Casting cast iron cookware. Cast iron cookware. Equipment for the production of ceramic tableware

WITH The current market situation in recent months is forcing many companies to reconsider their current development goals, switching to a saving mode that will help them survive the reduction in consumer demand with minimal losses. However, even in today’s difficult times, there are players in the tableware market who are investing effort and money in expanding their business, mastering new technologies, and expanding their customer base. One such example is the Biol company, which at the last exhibition not only declared its ambitions to become a leading player in a new market for cast iron cookware, but also supported them with convincing arguments, presenting a wide range of cast iron cookware, attractive prices and entering production volumes that are significant for this market segment. Oleg Dunaev, director of the Biol company, spoke about the production and promotion of cast iron cookware in an exclusive interview with our website, which took place at the HouseHold Expo exhibition held in Moscow.

- At the last two HouseHold Expo exhibitions, cast iron cookware was already presented at your stands, but it occupied a modest place. Judging by this year's stand, you have come quite far in the production of cast iron over the past year?

- Yes, in the last year since the last HouseHold Expo exhibition, we have concentrated our efforts mainly on the production of cast iron cookware and have achieved some success. Today we have almost completely debugged the foundry production of cast iron cookware and created an almost complete product line, which we will work with in the coming years. Now we are preparing the next steps - applying different coatings to cast iron cookware. It is planned that these will be both classic enamel coatings and non-stick coatings. Now we are communicating quite closely on this topic with our partners - the companies Weilburger Coatings and Ferro and hope to introduce cast iron cookware with different coating options by next year.

- As you know, there are different technologies for producing cast iron cookware. Which ones does Biol use?

Our cast iron cookware is produced by chill casting. Unlike the common sand casting technology, chill casting allows you to obtain products with a higher quality surface with a minimum number of defects and low porosity.

There are many similarities in how cast iron and cast aluminum cookware are used. Here, the thickness of the bottom and walls is of paramount importance; the cost is influenced by the quality of the fittings and packaging. Our cookware was initially made with the expectation that we would continue to make it with different coatings, and when choosing the technologies and components used, we took into account all our long experience in the production of cast non-stick aluminum cookware. For example, we have developed special removable handles for cast iron, which, on the one hand, are of high quality and beautiful, and on the other, reliable and will fit well into various production chains.

Once we have the equipment to coat cast iron cookware, we can experiment with all the shapes we have. This will give us flexibility and the ability to produce the required products in the required volumes with one or another coating, or without coating, as the client wants.

If we talk about the raw materials, we produce our dishes from foundry cast iron (there is conversion and foundry cast iron) of six grades L1, L2, L3, L4, L5, L6. All of them are suitable for making tableware and meet hygienic requirements.

- What range of Biol cast iron cookware do you offer to customers today?

We are now ready to offer more than 30 different positions. These include frying pans of two series “Classic” and “Optima” with removable handles of the most popular diameters from 22 to 26 cm, frying pans, saucepans with cast iron and glass lids, cauldrons. There are also unique products in the range, for example, a grill pan with a press. We can say that our assortment is ninety percent complete. There are still plans to expand the line of Asian cauldrons with larger sizes (up to 100 liters), which are in good demand.

- Is it difficult to promote cast iron cookware?

At the very beginning of the launch of our cast iron cookware program, we had to make some efforts, since the product was new and the range was narrow. Now the main problem is increasing production volumes. Today we sell everything we can make, while a certain part of the demand remains unsatisfied. If we talk about current volumes, today we produce about 120 tons of cast iron cookware per month and in the near future we set ourselves the task of significantly increasing this figure.

- Your cast iron cookware is very similar to your cast aluminum cookware. Was this done intentionally?

When designing the forms, we assumed that the brand should confirm its authenticity. Therefore, the appearance of cast aluminum and cast iron pans is very similar. In addition, this is due to technical features. Thus, we use lids made of heat-resistant glass from the Czech plant Kavalier for our dishes; accordingly, the shapes of frying pans and pots must fit these lids.

We have been working with cast aluminum cookware for a long time and know very well what shapes and what diameters are in greatest demand among customers. Therefore, the formation of an assortment of cast iron cookware did not cause us much problems and searches - we rely on those items that will definitely sell well.

- Cast iron cookware is presented on the market today in a variety of segments - from economy to premium. What kind of buyer is your cookware designed for and who will you compete with?

We strive to ensure that our cast iron is affordable and priced next to Chinese. This is necessary to feel confident in the market. Supplies of cast iron from China usually come in waves—everyone has brought it, but there are times when no one has it, and everyone begins to worry and think about bringing it. Therefore, our task is to make Biol cast iron cookware competitive with Chinese ones. Naturally, you can bring cast iron of very poor quality from China, which will be cheaper than ours, but with comparable quality we must fall within this price.

Recently, the so-called “lightweight cast iron” has also appeared on the market. Do you plan to develop in this direction?

It is more correct to call such cast iron thin-walled, because its specific gravity does not differ from the specific gravity of ordinary cast iron. To obtain cast iron cookware with thin walls, you need to use a slightly different technology using a press. We took thin-walled cast iron cookware for testing and tested it in the laboratory. The so-called “lightweight cast iron” is close in its functional properties to carbon steel. But from the point of view of cost and production technology, it is more rational to immediately make frying pans from carbon steel, rather than engage in expensive technology for thinning cast iron, worsening its consumer properties, since all the advantages of cast iron lie in its thick bottom and walls, high heat capacity and slow heating.

The same situation applies to aluminum cookware. It is possible to greatly reduce the thickness of, for example, our cast aluminum cookware, making it as thin as stamping. But all the advantages of cast utensils are immediately lost, despite the fact that the price of such utensils will be more expensive than stamping. The same principle applies in the opposite direction. If you take a sheet of aluminum of great thickness, say, 4 mm, and make a frying pan out of it, then with comparable properties in terms of heat distribution, absence of overheating, and anti-deformation properties, such utensils will be close to cast ones, but the cost will be more expensive.

For now, technologies themselves define the boundaries beyond which there is no particular reason to go. Therefore, we do not yet see any rational reasons for the passion for thin-walled cast iron. In pursuit of fashion, you can make some products, but this, as a rule, entails a lot of difficulties, since consumers receive dishes that are inconvenient to use.

- Where can you buy Biol cast iron cookware today?

All our main Russian partners are already working with cast iron cookware. There is also cast iron in the warehouse of our Russian representative office in Belgorod - “South-Western Trading Company”. Ukrainian buyers have the opportunity to purchase any batches of our products through our company online store.

Well, the last question is: are buyers of Biol products suffering because of the events in Ukraine? Are the goods being supplied?

Yes, deliveries are now underway. We had some minor problems in the summer related to the tightening of the passage of goods across the border, but we solved them and today the goods arrive to our customers in Russia on schedule. The only thing is that the political situation that has developed around Ukraine causes anxiety and a sense of uncertainty. But for now we are working as we always did.

A business idea for the production of wooden utensils is easy to organize at home. But in order to develop it into a profitable business with short payback periods, you need to increase productivity and reduce costs. This effect can only be achieved with special equipment. This business idea discusses the rapid production of tableware from wood with a hemispherical shape.

An inexpensive woodworking lathe allows you to produce a whole set of wooden utensils from one piece. The unique operating principle of the machine saves consumables and significantly reduces the time for the production of wooden bowls, plates, bowls, etc.

Wooden utensils have many advantages, which makes them attractive to consumers. She has a place in every kitchen.

Advantages of wooden utensils

Wooden utensils are in demand due to their irreplaceable advantages:

1. Allows you to keep food hot for a longer time. At the same time, it does not burn your hands when serving hot dishes.
2. Improves the taste of food.
3. Has tonic bactericidal properties.
4. Absolutely eco-friendly.
5. Unbreakable, strong and durable.
6. Can be used to heat in the microwave ( only for the microwave for no more than 20 minutes, otherwise it will dry out, but for the grill - not!).
7. Caring for wooden utensils does not require large expenses. If over time the wood has darkened, you can wipe it with hydrogen peroxide to restore its original appearance (after which you must rinse it).

Retail prices for wooden utensils depend on the complexity of the product, size and type of wood. Comparative prices for pine wood cookware:

When using a special woodworking lathe, it takes less than 20 minutes to produce one medium-sized bowl, including sanding and polishing. You can sell wooden utensils through an online store, at fairs and markets, or to friends. Depending on the volume of home production.

Unique equipment for making wooden utensils

The woodworking equipment for the production of wooden utensils depends on:

• quality of finished products;
• home production productivity;
• business profitability.

To economically produce wooden bowls, which are in good demand, a special machine is needed. Its peculiarity lies in its unique operating principle.

The base is no different from a standard woodworking lathe. The advantage lies in special arc-shaped cutters, which are mounted on hinges and upgraded with compressed air supply. At the hinge points there are adjusting screws that allow you to adjust the precise movement of the cutters along the required path. The compressed air supply nozzle is aimed at the place where the cutters work, which allows not only to remove chips from the cut channels, but also to cool the cutter itself for its high-quality operation. The advantage of the operating principle of such a device is clearly displayed during the processing of workpieces.

The operating principle of a unique woodworking machine

Before starting work, you should adjust the radius of movement of the arcuate cutter around its axis. Using the adjusting screws we set the arc of the path of the cutter's movement. In fact, we are setting the shape of our future bowl.

Next, you should firmly secure the workpiece in the chuck of the lathe and fill the compressor receiver with compressed air. Then turn on the machine to rotate the workpiece. We bring the end of the arcuate cutter to the workpiece, slowly moving it around its axis on a hinge. At the moment of contact of the cutter with the workpiece, turn on the compressed air supply.

Next, the cutter passes the radius along the trajectory inside the workpiece. Thus, a spherical bottom of the first wooden bowl is formed on its outer side. In the process of deepening the cutter, a deep internal roll is formed, from which chips are constantly removed thanks to compressed air. At this time, the cutter does not overheat and smoothly cuts out the shape of the product.

In the next stage, you should move the cutter to the initial position and retreat the required distance to form the thickness of the bowl wall. Already at the second stage, the cutter simultaneously cuts out the inner spherical surface of the bottom for the first bowl, and the outer one for the second. After turning, the finished dishes are ground and polished.

Innovation makes business profitable quickly

This unique principle of wood processing allows you to significantly:

1. Save wood consumption for making bowls.
2. Increase production productivity.
3. It is easy to create complex and sphere-shaped shapes in wooden dishes.
4. Receive a wide range of hemispherical dishes.
5. Quickly produce sets of bowls with already suitable shapes for inserting matryoshka dolls (one into the other).

An arcuate cutter can cut out a variety of shapes (as shown in the picture). For this purpose, settings for the trajectories of movement of the cutters are provided. Or you can replace the cutter itself with another one with a different arc shape. Depending on what shape of wood needs to be cut:

• bowls;
• plates;
• casanova;
• bowls

All these types of dishes can be produced on this machine in whole sets of 2-5 pieces. in one (depending on the shape).

This is excellent equipment for quickly creating a business at home without large investments. Some craftsmen may even try to make such a machine with their own hands. Its principle of operation is simple and clear. And the production of such a machine does not require large investments. The wooden products produced there will be sold and, of course, will be useful for personal use.

Foundry business is relevant and profitable. When opening, provide your plant with the necessary equipment. The quality of your products will depend on the quality of industrial machines. Do not forget to comply with safety standards and arrange the workshop premises in accordance with established rules.

First of all, determine what type of pans your company will produce. The wider the range, the more successful the business. Choose a specific raw material; utensils made of aluminum and cast iron require different equipment, it is very expensive, so it is better to decide on one material.

Equipment for the production of cast iron frying pans

The production of cast iron frying pans requires the following equipment:

• special preheating oven 300°C;
• induction melting electric furnace;
• transfer container;
• sand mold machine;
• vibrating tape;
• special pipe for cleaning;
• Natural non-stick coating sprayers.

Necessary for melting metal at a temperature of 1500°C. Large production of frying pans requires equipment that can accommodate at least 3 tons of molten raw materials. IST-1800 installations correspond to this indicator / 0.3, UIP-1600-0.25-3.0.

To the melting complex IST-1800 / 0.3 includes:

• induction furnace equipped with hydraulic cylinders;
• frequency converter;
• compensating block of capacitors;
• cooling installation;
• remote control panel;
• water-cooling equipment;
• complete set of busbars;
• set of sleeves, clamps;
• oil processing apparatus;
• a remote control responsible for raising and lowering the stove.

UIP-1600-0.25-3.0 has similar equipment and characteristics:

Molten cast iron is capable of melting any other metal, so special industrial sand is used as a material for casting molds in the production of cast iron frying pans.

Sand Mold Making Machine produces up to 1,500 molds per hour. Modern devices are equipped with a 3D system. The ExOne line of printers has such a device:

Equipment for aluminum frying pans

If you decide to produce aluminum products, you will need:

• melting devices;
• lathes;
• sandblasting machine;
• automatic or semi-automatic coating lines;
• conveyor oven.

From the domestic manufacturer InterMash LLC are presented in two types:

• stationary;
• inclined.

Such equipment is convenient to use and is aimed at processing aluminum ingots, pigs, and scrap. InterMash devices have the following advantages:

• automatic process control (PLC);
• large window for loading raw materials;
• refractory lining;
• the drain hole is equipped with a partition, which is controlled by a pneumatic cylinder;
• systems for purification of generated gases;
• maximum heating up to 1300°C;
• combustion system based on regenerative burners.

Induction-type thyristor furnaces are also suitable for melting aluminum. For example, IPK-ST-3/2500-TG1.

They process products from excess pieces of metal and help give the pans the desired shape. Choose equipment depending on functionality and scale of production. Below are Jet metal machines with different performance.

Used for deep cleaning of products under pressure. Abrasive-type equipment removes all particles formed during the manufacturing process from the surface of the frying pan.

The Contracor DBS-100 device has:

• pressure of 12 atm;
• productivity 37 m2/h;
• separator filter.

The Russian-made model DSG-1000 from VMZ LLC uses the following materials as materials:

• steel shot;
• cast iron shot;
• steel sand;
• silicon carbide;
• electrocorundum

The cost of sandblasting machines is 15,000-50,000 rubles.

Equipment for applying Teflon

In the case of the production of Teflon-coated frying pans, you will need:

• spray device;
• conveyor or chamber oven (360-450°C).

First of all, select a suspension with Teflon particles of the required size. The further choice of the spray device will depend on this. The quality of domestic equipment and raw materials for the production of Teflon coating is inferior to foreign analogues by 5-15%.

Video: How steel pans are made

Cast iron is produced by fusing carbon and iron. The quality and properties of the metal depend on the proportions and impurities in the alloy. If the percentage of iron exceeds the norm, then the future alloy will be susceptible to corrosion. Therefore, specialists carefully monitor the purity of the alloy and the presence of unacceptable amounts of impurities.

At the plant, gray cast iron cast using a special technology is used to make cast iron cookware. It can be used for a long time, does not lose its properties and is not susceptible to corrosion.

At all enterprises, the production of cast iron cookware takes place on modern equipment using finishing processing. Most often, impurities of metals such as phosphorus and silicon can be found in cast iron. Cast iron cookware gained its popularity due to many advantages that did not disappear even with the advent of new materials.

Forms and processing

Mass production requires the use of iron casting molds and equipment. In foundries, only gray cast iron that meets all requirements is used to make cast iron cookware.

After hot cast iron is poured into the mold, you must wait until it cools down to disassemble the mold and remove the finished product. It is in the molds that various cast iron products are cast. This:

Frying pans;

Pots;

Cauldrons;

Ducklings;

They also make pots, plates, forks, spoons and many other items that can be found in the kitchen. The need for final machining depends on the quality of the mold and the finishing.

If the mold is made accurately and has no defects, then after disassembly the product is immediately sent to the warehouse and does not require additional processing. Some products require grinding and removal of excess metal. The quality of each dish is determined by experienced specialists who monitor the manufacturing process.

If necessary, processing consists of removing sprues, burrs and cavities from the metal surface. This is done with the help of grinding and sandblasting machines, which are capable of efficiently processing a large number of dishes per shift.

The use of tools and various equipment allows us to produce cast iron cookware in large quantities and in a wide range. The quality remains high and does not decrease.

Graphitizing annealing

A protective film of iron oxide forms on the surface of any cast iron frying pan or pot. It is this that protects against corrosion and does not come into contact with food. The stable properties of gray cast iron are achieved using a process such as graphitizing firing at temperatures from +600˚C to + 800˚C.

This process must be repeated twice and after each time the metal must be cooled in the open air. Graphitization is carried out after polishing the finished product and allows you to obtain cast iron cookware in the form in which everyone is accustomed to seeing it on store shelves.

Owners of patent RU 2340272:

The group of inventions relates to kitchen cast iron cookware and a method for its manufacture. Cast iron cookware is made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 is formed. A method for making cast iron cookware includes casting gray cast iron, removing sprues and burrs, roughing, grinding, sandblasting the casting and forming a protective coating of iron oxide Fe 3 O 4 on the casting by heating it and immersing it in oil. When casting gray cast iron, silicon is introduced into the charge in an amount of at least 4.1% in proportion to the weight of the cast iron cookware. After grinding, graphitizing annealing of the casting is performed at least twice at a temperature of 680÷800°C for 0.5÷1.0 hours, followed by cooling in air until a gray tarnish color is achieved. The technical result consists in ensuring the stability of the material properties, geometric parameters and shape of the dishes, as well as increasing the adhesion strength of the oxide film to the metal. 2 n. and 1 salary f-ly.

The group of inventions relates to cast iron kitchen utensils for cooking, baking and frying food products, as well as to methods for their manufacture.

From the prior art, cast iron cookware is known, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating is formed in the form of a layer of enamel / GOST 24303-80. Household cookware made of cast iron, enameled. General technical requirements, analogue/.

A method of manufacturing cast iron cookware is known from the prior art, including casting gray cast iron into a mold to obtain a bowl-shaped casting, removing sprues, scoring, roughing, grinding, sandblasting the casting and forming a protective coating on the casting in the form of a layer of enamel /Handbook of Cast Iron Casting. Edited by Dr. Tech. Sciences N.G. Girshovich. - 3rd ed., revised. and additional - L.: Mechanical engineering. Leningrad, department, 1978. - 758 pp., pp. 642-645, analogue/.

Forming a protective coating on a casting involves priming and firing, as well as enamel application and firing.

Applying enamel and firing is repeated 3-5 times.

The disadvantage of such cast iron cookware and the method of manufacturing this cast iron cookware is the formation of defects on the enamel coating of cast iron cookware in the form of bubbles, pinholes, chips and cracks.

The first two defects are associated with gas formation during firing, the latter - with stresses arising during the temperature processing of food in the mentioned cast iron cookware, at the cast iron-enamel interface due to the difference in the expansion coefficients of cast iron and enamel.

In addition, with a significant degree of oxidation of the surface of an iron casting, a thick, easily removable layer of scale is formed, as a result of which the adhesion of the soil and enamel is reduced.

This reduces the strength of the enamel coating and the service life of cast iron cookware with a protective coating applied in this way.

Cast iron cookware is also known from the prior art, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating is applied in the form of a layer of preservative lubricant consisting of 50% paraffin and 50% medical petroleum jelly. RST USSR 114-88. Black cast iron cookware. General technical conditions, paragraphs 1.2., 2.2.2., 2.3.1., 2.5.1., analogue/.

The prior art also knows a method for manufacturing cast iron cookware, which includes casting gray cast iron into a mold to obtain a bowl-shaped casting, removing sprues, scoring, roughing, grinding, sandblasting the casting and applying a protective coating to the casting in the form of a layer of conservation lubricant consisting of 50% paraffin and 50% medical petroleum jelly / PCT URSR 114-88. Black cast iron cookware. General technical conditions, clause 2.5.1., analogue/.

The disadvantages of such cast iron cookware and the method of manufacturing this cast iron cookware are the low effectiveness of the anti-corrosion resistance of the protective coating, made in the form of an applied conservation lubricant, both during transportation and during operation of the cast iron cookware.

As a result, the service life of cast iron cookware with a protective coating applied in this way is significantly reduced.

Also known from the prior art is the cast iron cookware that is closest in purpose and number of common features, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 /UA 56079 A is formed (SONKIN A.L. ), 04/15/2003, the closest prototype analog/.

The casting is made of gray cast iron containing silicon in an amount of 2.5-4.0%.

Also known from the prior art is the method of manufacturing cast iron cookware that is closest in purpose and number of common features, including casting gray cast iron into a mold to obtain a bowl-shaped casting, removing sprues, scoring, stripping, grinding, sandblasting the casting and forming a protective oxide coating on the casting. iron Fe 3 O 4 by heating it and immersing it in oil /UA 56079 A (SONKIN A.L.), 04/15/2003, the closest analogue prototype/.

When casting gray cast iron into a mold to obtain a bowl-shaped casting, silicon is added to the charge in an amount of 2.5-4.0%.

When forming a protective coating of iron oxide Fe 3 O 4 on the casting, it is heated to a temperature of 830-900°C.

The disadvantages of such cast iron cookware and the method of manufacturing this cast iron cookware is its low corrosion resistance when preparing food products containing organic acids, including citric, acetic and lactic acids.

This is explained by the fact that the charge contains silicon in insufficient quantities (2.5-4.0%).

As a result, the low silicon content in gray cast iron does not allow for a more stable silicon content and reduces the activity of carbon, which leads to a high degree of oxidation of cast iron and has a great influence on the composition of the oxide film (iron oxide Fe 3 O 4) on the surface of the casting.

This does not allow achieving high adhesion strength of the oxide film to the metal and reduces the service life of cast iron cookware.

In addition, at the selected heating temperature of 830-900°C, the cast iron heats up excessively, becomes plastic and “floats”, distorting the original shape of the casting.

As a result, the geometric parameters and shape of the casting are violated, and the high quality of cast iron cookware obtained by this method is not achieved, which reduces its performance properties.

The technical problem to be solved by the invention is to ensure a more stable silicon content in cast iron cookware and the method of manufacturing cast iron cookware by making a casting from gray cast iron with a high silicon content to increase the activity of carbon and its complete conversion into graphite during heat treatment of the casting in optimal conditions .

The technical result that is achieved when solving the stated technical problem is to ensure the stability of the properties of the material, geometric parameters and shape of the dishes, as well as to increase the adhesion strength of the oxide film to the metal, which increases the corrosion resistance to organic acids of the coating, service life, quality and performance properties of cast iron cookware.

The stated technical problem is solved, and the technical result is achieved by the fact that in cast iron cookware, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 is formed, according to the invention, the casting is made of gray cast iron, containing silicon in an amount of at least 4.1%.

The increased silicon content (at least 4.1%) in gray cast iron leads to a more stable content, thereby increasing the activity of carbon in the manufacturing process of cast iron cookware and achieving the possibility of its complete transformation into graphite during heat treatment of the casting in optimal heating conditions.

This ensures stable properties of the cookware material and a dense coating with high protective properties.

The stated technical problem is solved, and the technical result is also achieved by the fact that in the method of manufacturing cast iron cookware, including casting gray cast iron into a mold to obtain a bowl-shaped casting, removing sprues and burrs, stripping, grinding, sandblasting the casting and forming a protective coating on the casting from iron oxide Fe 3 O 4 by heating it and immersing it in oil, according to the invention, when casting gray cast iron into a mold to obtain a bowl-shaped casting, silicon is introduced into the charge in an amount of at least 4.1%, and after grinding, at least , twice, graphitizing annealing of the casting at a temperature of 680-800°C for 0.5-1.0 hours, followed by cooling in air until a gray tarnish color is achieved.

The introduction of silicon into the composition of the charge in an increased amount (at least 4.1%) leads to a more stable content in cast iron, due to which the activity of carbon increases in the process of manufacturing cast iron cookware and the possibility of its complete transformation into graphite is achieved during heat treatment of the casting in the proposed optimal heating modes.

And multi-stage annealing of the casting after grinding and before sandblasting at a temperature of 680-800°C for 0.5-1.0 hours, followed by cooling in air until a gray tarnish color is achieved ultimately ensures stable properties of the tableware material and a dense oxide film with high protective properties when forming a protective coating, which improves the performance properties of cast iron cookware.

The selected temperature regime for graphitizing annealing of 680-800°C of the casting was determined experimentally and is optimal for obtaining the best conditions for complete graphitization of carbon, stabilizing the properties of the casting material, geometric parameters and shape of the cookware, as well as increasing the adhesion strength of the oxide film to the metal during the formation of a protective coating .

It has been experimentally established that choosing a graphitizing annealing temperature of a casting less than 680°C is not advisable, since in this case the process of carbon graphitization slows down, as a result of which stabilization of the properties of the casting material is not achieved and the adhesion strength of the oxide film to the metal during the formation of a protective coating is reduced.

It has also been experimentally established that choosing a graphitizing annealing temperature of a casting greater than 800°C is also not advisable, since in this case the cast iron heats up excessively, becomes plastic and “floats”, distorting the original shape of the casting, resulting in a decrease in the quality of cast iron cookware.

In addition, at the selected heating temperature of 680-800°C, the casting acquires a crimson tarnish color, which allows additional visual control of the temperature regime of graphitizing annealing, which is an additional technical result.

The method of making cast iron cookware has other differences, which are used in some cases to improve the technical result.

Thus, in the method of manufacturing cast iron cookware, according to the invention, when forming a protective coating of iron oxide Fe 3 O 4 on the casting, it is heated to a temperature of 680-800°C.

The selected heating temperature regime of 680-800°C for the casting was determined experimentally and is optimal for obtaining the best ratio of corrosion resistance, stabilization of the design geometric parameters and shape, service life and quality of cast iron cookware manufactured by this method.

When the heating temperature of the casting exceeds 800°C, the cast iron heats up excessively, becomes plastic and “floats”, distorting the original shape of the casting, and the thickness of the oxide film layer increases excessively, as a result of which the corrosion resistance of the protective coating, as well as the service life and quality of cast iron cookware, also decrease .

At the selected heating temperature regime of 680-800°C, the casting acquires a crimson tarnish color, by which the temperature regime of its heating is additionally visually monitored.

Thus, by manufacturing a casting from gray cast iron with a high silicon content, its more stable content is ensured to increase the activity of carbon and its complete transformation into graphite during heat treatment of the casting in the proposed optimal heating modes.

This makes it possible to ensure the stability of the material properties, geometric parameters and shape of the cookware, as well as to increase the adhesion strength of the oxide film to the metal, which increases the corrosion resistance to organic acids of the coating, service life, quality and performance properties of cast iron cookware.

From the state of the art, the applicant has not identified solutions that coincide with the set of general and distinctive essential features of improved cast iron cookware and an improved method for manufacturing cast iron cookware, on the basis of which we can conclude that the claimed technical solutions of this group of inventions are not part of the state of the art and meet the criterion of the invention “ novelty".

From the prior art, the applicant also did not identify solutions that coincide with the distinctive essential features of improved cast iron cookware and an improved method for manufacturing cast iron cookware.

Based on this, we can conclude that the claimed technical solutions of this group of inventions are not obvious to a specialist, that is, they do not fall outside the state of the art and meet the invention criterion of “inventive step”.

In a specific example, the inventive cast iron cookware is made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 is formed.

The casting is made of gray cast iron containing silicon in an amount of at least 4.1%.

Carbon in cast iron is in the form of graphite.

The metal base of cast iron is ferrite.

In a specific example, the claimed method for manufacturing such cast iron cookware is carried out as follows.

For casting cast iron cookware, gray cast iron is used, the chemical composition of which includes iron, as well as, in quantities permitted by health authorities, carbon, silicon, manganese, phosphorus and sulfur with the permitted content of chromium, nickel and copper.

First, a charge is prepared for melting gray cast iron, into which the necessary components are added to obtain cast iron with the required chemical composition.

Silicon is introduced into the charge in an amount of at least 4.1%.

The amount of silicon is chosen in proportion to the weight of the cast iron cookware.

For light weight cast iron cookware, such as a pancake pan, silicon is added in an amount close to 4.1%.

The greater the mass of cast iron cookware, the greater the amount of silicon introduced into the charge to improve the filling of the casting mold with molten cast iron.

For example, for a pan, silicon is introduced in an amount close to 7.0%.

After the charge is melted, gray cast iron is cast into a mold to obtain a bowl-shaped casting.

In practice, gray cast iron with predominantly the following chemical composition (in percentage) is used for casting cast iron cookware:

The presence of chromium up to 0.2%, nickel up to 0.3% and copper up to 0.5% is allowed.

Bowl-shaped castings are used to make various cast iron kitchen utensils, including:

round frying pan with one handle;

round frying pan with two handles;

round pancake pan with one handle;

round frying pan with one handle;

round frying pan with two handles;

frying pan with two handles;

saucepan with lid;

other dishes.

The casting is then subjected to machining, which involves sequentially removing sprues, scoring, roughing and grinding the surface.

After grinding, graphitizing annealing of the casting is performed at least twice at a temperature of 680-800°C for 0.5-1.0 hours, followed by cooling in air until a gray discoloration is achieved.

This temperature regime of graphitizing annealing of 680-800°C of the casting is optimal for obtaining the best conditions for complete graphitization of carbon, stabilizing the properties of the casting material, geometric parameters and shape of the cookware, as well as increasing the adhesion strength of the oxide film to the metal during the formation of a protective coating of iron oxide Fe 3 O 4 .

When the temperature of graphitizing annealing of the casting is less than 680°C, the process of carbon graphitization slows down, as a result of which stabilization of the properties of the casting material is not achieved and the adhesion strength of the oxide film to the metal decreases during the formation of a protective coating of iron oxide Fe 3 O 4 .

When the temperature of graphitizing annealing of a casting is more than 800°C, the process is also not advisable, since in this case the cast iron heats up excessively, becomes plastic and “floats”, distorting the original shape of the casting, resulting in a decrease in the quality of cast iron cookware.

After this, the surface is sandblasted using a sandblasting unit and a protective coating of iron oxide Fe 3 O 4 is formed on the casting by heating it in a heating device and immersing it in oil.

When forming a protective coating of iron oxide Fe 3 O 4 on the casting, it is heated to a temperature of 680-800°C.

This temperature regime of heating 680-800°C of cast iron is optimal for obtaining the best ratio of corrosion resistance, stabilization of design geometric parameters and shape, service life and quality of cast iron cookware manufactured by this method.

When the heating temperature of the casting is less than 680°C, the thickness of the oxide film layer decreases excessively, resulting in a decrease in the corrosion resistance of the protective coating, as well as the service life and quality of cast iron cookware.

When the heating temperature of the casting exceeds 800°C, the cast iron heats up excessively, becomes plastic and “floats”, distorting the original shape of the casting, and the thickness of the oxide film layer increases excessively, resulting in a decrease in the corrosion resistance of the protective coating, as well as the service life and quality of cast iron cookware.

At the selected heating temperature of 680-800°C of gray cast iron, the casting acquires a crimson tarnish color, by which the temperature of its heating is additionally visually monitored.

The invention is illustrated by examples 1-5 of the implementation of a method for manufacturing cast iron cookware with different temperature conditions for heating the casting.

Cast iron cookware was made - a pancake frying pan, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 was formed.

The casting was made of gray cast iron containing silicon in an amount of 4.0%.

After grinding, graphitizing annealing of the casting was performed once at a temperature of 670°C for 0.4 hours, followed by cooling in air until a gray tarnish color was achieved.

When forming a protective coating of iron oxide Fe 3 O 4 on the casting, it was heated to a temperature of 670°C and immersed in oil.

At this temperature of a one-time graphitizing annealing of the casting for 0.4 hours, followed by cooling in air until a gray tarnish color is achieved, the process of carbon graphitization slowed down, as a result of which stabilization of the properties of the casting material was not achieved and the adhesion strength of the oxide film to the metal was reduced when forming a protective coating from iron oxide Fe 3 O 4.

However, the thickness of the oxide film layer decreased, resulting in a decrease in the corrosion resistance of the protective coating and the service life of cast iron cookware.

Cast iron cookware was made - a pancake pan with a small mass, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 was formed.

The casting was made of gray cast iron containing silicon in an amount of 4.1%.

The method for manufacturing such cast iron cookware included all the operations of the proposed method.

After grinding, graphitizing annealing of the casting was performed twice at a temperature of 680°C for 0.5 hours, followed by cooling in air until a gray tarnish color was achieved.

When forming a protective coating of iron oxide Fe 3 O 4 on the casting, it was heated to a temperature of 680°C and immersed in oil.

At this temperature of two-time graphitizing annealing of the casting for 0.5 hours, followed by cooling in air until a gray tarnish color is achieved, the process of carbon graphitization was activated, as a result of which stabilization of the properties of the casting material was achieved and the adhesion strength of the oxide film to the metal increased during the formation of a protective oxide coating iron Fe 3 O 4.

With this mode of heating and immersion in oil, the initial geometric parameters and shape of the casting did not change and corresponded to its design values.

The strength of the protective coating, as well as the quality and performance properties of cast iron cookware obtained by this method, are satisfactory.

Cast iron cookware was made - a frying pan with medium weight, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 was formed.

The casting was made of gray cast iron containing silicon in an amount of 5.5%.

The method for manufacturing such cast iron cookware included all the operations of the proposed method.

After grinding, graphitizing annealing of the casting was performed twice at a temperature of 740°C for 0.75 hours, followed by cooling in air until a gray tarnish color was achieved.

When forming a protective coating of iron oxide Fe 3 O 4 on the casting, it was heated to a temperature of 740°C and immersed in oil.

At this temperature of two-time graphitizing annealing of the casting for 0.75 hours, followed by cooling in air until a gray tarnish color is achieved, the process of carbon graphitization was further intensified.

With this mode of heating and immersion in oil, the initial geometric parameters and shape of the casting did not change and corresponded to its design values.

The thickness of the oxide film layer increased, resulting in an increase in the corrosion resistance of the protective coating and the service life of cast iron cookware.

The method for manufacturing such cast iron cookware included all the operations of the proposed method.

After grinding, graphitizing annealing of the casting was performed three times at a temperature of 800°C for 1.0 hour, followed by cooling in air until a gray tarnish color was achieved.

At this temperature, three times graphitizing annealing of the casting for 1.0 hour followed by cooling in air until a gray tarnish color was achieved, the process of carbon graphitization was further intensified.

As a result, complete stabilization of the properties of the casting material was achieved and the adhesion strength of the oxide film to the metal was increased during the formation of a protective coating of iron oxide Fe 3 O 4.

With this mode of heating and immersion in oil, the initial geometric parameters and shape of the casting did not change and corresponded to its design values.

The thickness of the oxide film layer increased, resulting in an increase in the corrosion resistance of the protective coating and the service life of cast iron cookware.

The strength of the protective coating, as well as the quality and performance properties of cast iron cookware obtained by this method are good.

Cast iron cookware was made - a saucepan with medium weight, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 was formed.

The casting was made of gray cast iron containing silicon in an amount of 7.0%.

The method for manufacturing such cast iron cookware included all the operations of the proposed method.

After grinding, graphitizing annealing of the casting was performed three times at a temperature of 810°C for 1.1 hours, followed by cooling in air until a gray tarnish color was achieved.

Under this regime of graphitizing annealing, the cast iron became excessively heated, became plastic and “floated”, distorting the original shape of the casting, and the thickness of the oxide film layer increased excessively, resulting in a decrease in corrosion resistance and service life of the protective coating.

When forming a protective coating of iron oxide Fe 3 O 4 on the casting, it was heated to a temperature of 800°C and immersed in oil.

With this mode of heating and immersion in oil, the same processes occurred that were characteristic of the graphitizing annealing of the casting.

As a result, the initial geometric parameters and shape of the casting changed and did not correspond to its design values.

The strength of the protective coating, as well as the quality and performance properties of cast iron cookware obtained by this method, are unsatisfactory.

Examples 2, 3, 4 indicate that the increased silicon content (at least 4.1%) in cast iron, as well as the stated modes of graphitizing annealing and heating of the casting, are optimal for ensuring stabilization of the properties of the material, geometric parameters and shape of the cookware.

This allows you to increase the adhesion strength of the oxide film to the metal, corrosion resistance to organic acids, service life, quality and performance properties of cast iron cookware.

Examples 1, 5 indicate that a reduced silicon content (less than 4.1%), as well as performing graphitizing annealing and heating of the casting outside the stated modes is not advisable, since this does not ensure stabilization of the properties of the material, the geometric parameters and shape are distorted dishes.

This leads to a decrease in the adhesion strength of the oxide film to the metal, corrosion resistance to organic acids, service life, quality and performance properties of cast iron cookware.

The proposed cast iron cookware and the method of manufacturing cast iron cookware can be repeatedly implemented industrially at any enterprise for casting household cast iron cookware using standard equipment and traditional materials, which indicates that the claimed technical solutions of this group of inventions meet the invention criterion of “industrial applicability”.

1. Cast iron cookware, made in the form of a bowl-shaped casting made of gray cast iron, on the surface of which a protective coating of iron oxide Fe 3 O 4 is formed, characterized in that the casting is made of gray cast iron containing silicon in an amount of at least 4.1% proportional to the mass of cast iron cookware.

2. A method for manufacturing cast iron cookware, including casting gray cast iron into a mold to obtain a bowl-shaped casting, removing sprues and burrs, roughing, grinding, sandblasting the casting and forming a protective coating of iron oxide Fe 3 O 4 on the casting by heating it and immersing it in oil, characterized in that when casting gray cast iron into a mold to obtain a bowl-shaped casting, silicon is introduced into the charge in an amount of at least 4.1% in proportion to the weight of the cast iron utensils, and after grinding, graphitizing annealing of the casting is performed at least twice at a temperature of 680÷800°C for 0.5÷1.0 hours, followed by cooling in air until a gray tarnish color is achieved.

Cast iron cookware and method of making cast iron cookware