal casting molds requires the application of a chair with the aim of reducing erosion, the sticking of the gun block to the plastic, ceramic insert and filling the gaps between the insert : l form the basic component of the Met a 3 Igussfurm, om the penetration of the metal to v ^ i-Miidum and around a Binuun ;; between the: ¹ · plastic insert and: 3 mandrel-eroded basic component to form the metallic Gu 3 for si.

Evaluation of the invention example \ ^r JU

In ei nor erodi orton Stuhlhfiblnng vif ^j r Z-shaped I.'etallHnkorrleniente der Γο1 /; (·!.) · Ϊ́ί! Η D.iiM: niiioiK-n be foot i / -J ·: f ', ⁷ ' 5 err χ 7.6 op χ G _t y.) Om. 'Aic \ o> den in L .-' / .- oii, v.ic in Fig. 1 of the Z "icJmuri ^ clnT-f'-üi-e"! Ii i:? T, angrln-rOlit and then j of, 'end ä: re :; p "zifi: ^.'] N: bi> -. C; ln · ^; .d.-ii.; Ü : Ί; \ ρί'βθΛΐΛ ; u: h o added. This composition was added ·; i «« ΐ ί- Jii 1 j Ί; a Üa ;; f; ickr? L wa'rrr.e, "; ehär1 et. ]) he so rep.'u · U'v1 <■ Stuhl wurrif! ni ^ jnn

2098 P0 / 0728

ORIGINAL BATHROOM

with. Chair cover material treated to seal any possible gaps and to prevent penetration of metal to prevent erosion and then about the adhesion of the cast block to the ceramic insert to decrease or turn off. The repaired chair was used 26 times in steel casting, of which approximately 1200 Tons of steel were poured.

- 3o -

20 9850/0728

BATH ORIGINAL

Claims (1)

Claims 1. A method for producing refractory inserts which are introduced into the upper surface of a basic component of a casting mold, characterized in that your buildings originally containing a cavity in the surface or inderr. the surface has been ground in the form of a cavity, at least two irregularly shaped metal anchor elements are attached in the cavity, the cavity is filled with thermally resistant, plastic refractory material, this plastic refractory material is heat-hardened and then a mud is applied to the upper surface made of refractory material suspended in a binder; is, is applied to produce a coating of sufficient thickness to prevent erosion and the sticking and this sludge is dried, whereby a protective, solid coating is formed on the basic component, the Schiamrc at least one of the refractory materials silicate glass, crystalline silicate , Al urnittiunir.il ikat, ^ luminiun: gx * aphit, zirconium silicate, magnesiUEsil ikat and clay. contains suspended as aqueous in at least one of the binders: alkali silicate, colloidal Siliknsol, liquid, acidic Aluminiurnphoaphat and Äthy] si] icate, wherein ass binder bonds the refractory particles and thereby form an adherent coating AuaB-ildet, which bound to the surface is. 2, method according to claim 1, characterized in that the irregularly shaped Ketallanke releinente Z - fönnig and with their basic part Touch the surface of the mold. 5 demonstrations HMch claim 1 or 2, whereby g e - ke η η ζ e I need that the plastic, uuv < fire- 209 8 50/0728 -j> J » BAO ORIGINAL solid material consisting of an aluminum oxide containing ramming mass. 4. The method according to claim 3, 2 or 3> thereby g e denotes that the refractory coating consists of aqueous, colloidal silicate sol as a binder and silicate glass made of refractory material. 209850/0728 Si Blank page