Casting into metal molds. Injection molding

Casting is a product obtained by pouring a liquid alloy into molds, in which, after cooling and solidifying, formation occurs. It can be a completely finished product or require further mechanical processing.

Divided into the following types:

• semi-finished products are ingots, which subsequently require a processing process;
• ingots processed under pressure;
• shaped castings – processed by cutting;
• finished products that do not require any mechanical processing are only cleaned or painted with decorative paint.

To produce castings, many types of metal and alloys, glass, plastic, wax and other starting materials are used. About 80% of blanks are obtained by sand casting, but the casting obtained in this way requires mandatory processing before being sent to the customer.

Foundry production makes it possible to obtain high-precision workpieces even with the most complex configuration, while gaps requiring processing are insignificant. The technology for producing castings is selected taking into account their size and production method.

There are three groups for producing castings:

1) in one-time forms;

2) according to soluble models;

3) casting in semi-permanent and combined type molds made of refractory materials:

These are the main types of casting, but in practice combined options are also used.

A little history

The most important feature of iron, when it solidifies, to take the form “proposed” to it, was noticed by man back in ancient times. Today, almost all scientists assume that man’s initial acquaintance with metal took place thanks to meteorites. Meteoric iron was fusible and easy to process, so some nascent civilizations had been studying the basics of casting for a very long time.

In our country, metal casting has been a respected and honorable business from time immemorial; people have always treated this craft with great respect. The “Tsar Cannon” and “Tsar Bell” are widely known, being masterpieces of Russian foundry craftsmanship, even if one of them never rang and the other never fired. During the reign of Peter the Great, the Ural foundry workers gained particular fame as suppliers of reliable weapons for the army. However, they rightfully bear this title even now. Before we look at the main types of metal casting, it is necessary to say a few words about the required characteristics of the raw materials.

Where do the supplies of raw materials and equipment come from?

Ferroalloys, alkali metal salts, boric acid, bentonite, etc. are used as the main chemical components. The main suppliers and delivery conditions are presented in the table:

Domestic raw materials are used, as well as those supplied from China, Sweden, and Ukraine.

What type of metal should be used for casting?

The most important property of the metal that is supposed to be used for casting is its fluidity. The alloy in molten form should flow as easily as possible from one crucible to another, while filling its smallest recesses. The higher the fluidity, the thinner the walls can be made of the finished product. It’s much more difficult with metal that doesn’t flow well. Under normal conditions, it manages to set much earlier than it fills all the gaps in the form. It is this complexity that industrialists face when casting metal alloys.

It is not surprising that cast iron became the favorite material of foundries. This is because this alloy has excellent fluidity, making it relatively easy to work with. Steel is far from being so fluid, and therefore to completely fill the mold (so that there are no cavities and voids) you have to resort to a variety of tricks.

In the simplest case, when home-made metal casting is required, the raw materials are melted and poured into water in small portions: this way, in particular, fishing sinkers can be made. But this method is relatively widely used even in the weapons industry! From the top of a special tower, whose outline resembles a cooling tower, molten metal also begins to pour out in measured doses. The height of the structure is such that a perfectly formed droplet, already cooled, reaches the ground. This is how shot is produced in industrial quantities.

Squeeze casting

The technology is used when constant compensation for material shrinkage is required, and is used for casting large castings with thin walls. To do this, the movable half-mold receives forced movement towards the surface of the melt - by rotation, screw or plane-parallel movement. The sequence of transitions is as follows. The metal is poured into the lower part of the mold, then its moving part is moved until it comes into contact with the melt, while the excess is poured into the receiving ladle of the installation. Since constant thermal contact is maintained between it and the base metal, heat loss is minimal, and the physical and mechanical parameters of the material are uniform in all sections. The form completion rate also increases. After solidification, the movable half-mold moves to its original position, and the finished casting is pushed out of the cavity.

Advantages of the process:

1. Increased structural homogeneity of the casting.
2. High uniformity of physical and mechanical characteristics of the material.
3. High process productivity.

Press casting is mainly used to produce products from aluminum cast alloys.

"Earth" casting method

The simplest and most ancient method is to cast metal into the ground. But its “simplicity” is a relatively relative concept, since this work requires extremely painstaking preparation. What does it mean?

First, a full-size and maximally detailed model of the future casting is made in the model shop. Moreover, its size should be slightly larger than the product that should be obtained, since the metal will settle during cooling. As a rule, the model is made detachable, from two halves.

Once this is completed, a special molding mixture is prepared. If the future product must have internal cavities and voids, then you will also have to prepare rods, as well as additional molding composition. They must temporarily fill those areas that are “empty” in the finished part. If you are interested in casting metals at home, be sure to remember this circumstance, since otherwise the already filled flask may simply be torn apart by pressure, and the consequences of this may be the most tragic.

Basic methods of metal casting

Casting into the ground

Traditional way. A simple or composite model is made from wood or other modeling materials, then a matrix is ​​made from a sand-clay mixture based on the model. Read more about this method in the corresponding article.

Earth casting technology

The model is removed from the mold, its parts are assembled together, and a gating system is created. The form is pricked with thin sharp needles to ensure gas removal. They make a casting, wait for it to cool,

Metal casting

A split mold, called a mold, is made from metal parts. Matrix parts are produced by casting or, if high surface quality and dimensional accuracy are required, by milling. The molds are lubricated with non-stick compounds and filled.

Metal casting

After cooling, the molds are disassembled, the castings are removed and cleaned. The metal matrix can withstand up to 300 operating cycles.

Casting using gasified models

The model is made not of wood or wax, but of a low-melting and gasifying material, mainly polystyrene. The model remains in the mold and evaporates when the metal is poured.

Casting using gasified models

Advantages of the method:

• the model does not need to be extracted from the matrix;
• you can make models of as complex castings as you like; complex and composite molds are not needed;
• The complexity of modeling and molding has been significantly reduced.

Gasification casting is becoming increasingly popular in modern metallurgical industries.

What are molding sands made from?

The basis is various types of sands and clays, as well as binding compositions. Their role can be natural and synthetic oils, drying oil, resin, rosin, and even tar.

Next comes the time of molders, whose task is to make casting molds. To explain it more simply, this is done like this: take a wooden box, put half of the mold in it (it’s also detachable), and the spaces between the walls of the model and the mold are clogged with molding compound.

They do the same with the second half and fasten both parts with pins. It is important to note that two special cones are inserted into the part of the mold that will be at the top when pouring. One of them is used to pour in molten metal, the second is used to release expanding gases.

Features of metal casting

Compared to other materials, such as wax or plaster, metal casting differs in several ways. The first of them is the high temperature of transition from solid to liquid state. Wax, plaster and cement harden at room temperature. The melting point of metals is much higher - from 231 °C for tin to 1531 °C for iron. Before you can start casting the metal, it must be melted. And if tin can be melted in a clay bowl on a simple fire made from nearby branches, then to melt copper, not to mention iron, you will need a specially equipped furnace and prepared fuel.

Tin

Lead

Tin and lead - the softest and most fusible metals - can even be cast into wooden dies.

For casting more refractory metals, molds made from a mixture of sand and clay will be required. Some metals, such as titanium, require metal molds for casting.

After pouring, the product needs to cool. Reusable dies are disassembled, disposable molds are destroyed, and the casting is ready for further machining or use.

End of the preparatory stage

And now the time comes for perhaps the most important part of the operation. The flasks are separated very carefully, trying not to damage the integrity of the molding sand. After this, two clear and detailed imprints of the future part remain in the ground. After this they are coated with special paint. This is done so that the molten metal does not come into direct contact with the ground of the molding sand. Metal casting technology should not allow this, since otherwise the quality of the finished product may significantly deteriorate.

If there is a need for this, at the same time an additional gating passage is cut, which is necessary for pouring the melt. The flasks are folded again and connected as firmly as possible. Once the molding mixture has dried slightly, you can begin casting.

Start of casting

First, cast iron billets are melted in cupola furnaces, that is, special furnaces. If steel is required to be cast, the raw materials are melted in blast furnaces, open-hearth furnaces, inverter furnaces and other furnaces. To bring non-ferrous metals into a state of melting, specialized melting devices are used.

That's it, you can start casting. If there is only one mold, then the melt is poured into it with a ladle, individually. In other cases, as a rule, a conveyor is organized: either a belt with workpieces goes under the bucket, or the bucket moves over the rows of flasks. Here everything depends solely on the organization of production. When the time comes and the metal has cooled, it is removed from the mold. In principle, this method is ideal in cases where metal casting is required at home (for a forge, for example). It’s still not possible to achieve anything more perfect under such conditions.

Sandblasting or grinding machines are used to remove scale and adhering molding sand from the finished product. By the way, this method was actively used in the production of tanks during the Great Patriotic War. This is exactly how cast turrets were produced, and the simplicity and manufacturability of this process made it possible to produce a huge number of combat vehicles that were so needed by the front. What other types of metal casting are there?

Equipment and forms

Arc or induction electric furnaces are used as melting equipment in foundries. The type of equipment is determined by the metals the foundry/site is working with: electric arc furnaces are ideal for working with steel or cast iron, while a foundry specializing in copper is more likely to use an induction furnace. Ovens can range in size from small tabletop units to those that weigh several tons.

Modern foundries are mechanized. Almost all operations of the cycle are subject to mechanization: from the production of cores to the actual casting. Molding machines are used in the serial production of castings. Manual molding is common only in small repair industries.

The main equipment includes:

• Melting furnaces;
• Pouring ladles;
• Loading and transport equipment - loaders, cranes, conveyors, etc.
• Control and automation equipment.

An electric arc furnace operates on the principle of periodic melting. The metal is melted by introducing electrical energy into the furnace through graphite electrodes. Additional chemical energy is supplied by oxy-fuel burners. Oxygen is introduced to remove impurities and other dissolved gas. When the metal is melted, slag forms and floats to the top of the melt; the slag, which often contains undesirable impurities, is removed before discharge.

An induction furnace transfers electrical energy by induction, where a high voltage electrical source induces a low voltage, high current in a secondary coil. Induction furnaces are capable of operating with minimal loss of raw materials, but are more used in the production of castings from non-ferrous metals and alloys.

All foundry equipment is specifically designed to operate reliably at elevated temperatures. The dominant trends in the production of this technology are scale, automation, rapid finishing of castings, increased safety and efficiency.

What lubricants are used? The choice depends on the brand of material and casting method. The initial concentrate in liquid form must be water-soluble, and in solid form heat-resistant pastes are used.

Chill casting

But now they use much more advanced and technological methods for the production of cast products. For example, casting metal into a chill mold. In principle, this method is in many ways similar to the one we described above, since in this case, casting molds are used. Only at the same time they are metal, which greatly simplifies the process of large-scale production.

So, cones and rods are inserted into the two halves (to pour metal and create voids), and then firmly fasten them to each other. That's it, you can start working. The peculiarity of this method is that here the molten metal solidifies extremely quickly, there is the possibility of forced cooling of the molds, and therefore the release process is much faster. With just one die, you can produce hundreds, or even thousands, of castings without spending a lot of time on individual preparation of molds and molding sands.

Technology of foundry production of ferrous and non-ferrous metals

The casting properties of materials take into account not only fluidity, but also the decrease in volume that occurs during the cooling process of the casting. This phenomenon is called shrinkage; it is 1...3% of the original dimensions. Since all metals are anisotropic, a distinction is made between linear and volumetric shrinkage, which determine the final balance of the metal. The first parameter is important for castings with an increased length to width ratio, and the second is important for castings of complex shapes.

During the cooling process of the metal, segregation is observed in its structure - heterogeneity of grains, which is caused by the different properties of the components. Impurities and non-metallic inclusions are also formed. Liquation negatively affects the properties of the final product, so they try to reduce the heterogeneity of the structure by all acceptable means. In particular, the current GOST 26645-85 “Castings from metals and alloys” limits the content of phosphorus, sulfur (as well as their compounds - sulfides and phosphides), a number of gases - hydrogen, oxygen, as well as the amount of slag not removed from the metal.

Depending on the casting properties of metals, a decision is made on the choice of appropriate technology for producing castings. There are free casting in molds (sand or metal), injection molding, squeeze casting, centrifugal casting, as well as combined methods, for example, liquid stamping.

Some disadvantages of the method

The disadvantage of this casting method is the fact that only those types of metals that are characterized by increased fluidity in molten form are suitable for it. For example, only injection molding is suitable for steel (more on this below), since this material does not have good fluidity at all. Under the influence of compressed air, even the most “ductile” steel grades take the required shape much better. The bad thing is that an ordinary mold simply won’t withstand such extreme production conditions and will fall apart. Therefore, we have to use a special production method, which we will discuss below.

Injection molding

How is metal injection molded? We have already discussed some aspects above, but it is still necessary to discuss this issue in a little more detail. Everything is quite simple. Firstly, you need a casting mold made of high-quality steel, which can be multi-stage, with a complex internal shape. Secondly, you need injection equipment capable of delivering from seven to seven hundred MP.

The main advantage of this smelting method is high productivity. What else does injection molding provide? In this case, much less metal is used, and the surface quality of the finished product is very good. The latter circumstance involves abandoning the complex and rather tedious procedure of cleaning and polishing. With this production method, what materials are most preferable to produce finished products and parts from?

The most commonly used alloys are based on aluminum, zinc, copper and tin-lead (non-ferrous metal casting). Their melting point is relatively low, and therefore very high manufacturability of the entire process is achieved. In addition, this raw material has a relatively small sediment upon cooling. This means that parts can be produced with very tight tolerances, which is extremely important in modern technology.

The complexity of this method is that when separating finished products from molds, they may be damaged. In addition, this method is only suitable for the manufacture of parts with relatively small wall thickness. The fact is that a thick layer of metal will harden extremely unevenly, which will predetermine the formation of cavities and cavities.

Die casting

All types of chill casting are a group of methods especially suitable for producing castings from non-ferrous alloys - aluminum, magnesium and brass. Before casting, the functional surfaces of the molds are treated with a special kaolin or similar coating, which will effectively separate the surfaces. Molds that cannot be removed from the mold are often made using sand cores. After casting, the cores are destroyed.

Compared to sand casting, the solidification of the mold occurs faster due to better thermal conductivity. A casting is formed with a relatively fine and dense material structure, which, at the same time, has better mechanical properties compared to a casting from the same material, but cast in a sand mold.

Advantages of die casting:

• due to faster solidification, chill casting has better mechanical properties and a relatively fine and dense material structure;
• slight surface porosity;
• high dimensional accuracy and reduced surface roughness;
• reduction of metal loss coefficient.

Chill casting is a good choice for producing medium-sized castings for runs of 1,000 to 10,000 pieces, with a minimum production run of 100 pieces.

The process is used to produce medium-sized castings of instrument housings, drive covers, racks, brass or steel sealing inserts (nuts, bearing housings, pins, etc.).

Types of installations for "spinning" casting

All machines that are used in this method of casting metal products are divided into two large groups: with a hot and cold casting chamber. The "hot" variety can most often only be used for zinc-based alloys. In this case, the casting chamber itself is immersed in hot metal. Under the pressure of air or a special piston, it flows into the casting cavity.

As a rule, a strong injection force is not required; pressure up to 35-70 MPa is enough. So, in this case, molds for metal casting can be much simpler and cheaper, which has the most favorable effect on the final cost of the product. In cold casting molds, the molten metal has to be “driven” deep into the casting chamber under particularly high pressure. Moreover, it can reach 700 MPa.

Metals for pouring

Black metals

In the metallurgical industry, a distinction is made between non-ferrous and ferrous metals. Blacks include iron, manganese, chromium and alloys based on them. This includes all steels, cast irons and ferroalloys. Ferrous metals account for more than 90% of the world's consumption of metal alloys. Steel is used to produce hulls and parts of vehicles from scooters to supertankers, building structures, household appliances, machine tools and other industrial equipment.

Cast iron

Cast iron is an excellent metal for casting large, strong, durable structures that are not subject to bending or twisting stresses.

Non-ferrous metals, in turn, depending on their physical properties, and above all, specific gravity, are divided into two large groups

Light non-ferrous metals

This group includes aluminum, titanium, magnesium. These metals are less common than iron and are more expensive. They are used in those industries where it is necessary to reduce the weight of a product - the aerospace industry, the production of high-tech weapons, the production of computing and telecommunications equipment, smartphones and small household appliances.

Titanium

Titanium, due to its excellent interaction with the tissues of the human body, is widely used for prosthetics of bones, joints and teeth.

Heavy non-ferrous metals

These include copper, tin, lead, zinc and nickel. They are used in the chemical industry, production of electrical materials, electronics, transport - wherever sufficiently strong, elastic and corrosion-resistant alloys are required.

Copper

Zinc

Nickel and its alloys

Noble metals

This group includes gold, silver, platinum, as well as rarer ruthenium, rhodium, palladium, osmium, and iridium.

The first three have been known to man since prehistoric times. They were rarely (relative to copper and iron) found in nature and therefore served as a means of payment, material for valuable jewelry and ritual objects.

Gold and platinum

With the development of civilization, gold and platinum retained their role as a means of accumulating wealth, but they became very widely used in industry and medicine due to their unique physical and chemical properties.

Lost wax casting

As in the very first case we considered, from ancient times mankind knew about the method of pouring molten metal into a previously prepared model made of paraffin or wax. It is simply placed in the flask and the gaps are filled with molding sand. The melt dissolves the wax and ideally fills the entire volume of the primary workpiece. This method is good because the model does not need to be removed from the flask. In addition, it is possible to obtain parts of simply ideal quality; this metal casting process is relatively easy to automate.

Shell casting

If the casting is relatively simple, and “cosmic” strength is not required from the finished product, the method of casting into shell molds can be used. They have been made since time immemorial, using fine quartz sand and resin as the base. Today, naturally, various synthetic compounds are used as the latter.

Then dismountable metal models, consisting of two halves, are taken and placed on a surface heated to approximately 300 degrees Celsius. Then the molding mixture (from sand and dry resin) is poured there so that it completely covers the surface of the metal models. Under the influence of heat, the resin melts, and a fairly strong “molding flask” appears in the thickness of the sand.

As soon as it all cools down slightly, the metal pigs can be removed, and the sand can be sent to the oven for “roasting”. After this, fairly strong forms are obtained: by connecting their two halves, you can pour molten metal into them. What other metal casting methods are there?

Defects in casting alloys

Before the casting production cycle is completed, the physical properties and structural integrity of the final product must be verified. Test methods can be destructive or non-destructive. The choice of defect detection method depends on the technological purpose of the part. Some purely aesthetic products require only a brief visual inspection to determine dimensional accuracy, presence of cracks, and quality of finish. For castings with industrial applications, all physical and mechanical properties of the metal (ductility, tensile strength, elongation, impact strength, hardness, etc.) are established during testing.

The most common casting defects are:

1. Shrinkage defects. When metal hardens after being poured into molds or casting, it should shrink. When there is not enough metal, shrinkage of the cast iron will cause holes or voids to form in the casting. There are many types of shrinkage depending on its cause. With axial shrinkage, the material in the center takes longer to harden compared to the metal at the periphery, which leads to the formation of a cavity. This may be caused by the temperature at which the molten metal is poured, the speed of pouring, or the quality of the feedstock.
2. Dispersive shrinkage. Dimensional changes in alloy elements can lead to a type of shrinkage where cavities form perpendicular to the casting surface. High nitrogen content or low carbon content can lead to this type of defect.
3. Sometimes all foundry products may have the same type of defects in size. The reason is the different speed of solidification of different parts of the casting.
4. Stitches or scars. This is a metallurgical defect, which is characterized by the presence of depressions on the surface of the casting. A defect is likely when graphite moves into shrinkage cavities during the melting process.
5. Slag inclusions. They are small spots found on the surface of castings. Such inclusions are caused by contamination of the parent metal with carbides, calcites, oxides and sulfides.
6. Failure to complete certain areas. Caused by the presence of gas in certain parts of the mold, reduced fluidity of the material. It will be necessary to increase its heating temperature and/or melt it in a vacuum.

Centrifugal casting

In this case, the melt is poured into a special mold, which rotates at a very high speed in a horizontal or vertical projection. As a result of the action of powerful equally applied centrifugal forces, the metal flows evenly into all spaces of the mold, thereby achieving high quality of the finished product. This casting method is ideal for producing various types of pipes. It allows you to mold a much more uniform wall thickness, which is extremely difficult to achieve using “static” methods.

Centrifugal casting

Centrifugal casting is used to produce parts with the shape of a rotating body made of cast iron, aluminum, steel and bronze. The melt is poured into a metal mold, which rotates at speeds of up to 3000 rpm.

Due to centrifugal force, the melt is evenly distributed inside the mold, and after crystallization, a casting is formed. This method makes it possible to obtain two-layer workpieces consisting of various alloys. The casting obtained in this way has a high density and good physical and mechanical properties.

The big advantage of centrifugal casting is the possibility of forming internal cavities without the need to use rods, as well as saving alloy due to the absence of a gating system. This method produces up to 95% of suitable products.

The production process uses equipment equipped with horizontal axes of rotation. The centrifugal casting method is widely used to produce castings of sleeves, bushings and other parts with the shape of a rotating body.

Electroslag casting

Are there any methods of metal casting that can rightfully be called modern? Electroslag casting. In this case, liquid metal is first obtained by exposing previously prepared raw materials to powerful electric arc discharges. The arcless method can also be used, when the iron melts from the heat accumulated by the slag. But the latter is affected by powerful discharges.

After this, the liquid metal, which has never come into contact with air throughout the entire process, enters the crystallization chamber, which also doubles as a casting mold. This method is used for relatively simple and mass castings, for the production of which many conditions do not need to be met.

Historical reference

The most ancient products (blanks of beads, plate overlays and pendants, fishhooks, etc.), cast from native copper in open molds and processed by hot forging, were discovered during excavations of the “pre-ceramic Neolithic” monuments of the Middle East, dated to the end. 8th – 7th millennium BC e. (Magzaliya, Chayenu-Tepezi, Çatalhöyük, etc.). Lithuania in detachable and composite stone forms (tools, weapons, jewelry, religious objects, etc.) originated in the Chalcolithic of the Southeast. Europe in the system of the Balkan-Carpathian metallurgical province (5–4th millennium BC). L. in closed stone, clay and metal. forms and melted models spreads in the Early Bronze Age in the system of the Circumpontic metallurgical province, reaching its peak in the Old World in the Late Bronze (2nd - early 1st millennium BC) and early Iron Ages. L. technology was widely used in the Middle Ages.

In Russia, in 1479, the first foundry was built - the “cannon hut” (Moscow). During the reign of Ivan IV, foundries were created in Tula, Kashira and other cities; under Peter I - foundries in the Urals, in the south and north of Russia. states. One of the largest castings in the world, made in 1873 at the Perm plant, is the chabot (the lower part that receives the impact) of a steam hammer (650 tons). The skill of the old Russian foundry workers is well known. factories - Kaslinsky, Putilovsky, Sormovsky, Kolomensky, etc. Until the 19th century. in L. they used the previously accumulated centuries-old experience of craftsmen. Only at the beginning 19th century were laid down theoretically. fundamentals of foundry technology. Growing up at work. scientists P. P. Anosov, N. V. Kalakutsky and A. S. Lavrov, D. K. Chernov for the first time scientifically explained the processes of crystallization, the occurrence of liquation and internal. stresses in castings, ways to improve the quality of castings are outlined.

Vacuum filling

It is used only in the case of “elite” materials, such as gold, titanium, high-quality steel. In this case, the metal is melted under vacuum conditions, and then quickly (under the same conditions) distributed into molds. The good thing about this method is that when it is used, the formation of air cavities and cavities in the product is practically eliminated, since the amount of gases present there is minimal. It is important to remember that the weight of the castings in this case cannot exceed hundreds or two kilograms.

Is it possible to obtain parts of greater weight?

Yes, such technology exists. But it can only be used in cases where one hundred tons of steel or more are simultaneously processed. First, the metal is melted under vacuum conditions, and then it is poured not into molds, but into special molding ladles, which are also protected from air entering their cavity.

After this, the finished melt can be distributed into molds, from which the air has also been previously pumped out with a pump. The steel obtained as a result of this technological process is quite expensive. It is used for forging, as well as some types of casting, when it is required to obtain blanks and parts of the highest possible quality.

Casting using gasified (burnt out) models

In terms of casting quality and simplicity, this method is one of the most profitable, and therefore it is used more and more widely in modern industry. This type of metal casting, the production of which is increasing year by year, is especially popular in China and the USA, since the industrial bases of these two countries have the greatest need for high-quality steel. The advantage of this method is that it allows the production of castings without any restrictions on weight and size.

In many ways, this method is similar to those described above: for example, in this case, the primary model is used not from wax or plasticine, but from the now widespread foam plastic. Since this material has its own specifics, the binding sand mixture is filled into the flask under a pressure of approximately 50 kPa. Most often, this method is practiced in cases where it is necessary to make parts weighing from 100 grams to two tons.

However, we have already said that there are no strict restrictions on the size of parts. Thus, using this casting method, even components for ship engines, which have never had “modest” dimensions, can be produced. For each ton of metal raw materials, the following amount of additional materials is consumed:

• Fine quartz sand - 50 kg.
• Special non-stick coating - 25 kg.
• Granulated polystyrene foam - 6 kg.
• Thick polyethylene film - 10 sq. m.

The entire molding mixture is pure quartz sand without any additional additives or additives. It can be approximately 95-97% reused, which significantly increases efficiency and reduces the cost of the process.

Thus, metal casting (the physics of the process was partially considered by us) is a “multifaceted” phenomenon, since today there are a lot of new techniques. In parallel, modern industry uses methods that were in use several thousand years ago, slightly adapting them to current realities.

Composition of chill coatings

To increase the durability of chill molds, fire-resistant linings and paints are used. The forming surfaces of the mold are coated two to three times per shift or, if necessary, can be coated more often, with a fire-resistant lining with a layer of 0.1 - 1 mm or more, and are coated with paint before each metal pouring. See the table below for coating compositions.

Paints for determining chill temperature

Composition of fire-resistant linings

Composition of paints for coating molds