Foundry is the main base of the machine-building complex and its development depends on the pace of development of machine-building as a whole.
At the XI Congress of foundry workers of Russia in Yekaterinburg in September 2013, the question of the state of the foundry industry, which is inextricably linked with the development of mechanical engineering, was sharply raised.
The production of Russian castings over the years of reform has decreased by 4.5 times from 18.5 million tons to 4.2 million tons and tends to decrease below 4.0 million tons in 2013. The number of foundries has decreased almost three times from 3500 to 1250 enterprises. 10 research institutes liquidated foundry.
The export of casting is insignificant, the export of foundry equipment is practically non-existent. At the same time, the import of foundry equipment, including for foundries metallurgical plants for 10 years since 2003 has increased almost 9 times, exceeding 1.0 billion US dollars. USD in 2012.
Urgent measures are needed to revive the Russian foundry industry, for which it is necessary to unite the efforts of foundries, the engineering industry, and scientific potential with real support government organizations and financial institutions for development within the framework of public-private partnership.
The article of the President of the Association of foundry workers of Russia prof. Dibrova I.A.

Fig.1. Casting output by country in 2011

Foundry production in Russia is the main base of the machine-building complex and its development depends on the pace of development of machine-building as a whole. The prospects for the development of foundry production are determined by the need for cast billets, their production dynamics, the authority of foundry technologies and competitiveness among developed foreign countries.

Consider the state of foundry production in Russia.

In 2011, 98.6 million tons of castings from ferrous and non-ferrous alloys were produced in the world, including 4.3 million tons in Russia, which is 4.36%

The output of castings by country is shown in fig. 1, which shows that the leading place in the production of castings is occupied by China, which today produces about half of the world's output of cast billets.

Fig.2. Casting output in BRICS countries in 2011

Russia ranks 6th after China, USA, India, Germany and Japan.

Casting output in the BRICS countries in 2011 amounted to 59.49 million tons, which is 60% of the world production (Fig. 2). Russia ranks third among the BRICS countries and produces 8.22% of the output of castings by these countries.

Foundry production in Russia occupies a leading position among such procurement bases of mechanical engineering as welding and a forge. Metal utilization ratio (from 75 to 95%). On the other hand, foundry production is the most knowledge-intensive, energy-intensive and material-intensive production. For the production of 1 ton of castings, it is required to remelt 1.2-1.7 tons of metal charge materials, ferroalloys and fluxes, process and prepare 3-5 tons of foundry sands (when casting into sand-clay molds), 3-4 kg of binders (with casting in molds from XTS) and paints. In the cost of casting, energy costs and fuel account for 50-60%, the cost of materials 30-35%.

Fig.3. Casting production volumes in Russia from 1990 to 2012

Dynamics of casting production in Russia from 1990 to 2012 shown in fig. 3. The highest production volumes of castings were in 1985 and amounted to 18.5 million tons. After that, a sharp decline in production began, associated with a violation general principles cooperation of engineering products between the republics of the USSR, privatization and liquidation of enterprises. About 20 enterprises were closed in Moscow alone, including AMO ZIL, the Stankolit, Dynamo plants, the plant named after. Voykov, which produced about 500 thousand tons of casting. From 2001 to 2008 casting production stabilized at 7 million tons. In the future, the decline in the production of castings is associated with the economic crisis, the reduction of qualified personnel, primarily pensioners, and the closure of enterprises. In recent years, the production of castings from ferrous and non-ferrous alloys has stabilized at the level of 4.2 - 4.4 million tons.

The total number of foundries in Russia is about 1250, which produce castings, equipment, and related materials.

The output of castings per worker in 2012 amounted to about 14.3 tons per year.

The foundry industry of mechanical engineering and metallurgy (according to expert estimates) employs about 300 thousand people, including 90% of workers, 9.8% of engineers and 0.2% of scientists.

The main number of foundries in Russia (78%) are small foundries with an output of up to 5,000 tons of castings per year.

Data on capacities, output volumes and the number of employees in foundries, according to information available to the association, are given in Table. one.

Table 1. Analysis of the state of production in Russia by capacity, output and number of employees

№	Casting output (t per year)	Number of working people	Number of enterprises	%	Notes
1	50000-100000	2000-3000	12	1	Foundry shops of automobile plants, power engineering, defense complex
2	10000-50000	500-2000	84	6,7	Foundry shops of large machine-building plants
3	5000-10000	200-500	180	14,4	Workshops of machine-building plants and individual workshops
4	1000-5000	50-200	430	34,4	Shops of machine-building enterprises
5	Less than 1000	50-100	544	43,5	Small workshops for various purposes

According to technological processes, the production of castings is distributed as follows:

Table 2. Production of castings by technological processes, %

78% of castings are produced on mechanized lines and machines and manually. The level of automation and mechanization of foundry production in Russia is presented in Table. 3.

Table 3. The level of automation and mechanization of foundry production

Currently, the export of castings is 30 thousand tons per year to such countries as Germany, England, France, Israel, Sweden, Norway, Finland, imports are about 70 thousand tons.

Casting production volumes significantly depend on the production volumes of domestic foundry equipment for own needs and export supplies.

A number of major manufacturers of foundry equipment in Russia have retained and expanded their specialization, but they do not meet the needs of foundries and factories. The following equipment is not produced in Russia:

• automatic and mechanized lines for the manufacture of flask-free molds from sand-clay and cold-hardening mixtures;
• machines for making molds from sand-clay mixtures with flask sizes from 400x500mm to 1200x1500mm;
• machines for the manufacture of foundry cores for hot and cold tooling;
• equipment for painting molds;
• chill machines;
• low pressure casting machines;
• centrifugal casting machines;
• medium-frequency induction furnaces with a capacity of more than 10 tons for iron and steel smelting;
• batch and continuous mixers for the preparation of cold hardening mixtures with a capacity of more than 10 tons/hour;
• equipment for the regeneration of cold-hardening mixtures with a capacity of more than 10 tons / hour.

An incomplete range of high pressure casting machines is produced.

The foundry equipment fleet has been updated slightly over the past 5 years, its average age is 28 years.

Fig.4. Dynamics of imports of foundry equipment from 2003 to 2012

In this regard, it is expected that in the next 5-10 years the missing equipment will be purchased from foreign companies in Germany, Italy, the USA, Japan, Turkey, Denmark, England, the Czech Republic, France, etc.

Let's evaluate the market for imported equipment.

Dynamics of imports of foundry equipment to Russia from 2003 to 2012 (million US dollars) is presented in Figure 4.

In 2012, imports of equipment, spare parts and fixtures for foundry and related industries from all over the world amounted to about 705 million dollars. USA. Dynamics of imports of foundry equipment from all countries of the world from 2007 to 2012 (million US dollars) is presented in Table. 4.

Table 4. Dynamics of imports of foundry equipment from 2007 to 2012

2007	2008	2009	2010	2011	2012
833,1	948,1	632,2	499,15	676,24	1081,5

Until 2012, the highest volumes of supplies of foundry equipment to Russia from all countries of the world were in 2008, but in 2012 the volume of supplies of equipment increased and amounted to more than 1 billion dollars. USA. Deliveries of foundry equipment alone amount to 720 million US dollars, the remaining 259.5 million dollars. The United States supplied Russia with castings, moulds, pallets, various fixtures and fittings, including those for foundry shops in metallurgical production. Deliveries of foundry equipment from the leading countries of the world for the last three years (2010-2012) are presented in Table. 5 (million US dollars).

Table 5. Deliveries of foundry equipment from the leading countries of the world in 2010-2012

Table 5 shows that casting equipment is mainly supplied from Germany and Italy. In general, 72% of foundry equipment is purchased from foreign countries. Therefore, the production of castings for the manufacture of domestic equipment is declining.

Despite the low level of casting production in recent years, many factories are reconstructing their foundry production based on new technological processes and materials, advanced equipment.

The main purpose of the reconstruction is to expand production volumes, improve the quality of products that meet modern customer requirements, improve the environmental situation and working conditions. During the reconstruction, a deep study of the product sales market, analysis of modern technological processes, equipment and materials, development of optimal technological planning and equipment placement, development of a working project are required. For technological and working design, qualified specialists are needed. Unfortunately, today in Russia there is a limited number of organizations that are able to fully undertake the technological and working design of a workshop or site. Therefore, creative groups of specialists and organizations performing this kind of work are being created.

Over the past 3 years, more than 90 foundry shops and sites have been completely or partially reconstructed.

Reconstruction of workshops and factories is carried out on the basis of mechanized lines, replacing manual labor. In the last 4 years alone (2008-2012), 25 automated and mechanized lines for the manufacture of molds have been installed in foundries.

Introduction of promising technologies

For the production of cast iron and steel, technological processes of melting in induction and electric arc furnaces are promising, providing a stable chemical composition and heating temperature of the melt for effective out-of-furnace processing.

For the smelting of casting alloys, the following are promising:

For melting cast iron:

• Induction crucible furnaces of medium frequency with a capacity of up to 10-15 tons. Such furnaces are produced by domestic companies: RELTEK LLC, Yekaterinburg, Elektroterm-93 OJSC, Saratov, Novozybkovsky Plant of Electrothermal Equipment OJSC, Kurai LLC, Ufa, Institute of Electrotechnologies NPP CJSC, Yekaterinburg, SODRUGESTVO LLC and others,
  as well as foreign firms ABP, Juncker (Germany), Inductotherm, Ajax (USA), EGES, Turkey, which are most widely used in Russia;
• DC arc furnaces manufactured by OAO Sibelektroterm, Novosibirsk, OOO NTF EKTA, Moscow, OOO NTF Komterm, Moscow.

For iron smelting, medium-frequency induction crucible furnaces are more technologically flexible.

Fig.5. Increase in production of pig iron smelted in induction furnaces (%)

Unfortunately, in recent years, no work has been carried out to improve the technology of cupola melting of cast iron. No, and there has never been a mass production of cupolas in Russia. In this regard, all operating cupolas are made in a handicraft way without heating the blast and high-quality purification of exhaust gases from dust and harmful components. Gas cupola furnaces have not found proper distribution in our country due to the lack of its reliable design and are used only to obtain low grades of cast iron.

Figure 5 shows data on an increase in the production of castings from cast iron smelted in induction furnaces, and a decrease in the production of castings from cupola iron.

The production of castings from various types of cast iron in 2012 is presented in Table. 6.

Table 6. Production of castings from various types of cast iron in 2012

Fig.6. Growth in the production of castings from aluminum and magnesium alloys (%)

Increasing the production of low-sulfur cast iron in induction furnaces has increased the production of ductile iron castings with nodular and vermicular graphite. Between 2006 and 2012 the output of castings from ductile iron with nodular graphite increased by 12% (Fig. 6) due to a decrease in the production of castings from gray and special cast irons and steel.

For melting steel:

• AC and DC electric arc furnaces, medium and high frequency induction furnaces.

Production of castings from various types of steel in 2012. Presented in Table. 7.

Table 7. Production of castings from steel

For melting non-ferrous alloys:

• Electric induction, arc and resistance furnaces, gas and oil furnaces.

The production of castings from non-ferrous alloys in 2012 is presented in Table. eight.

Table 8. Production of castings from non-ferrous alloys

In recent years, there has been an increase in the production of castings from aluminum and magnesium alloys, which in some cases replace

The production of shaped castings in Russia from aluminum alloys by various methods is presented in Table. 9.

Table 9. Production of shaped castings from aluminum alloys by various methods

At present, the development of the production of high-quality castings based on modern technological processes in various industries mechanical engineering is carried out unevenly. The highest production volumes of castings are observed in the transport (automobile, railway and municipal) engineering, heavy and power engineering and the defense industry.

Fig.7. Production of castings by industry in 2012

Casting production volumes by industry are shown in fig. 7

An analysis of the dynamics of the production of castings and domestic foundry equipment over the past 10 years does not allow us to determine the prospects for the development of foundry production in the coming years. An increase in the production of castings from ferrous and non-ferrous alloys is not expected, as the policy and practice of purchasing engineering products abroad continues. The trend of increasing purchases of castings abroad also continues. The need of the domestic industry for cast billets is decreasing. Cast blanks are not competitive in the world market due to their high cost and in terms of "price-quality" we are inferior to developed foreign countries.

New foundry technologies have not been developed in recent years, as 10 research institutes involved in foundry production have been liquidated by the privatization system. Scientific research only foundry departments of universities are engaged in, the main task of which is to train young specialists. The main number of departments is not equipped with modern instruments and equipment. There is no coordination of scientific activity in Russia. The number of scientific workers over the past 15 years has decreased from 8 to 0.2% of all employees in the foundry. The connection between science and production has been broken, and sectoral science is absent.

In the current conditions, for the further development of foundry production, the reconstruction of old foundry shops and the construction of new ones based on new technological processes and modern environmentally friendly equipment, an important role is played by information activity held by the Russian foundry association. The Association regularly organizes specialized scientific and technical conferences, once every 2 years a foundry congress and an exhibition with the participation of foreign experts are held, in addition, it organizes trips of specialists to international exhibitions on foundry production and foundries of foreign countries in order to familiarize themselves with innovative technical solutions and exchange experience. Publishes monthly scientific and technical magazine "Founder of Russia".

It should be noted that along with the stabilization of production volumes of castings in the last 4 years, the quality of castings has significantly increased, dimensional accuracy has increased and, accordingly, their weight has decreased, strength and operational characteristics have increased, and presentation has improved.

The technological equipment of a number of enterprises has significantly improved; over the past 15 years, about 350 enterprises have carried out reconstruction, which is constrained by the lack of working capital at many enterprises.

We hope that Team work foundries with scientific and public organizations with the support of the Government of the Russian Federation will allow for the further development of the foundry industry in Russia.

• Tags:

FOUNDRY, one of the technological processes for obtaining a product by filling a pre-prepared form with molten metal, in which the metal solidifies. The significance of foundry production in mechanical engineering is characterized by the fact that more than 75% by weight of all parts of machines and tools are cast. The production of parts by casting is not only a simple and therefore cheap method, but often with very complex designs and large dimensions of parts - and the only one. The casting process can also produce products from such metals that do not have the ability to be forged. In the foundry, machine parts are produced individually, serially, and in some cases in mass order.

The foundry materials are: foundry materials (cast iron, steel, copper and its alloys, aluminum and its alloys, etc.); molding materials (sand, clay, etc.); auxiliary materials: fuel, refractory materials, fluxes, etc. The main operations in the foundry are as follows: 1) preparation of molding earth, 2) mold production (molding), 3) metal melting, 4) assembly and pouring of the mold, molds (knockout), 6) casting cleaning (cutting, cleaning and trimming), 7) heat treatment (annealing or complete heat treatment).

Making molds (molding). The following are used in the foundry industry: temporary molds, mainly made of clay and sand, and permanent metal molds, ch. arr. of steel. During solidification, the metal decreases in volume (shrinkage phenomenon), so the mold is made in size larger than the product by the amount of shrinkage. The phenomenon of shrinkage is reflected in the strength of the casting, and sometimes even in its integrity, when, for example, the molding mass (rods) surrounded by liquid metal is too strong and unyielding, and the casting metal shrinks when solidifying. Therefore, in temporary molds, the molding composition should be malleable; with constant forms, it is necessary (depending on the rate of solidification of the metal) to throw out products from them in time, which is achieved by a very precise (in time) action of the corresponding mechanisms.

Permanent forms were developed by Ch. arr. for casting non-ferrous metals with a low melting point, and partly for cast iron; for steel, permanent forms are rarely used, because it is very difficult (even for cast iron) to select a metal that resists repeated heating and cooling. Particularly widespread is casting into permanent molds (permanent molds) with metal bumps of aluminum alloys. Permanent molds include the so-called long-term reusable molds (long-life molds) proposed and patented by Holley Carburettor Co., Detroit. They are made of very durable refractory material. The whole difficulty in making these molds lies in finding the appropriate material (kaolin, magnesia, bauxite) and its good connection with the cast iron shell. The surface of the refractory layer can be touched up until it wears out, after which the refractory layer is applied again. Cast iron and other metals (except steel) are cast into such molds. There is no bleaching of cast iron, and the casting is well processed.

Temporary forms are made using models or templates, which are an exact copy of the casting (increased by the amount of shrinkage), and flasks - rectangular or square (rarely round) boxes without a bottom and a lid. The flasks serve to give strength to the molding material and to use the smallest possible amount of molding earth during molding. Much less often molding is carried out in the soil without flasks or with only one upper flask.

Schematically, the mold making process is as follows. 1) Half of the model is placed on a model plate (Fig. 1). 2) The lower half of the flask is placed on the slab and covered with a few mm of model earth (Fig. 2), slightly compacted around the model (in most cases by hand); after that, filler earth is poured into the flask (up to the top and more), which is then compacted b. or m. strongly depending on the size and nature of the casting; the form is ventilated (pierced in several places with a hairpin).

3) The stuffed flask is turned over together with the model board (Fig. 3); the under-model board is removed; the surface of the lower flask is sprinkled with separating sand. 4) On the lower half of the model, the upper half of the model is placed, covered with a layer of model sand, and the upper flask (Fig. 4), in which the sprue and vent models are placed (Fig. 5). 5) After compaction of the filling earth, the flasks are separated, and models are removed from each half. 6) A rod is inserted into the lower mold freed from the model (Fig. 6), which is prepared separately. 7) The lower flask with the rod is covered with the upper flask (Fig. 7); the assembled flasks are loaded, i.e., a load is placed on the upper flask to prevent it from floating when the mold is filled with liquid metal.

Methods for filling flasks with molding material and compacting it are shown in Fig. eight.

Molding machines are divided into three main types: pressing, shaking and sand throwers. Each molding machine is equipped with devices for releasing the model from the flask. The main methods for releasing the model from the flasks are shown in Fig. 9.

In accordance with the methods of releasing models from the flasks, molding machines are further divided into subgroups: 1) machines with lifting flasks, 2) machines with a turning plate and 3) machines with a broaching plate.

In FIG. 10 shows an ordinary press (with manual pre-pressing from below) molding machine; in fig. Figure 11 shows one of the latest types of Nichols compressed air shake-press machines.

The pattern plate of this machine is attached to the model holder B; the flask (not shown in the diagram) is connected either to the model plate or to the frame E, which serves as a support for the flask. Set the valve handle N to the right. There is shaking; in this case, the air passes inside the piston B under the piston A, which carries the pattern plate. Piston lift is controlled automatically by raising windows F by the lower edge of the piston. Through these windows, air flows into piston B and into the atmosphere. During shaking, the traverses H with the pressing block stand above the flask.

Then the valve handle N is turned to the left. Then the air goes through another wire under the piston B and raises both pistons with a model plate, frames D and E and a sand-filled flask and presses the latter against the press shoe, which achieves a seal. Turn the handle N again to the middle position, which opens the outlet of the press cylinder. Both pistons A and B, model holder D with model plate and frame E supporting the flask fall down, and in addition to the press piston B, round rods G serve as guides. stops while B-A-D system with a model plate continue to move down; while the model is pulled out of the form. Having pumped out a traverse with a press block, it is easy to remove a form. Four guide rods M in the shaking table are used to ensure the exact vertical movement of the model D holder. The rods G in the lower position are immersed in an oil bath, as well as the guides M, to ensure good lubrication and a calm fall of the frame E, for which the pawl C is turned to the right by moving the foot lever. , so that with a high model with steep walls, work according to the pull method. In both cases, the vibrator on frame D assists in the removal of the model. In FIG. 12 shows one of the many designs of a sandblaster - the latest molding machine that simultaneously fills the flask with molding earth and compacts the latter by centrifugal force.

The molding material is transferred by means of an elevator to a shaking chute, then to a belt, which transfers it to the sand thrower head; here the earth is picked up by a rapidly rotating bucket of the working head, which cuts off a portion of the earth from the total amount and directs the earth at a tremendous speed (12-18 m / s) into the flask, where it is compacted. The main advantage of the sand thrower in comparison with other types of molding machines is that it is not associated with a certain size of the flask, as is the case in other molding machines, and therefore only the sand thrower solves the problem of mechanizing the work of filling the flasks with molding material and compacting the latter. in foundries where individual work predominates. In addition, the sand thrower has an extremely high performance.

The internal outlines of the part, voids, etc. are obtained by means of rods or cones, which are prepared separately from the forms in the so-called. core boxes. Since, in the process of pouring, the cones are in most cases surrounded by molten metal, the issue of their proper ventilation becomes extremely important: the gas permeability of the cones should be. much higher than the gas permeability of the form itself. In FIG. 13 is a drawing of the rod (half of the core box).

To increase the gas permeability of the rod, a wax cord is laid inside it ( voskovitsa), the wax of which melts when dried, leaving thus. free passage for gas. To increase the resistance of the rod to the action of a column of molten metal, the rod is provided with a special metal frame. For the production of such critical and complex castings, such as autoblocks, radiators, etc., so-called. oil rods, which are prepared in most cases from pure quartz sand with the addition of various binders to bind; of these, linseed oil should be recognized as the best, but bean, maize oil, molasses, dextrin, gluten, etc. are also used. Using cones, you can get not only the internal, but also the external outline of the part ( flaskless molding). Many factories in America are adopting this method, omitting all molding work and replacing it with core work, which does not require very skilled labor.

The made forms are dusted with finely ground coal or graphite, or they are painted with a specially made mass ( beluga or paint), which is a very liquid mixture of refractory clay, flour and glue; when finishing molds for iron casting, fine graphite or coke is added to such a mass. Smoothing the surface of the mold with a trowel is prohibited. After finishing, the mold is either placed in a dryer (more often) and collected for pouring, or (less often) it enters the pour in its raw form - casting in raw. Drying molds for different metals is carried out at different temperatures: for steel 500-600°C, for cast iron 200-300°C, for non-ferrous metals 150-250°C. Permanent and long-term molds are always slightly heated before casting (up to 75-100°C), then for the following castings, on the contrary, they are cooled so that their temperature is not higher than 75-100°C. special care should be given to the issue of drying the rods, for which successively used dryers continuous operation, allowing you to control the drying temperature within strictly defined limits with a fluctuation of ± 5°C. Because the wet mold is more malleable than the dry mold, often many castings that fail to dry successfully come out wet. However, the raw form requires special attention to the composition of the molding mass (high porosity is needed to remove not only gases released from the metal, but also water vapor) and proper compaction of the mold. Do not re-compact (“call”) and not fill the molding mass too loosely (otherwise the liquid metal will wash out the walls of the mold) - a task that can only be solved by a very experienced worker.

Metal melting. Casting materials must have the following properties: a) fluidity, i.e., the ability of the molten metal to fill the mold; b) minimum shrinkage, i.e., the ability of the casting to maintain its shape; c) the least tendency to segregation; d) possibly low melting point. Almost all industrial metals (with the exception of aluminum) in their pure form do not satisfy these conditions: for example, iron has a very high melting point and has low fluidity and high shrinkage; copper, although it does not have a very high melting point, but due to its excessively high tendency to dissolve gases, obtaining dense bubble-free castings is very difficult and requires special conditions to avoid casting defects. Impurities of other metals and metalloids to the base metal (iron, copper, etc.) significantly improve casting qualities in terms of lowering the melting point, reducing the shrinkage coefficient, etc. The admixture of carbon to iron in an amount of 1.7% or more lowers the temperature melting of iron from 1528°С to 1135°С, shrinkage coefficient - from 2% to 1%; admixture of zinc or tin to copper and aluminum significantly improves their casting qualities. Aluminum-copper and aluminum-silicon alloys have the best casting qualities. Casting steel is used in two types: with a C content of 0.15 to 0.18% (tensile strength 36 kg / mm 2) and from 0.30 to 0.35% (54 kg / mm 2); Mn< 0,6-0,8%, Si < 0,20%; S и Р обыкновенно менее 0,05%. Этот состав обеспечивает плотность отливки. Специальные стали для литья применяются редко. В табл. 1 приводятся наиболее употребительные литейные сплавы алюминия.

In order to obtain a casting of the required qualities at its lowest cost, it is necessary to know under what conditions the casting will work, what qualities will be required from it, and what changes will occur in the metal during its remelting. Based on this, the calculation of the charge is made. In addition to the original foundry materials, the charge also includes foundry shop waste (sprues, upstream, rejected castings, splashes from foundry ladles, etc.) and metal scrap.

Below is an example of a numerical calculation of the charge (according to Moldenka) of acid-resistant gray cast iron (Table 2).

It is required to calculate the charge of the following composition: 3.25% C, 1.53% Si, 1.25% Mn, 0.20% P, 0.05% S. certain quantities waste of elements during melting in a cupola. The task is to determine the relative quantities in which it is necessary to mix cast iron groupsIII and III to obtain a mixture of composition (in%): 1.82 Si, 1.91 Mn, 0.1 P, 0.016 S.

For this, on the M axesn-Si (Fig. 14), we set aside the corresponding contents of Si and Mn; connecting the points corresponding to three cast irons (casting lines 4, 5 and 6), we see that the point of the average composition of the required mixture is inside the triangle I-II-III, which indicates the possibility of compiling the required mixture from these 3 grades of cast iron. We connect the vertices of the triangle I-II-III with point O and continue straight lines IO,IIO and IIIO until they intersect with opposite sides of the triangle at points a, b and c.

Then we take an arbitrary line O 2 O 1, (Fig. 15), divided into 100 equal parts (100%), and at the ends of this line we draw straight lines 0 2 K and 0 1 L parallel to each other at an arbitrary angle. From the point O 1, set aside the segments O 1 l, O 1 lI, O 1 III, equaloi,OII, OhIII. In the same way, from the point O 2 we set aside the straight lines O 2 a, O 2b and O 2 c, respectively equal to Oa, Ob and Os. By connecting points a with I, b withII and c with III, we immediately read on the straight line O 2 O 1 that cast iron I must be taken 34%, cast ironII - 51% and cast iron III - 15%. Therefore, every 150 kg of charge will consist of 34 kg of cast iron I, 51 kg of cast iron II, 15 kg of cast iron III; 30 kg of own scrap and 20 kg of purchased scrap.

For the melting of various metals, furnaces of the most diverse design are used: for melting steel - open-hearth furnaces (acidic and basic), small Bessemers (for example, Tropenas, Robert); cast iron - cupola furnaces, reverberatory furnaces and crucible installations; for aluminum, copper and their alloys - various designs of crucible, flame and electric furnaces. The cupola melting process is the most economical and therefore the most common; the use of crucibles is limited by the high cost of the process and the extreme inconvenience of producing castings (for example, steel shaped castings) from crucibles. Flame furnaces for non-ferrous casting are inconvenient because the oxidizing effect of the flame spoils the quality of the metal, and metal oxides released in the room have a harmful effect on the health of workers; in addition, it is required that the pouring temperature of non-ferrous metals be within very narrow, predetermined limits (for example, for aluminum 700±20°C). Per Lately electric furnaces became widespread various systems for melting Ch. arr. steel and non-ferrous metals. The main advantage of electric furnaces is their indifference to the chemical reactions that take place during melting, and, as a result, more pure metal; then the ability to regulate over a very wide range the degree of overheating of the metal, its lower waste, etc. To melt cast iron, the use of electricity is much more expensive than melting in cupolas, and therefore is relatively rare, and then only in the form of a combined process: cupola-electric furnace or cupola- Bessemer-electric furnace, in accordance with the special requirements of the production. When melting non-ferrous metals in electric furnaces, waste is reduced: for example, brass waste in crucibles is 4-6%, in electric furnaces 0.5-1.5%. In table. 3 shows comparative data on the cost of melting 1 ton of brass in crucibles and electric furnaces of the Ajax system.

Casting technique. The supply of molten metal to the mold is one of the most important operations in the foundry; metal perfectly composed (according to analysis), molten and deoxidized according to all the best prescriptions, m. b. spoiled by the inept supply of it into the form. First of all, it is necessary to take care that the metal jet going into the mold is continuous and fills the channels that bring the metal to the mold completely. To do this, it is necessary to correctly calculate the mutual ratio of the cross sections of the sprue, slag trap and feeders (Fig. 16); so, with a gate diameter of 20 mm, the cross-sectional area of ​​the gate = 315 mm 2, the area of ​​the slag trap should be taken smaller, namely 255 mm 2, and the sum of the areas of the feeders should not exceed 170 mm 2.

In FIG. 17-22 are examples of correct and incorrect installations of sprues, slag traps and feeders.

Fig. 17, 18 and 19 give examples of correct installation, FIG. 20 - incorrect installation because the gate section is too small and during casting the metal will not completely fill the slag trap, as a result of which the slag will enter the mold and ruin the casting. In FIG. 21 shows the wrong installation: the gate is placed directly above the feeder, the slag directly enters the mold. In FIG. 22 the sprue is displaced and placed directly above the feeder, the slag enters the mold. Two profits are placed in steel castings to avoid shrinkage cavities. Profits in steel castings occupy about 25-30% of the weight of the casting. Steel small castings, cast iron (with the exception of very important ones) and non-ferrous castings are cast without profits. Filling shapes requires a certain amount of skill. Metal cannot be poured into the sprue with jet breaks. In some cases, when a large pressure is required, they try to direct a stream of steel from the ladle directly into the sprue, thus creating. steel strike. The pouring of steel is considered complete when the metal appears in profit. At this point, in large castings, they prefer to add metal in the head, and not through the sprue. That. a hot profit is created that feeds the casting (with a reduction in the volume of solidifying metal) from above, but not from below (which is harmful). The finished metal is recommended to be deoxidized with a silicospigel before release. This additive makes the metal calmer and it pours well. Shrinkage cavities form in the thickest parts of the castings. The common view that the presence of shrink bubbles in castings reduces the strength of the metal is not always correct: the bubble enclosed in the metal is a sphere (like a vault) with regularly arranged crystals and offers significant resistance to fracture, especially crushing. The forging of this bubble forms a fold, the presence of which already certainly weakens the metal. To avoid the formation of shrinkage bubbles, centrifugal casting and injection molding are used.

Centrifugal casting consists in the fact that molten metal is introduced into a rapidly rotating metal mold, where, under the action of centrifugal force, it adheres to the outer surface of the rotating mold. That. you can prepare a variety of bodies of revolution. The scheme of operation of the centrifugal casting machine is given in Fig. 23.

The cylinder A serves as the form. By means of the handle C, the form A can be. moved back (on the drawing - to the right). The piston at the end of the spindle with a cooling ribbed surface F forms the rear wall of the mould. At the beginning of the casting, mold A is pressed quite tightly against body B, after which the ladle B filled with molten metal is rolled into mold D, which is simultaneously set into rotation. By turning handwheel E, the molten metal is poured into the mould. As soon as the metal hardens, the mold A is moved to the right on the piston, which extrudes the casting. The method of centrifugal casting in the manufacture of cast-iron pipes has become especially widespread. The material from which the molds for centrifugal castings are prepared must be chosen especially carefully depending on the operating conditions of the centrifugal casting machine. For molds with a high degree of heating, cast iron, due to its tendency to grow (volume increase with repeated heating), is not recommended; the use of steel gives the best results. Unlined, heated or water-cooled molds can be made from steel, but their service life is short. Therefore, it is preferable to make molds from nichrome (60% Ni and 40% Cr) or from Becket metal, as well as from an alloy of the following composition: 80% Ni and 20% Cr. This alloy withstands prolonged and repeated temperature loads above 1370°C. It is essential that the steel molds have no cavities closer than 3 mm from the inner surface of the mold and that this surface be perfectly smooth; the wall thickness is chosen so that during casting the mold does not heat up above the critical point of the given metal.

In injection molding, molten metal is injected under high pressure into a metal mold, resulting in parts that fit the given dimensions so precisely that they do not need further machining. This is of particular benefit in the mass production of small and highly precise parts (eg meter parts, small machine parts). The most important industrial alloys for die castings are those of zinc, aluminum and, to some extent, copper. In table. 4 shows the characteristics of various alloys used for injection molding.

Machines used for injection moldings are divided into two main groups. 1) For alloys with a low melting point, piston machines are used (Fig. 24).

The liquid metal bath contains a pump driven by a lever or compressed air. When the piston is lowered down, the metal is pressed into the mold through the nozzle. Piston machines for alloys with a higher melting point (aluminum, etc.) proved unsuitable: the metal hardens between the piston and cylinder walls, which causes frequent cleaning and a sharp increase in overhead costs. 2) For refractory alloys, therefore, machines are used (Fig. 25 and 26), equipped with a special scoop (goose), which, with the help of a special device, each time captures the strictly necessary portion of the metal; the metal is exposed to compressed air only in this scoop on a relatively small surface, which avoids excessive oxidation of the metal.

Casting knockout. The speedy release of the molded product from the molds has a significant impact on its integrity. It should also be borne in mind that a hot casting is easily deformed by an awkward blow when it is released from the mold. It is especially important to release the central knobs of the castings as soon as possible. For this purpose, when cones are made, the part of the frame, which is the skeleton of the cone, is led out through the "sign" so that after pouring with a sledgehammer, the cone can be easily knocked out along this protruding part and thereby allow the casting to contract freely during its further cooling.

The operation of knocking out the flasks in modern foundries is fully mechanized. The simplest device for this purpose is that a vibrator suspended from a pneumatic lift can be used with a special device. attached to the flask, which at the same time rises slightly; the vibrator is then activated and after a few seconds the flask is emptied. With another method of knocking out, the flasks are placed on a grate, which is set in oscillatory motion with the help of cams; earth from the flasks falls through the grate. To prevent the hot earth from falling onto the earth-removing belt conveyor with too large masses, two feed rollers are installed under the grate, which evenly feed it onto the conveyor. The knocking out of the rods is done either manually, or by means of a high pressure water jet, or on specially designed pneumatic vibrating machines (Fig. 27) of the Stoney system.

Castings from the trolley are installed in special holders of the machine using an air lift located at each machine. Then the vibrator is activated, and the rods are knocked out for 3-6 seconds.

Casting cleaning. The casting taken out of the mold has a number of tides (sprues, risers and profits) that are unnecessary according to the product drawing, but necessary during production. The earth adhering to the casting, sprues and upstream are removed with a stump, and the profits are removed with a cut. Cleaned casting with profits is called black, and without profits - cut off, or clean. Cast iron b. hours are left without trimming. In some cases, casting cleaning is difficult, for example, during metal explosions, a “blockage” is obtained in the casting, if the torn off mass has not been taken out into profit or extrusion; if the sprue is set incorrectly, the cutter can break the sprue with the casting case; in this case, it is better to send the casting with the sprue for trimming; when removing deep buds, it is very difficult to pick a thin bud from a long tube; in this case, the shift of the frame during the solidification of the metal can not only help maintain the integrity of the casting, but also facilitate knockout. Cleaning of the outer surface of the castings from burnt earth is carried out in modern foundries in rotating drums or with a jet of sand in sandblasting machines and chambers. The first method is predominantly common in America, the second - in Europe. The disadvantage of the method of cleaning the casting in ordinary drums is the large expenditure of labor and time for manual loading and unloading it. A significant simplification is obtained in the case of using instead of ordinary drums - drums of continuous action (Fig. 28).

The drum has internal and external cavities. The castings enter the inner cavity of the rotating drum from the right side. Hardened cast-iron sprockets enter there from the outer cavity through special slots. With a slow movement towards the opposite end of the drum, the casting has time to be cleaned. Before reaching the end of the drum, cast iron sprockets fall through small slots from the inner to the outer cavity of the drum, from where they are transferred to the head of the drum by means of spiral guides. More complex castings, which, when cleaned in drums, could be afraid of a large% rejection due to breakage and which are subjected to significant machining, are cleaned in continuous sandblasting chambers. The method of hydraulic cleaning of castings, which was first successfully applied at the Allis Chalmers Co plant, turned out to be very successful. (Milwocky): Cleaning time reduced from hours to minutes. The device is used for cleaning turbine wheels, gasometer cylinders and similar heavy castings. Castings are cleaned in a closed concrete chamber (Fig. 29) located in the middle of the foundry.

The internal dimensions of the chamber are 10370x18725x6100 mm. The thickness of the concrete walls is 305 mm. To protect the walls from the eroding action of water, they are covered with steel plates. Inside the chamber there are two turning circles with a diameter of 3050 mm (lifts 100 tons) and 6100 mm (300 tons). Both circles rotate on ball bearings and are driven by motors of 25 and 35 HP. The service room is located in one of the corners of the chamber. Installed 2 apparatus with three nozzles located at equal heights. Nozzles m. b. placed at any height. The nozzle for the larger table has a diameter of 27 mm, for the smaller one - 16 mm. The 3500 l/min pump is driven by a 300 HP motor. With two simultaneously operating nozzles, the water pressure is 28 atm. The dirt resulting from the cleaning is settled in two receivers lying under the floor, from which it is continuously removed using an elevator. The earth is separated from the water, brought to 7% humidity and put back into production. The advantage of this cleaning method is its cheapness, the complete absence of dust, and the fact that the rod frames do not deteriorate and can be used again.

Heat treatment. After cleaning, the casting is sometimes subjected to heat treatment. Cast steel and ductile iron must be annealed. With regard to cast iron, it has now been proven that it can. subjected to heat treatment similar to steel, and the structure of cast iron ferrite-graphite-cementite turns into a perlite-graphite structure with an increase in mechanical qualities (elongation up to 8%, tensile strength up to 40-45 kg / mm 2). Particularly facilitates heat treatment by casting cast iron into permanent molds. Bronze casting can also be used in many cases. improved through heat treatment. Aluminum casting is always quenched at 500±10°C and tempered at 140±10°C.

Basic principles for designing foundries. When designing a new foundry, first of all, one has to take into account the location of the main metalworking shops and choose a location for the foundry in such a way as to be able to deliver the castings to the processing shops as simply and cheaply as possible. The work program of the foundry d.b. determined with the most accurate details, both in quantitative and weight, and in overall terms, which will make it possible to choose the most suitable equipment for the given case and the most appropriate technological process. The scheme for calculating the foundry is reduced in this case to the following. Having an exact program of work, they make up an album of moldings, which will also give the basic principles for organizing individual operations. technological process and the number of flasks required for the production and their types, as well as the required amount of molding materials, and hence the power of the agricultural device. Having received so. arr. indicative data on the consumption of raw materials, on the size of the required space, begin to clarify the individual operations of the production process, its possible mechanization as a whole or in separate parts. Various options for calculating the relative position of individual foundry shops will make it possible to most appropriately resolve the issue of organizing a given production process. If the program is not m. defined with b. or m. acceptable accuracy, then you have to calculate the main and auxiliary shops of the foundry according to the so-called coefficients. In FIG. 30 shows the usual types of foundry buildings;

fig. A - gray cast iron foundry for individual casting; B - malleable iron foundry with installation of flame furnaces; B - shaped steel with a department of open-hearth furnaces; G - shaped steel with converters; D - steel with electric furnaces.

Occupational hazards and safety precautions. Everything production processes flowing in foundries are associated with the occurrence of certain occupational hazards. So, in the preparation and processing of molding materials, knockout, trimming and cleaning of castings, a great amount dust (from 20 to 180 mg / m 3). Adequate ventilation should be installed to combat dust pollution in the air; especially favorable in this regard is the use of a hydraulic method for cleaning castings. In molding work, in cases where molding is done on the floor of a foundry, workers are forced to keep their bodies in a bent, often in a highly unnatural position, which can lead to curvature of the bones of the skeleton. These hazards are eliminated in the production of work on molding machines. Low temperatures in foundries in winter (often below 0°C), high dampness, always cold and often frozen earthen floors cause frequent colds in moulders, especially rheumatism. When servicing melters, workers are exposed to the harmful effects of sudden temperature fluctuations. When casting from molten metals, harmful gases are released. Of the latter, the most important are the following: carbon monoxide, sulfur dioxide and zinc oxide. The concentration of CO in the air of foundries varies on average within the range of 0.03-0.05 mg/l, reaching at some moments of casting above the flasks up to 0.21-0.32 mg/l. (The Institute for Labor Protection has set a standard of 0.02 mg / l.) The amount of sulfur dioxide (SO 2) in the air of foundries, depending on the type of metal and coke used, reaches 0.045-0.15 mg / l (norm 0.02- 0.04 mg/l). Inhalation of zinc oxide fumes in copper foundries causes workers to have attacks of foundry fever. When manually loading the charge into melters, when pouring metal into flasks manually, an extremely large muscle tension is observed, which, due to high temperature work causes severely debilitating sweating. These hazards are eliminated by the use of conveyors, mechanization of loading furnaces and transport, as well as pneumatic knockout of flasks.

The greatest number of accidents in the iron and copper foundry occurs from burns by molten and red-hot metal during manual carrying or transporting it. Particularly serious consequences are caused by the contact of molten metal or slag with moisture (explosions). To eliminate these phenomena, it is necessary to have even paths made of brick, concrete, reinforced concrete, etc. in places not occupied by molding, and the main passage should be. not already 2 m; b. the flow of people with empty ladles and molten metal is properly organized; places of castings and pouring out of slag must be dry; buckets e. b. well dried and warmed up; ladle shrouds should have small openings to remove fumes from the coating, etc. Workers handling molten metal should b. equipped with proper overalls, goggles, respirators, etc., and the shirt should not be tucked into pants and pants into boots, and the brim of the hat should be. bent down. Hand molding is accompanied by a large number of pins on the iron pins found in the old molding earth. The means of struggle is to pass the earth through a magnetic separator. When carrying ladles with molten metal, their center of gravity must be below the axis of rotation (up to 50 mm) to avoid tipping over. All chains, ropes and rocker arms must be fully loaded at least once every 2 months and thoroughly inspected at least once every 2 weeks. All machines must be equipped with reliable guards of dangerous places.

In order to legally regulate working conditions in foundries, the People's Commissariat of Labor has issued a number of mandatory regulations. These primarily include the “Safety Rules for Work in the Iron and Copper Foundry”; resolutions on the restriction of the employment of women and adolescents in the most harmful and hazardous work in foundries; shortened working hours and additional leave for certain categories of workers (copper foundries, sandblasters, etc.).

Foundries in Russia are enterprises that produce castings - shaped parts and blanks - by filling molds with liquid alloys. The main consumers of foundry products are enterprises of the machine-building complex (up to 70% of all cast billets produced), and the metallurgical industry (up to 20%). Approximately 10% of products produced by injection molding are sanitary equipment.

Casting is the best way to obtain workpieces of complex geometry, as close as possible in configuration to finished products, which is not always possible to achieve by other methods (forging, welding, etc.). In the casting process, products of the most diverse thickness (from 0.5 to 500 mm), length (from a few cm to 20 m) and weight (from a few grams to 300 tons) are obtained. Small allowances - an advantageous feature of casting blanks, which allows to reduce the cost finished products by reducing the consumption of metal and the cost of machining products. Over half of the parts used in modern industrial equipment are made by casting.

The main types of raw materials in foundry production are:

• gray cast iron (up to 75%);
• steel - carbon and alloyed (20%);
• malleable iron (3%);
• non-ferrous alloys - aluminum, magnesium, zinc copper (2%).

The casting process is carried out in a variety of ways, which are classified:

1) according to the method of filling molds:

• ordinary casting;
• casting with insulation;
• injection molding;
• centrifugal casting;

2) according to the method of manufacturing casting molds:

• into one-time molds (sand, shell) intended for obtaining only one casting;
• in forms of multiple use (ceramic or clay-sand), withstanding up to 150 fills;
• into permanent metal molds (for example, chill molds) that can withstand several thousand pours.

The most common method of casting in sand molds (up to 80% by weight of all castings carried out in the world). The technology of this type of casting includes:

• preparation of materials;
• preparation of molding and core sands;
• creation of forms and rods;
• suspension of rods and assembly of forms;
• melting metal and pouring it into molds;
• metal cooling and knockout of the finished casting;
• casting cleaning, heat treatment and finishing.

The first Russian foundry (the so-called "cannon hut") appeared in Moscow in 1479. Under Ivan the Terrible, foundries appeared in Kashira, Tula and other cities. During the reign of Peter the Great, the production of castings was mastered in almost the entire state - in the Urals, in the southern and northern parts of the country. In the 17th century, Russia began to export cast iron castings. Remarkable examples of Russian foundry art are the 40-ton Tsar Cannon, cast by A. Chokhov in 1586, the Tsar Bell, weighing over 200 tons, created in 1735 by I.F. and M.I. Matorins. In 1873, the workers of the Perm plant cast a chabot (the lower part that receives the impact) of a steam hammer weighing 650 tons, which is one of the most gigantic castings in the world.

Federal State Educational Institution of Higher Professional Education "Ural Federal University named after the first President of Russia B.N. Yeltsin"

Institute of Materials Science and Metallurgy

Department of "Foundry and hardening technologies"

Abstract of lectures on the discipline "Foundry"

Lecture 1

Basic concepts of foundry production

Lecture plan

1. The concept of foundry.

2. A brief historical review of the development of foundry production. The role of Russian scientists in the development of scientific foundations and organization of the production of castings and ingots.

3. Classification of foundry alloys and areas of their application.

Modern life cannot be imagined without metals. Metals are the basis of technological progress, the foundation of the material culture of all mankind. But metal becomes useful to a person only when products are obtained from it. There are three main types of production of metal products. These are foundry production, metal forming and metal cutting. The course "Foundry" is devoted to the first type of metalworking.

In this abstract of lectures, the theoretical foundations of foundry production are considered in sufficient detail, in addition, the technological processes for obtaining various products and the equipment and tools used in this are described.

The abstract of lectures is devoted to the foundry production of ferrous and non-ferrous metals. It outlines the fundamentals of the theory, technological processes and equipment designed to produce castings in various ways (in disposable sand-clay molds, according to investment models, in a chill mold, under pressure, etc.).

The main attention in the presentation of the material is given to the consideration of the physical and physico-chemical essence of the processes of a particular technology, the features of the design of equipment, the purpose of technological modes, the equipment used and automation tools.

Along with the presentation of specific material for each technological method of obtaining blanks, special attention is paid to the main "bottlenecks", problems of technological processes, analysis of ways and means of solving them to obtain products of a given quality and achieve high production efficiency; on the basis of the same approach, the prospects for the development of each process are also considered.

The concept of foundry

The essence of foundry production is reduced to obtaining liquid, i.e. heated above the melting point, an alloy of the required composition and quality, and pouring it into a pre-prepared form. After cooling, the metal solidifies and retains the configuration of the cavity into which it was poured. Thus, to make a casting, you must:

1) determine the materials that need to be introduced into the charge for melting, calculate them, prepare these materials (cut into pieces, weigh the required amount of each component); load materials into the melting furnace;

2) to carry out melting - to obtain a liquid metal of the required temperature, fluidity, proper chemical composition, without non-metallic inclusions and gases, capable of forming a fine-crystalline structure without defects with sufficiently high mechanical properties upon solidification;

3) before the end of melting, prepare casting molds (for pouring metal into them) that are capable of withstanding the high temperature of the metal, its hydrostatic pressure and the eroding effect of the jet without collapsing, as well as capable of passing gases released from the metal through pores or channels;

4) release the metal from the furnace into the ladle and deliver it to the molds; fill casting molds with liquid metal, avoiding jet breaks and slag entering the mold;

5) after solidification of the metal, open the molds and extract the castings from them; PRODUCTION

6) separate all sprues from the casting (metal frozen in the sprue channels), as well as the tides and burrs formed (due to poor-quality casting or molding);

7) clean the castings from the particles of the molding or core sand;

8) to control the quality and dimensions of the castings.

At present, the largest number of castings are obtained in one-time (sand) molds made from a molding mixture consisting of quartz sand, refractory clay and special additives. After the metal hardens, the mold is destroyed and the casting is removed. In addition to disposable, semi-permanent molds are used, made of highly refractory materials (chamotte, graphite, etc.), they are used for pouring several tens (50–200) castings, and permanent molds are metal, they serve to obtain several hundred, and sometimes thousands castings until mold wear. The choice of a casting mold depends on the nature of production, the type of metal being poured, and the requirements for casting.

A brief historical overview of the development of foundry production. The role of Russian scientists in the development of scientific foundations and organization of the production of castings and ingots

Foundry is one of the most ancient forms of metalworking art known to mankind. Numerous archaeological finds discovered during excavations of mounds in various parts of our country indicate that in Ancient Russia copper and bronze castings were produced in fairly large quantities (bowlers, arrowheads, jewelry - earrings, wrists, rings, hats, etc.). During the excavations, surviving furnaces and furnaces, stone molds were found that served to cast hollow axes, rings, bracelets, metal beads, crosses, etc. However, most of the castings found in Ancient Russia were obtained by casting on a wax model.

The method of making the model is original: a pattern was woven from wired cords, representing a copy of the future product; clay was applied to this wax model until a sufficiently strong form was obtained, after drying, the form was calcined, the wax was melted, and the cords burned out, metal was poured into the cavity formed, after cooling, a casting of complex shapes was obtained.

In the XI century. in Russia, local production centers arose for casting church items (copper crosses, bells, icons, candlesticks, etc.) and household items (kettles, washstands, etc.) use. In addition to Kiev, Novgorod the Great, Ustyug the Great, Tver became major centers for the production of copper-cast products. The Tatar invasion caused a stagnation that lasted until the middle of the 14th century, after which the foundry industry began to rise. This is explained by the fact that a centralized large state was created, in connection with which cities began to develop and weapons were required, now firearms. From the production of welded cannons, they switched to bronze - cast, they cast bells, created copper-casting workshops for artistic casting. By the middle of the XVI century. Moscow artillery occupied quantitatively the first place among the artillery of European states.

The Petrine era represents a leap in the development of foundry production. Large Tula and Kaluga factories by Nikita Demidov and Ivan Batashov were created. The first steel castings were obtained in the second half of the 19th century. almost simultaneously in different European countries. In Russia, they were made in 1866 from crucible steel at the Obukhov plant. However, the quality of the castings turned out to be low, since the casting properties of steel were significantly inferior to those of cast iron. Thanks to the work of Russian scientists metallurgists A.S. Lavrova and N.V. Kalakutsky, who explained the segregation phenomena and presented the mechanism of the occurrence of shrinkage and gas shells, as well as developed measures to combat them, fully revealed the advantages of steel castings. Therefore, shaped castings obtained by A.A. Iznoskov from open-hearth steel at the Sormovo plant in 1870, turned out to be of such high quality that they were shown at an exhibition in St. Petersburg.

After leaving scientific papers the founder of metallography D.K. Chernov, who created the science of transformations in alloys, their crystallization, structure and properties, they began to use heat treatment, which improved the quality of steel casting. The theory of metallurgical processes was introduced in the higher school by A.A. Baikov in 1908 at the St. Petersburg Polytechnic Institute. Between 1927 and 1941 there is an unprecedented growth in industry for the former Russia, the largest mechanized factories are being built. Foundry shops are being built and put into operation, operating in a flow mode, with a high degree of mechanization, with conveyors, with an annual output of up to 100 thousand tons of casting.

At the same time, research work is being carried out, theories of work processes and methods for calculating foundry equipment are being created. The scientific school of the Moscow Higher Technical School is being formed, founded and headed by prof. N.P. Aksenov.

The widespread use of foundry production is explained by its great advantages compared to other methods of producing blanks (forging, stamping). Casting can produce blanks of almost any complexity with minimal processing allowances.

In addition, the production of cast billets is much cheaper than, for example, the production of forgings. The development of foundry production to the present day took place in two directions:

1) development of new casting alloys and metallurgical processes;

2) improvement of technology and mechanization of production.

Great progress has been made in the field of studying and improving the mechanical and technological properties of gray cast irons - the most common and cheap casting alloys. Special types of casting are becoming more widespread and improved: chill casting, under pressure, in shell molds, investment models, etc., which provide accurate castings and, consequently, reduce the cost of machining.

Classification of casting alloys and their areas of application

On average, cast parts account for about 50% of the mass of machines and mechanisms, and their cost reaches 20–25% of the cost of machines. Depending on the method of obtaining cast billets, alloys are divided into cast and deformed. Cast alloys are either prepared from the original components (charge materials) directly in the foundry, or obtained from metallurgical plants in finished form and only remelted before pouring into molds. Both in the first and in the second case, individual elements during the melting process can oxidize (burn out), volatilize at elevated temperatures (sublimate), enter into chemical interaction with other components or with the furnace lining and turn into slag.

To restore the required composition of the alloy, the loss of individual elements in it is compensated by introducing into the melt special additives (ligatures, ferroalloys) prepared at metallurgical enterprises. Ligatures contain, in addition to the alloying element, also the base metal of the alloy, therefore they are more easily and more fully assimilated by the melt than a pure alloying element. When melting non-ferrous metal alloys, ligatures are used: copper-nickel, copper-aluminum, copper-tin, aluminum-magnesium, etc.

When casting ferrous alloys, ferroalloys (ferrosilicon, ferromanganese, ferrochromium, ferrotungsten, etc.) are widely used to introduce alloying elements, as well as to deoxidize the melt. In the process of deoxidation, the elements contained in ferroalloys act as reducing agents: they combine with the oxygen of the oxide dissolved in the melt, reduce the metal, and, having oxidized themselves, pass into slag. Purification (refining) of the melt by deoxidation contributes to a significant improvement in the quality of the casting metal, increasing its strength and ductility. A number of alloys, as well as non-metallic materials (salts, etc.), are used as modifiers, which, when introduced into a cast alloy in small quantities, significantly affect its structure and properties, for example, refine the grain and increase the strength of the metal. So, to obtain high-strength cast iron, magnesium modification is used.

The main criteria for the quality of cast metal are mechanical properties, indicators of structure, heat resistance, wear resistance, corrosion resistance, etc., specified in the technical requirements.

Alloys are usually divided, like metals, primarily into ferrous and non-ferrous, the latter also including light alloys. Alloys are divided into groups depending on which metal is the basis of the alloy.

The most important groups of alloys are the following:

cast irons and steels - alloys of iron with carbon and other elements;

aluminum alloys with various elements;

magnesium alloys with various elements;

bronzes and brasses are copper alloys with various elements.

At present, alloys of the first group are most widely used, i.e. ferrous alloys: about 70% of all castings by weight are made from cast iron and about 20% from steel. The remaining groups of alloys account for a relatively small part of the total mass of castings.

In the chemical composition of the alloy, the main elements are distinguished (for example, iron and carbon in cast iron and steel), permanent impurities, the presence of which is due to the alloy production process, and random impurities that have entered the alloy due to various reasons. Harmful impurities in steel and cast iron include sulfur, phosphorus, ferrous oxide, hydrogen, nitrogen and non-metallic inclusions. Harmful impurities in copper alloys are cuprous oxide, bismuth and, in some of them, phosphorus. The properties of tin bronze are sharply worsened by impurities of aluminum and iron, and in aluminum bronze, on the contrary, tin. In aluminum alloys, the content of iron should be limited, in magnesium, in addition, copper, nickel and silicon. Gases and non-metallic inclusions in all alloys are harmful impurities.

The requirements for each casting alloy are specific, but there are a number of general requirements:

1. the composition of the alloy must ensure the desired properties of the casting (physical, chemical, physico-chemical, mechanical, etc.);

2. the alloy must have good casting properties - high fluidity, resistance to saturation with gases and the formation of non-metallic inclusions, low and stable shrinkage during solidification and cooling, resistance to segregation and the formation of internal stresses and cracks in castings;

3. the alloy should be as simple as possible in composition, easy to prepare, not contain toxic components, not emit highly polluting substances during melting and pouring. environment products;

4. the alloy must be technological not only in the manufacture of castings, but also in all subsequent operations for obtaining finished parts (for example, during cutting, heat treatment, etc.);

5. The alloy should be economical: contain as few expensive components as possible, have minimal losses during the processing of its waste (sprues, rejects).

Control questions and tasks

1. What is the history of foundry development in Russia?

2. What is the role of Russian scientists in the development of the scientific foundations and organization of the production of castings from ferrous and non-ferrous alloys?

3. What are the production methods for cast billets?

4. What molds can be used to make shaped castings?

5. How are casting alloys classified?

6. What are the requirements for casting alloys?

7. List the main areas of application of casting alloys.

8. What is the essence of foundry technology?

Foundry is one of the branches of industry, the main products of which are those used in mechanical engineering. There are many factories of this specialization in Russia. Some of these enterprises have small capacities, others can be attributed to real industrial giants. Further in the article, we will consider what the largest foundry and mechanical plants in Russia exist on the market (with addresses and descriptions), and what specific products they produce.

Products manufactured by LMZ

Of course, such enterprises are essential part National economy. Russian foundries produce a huge number of various products. Manufactured in the workshops of such enterprises, for example, castings, ingots, ingots. Finished products are also produced at the enterprises of this industry. These can be, for example, grates, sewer manholes, bells, etc.

The iron foundries of Russia supply their products, as already mentioned, mainly to enterprises in the engineering industry. Up to 50% of the equipment produced by such factories falls on cast billets. Of course, companies of other specializations can also be partners of LMZ.

The main problems of the industry

Unfortunately, the situation with the foundry industry in the Russian Federation today is not simple. After the collapse of the USSR, the country's machine-building industry fell into almost complete decline. Accordingly, the demand for shaped and foundry products has also significantly decreased. Later, the sanctions and the outflow of investments had a negative impact on the development of LMZ. However, despite this, Russian foundries continue to exist, supply quality products to the market and even increase production rates.

The main problem of enterprises of this specialization in the Russian Federation for many years has been the need for modernization. However, the implementation of new technologies requires additional costs. Unfortunately, in most cases, such companies still have to buy the equipment necessary for modernization from abroad for a lot of money.

List of the largest foundries in Russia

About 2,000 enterprises are engaged in the production of shaped products from cast iron, steel, aluminum, etc. today in the Russian Federation. The largest foundries in Russia are:

• Balashikhinsky.
• Kamensk-Uralsky.
• Taganrog.
• "KAMAZ".
• Cherepovets.
• Balezinsky.

COOLZ

This enterprise was founded in Kamensk-Uralsky during the war - in 1942. At that time, the Balashikha foundry was evacuated here. Later, the facilities of this enterprise were returned to their place. In Kamensk-Uralsk, its own foundry began to operate.

In Soviet times, KULZ products were mainly focused on the country's military-industrial complex. In the 1990s, during the conversion period, the enterprise changed its profile to the production of consumer goods.

Today KULZ is engaged in the production of shaped and foundry blanks intended for both military equipment as well as for civilians. In total, the enterprise produces 150 types of products. The plant supplies the market with brake systems and wheels for aviation technology, radio components, blanks made of biometal and cermets, etc. The head office of KULZ is located at the following address: Kamensk-Uralsky, st. Ryabova, 6.

BLMZ

Almost all foundries in Russia, the list of which was provided above, were put into operation in the last century. BLMZ is no exception in this regard. This oldest enterprise in the country was founded in 1932. Its first products were spoked wheels for aircraft. In 1935, the plant mastered the technologies for the production of shaped products from aluminum and in the post-war period, the enterprise specialized mainly in the production of aircraft take-off and landing devices. In 1966, it began to produce products made of titanium alloys.

During the collapse of the USSR, the Balashikha plant managed to maintain the main direction of its activity. In the early 2000s, the enterprise actively upgraded its technical fleet. In 2010, the plant began to develop new production facilities in order to expand the range of products.

Since 2015, BLMZ, together with the Soyuz scientific complex, began implementing a project to produce gas turbine plants power up to 30 MW. The BLMZ office is located at the address: Balashikha, Entuziastov Highway, 4.

Taganrog foundry

The main office of this enterprise can be found at the following address: Taganrog, Northern Square, 3. TLMZ was founded quite recently - in 2015. However, today its capacity is already about 13 thousand tons per year. This was made possible through the use of state-of-the-art equipment and innovative technologies. At present, the Taganrog LMZ is the most modern enterprise foundry industry in the country.

The TLMZ was under construction for only a few months. In total, about 500 million rubles were spent during this time. The components for the main production line were purchased from Danish companies. Furnaces at the factory are Turkish. All other equipment is made in Germany. Today, 90% of the products of the Taganrog plant are supplied to the domestic market.

The largest foundries in Russia: ChLMZ

The decision to build the Cherepovets enterprise was made in 1950. Since 1951, the plant began producing spare parts for road-building machines and tractors. All subsequent years, until the restructuring, the company was constantly modernized and expanded. In 2000, the management of the plant chose the following strategic directions of production:

• production of furnace rollers for metallurgical plants;
• production of furnaces for machine-building enterprises;
• pump casting for the chemical industry;
• production of radiator heaters for furnaces.

Today ChLMZ is one of the main Russian manufacturers similar products. Its partners are not only machine-building enterprises, but also light industry, housing and communal services. The office of this company is located at: Cherepovets, st. Construction industry, 12.

Balezinsky foundry

This largest enterprise was founded in 1948. Initially, it was called the artel "Founder". In the first years of its existence, the plant specialized mainly in the manufacture of aluminum utensils. A year later, the company began to produce iron castings. The artel was renamed Balezinsky LMZ in 1956. Today, this plant produces about 400 items of a wide variety of products. The main direction of its activity is the production of furnace castings, dishes and bakery molds. Company address: Balezin, st. K. Marx, 77.

Foundry "KamAZ"

This company operates in Naberezhnye Chelny. His production capacity make up 245 thousand castings per year. The KamAZ foundry manufactures products from high-strength cast iron, gray, with vermicular graphite. This plant was built in 1975. The first products of the plant were aluminum castings of 83 items. In 1976, the enterprise mastered the production of iron and steel products. Initially, the plant was part of the well-known joint-stock company"KAMAZ". In 1997, he gained an independent status. However, in 2002, the enterprise again became part of KamAZ OJSC. This plant is located at the address: Naberezhnye Chelny, Avtozavodsky prospect, 2.

Nizhny Novgorod enterprise OJSC LMZ

The main products of OJSC "Foundry and Mechanical Plant" (Russia, Nizhny Novgorod) are cast-iron pipeline fittings. The products manufactured by this enterprise are used in the transportation of gas, steam, oil, water, fuel oil, oils. The plant began its activity in 1969. At that time it was one of the workshops of the Gorky Flax Association. Today, its partners are many enterprises of mechanical engineering, housing and communal services and water supply.

Instead of a conclusion

The well-being of the entire country as a whole largely depends on how smoothly and stably the foundries of Russia described above will function. They will not be able to work without the products manufactured by these companies domestic enterprises engineering, metallurgy, light industry, etc. Therefore, paying maximum attention to the development, reconstruction and modernization of these and other foundries, providing them with comprehensive support, including at the state level, is certainly necessary and very important.