Cast iron color. Cast iron. Cast iron types: white, gray, malleable, high-strength. Features of alloy cast irons

Cast iron entered our life many centuries ago and remains popular to this day.... It has found wide application in many areas. However, in order to understand what cast iron is, it is important to know its properties and chemical composition, structure and features of its alloys, the advantages and disadvantages of this material, as well as its production and applications.

The chemical composition of cast iron

Cast iron is an alloy of iron and carbon, in which the percentage of carbon is not less than 2.14%, but not more than 4.5%. Carbon is included in cast iron in the form of cementite or graphite. If the percentage of carbon is less than 2.14%, the alloy is called steel.

It is known that cast iron alloy was first produced in China in the 6th century. The secret of its production came to Europe in the XIV century, and in Russia its composition was brought to perfection only in the XVII. For all this for a long time the cast iron formula has not changed.

The highest quality material was produced at foundry brothers Demidov, located in the Urals.

Over the centuries, it not only has not lost its relevance, but also acquired an even wider range of applications.

There are such types of cast iron as ultimate and casting... The first is used in the production of steel by the oxygen-converter route. Silicon and manganese in such an alloy are contained in very small quantities. Foundry type of material is more widely used in industry and manufacturing. He, in turn, is subdivided into the following types:

• White cast iron - in it, carbon is iron carbide. At the same time, a white ebb is visible on its fault, which is where its name came from. It is not used in its pure form. It is used in the production of ductile iron.
• For gray cast iron, a silvery sheen at the fracture is characteristic. It has a wide range of applications and can be perfectly processed with cutters.
• High-strength alloy is used to improve the strength characteristics of the material being produced. It is obtained from gray cast iron by adding magnesium impurities to its mass.
• Ductile iron is also a type of gray cast iron. Its name suggests that it has increased ductility, and it is obtained from white cast iron by annealing.
• Half - has special properties. Part of the carbon in its composition is in the form of graphite, the rest is in the form of cementite.

Alloy features

The main feature of cast iron is hidden in the manufacturing process. The fact is that different types This alloy has a melting point of 1200 ° C, while that of steel is 1500 ° C. This factor is influenced by too high carbon content. The iron and carbon atoms are not very closely related to each other.

When smelting occurs, carbon atoms cannot fully penetrate the molecular lattice of iron, which makes the cast iron alloy brittle. In this regard, it is not used in the production of parts that will be constantly subjected to stress.

This material belongs to the ferrous metallurgy industry and is similar in its characteristics to steel. Cast iron and steel products are widely used in everyday life, and it is entirely justified.

Comparing the characteristics of these metals, the following conclusions can be drawn:

1. The cost of steel products is higher than the cost of cast iron.
2. Differences in color: cast iron is dark and matt and steel is light and shiny.
3. Steel is less susceptible to casting, but, unlike cast iron, it is easier to forge and weld.
4. Steel has greater strength than cast iron alloy.
5. Steel is heavier in weight.
6. It has a lower carbon content than cast iron.

Advantages and disadvantages

This material, like any other, has its own strengths and weaknesses.

The advantages of cast iron include the following factors:

• Sometimes it is even compared in terms of its characteristics with steel, because certain types of it are distinguished by increased strength.
• Keeps temperature for a long time: when heated, heat is distributed over it evenly and remains unchanged for a long time.
• It is an environmentally friendly material, due to which it is often used in the manufacture of dishes in which food will be directly prepared.
• Does not react to acid-base environment.
• It is a durable material.
• The longer a product made from this material is used, the better its quality becomes.
• This material is absolutely harmless to the human body.

The disadvantages include the following factors:

Characteristics and properties of cast iron

This metal alloy has the following properties:

1. Physical properties: specific gravity, actual shrinkage, coefficient of linear expansion. For example, the carbon content in cast iron directly affects its specific gravity.
2. Thermal properties. Thermal conductivity is usually calculated using the displacement rule. For the solid state of the metal, the volumetric heat capacity is 1 cal / cm3 * oC. If the metal is in a liquid state, then it is approximately equal to 1.5 cal / cm3 * oC.
3. Mechanical properties. It is noteworthy that these properties are influenced by both the base itself and the shape and size of the graphite. Gray cast iron with a pearlite base is the most durable, and with a ferritic one - the most ductile. The lamellar form of graphite is characterized by the maximum reduction in strength, while in the spherical form this reduction is minimal.
4. Hydrodynamic properties. The presence of manganese and sulfur in the composition affects the viscosity of the material. It also tends to increase when the temperature of the alloy goes over the point of solidification.
5. Technological properties... This metal is characterized by excellent casting properties as well as resistance to wear and vibration.
6. Chemical properties... As the electrode potential decreases, the structural components of the alloy are arranged in the following order: cementite - phosphide eutectic - ferrite.

The properties of the alloy are also influenced by special impurities:

Metal composition and structure

Cast iron as a structural material is represented by a metal cavity with graphite inclusions. Its main components are perlite, ledeburite and plastic graphite. Interestingly, in different types alloys, these elements are present in unequal proportions or may be completely absent.

According to its structure, the cast iron alloy is divided into the following varieties:

• Perlite.
• Ferritic.
• Ferrite-pearlite.

Moreover, graphite can be present in it in one of the following forms:

Manufacturing technologies

As you know, pig iron is produced in special blast furnaces. The main raw material for its production is iron ore. Technological process manufacturing consists in the reduction of iron ore oxides and obtaining as a result of this other material - cast iron. For its manufacture, such fuels as coke, thermoanthracite, natural gas are used.

To produce one ton of pig iron, about 550 kilograms of coke and about a ton of water are required. The amount of ore loaded into the furnace will depend on its iron content. As a rule, ore is used, which contains at least 70% iron. The point is that it is economically impractical to use a lower concentration.

The first stage pig iron production is its smelting. Ore is poured into the blast furnace, and then - coking coal, which is necessary to pump and maintain the required temperature inside the furnace shaft. During combustion, these components take active participation in ongoing chemical reactions as iron reducing agents.

Meanwhile, flux is immersed in the furnace, which acts as a catalyst. By accelerating the melting of rocks, it thereby maintains the speedy release of iron. It is important to know that the ore undergoes the necessary preliminary processing before being loaded into the furnace. It is crushed in a crushing plant because the finer particles melt faster. It is then washed to remove non-metal particles. Further, the raw material is fired, as a result of which sulfur and other foreign components are extracted from it.

At the second stage of production, natural gas is fed into the furnace, which is filled and ready for operation, through special burners. Coke is involved in heating the raw material. Carbon is released, which, combining with oxygen, forms an oxide. It, in turn, promotes the recovery of iron from the ore.

As the volume of gas in the furnace increases, the rate of the chemical reaction decreases. It can stop completely when a certain gas ratio is reached. Carbon permeates the alloy and combines with iron to form cast iron. Unfused elements remain on the surface and are soon removed. This waste is called slag. It is used to make other materials.

Scope of use

This metal is used in various industries. For example, it is widely used in mechanical engineering for the production of various parts.

Most often this material is used in the manufacture of blocks for engines and crankshafts. For the production of the latter, an improved alloy with the addition of special impurities from graphite is required. This metal is resistant to abrasion, which is why high quality brake pads are made from it.

In tough climatic conditions cast iron alloy is irreplaceable, as it allows machine parts made from it to operate smoothly even at the lowest temperatures.

In the metallurgical industry, he also proved himself excellent. Its excellent casting properties and relatively low price are highly appreciated. Products made from it are distinguished by very high strength and wear resistance.

A great variety of plumbing products are made from cast iron alloy. These are batteries, sinks, various sinks and pipes. Cast iron baths and heating radiators are very popular. Their service life is very long. These products are still used in many apartments, because they retain their original appearance for a long time and rarely need restoration.

It is also important that the excellent casting properties of cast iron make it possible to make whole works of art from it: such as openwork wrought iron gates and all kinds of architectural monuments.

It is noteworthy that the price for 1 kilogram of cast iron is due to the amount of carbon in its composition, as well as the presence of various impurities and alloying components. The price of a ton of cast iron is about 8,000 rubles.

Today, there is not a single sphere where this metal is used. Its casting and alloys are the basis of many assemblies, mechanisms and parts. Sometimes it is used as an independent product, doing an excellent job with the functions assigned to it. This iron-containing compound is unique in its kind. It remains irreplaceable to this day.

Cast iron - an alloy of iron (Fe\u003e 90%) with carbon (C from 2.14% to 6.67%).
Carbon can be contained in cast iron in the form of graphite (C) or cementite (Fe3C).
Also, cast iron contains impurities of silicon, manganese, phosphorus and sulfur.
Cast irons with special properties also contain alloying elements - chromium, nickel, copper, molybdenum, etc.

Cast iron is the most widely used material for the manufacture of cast parts used at relatively low stresses and low dynamic loads. The advantages of cast iron in comparison with steel are high casting properties and low cost. Cast irons are also better cut than most steels (except for free-cutting steels), but they do not weld well, have less strength, stiffness and ductility.

Depending on the state of carbon in cast iron, there are:
white cast iron
gray cast iron(GOST 1412 - "Lamellar graphite cast iron for castings")
malleable iron(GOST 1215 - "Malleable iron castings")
ductile iron(GOST 7293 - "Spheroidal graphite iron for castings")

White cast iron

In white cast iron, all carbon is bound in the form of cementite Fe3C.
White cast iron has high wear resistance and hardness, but it is brittle and poorly machined by cutting, therefore, in mechanical engineering, they find limited use and are mainly converted to steel.
By carbon content, gray cast iron is subdivided into:
Hypoeutectic with a carbon content from 2.14% to 4.3%
Eutectic with a carbon content of 4.3%
Hypereutectic with a carbon content of 4.3% to 6.67%.

In gray, malleable, ductile iron, all or most of the carbon is in the form of graphite of various shapes (they are also called graphite).

Gray cast iron

The structure of gray cast irons contains lamellar graphite.
Gray cast irons contain: 3.2-3.5% carbon, 1.9-2.5% silicon, 0.5-0.8% manganese, 0.1-0.3% phosphorus and less than 0.12% sulfur ...
Castings of parts from gray cast irons are obtained in chill molds - earth or metal molds.
Gray cast iron is widely used in mechanical engineering. In view of the low mechanical properties of gray iron castings and the ease of obtaining them, they are used for the manufacture of parts of a less critical purpose, parts that operate in the absence of shock loads. In particular, covers, pulleys, machine beds and presses are made of them.
An example of the designation of gray cast iron: СЧ32-52. The letters denote gray cast iron (SCH), the first number denotes tensile strength (32 kgf / mm2 or 320 MPa), the second number denotes ultimate bending strength.

Malleable cast iron

In the structure of malleable cast irons, graphite is flaky.
Malleable cast irons contain: 2.4-3.0% carbon, 0.8-1.4% silicon, 0.3-1.0% manganese, less than 0.2% phosphorus, no more than 0.1% sulfur.
Ductile iron is obtained from white cast iron by heating and long holding. This procedure is called graphitizing annealing or languishing.
An example of the designation of ductile iron: KCH45-6. The letters denote ductile iron (CN), the first number is the tensile strength (45 kgf / mm2 or 450 MPa), the second is the elongation in% (6%).

Ductile iron

Ductile iron contains nodular graphite.
It has the highest strength properties.
Ductile iron contains: 3.2-3.8% carbon, 1.9-2.6% silicon, 0.6-0.8% manganese, up to 0.12% phosphorus and no more than 0.3% sulfur.
Ductile iron is produced by modifying (i.e. introducing a modifying additive - magnesium) of a liquid melt. Modifiers promote the formation of spherical graphite inclusions, due to which mechanical properties such cast iron approach the properties of carbon steels, and the casting properties are higher (but lower than that of gray cast irons).
High-strength cast irons are used to manufacture critical parts for mechanical engineering - pistons, cylinders, crankshafts, brake pads. Pipes are also made from ductile iron.
An example of the designation of ductile iron: VCh45-5. The letters denote high-strength cast iron (VCh), the first number indicates the tensile strength (45 kgf / mm2 or 450 MPa), the second indicates the elongation in%.

Many people know about such a material as cast iron and its strength characteristics. Today we will deepen this knowledge and find out what cast iron is, what it consists of, what types it is and how it is produced.

Composition

What is cast iron? It is an alloy of iron, carbon and various impurities, thanks to which it acquires the necessary properties. The material must contain at least 2.14% carbon. Otherwise, it will be steel, not cast iron. It is thanks to carbon that cast iron has increased hardness. At the same time, this element reduces the ductility and ductility of the material, making it brittle.

In addition to carbon, cast iron must include: manganese, silicon, phosphorus and sulfur. In some brands, additional additives are also added to give the material specific properties. Commonly used alloying elements include chromium, vanadium, nickel and aluminum.

The material has a density of 7.2 g / cm 3. For metals and their alloys, this is a fairly high indicator. Cast iron is well suited for the production of all kinds of products by casting. In this respect, it surpasses all iron alloys except for some steel grades.

The melting point of cast iron is 1200 degrees. For steel, this indicator is 250-300 degrees higher. The reason for this lies in the increased content of carbon in cast iron, which causes less close bonds between iron atoms. During the smelting of cast iron and its subsequent crystallization, carbon does not have time to fully penetrate into the structure of iron. Therefore, the material is brittle. The structure of cast iron does not allow it to be used for the production of products that are constantly exposed to dynamic loads. But what cast iron is ideal for is for parts that must have increased strength.

Receiving

Pig iron production is a very costly and material-intensive process. To get one ton of alloy, you need 550 kg of coke and 900 liters of water. As for the ore, its amount depends on the iron content in it. As a rule, ore with a mass fraction of iron of at least 70% is used. Processing less rich ores is economically impractical.

Before going to be smelted, the material is enriched. Pig iron production in 98% of cases takes place in blast furnaces.

The technological process includes several stages. First, ore is loaded into the blast furnace, which includes magnetic iron ore (a compound of bivalent and trivalent iron oxide). Ores containing hydrous oxide of iron or its salts can also be used. In addition to raw materials, coking coals are placed in the furnace, which are necessary to create and maintain a high temperature. The products of coal combustion as iron reducing agents also participate in chemical reactions.

Additionally, a flux is fed into the furnace, which plays the role of a catalyst. It speeds up the process of melting rocks and releasing iron. It is important to note that ore must undergo special processing before entering the furnace. Since small parts melt better, it is pre-crushed in a crushing plant. The ore is then washed to remove non-metal impurities. Then the raw material is dried and fired in ovens. Firing removes sulfur and other foreign elements from it.

After the furnace is fully loaded, the second stage of production begins. When the burners are started, the coke gradually heats up the feed. This releases carbon, which reacts with oxygen to form an oxide. The latter takes an active part in the reduction of iron from the compounds found in the ore. The more gas accumulates in the furnace, the slower the reaction proceeds. When the required proportion is reached, the reaction stops altogether. Excess gases further serve as fuel to maintain the required temperature in the furnace. This method has several strengths. Firstly, it allows you to reduce fuel costs, which makes manufacturing process... And, secondly, combustion products do not enter the atmosphere, polluting it, but continue to participate in production.

The excess carbon is mixed with the melt and absorbed by the iron. This is how cast iron turns out. Impurities that have not melted float to the surface of the mixture and are removed. They are called slag. Slag is used in the production of some materials. When all excess particles are removed from the melt, special additives are added to it.

Varieties

What is cast iron and how it is obtained, we have already found out, now we will deal with the classification of this material. Pig iron and foundry pig iron are obtained in the way described above.

Pig iron is used in the production of steel by the oxygen-converter route. This type is characterized by a low content of silicon and manganese in the alloy. Cast iron is used in the manufacture of all kinds of products. It is divided into five types, each of which we will consider separately.

White

This alloy is characterized by the content of an excess part of carbon in the form of carbide or cementite. The name was given to this species for the white color at the fault. The carbon content in such cast iron usually exceeds 3%. White cast iron is highly fragile and brittle, therefore it is used to a limited extent. This type is used for the production of parts of a simple configuration, which perform static functions and do not bear heavy loads.

Due to the addition of alloying additives to the composition of white cast iron, the technical parameters of the material can be increased. For this purpose, chromium or nickel is most often used, less often vanadium or aluminum. The brand with this kind of additives was named "sormite". It is used in different devices as a heating element. Sormite has a high resistivity and works well at temperatures no higher than 900 degrees. The most common use of white cast iron is in the manufacture of domestic baths.

Gray

This is the most common type of cast iron. She found application in various areas of the national economy. In gray cast iron, carbon is presented in the form of pearlite, graphite, or ferrite-pearlite. In such an alloy, the carbon content is about 2.5%. As for cast iron, this material has high strength, therefore it is used in the manufacture of parts that receive cyclic stress. Bushings, brackets, cogwheels and industrial equipment housings are made of gray cast iron.

Thanks to graphite, gray cast iron reduces frictional forces and improves lubrication performance. Therefore, parts made of gray cast iron are highly resistant to this type of wear. When operating in particularly aggressive environments, additional additives are introduced into the material, which make it possible to neutralize the negative effect. These include: molybdenum, nickel, chromium, boron, copper and antimony. These elements protect the gray cast iron from corrosion. In addition, some of them increase the graphitization of free carbon in the alloy. This creates a protective barrier that prevents destructive elements from entering the cast iron surface.

Half

The intermediate material between the first two varieties is half cast iron. The carbon contained in it is presented in the form of graphite and carbide in approximately equal proportions. In addition, such an alloy may contain insignificant amounts of lideburite (no more than 3%) and cementite (no more than 1%). The total carbon content in half cast iron ranges from 3.5 to 4.2%. This type is used for the production of parts that are operated under conditions of constant friction. These include automotive brake pads, as well as rolls for shredding machines. To further increase the wear resistance, all kinds of additives are added to the alloy.

Malleable

This alloy is a kind of white cast iron, which is subjected to a special firing in order to graphitize the free carbon. Compared to steel, such cast iron has improved damping properties. In addition, it is not as sensitive to notches and works well in low temperatures. In such cast iron mass fraction carbon is no more than 3.5%. In the alloy, it is presented in the form of ferrite, granular pearlite containing inclusions of graphite or ferrite-pearlite. Malleable cast iron, like half cast iron, is used mainly in the production of parts operated under continuous friction conditions. To improve the performance of the material, magnesium, tellurium and boron are added to the alloy.

High strength

This type of cast iron is obtained due to the formation of nodular graphite inclusions in the metal lattice. Because of this, the metal base of the crystal lattice is weakened, and the alloy acquires improved mechanical properties. The formation of nodular graphite occurs due to the introduction of magnesium, yttrium, calcium and cerium into the material. Ductile iron is similar in its parameters to high carbon steel. It lends itself well to casting and can completely replace the steel parts of mechanisms. Due to its high thermal conductivity, this material can be used for the manufacture of pipelines and heating devices.

Industry difficulties

Today, cast iron casting has dubious prospects. The point is that due to high level costs and a large amount of waste, industrialists are increasingly abandoning pig iron in favor of cheap substitutes. Thanks to the rapid development of science, it has long been possible to obtain better quality materials at lower costs. Protection plays an important role in this matter. environment, which does not accept the use of blast furnaces. It takes years, if not decades, to fully transfer pig iron smelting to electric furnaces. Why so long? Because it is very expensive, and not every state can afford it. Therefore, it remains only to wait until the mass production of new alloys is established. Of course, stop completely industrial application cast iron will not work in the near future. But it is obvious that the scale of its production will decline every year. This trend began 5-7 years ago.

Conclusion

Having dealt with the question: "What is cast iron?", Several conclusions can be drawn. First, cast iron is an alloy of iron, carbon, and additives. Secondly, it has six types. Thirdly, cast iron is a very useful and versatile material, so its expensive production was expedient for a long time. Fourthly, today cast iron is already considered a relic of the past, and is systematically giving way to more reliable and cheaper materials.

Surely many have come across in everyday life or in production with cast iron products. This material has good toughness and excellent casting properties.

Cast iron is a steel, or, more correctly, an iron-carbon alloy consisting of iron and carbon, which has a volume of 2.14% to a maximum of 6.67% and can be included in the composition as cementite or graphite. By definition, pig iron refers to an engineering material that is cheap and easy to manufacture and serves as the basis for steel smelting. Its receipt refers to complex chemical processes occurring at certain stages of production.

Main characteristics and composition

This alloy, in addition to iron with carbon, includes additional impurities that affect its properties. The varied composition of cast iron provides it with high hardness, fluidity, and increases fragility. It includes: sulfur, silicon, manganese, phosphorus. The cast iron alloy, due to the incoming carbon, has high hardness values, but at the same time, ductility and ductility of the substance are reduced. Some additives are added to give the metal its special characteristics. The following alloying components are used: nickel, vanadium, as well as chromium, aluminum. The cast iron formula consists of an iron-carbon base with additional inclusions. It has a density of about 7.2 g / cm3, which is a fairly high value for metal compounds.

Cast iron consists of several components, due to which the properties of its variations can differ significantly. In addition to carbon and iron, the composition includes up to 2% manganese, 1.2% phosphorus, 4.3% silicon and up to 0.07% sulfur. Silicon is responsible for the state of fluidity, significantly improves castability, and also makes it softer. Manganese is used to enhance the strength. The addition of sulfur reduces the refractoriness and lowers its fluidity. In addition, it has a harmful effect, manifested in the appearance of cracks on hot castings (red brittleness). The presence of phosphorus reduces the mechanical properties, however, it makes it possible to cast objects of complex shapes.

The structure of cast iron looks like a metal base with inclusions of graphite. Depending on the species, it includes pearlite, lamellar graphite, and ledeburite. These elements determine its characteristics and are present in varying quantities or are completely absent.

Melting temperature ranges from +1160 ° С minimum to +1250 ° С maximum. It has high anticorrosive properties and actively resists both dry (chemical) and wet corrosion. Thanks to him, stainless steel was born - a steel alloy with a high content of chrome component.

Application area

Cast iron is widely used in mechanical engineering for the casting of various parts. It is used for the manufacture of crankshafts and engine blocks. In addition, high quality pads with high abrasion resistance are produced. They are used at low temperatures, where cast iron is used exclusively due to its high performance properties. These qualities are used in the production of various machine elements, where a cast iron alloy is used to work in harsh climates. This material is widely used by metallurgists due to its excellent casting characteristics and low price. Cast products have high wear resistance and increased strength.

Many plumbing fittings are also made from cast iron. These are batteries, heating radiators, pipes, baths, various sinks with sinks. Many products still serve today, although they were installed several decades ago. These items retain their original appearance for many years and do not require restoration work. In addition, cast iron cookware is considered one of the most convenient for cooking many dishes.

Varieties

According to its characteristics, cast iron alloy is subdivided into conversion and foundry. The first is used in steelmaking using the oxygen-converter method. This type is characterized by a reduced amount of manganese and silicon. Cast iron material is used for the production of numerous parts. Samples of products from this base can be seen in the corresponding photos.

Nickel-chromium alloys (nichards) are a special variety. These include low carbon as well as high carbon cast iron. The first is characterized by increased strength, and the second - increased wear resistance. The main varieties are white and gray alloys. These materials differ in carbon content as well as properties. In addition, malleable, alloyed and high-strength types are actively used.

Gray

Gray cast irons have low ductility, toughness, and are easy to cut during processing. They are used in the manufacture of irrelevant parts, as well as elements that work for wear. In gray cast iron, carbon is contained in the form of graphite, pearlite or ferrite-pearlite. Its amount is about 2.5%, which ensures high strength of the products. Housings of various industrial equipment, gears, brackets, bushings are made of a gray alloy. A material containing a high amount of phosphorus (about 0.3 - 1.2%) has good fluidity and is used in art casting.

White

Contains a large amount of carbon (over 3%), presented in the form of cementite or carbide. The white color at the fracture site of this material gave the name and connection. An alloy of this type has increased fragility and fragility, which significantly narrows the area of \u200b\u200buse. On its basis, uncomplicated parts are produced to perform static functions without the impact of significant loads. Specifications white material can be improved by adding alloying components. For this, nickel, chromium is used, much less often - aluminum or vanadium. The brand with such additives is called "sormite". It is used as a heating element in a variety of devices. Sormite is characterized by stable characteristics at temperatures not exceeding +900 ° С. This material serves as the basis for the manufacture of ordinary household baths.

Malleable

This type is obtained from white by casting with further heat treatment. In this case, long-term annealing is used, in which the cementite decomposes, forming graphite. This process is called graphitization with the formation of carbon flakes in the structure. Graphite acquires this shape due to prolonged annealing. This has a positive effect on the metal base, which becomes more solid, ductile and tough.

Ductile iron performs well at low temperatures and is not very sensitive to notches. It is used in the manufacture of elements operating under continuous friction. In addition, malleable alloy serves as the basis for products of a very complex configuration: elbows, brake pads, tees, car housings for rear axles and other structures. Improvement of properties is achieved by adding boron, tellurium, magnesium.

High strength

It has increased strength and is used to obtain products for critical purposes, and in some cases even replaces steel. This nodular cast iron is obtained by adding special impurities (cerium, calcium, yttrium, magnesium) to the gray type. Gears, pistons, crankshafts and other parts are produced from it. High thermal conductivity allows casting elements for heating units, as well as pipelines.

Alloy

The alloyed cast iron alloy contains additional impurities. The composition includes a high content of titanium, nickel, chromium, as well as zirconium, vanadium, molybdenum, aluminum and other elements. They impart high strength, hardness and wear resistance. Alloyed materials are used in the production of parts of mechanisms that interact with gaseous, corrosive media, and also work under the influence of aqueous solutions.

Metal advantages

This alloy is referred to as materials produced by ferrous metallurgy. It is often compared to steel when determining certain characteristics. The item made of cast iron has a low cost compared to its steel counterpart. In addition, cast iron elements are lighter and less durable. These properties of cast iron are significantly expanded due to the use of various additives in alloys. Its parameters have the following positive qualities:

• environmentally friendly material that is used in the production of household items, including tableware;
• resistant to acid-base environment;
• hygienic;
• ability to maintain temperature for a long time;
• some types have strength comparable to steel;
• the duration of operation at which it qualitative indicators only getting better;
• complete harmlessness to the body.

Production

Obtaining a cast iron alloy is a material-intensive and costly process. Smelting one ton of material will require about 900 liters of ordinary water and about 550 kg of coke. The melting temperature is about +1200 ° C, which requires specific melting equipment. To obtain the mass, ore is needed, where the mass fraction of the contained iron is over 70%. Depleted ore rocks are not used due to economic inefficiency.

The material is smelted in special blast furnaces. There, iron ore goes through a full technological cycle, starting with the reduction of ore oxides and ending with the production of a cast iron alloy. Casting the material requires fuel: coke, thermoanthracite, and natural gas. At the end of the reduction process, the iron in solid form is placed in a special part of the furnace to dissolve carbon in it. After the interaction, a cast iron mass is obtained, which in liquid form goes down. Unmelted impurities are pushed to the surface and subsequently removed. This slag is used for the production of numerous materials. After removing unnecessary particles from the melt, additives are added to obtain certain grades of cast iron alloys.