Casting methods. The essence of the foundry. Casting methods Modern methods to improve the efficiency of foundry production


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§ 5. Ways to improve the quality of castings

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

The composition of the molding mixture is of great importance for improving the quality of the produced castings. Provision of the site with high-quality raw materials, supply of the circulating mixture to the mixers in a cooled state, high-quality separation and screening of the waste mixture, accurate dosing of components, in particular the binder, have a beneficial effect on improving the quality of castings. Of great importance is a well-established regular control of the properties of molding materials in the laboratory of the workshop 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, cracked and do not contribute to achieving dimensional accuracy. Warping of flasks during the manufacture of molds, especially large ones, is unacceptable, this leads to a redistribution of loads in the plane of the connector, crumpling of the mold, as well as metal leakage from it.

The compacting 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 fluid mixtures that do not require compaction. Low surface roughness of the castings is ensured by the use of non-stick coatings of the molds.

Continuous professional development of the molders of the brigade at various courses is of great importance for obtaining high-quality castings.

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

The introduction of the latest advances in science and technology, an increase in the culture of production in the foundry are an indispensable condition for the release of high-quality products.

Control questions

1. Name the features of the formation of castings.

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

3. List the defects in castings that occur during manual molding.

4. Name the measures to improve the quality of castings.

Technological scheme of a machine-building plant

Topic 11: Fundamentals of mechanical engineering technology

Lecture plan

11.1. Technological scheme of a machine-building plant

11.2. The essence foundry... Casting methods

11.3. Metal forming methods (rolling, drawing, pressing, forging, stamping)

11.4. The essence of the assembly process

11.5. Types and organizational forms assembly process

11.6. Ways to Improve Assembly Efficiency

Mechanical engineering is the leading branch of modern industry. The importance of mechanical engineering in the national economy is determined by the fact that it creates one of the most important elements of the productive forces - the instrument of labor. Due to the various instruments of production and the social division of labor, mechanical engineering is subdivided into separate branches, of which the main ones are: machine-tool engineering, heavy engineering, transport, energy, agricultural, and nuclear.

Each branch of mechanical engineering has its own specific technological methods and techniques, however, in general, mechanical engineering is characterized by a commonality of raw materials (ferrous and non-ferrous metals, their alloys and the identity of the basic technological principles of converting them into parts (casting, forging, stamping, cutting), and parts into a product (welding, assembly).

In the production processes of mechanical engineering, the basic principles of the rational organization of production are used.

At machine-building plants, the following main ones are distinguished workshops :

v procurement: iron foundry, steel foundry, forge and press;

v processing: mechanical, thermal;

v manufacturing products: assembly.

Organization industrial production built on one of the principles - technological, subject or mixed. The above division of the main departments is inherent in the technological principle of organizing production. With the objective principle of organizing production, equipment for the manufacture of specific parts or assembly units is concentrated in separate workshops of the enterprise. With a mixed principle - in separate workshops processing of technologically homogeneous parts and execution of the same type technological processes and operations.

Otherwise, the structure of machine production is not much different from other industries, i.e. there are auxiliary shops and side shops, various services and facilities, enterprise management bodies that organize the production process and control it, ensure the development of technical documentation and technological equipment, accounting, and sales of finished products.

Thus, a machine-building enterprise is a collection of a number of industries linked by a single technological process. Depending on the scale of production, the possibilities of cooperation with other enterprises and on a number of other technical and economic conditions, the machine-building plant either itself carries out the entire technological process, i.e. manufactures all parts of the machine and assembles it, or manufactures only the main units of the machine, and receives parts and semi-finished products (casting, forgings) from other specialized enterprises and in its workshops performs only their processing and subsequent assembly. The technological scheme of the machine-building plant is as follows: raw materials and fuel from the charge yards, where they are stored and appropriately prepared for production, go to the foundries that produce castings. The resulting casting is sent to the machine shop, and the workpieces made by forging and stamping in the press-forging shop are also delivered there. In the mechanical workshop, further processing of workpieces is carried out by cutting on various metal-cutting machines. In addition to processing cast and forged blanks on metal-cutting machines, parts are made from rolled products. Parts requiring heat treatment are sent to the heat treatment department.


Finished parts from mechanical workshop are sent to the assembly shop, where the finished parts from other shops are received. Mechanical and assembly shops are often located in the same building, which reduces the cost of in-plant transportation of parts and assemblies. The most common processes in mechanical engineering are casting, rolling, drawing and pressing, forging, stamping, welding, and machining processes (cutting).

Foundry refers to the processes of obtaining shaped products (castings) by pouring molten metal into the resulting shape, which reproduces the shape and dimensions of the future part. After solidification of the metal in the mold, a casting is obtained, i.e. workpiece or part.

In the structure of the cost of casting, the main share is the cost of metal (up to 80%). When making a technical and economic analysis of the foundry, special attention must be paid to those stages and elements of the technological process that are directly related to possible losses of metal for waste, splashing, scrap, etc. The cost of casting depends on the volume of production, the level of mechanization and automation technological processes.

With all the variety of casting techniques that have developed over a long period of development of its technology, the schematic diagram of the casting process has not practically changed and includes 4 main stage :

1.Smelting metal.

2. Making molds and rods.

3. Pouring liquid metal into a mold.

4. Removing the hardened casting from the mold.

Benefits foundry:

v the possibility of obtaining complex thin-walled castings with the rational use of metal;

v low cost of production;

v relative ease of making castings.

disadvantages foundry:

ü low labor productivity;

ü inhomogeneity of the composition and reduced density of the material of the workpieces.

There are the following casting methods:

◭ casting in one-time sandy-clay molds (earthen);

◭ chill casting (permanent metal molds);

◭ injection molding;

◭ centrifugal casting method;

◭ investment casting;

◭ shell casting or shell casting;

◭ casting into thin-walled disposable molds;

◭ electroslag casting.

All of the above casting methods, except for casting in earth molds, are called special casting methods. Castings are widely used in mechanical engineering, metallurgy, and construction.

The most common and relatively simple way casting - casting in one-time sandy-clay forms. This method produces up to 80% of castings. Sandy-clay molds can be prepared either directly in the soil (in the floor of the foundry) according to templates, or in special boxes-flasks according to models. Large castings are made in soil, small ones - in moldings.

The technological process for the production of castings in moldings consists of three stages: preparatory, main (Fig. 11.2.1) and final.

The preparatory stage includes the design and manufacture of model equipment.

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UDC 621.74

MODERN CASTING 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 the manufacture of castings, methods of automation of foundry production, the composition of foundry conveyors, the use of a protective coating to improve the quality of products are considered.

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

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

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

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

Figure: 2 General form automatic molding line Disa

Disa's molding line includes a shuttle-type sandblowing press molding machine that pulsates flaskless molds onto a conveyor. In the casting area, an automatic casting unit (5) fills the molds with 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 stage is the homogenization of the circulating mixture, which enters the syringe of the final preparation of the mixture and into the mixer, where it is transferred with refreshing materials and a high-level mixture is obtained. The resulting mixture is transferred to a molding machine.

The castings enter the shot blasting machine (4) through an adapter (3) for surface treatment. Then there are painting, quality control and storage operations.

Currently, the industry uses special casting methods, for example, chill casting. This method allows for more accurate and dimensionally stable castings. The minimal physicochemical interaction of the metal of the casting and the mold contributes to the improvement of the quality of the casting surface, the absence of burn-in. Heat is quickly removed from the casting, which leads to its rapid hardening, provides an increase in mechanical properties.

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

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

Rice 3. Carousel chill mold: 1,2 - plate; 3 - shaft; 4 - pusher.

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

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

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

The main operations of casting in a chill mold are opening the chill mold, extracting cores and casting, applying a refractory coating, installing the cores, locking the chill mold, pouring the melt. All operations are performed by the mechanisms of a chill mold or a casting 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 machines is effective. In the mass and large-scale production of small and medium castings - automatic casting complexes and automatic lines.

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

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

The finished castings enter the container (7), and then are transported along the conveyor (5) for processing. The melt from the melting units is fed to the batcher along the monorail (9) with ladles. The production process is serviced by operators.

In fig. 4b shows an automated foundry complex for simple castings. The melt from the batcher (1) is poured into chill molds installed on the machines (2). After the casting has hardened and the chill mold is opened, the casting is removed by a manipulator (4) and transferred to a container (3). The complex is controlled by the operator from the console.

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.

These lines include melting units, vehicles to serve

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

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

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. The signals from the parameters of technological processes (T) are fed to the switches (K), and then the ADC and then to the control computer serving all the injection molding complexes. The quality control system of castings (SKKO) establishes the numerical values \u200b\u200bof the functions of quality indicators (T) from the parameters of the technological process (objective function) and transmits to the computer through the switch K3 and ADC3. The computer, on the basis of the program and the mathematical model of the technological process, linking the objective function, constant and variable (adjustable) parameters of the injection molding process, develop the optimal values \u200b\u200bof the controlled parameters. Through the feedback system, which includes switch K2 and ADC2, the control signal is transmitted to the system of regulators (p), which act on the executive mechanisms of the casting machine.

The operation of casting machines and units takes place at high loads and different temperature levels, in aggressive media and vacuum.

Industry uses different methods coatings using a variety of materials (metals, alloys, ceramics, plastics), as a result of which the physical and chemical state of the surface layer of the workpiece differs from the main material of the part. These include surfacing and spraying, electrolytic and chemical coatings, polymer coatings.

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

Conclusion. Automation of foundry production using modern technologies and equipment increases the level of productivity of enterprises, the competitiveness of 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 treatment of casting / B.S. Glazman // Monograph. - Rostov-on-Don: DSTU Publishing Center, 2014. - 88 p.

CONFERENCES SEMINARS EXHIBITIONS 121

IMPROVING TECHNOLOGY AND INCREASING THE EFFICIENCY OF CASTING PRODUCTION

The scientific and practical seminar "IMPROVEMENT OF TECHNOLOGY AND INCREASING THE EFFICIENCY OF CASTING 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 from far and near 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 forum is one of the major events in the calendar of business life in St. Petersburg and throughout Russia.

In 2008, the agenda of the forum included a discussion of the most important issues related to 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 theme fully meets the interests of the city (megalopolis), the tasks of its industrial policy aimed at the development of new types of products, the creation of science-intensive, competitive products of the world level.

An important event included in the program of the event was the scientific and practical seminar "Improving technology and increasing the efficiency of foundry", 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 workshop was attended by experts in the field of foundry and metallurgy: FSUTT "PO" Oktyabr ", OJSC" Rostvertol ", OJSC" NPK "Ural-Wagonzavod", CJSC "Kazan Giproniiaviaprom", CJSC "Technology-M", OJSC "BiKZ ", JSC" GPNII-5 ", JSC" AK OZNA ", LLC" Polygon "," KomMod "," Escalada "," Rontal-Impex "," SevZapEnergo ", TsNIIM, as well as the State Polytechnic Institute (technical university), Department of Automation of Technological Processes and Production, St. Petersburg State Mining Institute ( technical university) and etc.

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

"Complex modifiers for steel casting" (N.V. Ternovy, "ComMod"), "Computer modeling system" Polygon "(E.A. Ishkhanov)," Modern technologies iron casting "(S.S. Tkachenko, GPTU)," Experience of the enterprise in improving the technology of casting under pressure "(S.L. Samoilov," Escalada ")," New foundry steels and technologies for obtaining high-quality castings from them "(G. A. Shemonaeva, TsNIIM), “Modern technologies of titanium casting” (AM 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 model equipment "(T.N. Gavrilova," SevZapEnergo ")," Possibilities of using modern hardness testers of metals and eddy current flaw detectors "(M.Yu. Koroteev," Constant ") and others.

On October 9, an off-site meeting was held at the Catenary Armature Plant, at which the problems of “Investment casting production” and “Gasified casting production” (A.A. Lisovoy) were discussed.

On the final day of the seminar, October 10, an exchange of experience on the problems of the foundry industry and 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, the development of which depends on the level of the machine building complex as a whole. The machine-building complex of Russia includes about 7,500 enterprises. The share of machine building in the total industrial output is about 20%, including the share of machine tool building and instrument making is 2.5%.

Currently, there are about 1,650 foundries in Russia, which, according to expert estimates, produced 7.68 million tonnes of castings in 2006, including 5.28 million tonnes of cast iron, 1.3 million tonnes 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. At that time, the structure of the Ministry of Machine-Tool Industry included 238 foundries and 12 centrolites, which produced 1.35 million tons of castings and had - whether the technical potential (capacity) is more than 2 million tons. The foundry of the Ministry of Machine Tool Industry was considered the flagship of the USSR in the production of iron casting, especially large ones. During this period in foundries outside- | advanced technological processes of smelting, 5 shaping, finishing operations were scrapped. Foundry g

122 CONFERENCES SEMINARS EXHIBITIONS

about a dozen research institutes of all-Union significance worked in production. The Ministry of Machine Tool Industry manufactured 70 thousand metal-cutting and 20 thousand forging and pressing machines.

The production volumes of cast billets are proportional to the production volumes engineering products, since the share of cast parts in cars, tractors, combines, tanks, airplanes, etc. is 40-50%, and in metal-cutting machines and press-forging equipment it reaches 80% of the mass and up to 25% of the product cost.

A sharp decline, since the 1990s, in the production of metal-cutting, woodworking machines and press-forging 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 construction with a total capacity of about 1 million tons of castings per year, created in the 1970s, could not withstand competition, lost orders and practically ceased their activities. Foundries operating 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.

A rather difficult situation has developed. If orders for machine tools now appear, the foundries will not be able to produce high-quality, competitive castings, and castings weighing more than 30 tons cannot be produced by any of the remaining foundries. There are almost no highly qualified foundry specialists left in the industry, both workers and engineers, most of the research institutes have been liquidated.

An urgent reconstruction of foundries is required, which should be carried out on the basis of new, environmentally friendly technological processes and materials, progressive melting, mixing-preparatory and shaping equipment, ensuring the production of high-quality castings that meet European and international standards.

S. S. Tkachenko, I. N. Beloglazov

St. Petersburg State Mining Institute (Technical University)

HN\u003e UU fcxrnuSiOft ihOuSTl

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

ALUMINCO S.A. formed in 1982 in Greece. During its existence, it turned into one of the largest companies in Europe in the field of aluminum production. It supplies its products to more than 60 countries worldwide. The production facilities of the company allow to produce up to 7000 tons of aluminum profiles per year, up to 1000 tons of aluminum casting, up to 50,000 pieces. aluminum sandwich panels.

The production and technological 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 dies; design department; design studio.

The quality of the products is marked by the certificates 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 different wind loads;

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

aluminum casting grilles; gates and wickets made of cast aluminum; Street lights; outdoor and garden furniture; canopies over the entrance doors; stair railings;

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

In 1996, for the first time in Russia, decorative elements of interior facades were used during the construction of the Okhotny Ryad shopping center 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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