Modern methods of increasing the efficiency of foundry production. The essence of foundry. casting methods. Recommended list of dissertations

18.04.2020

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Cast alloys

Requirements for materials used to produce castings:

The composition of the materials must ensure that the specified physical-mechanical and physical-chemical properties are obtained in the casting; properties and structure must be stable throughout the life of the casting.

The materials must have good casting properties (high fluidity, low shrinkage, low tendency to cracking and absorption of gases, tightness), weld well, and be easy to process with a cutting tool. They should not be toxic and harmful for production. It is necessary that they provide manufacturability in production conditions and be economical.

Casting properties of alloys

Obtaining high-quality castings without cavities, cracks and other defects depends on the casting properties of the alloys, which manifest themselves during mold filling, crystallization and cooling of castings in the mold. The main casting properties of alloys include: fluidity, shrinkage of alloys, tendency to cracking, gas absorption, segregation.

Fluidity – the ability of molten metal to flow through the channels of the mold, fill its cavities and clearly reproduce the contours of the casting.

With high fluidity, the alloys fill all elements of the mold.

Fluidity depends on many factors: on the temperature range of crystallization, viscosity and surface tension of the melt, pouring and mold temperature, mold properties, etc.

Pure metals and alloys that solidify at a constant temperature have better fluidity than alloys that solidify over a range of temperatures (solid solutions). The higher the viscosity, the lower the fluidity. As the surface tension increases, the fluidity decreases. With an increase in the pouring temperature of the molten metal and the mold, the fluidity improves. Increasing the thermal conductivity of the mold material reduces fluidity. So, the sand mold removes heat more slowly, and the molten metal fills it better than the metal mold. The presence of non-metallic inclusions reduces fluidity. The chemical composition of the alloy also affects (with an increase in the content of sulfur, oxygen, chromium, the fluidity decreases; with an increase in the content of phosphorus, silicon, aluminum, carbon, the fluidity increases).

Shrinkage – the property of metals and alloys to reduce volume upon cooling in the molten state, during solidification, and in the solidified state upon cooling to ambient temperature. The change in volume depends on the chemical composition of the alloy, the temperature of the pour, the configuration of the casting.

Distinguish volumetric and linear shrinkage.

As a result of volumetric shrinkage, shrinkage cavities and shrinkage porosity appear in the massive parts of the casting.

To prevent the formation of shrinkage cavities, profits are installed - additional tanks with molten metal, as well as external or internal refrigerators.

Linear shrinkage determines the dimensional accuracy of the resulting castings, so it is taken into account in the development of casting technology and the manufacture of pattern equipment.

Linear shrinkage is: for gray cast iron - 0.8 ... 1.3%; for carbon steels– 2…2.4%; for aluminum alloys - 0.9 ... 1.45%; for copper alloys - 1.4 ... 2.3%.

Gas absorption – the ability of cast alloys in the molten state to dissolve hydrogen, nitrogen, oxygen and other gases. The degree of solubility of gases depends on the state of the alloy: with an increase in the temperature of the hard alloy, it increases slightly; increases during melting; increases sharply when the melt is overheated. During solidification and subsequent cooling, the solubility of gases decreases, as a result of their release in the casting, gas shells and pores can form.

The solubility of gases depends on the chemical composition of the alloy, the pouring temperature, the viscosity of the alloy, and the properties of the mold.

Segregation– heterogeneity of the chemical composition of the alloy in various parts of the casting. Segregation is formed during the solidification of the casting, due to the different solubility of the individual components of the alloy in its solid and liquid phases. In steels and cast irons, sulfur, phosphorus and carbon are noticeably eliminated.

Distinguish segregation honal, when different parts of the casting have different chemical composition, and dendritic, When chemical heterogeneity is observed in each grain.

UDC 621.74

MODERN FOUNDRY TECHNOLOGIES

B. S. Glazman

Don State Technical University, Rostov-on-Don, Russian Federation

UDC 621.74 MODERN FOUNDRY TECHNOLOGIES

Don State Technical University Rostov-on-Don, Russian Federation

The technologies for manufacturing castings, methods for automating foundry production, the composition of foundry conveyors, the use of a protective coating to improve the quality of manufactured products are considered.

Keywords: foundry, castings, chill mold, chill conveyor, molding, molding line

The article considers the technologies of making castings, methods of automation of foundry production, the composition of foundry conveyors and the application of protective coatings to improve the quality of manufactured products.

Keywords: foundry, castings, shell mold, permanent mold conveyor, block mold, block mold conveyor, forming, molding line

Introduction. Foundry production is one of the main procurement bases of mechanical engineering. Foundry production has a high metal utilization rate - 75-95%. Russia ranks third in the world in terms of the total production of cast billets after such large manufacturing countries as China and the USA.

Numerous casting methods are used in the industry. To increase labor productivity, they seek to use in-line production, full mechanization and automation of foundry production.

Casting technologies. At present, in the manufacture of castings by molding, molding lines and pouring machines are used, which make it possible to produce a large number of molds with high accuracy with a small number of attendants.

Fig.1 Molding line HWS: 1,4,11 - plate; 2 - rack; 3 - clamp; 5,9,10,12,14 - guide; 6.8 - mount; 7 - disk; 13 - bushing; 15 - clamp.

Rice. 2 General form automatic molding line Disa

The Disa molding line includes a shuttle-type sandblast molding machine that pulses the flaskless molds onto the conveyor. In the pouring section, the automatic pouring unit (5) fills the molds with the melt. Then the castings are cooled and transferred to a cooled knockout drum, where the castings are separated from the mixture, lumps are crushed, and the mixture and castings are finally cooled. The next step is the homogenization of the circulating mixture, which enters the syringe for the final preparation of the mixture and into the mixer, where it is transferred with refreshing materials and a high-ranking mixture is obtained. The resulting mixture is transferred to the molding machine.

Castings enter the shot blast machine (4) through an adapter (3) for surface treatment. Then the painting, quality control and warehousing operations take place.

At present, special casting methods are used in the industry, for example, die casting. This method allows to obtain more precise castings with stable dimensions. The minimum physical and chemical interaction of the casting metal and the mold contributes to the improvement of the quality of the casting surface, the absence of burn marks. Heat is quickly removed from the casting, which leads to its rapid hardening and provides an increase in mechanical properties.

Mechanization and automation of the technological process of mold casting provides an increase in labor productivity, stability of technological regimes, improvement in the quality of the casting and an increase in the economic efficiency of the production process.

On the industrial enterprises chill conveyors are used. On trolleys of a horizontally closed conveyor, a mold is installed for one or more different castings, which is an indicator of the productivity of foundry equipment.

Fig 3. Rotary chill machine: 1.2 - plate; 3 - shaft; 4 - pusher.

Rice. 4. Vertically closed mold conveyor: 1 - wheel; 2,3 - chain; 4 - tray; 5 - box;

6 - nozzle; 7 - spray gun; 8 - tank; 9 - transmission.

In the mold mold of the conveyor (Fig. 4), the cover opens automatically, and the castings from the mold through the tray (4) fall into the box (5). On the lower branch of the conveyor, open molds are cooled by air from nozzles (6), then painted with a spray gun (7) from a tank (8).

The main operations of mold casting are the opening of the mold, the extraction of cores and castings, the application of a refractory coating, the installation of cores, the locking of the mold, and the pouring of the melt. All operations are performed by the mechanisms of a chilling machine or a foundry complex, which is controlled by a worker-operator. When automating the chill conveyor, the mechanisms are controlled by a computer.

In serial and small-scale production of large castings of complex configuration, the use of automated chill molds is effective. In mass and large-scale production of small and medium-sized castings - automatic foundry complexes and automatic lines.

Fig.5 Schemes of automated foundry complexes for mold casting: a - for complex castings; b - for simple castings.

Figure 5a shows an automated casting complex for complex castings. The melt from the dispenser (1) is poured into the mold (2). Sand cores from the magazine (4) are installed in the mold with a manipulator (3). After hardening and opening of the mold, the castings are removed by the manipulator (6) and fed into the press (8) to harden the gating system.

Finished castings fall into the container (7), and then are transported along the conveyor (5) for processing. The melt from the melting units is fed into the dispenser along the monorail (9) by ladles. Manufacturing process operated by operators.

On fig. 4b shows an automated casting complex for simple castings. The melt from the dispenser (1) is poured into the molds installed on the machines (2). After the casting hardens and the mold opens, the casting is removed by the manipulator (4) and transferred to the container (3). The complex is controlled by the operator from the remote control.

In mass and large-scale production, specialized lines are used, designed both for the manufacture of one casting, and several castings of the same type.

Such lines include melting units, vehicles for filing

melt to loading devices, units for processing castings, vehicles for waste disposal, equipment for cleaning castings, installations and devices for quality control of castings. The lines are different high performance, energy efficiency.

Fig.6 Scheme of an automated control system for the casting process

under pressure by computer

Figure 6 shows a diagram of an automated control system for the technological process of injection molding using a computer.

Automated system functions as follows. Signals from parameters technological processes(T) enter the switches (K), and then the ADC and then to the control computer that serves all the injection molding complexes. The casting quality control system (QCS) sets the numerical values of the functions of quality indicators (T) from the parameters of the technological process (objective function) and transmits the computer through the switch K3 and ADC3. computer based program and mathematical model technological process, linking the objective function, constant and variable (adjustable) parameters of the injection molding process, produce optimal values of the adjustable parameters. Through the system feedback, including the switch K2 and ADC2, the control signal is transmitted to the system of regulators (p), which act on the actuators of the casting machine.

The operation of casting machines and units takes place under heavy loads and various levels of temperature, in aggressive environments and vacuum.

Used in industry various methods coatings using a variety of materials (metals, alloys, ceramics, plastics), as a result of which the physicochemical state of the surface layer of the workpiece differs from the main material of the part. These include surfacing and sputtering, electrolytic and chemical coatings, coatings with polymeric materials.

The galvanizing method is widely used in enterprises. The galvanizing process is carried out by vibration processing, which is fully automated. The method of electroplating is also widely used, providing high quality product surface.

Conclusion. Automation of foundry production using modern technologies and equipment increases the level of productivity of enterprises, the competitiveness of manufactured products and the efficiency of the industry as a whole.

Bibliographic list.

1. Gini, E. Ch. Technology of foundry production. Special types of casting / Gini E. Ch., Zarubin A. M., Rybkin V. A. - 3rd ed., Moscow: Academy, 2008. - 352 p.

2. Glazman, B. S. Automated and robotic casting. Finishing casting / B. S. Glazman // Monograph. - Rostov-on-Don: DSTU Publishing Center, 2014. - 88 p.

Shortcut http://bibt.ru

§ 5. Ways to improve the quality of castings

Improving the quality of castings is ensured by carrying out a whole range of organizational and technical measures in the foundry.

The composition of the molding sand is important for improving the quality of manufactured castings. Providing the site with high-quality raw materials, supplying the recycled mixture to mixers in a cooled state, high-quality separation and screening of the used mixture, accurate dosing of components, in particular the binder, have a positive effect on improving the quality of castings. Of great importance is the well-established regular control of the properties of molding materials in the workshop laboratory and, first of all, the control of strength and gas permeability.

The quality of castings also depends on the state of the technological equipment. Wooden model kits are warped, with cracks do not contribute to the achievement of dimensional accuracy. Warping of flasks during the manufacture of molds, especially large ones, is unacceptable; this leads to a redistribution of loads in the parting plane, collapse of the mold, and leakage of metal from it.

Compaction of the mold must be carried out strictly in accordance with the technical instructions. In the manufacture of large molds, it is advisable to use cold-hardening and liquid mixtures that do not require compaction. Low surface roughness of castings is ensured by the use of non-stick mold coatings.

Of great importance for obtaining high-quality castings is the continuous improvement of the skills of the brigade molders at various courses.

It is important to have well-organized control over the performance of all operations for the manufacture of casting molds in the workshop, to correctly follow the instructions of technological instructions, and to improve sanitary and hygienic working conditions.

The introduction of the latest achievements of science and technology, the improvement of the culture of production in the foundry are an indispensable condition for the production of quality products.

test questions

1. Name the features of the formation of castings.

2. Tell us about the methods of quality control of molds, cores used in the foundry.

3. List the casting defects that occur during manual molding.

4. Name the activities that improve the quality of castings.

CONFERENCES SEMINARS EXHIBITIONS 121

IMPROVING TECHNOLOGY AND INCREASING THE EFFICIENCY OF FOUNDRY PRODUCTION

The scientific-practical seminar "IMPROVING TECHNOLOGY AND INCREASING THE EFFICIENCY OF FOUNDRY PRODUCTION" was held on October 7-10, 2008 within the framework of the XII International Forum "Russian Industrialist".

The forum brought together industrialists and entrepreneurs from many regions of Russia, as well as representatives of countries near and far abroad. Every year this seminar becomes more and more representative, and its program is supplemented by the most relevant topics and directions that meet the requirements and demands of today. The holding of the forum is one of the most important events in the business calendar of St. Petersburg and all of Russia.

In 2008, the agenda of the forum included a discussion critical issues associated with the introduction of innovative technologies, the development of small business. In the address of the Governor of St. Petersburg V.I. Matvienko to the participants and guests of the International Forum "Russian Industrialist" it was noted that its topics fully meet the interests of the city (metropolis), its tasks industrial policy aimed at the development of new types of products, the creation of science-intensive, competitive world-class products.

An important event included in the program of the event was the holding of a scientific and practical seminar "Improving technology and increasing the efficiency of foundry production", which was held under the scientific guidance of prof., Dr. tech. Sciences Tkachenko Stanislav Stepanovich - President of the Association of foundry workers of St. Petersburg.

The seminar was attended by specialists in the field of foundry and metallurgy: FGUTT "PA" Oktyabr", OJSC "Rostvertol", OJSC "NPK "Ural-Vagonzavod", CJSC "Kazan Giproniyaviaprom", CJSC "Tekhnologiya-M", OJSC "BiKZ ”, OJSC GPNII-5, OJSC AK OZNA, LLC Polygon, ComMod, Escalada, Rontal-Impex, SevZapEnergo, TsNIIM, as well as the State Polytechnic Institute (Technical University), Department of "Automation of technological processes and production" of the St. Petersburg State Mining Institute (Technical University), etc.

A number of reports at the seminar aroused particular interest of the participants: “New materials and foundry technologies (G.A. Kosnikov, GPTU), “Computer analysis of foundry technology - problems and prospects” (V.M. Golod, GPTU), “Cast aluminum alloys and technologies for obtaining high-quality castings from them "(A.A. Abramov, TsNIIM),

“Complex modifiers for steel casting” (N.V. Ternovy, KomMod), “Polygon” computer modeling system (E.A. Ishkhanov), “ Modern technologies iron casting” (S.S. Tkachenko, State Pedagogical University), “The experience of an enterprise in improving the technology of injection molding” (S.L. Samoilov, “Escalada”), “New casting steels and technologies for obtaining high-quality castings from them” (G. A. Shemonaeva, TsNIIM), “Modern technologies of titanium casting” (A.M. Podpalkin, TsNIIM), “Computer analysis of model casting technology and the use of exothermic materials to improve the quality of castings” (D.A. Lukovnikov, Rontal-Impex ”), “Casting technologies using vacuum-film molding” (V.D. Ryabinkin, TsNIIM), “Experience in the manufacture of pattern equipment” (T.N. Gavrilova, SevZapEnergo), “Possibilities of using modern eddy current flaw detectors” (M.Yu. Koroteev, “Constant”), etc.

On October 9, an off-site meeting was held at the Fittings Plant contact network, where the problems "Production of casting by investment models" and "Production of casting by gasified models" (A.A. Lisova) were discussed.

On the final day of the seminar on October 10, an exchange of experience on the considered problems of foundry production and a discussion of the speeches of the seminar participants took place.

In the decision of the seminar, it was noted that the main procurement base of machine building is foundry production, the development of which depends on the level of the machine-building complex as a whole. AT machine-building complex Russia includes about 7,500 enterprises. The share of mechanical engineering in the total industrial output is about 20%, including 2.5% of machine tool and instrument making.

At present, there are about 1,650 foundries in Russia, which, according to expert estimates, produced 7.68 million tons of castings in 2006, including 5.28 million tons of cast iron, 1.3 million tons of steel, from non-ferrous alloys - 1.1 million tons.

In 1980, in the USSR, the volume of production of castings from alloys of ferrous and non-ferrous metals amounted to 25.8 million tons. - Is the technical potential (capacity) more than 2 million tons? During this period, foundries out- | advanced technological processes of melting, 5 shaping, finishing operations were used. In the foundry

122 CONFERENCES SEMINARS EXHIBITIONS

about a dozen research institutes of all-Union significance worked in production. The Minstankoprom produced 70,000 metal-cutting and 20,000 forging and pressing machines.

The volumes of production of cast billets are proportionally dependent on the volumes of production of machine-building products, since the share of cast parts in cars, tractors, combines, tanks, aircraft, etc. is 40-50%, and in machine tools and press-forging equipment reaches up to 80% of the mass and up to 25% of the cost of the product.

A sharp decline, since the 1990s, in the production of metal-cutting, woodworking machine tools and forging and pressing equipment, as well as power equipment for heavy engineering, shipbuilding, tractors, military equipment and others, led to the fact that the production of castings in Russia decreased from 18.5 million tons in 1991 to 4.85 million tons in 2000. Specialized centrolite plants for machine tool building with a total capacity of about 1 million tons of castings per year, created in the 1970s, could not stand the competition, lost orders and practically ceased their activities. Foundries working on the surviving mills

construction plants, in 2006 produced (according to expert estimates) 190-195 thousand tons of castings for own production and external customers.

Quite a difficult situation. If orders for machine tools now appear, foundries will not be able to produce high-quality, competitive castings, and none of the remaining foundries can produce castings weighing more than 30 tons. There are almost no highly qualified foundry specialists left in the industry, both workers and engineers, and most of the research institutes have been liquidated.

There is an urgent need for reconstruction of foundry shops, which should be carried out on the basis of new, environmentally friendly technological processes and materials, progressive melting, mixing-preparation and shaping equipment, ensuring the production of high-quality castings that meet European and world standards.

S.S. Tkachenko, I.N. Beloglazov

St. Petersburg State Mining Institute (Technical University)

HN>UU fcxrnuSiOft ihOuSTl

Official representative of Aluminco s.a. in Russia, EvrAzMetall-Center

ALUMINCO S.A. formed in 1982 in Greece. During its existence, it has become one of the largest companies in Europe in the field of aluminum production. It supplies its products to more than 60 countries of the world. Production capacity companies allow to produce up to 7,000 tons of aluminum profiles per year, up to 1,000 tons of aluminum casting, up to 50,000 pcs. aluminum sandwich panels.

The production and technology group includes:

extruder with a capacity of 7000 tons of profiles per year; Foundry;

painting line with preliminary anodizing; sandwich panel production line; bending line;

assembly shops;

tool line for the production of matrices; design department; design studio.

The quality of the products is certified by ISO 9001, QUALICOAT and BUREAU VERITAS. ALUMINCO S.A. campaign products:

7 profile systems designed for the manufacture of windows, doors, facades, office partitions, etc., in various combinations, which can work in both hot and cold climates, with various wind loads;

door aluminum sandwich panels of about 1000 different configurations, intended for use both for internal and external doors;

cast aluminum gratings; gates and wickets made of cast aluminum; Street lights; outdoor and garden furniture; visors over entrance doors; stair railing;

small architectural forms (columns, pylons, cornices, ports, etc.).

In 1996, for the first time in Russia, elements of decorative design of internal facades were used during the construction of the shopping center " Okhotny Ryad» on Manezhnaya Square.

Subsequently, the products of ALUMINCO S.A. were used in the construction of various shopping centers, residential buildings, settlements and other urban and social facilities.

Our website: www.aluminco.ru

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OGORODNIKOVA OLGA MIKHAILOVNA - 2011

Modern methods of increasing the efficiency of foundry production. The essence of foundry. casting methods. Recommended list of dissertations

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