What types of cast iron are there?

Characteristics of malleable cast iron and its use in the national economy

Malleable cast iron (DC) is an alloy of iron and carbon with high ductility; products from it are obtained through the casting process.

Scheme of annealing white cast iron for malleable.

Malleable cast iron has high performance characteristics, which determine its use in many sectors of the national economy.

What are cast iron, graphite and cementite

Cast iron as such is a brittle material, an alloy of iron and carbon. The structure of cast iron contains a metal base and graphite inclusions; the alloy has eutectic properties, i.e.

the material can be melted, which determines its use as an alloy for casting. It may contain permanent and alloying impurities to improve physical and chemical properties.

Permanent impurities are phosphorus, sulfur, manganese, silicon, alloying ones are vanadium, aluminum, nickel, chromium. Carbon in cast iron is present as cementite or graphite.

Cementite is considered to be iron carbide, the phase and structural component of iron-carbon alloys: steel and cast iron, perlite, troostite, ledeburite, etc. This component is the most fragile ingredient in the alloy. It does not have plasticity and can withstand only minor elastic deformations.

Scheme of microstructures of graphitized cast irons: a) gray; b) high strength; c) malleable; d) with vermicular graphite.

The higher the percentage of cementite contained in the alloy, the lower its hardness and the greater its ductility.

Graphite is one of the most stable modifications of carbon, which can be present in the alloy not in a specific, but in various transition forms.

Depending on the form of graphite, cast irons are distinguished:

• with lamellar graphite (ordinary white cast iron);
• with vermicular graphite having zigzag veins (gray vermicular alloys);
• with a spherical or globular ingredient (high-strength alloys);
• with graphite in the form of flakes (malleable cast iron).

Cast iron is produced using special equipment - blast furnaces, electric furnaces, cupola furnaces.

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Graphitization, features of malleable cast iron, the concept of ferritic and pearlitic cast iron

In metallurgy, malleable cast iron is produced by graphitization of white hypoeutectic cast iron containing graphite in an amount of 2%-4.3%. During graphitization, annealing occurs in which cementite (iron carbide) decomposes, all or part of the carbon is converted into graphite (annealing carbon).

Carbon in cast iron is an important element that determines its mechanical properties; the higher the grade of cast iron, the lower the graphite content. Thanks to the technological process that introduces transformations into the composition of the alloy, cast iron acquires plasticity; its properties are between gray cast iron and steel.

Unlike steel, the alloy has fluidity, damping capacity (vibration absorption), and higher wear resistance.

Physical properties of malleable cast iron.

CC is produced in continuous chamber and tunnel furnaces.

The undeniable advantages of CC are:

• uniformity;
• no stress;
• high mechanical and anti-corrosion properties;
• excellent stability in humid air, flue gases, water;
• plastic;
• strength;
• KCh is amenable to welding, caulking, pressing, cold and hot straightening, and cutting.

The high strength of CP is explained by the insignificant influence of the flake structure on the mechanical characteristics of the metal core. Products made from such an alloy are characterized by toughness and ductility, good resistance to impact loads, but the products are not forged, they are cast. The disadvantages of the material are the complex technology and the length of the production process.

According to the production method, CPs are classified into ferritic class F (black-core) and pearlite class P (white-core). Ferritic CN is produced by two-stage graphitizing annealing of white cast iron.

Pearlite grades are obtained by annealing in oxidizing environments. As a result, a change in the structure of cast iron and decarbonization occurs. This is one of the strongest types of cast iron.

In the alloy, the main high-strength mass with a metallic structure is complemented by the excellent shape of the graphite structure and its distribution.

Application of malleable cast iron in agriculture, automobile and shipbuilding

Mechanical properties of malleable cast iron according to GOST 1215-79.

CP is used in mechanical engineering, the main consumers being the areas of tractor construction and agricultural machinery. Ferritic cast iron has high viscosity and strength; it is used for the production of components that are not subject to abrasion, for example, flanges, levers, forks.

Various parts are made from pearlitic cast iron: diesel engine pistons, rocker arms, clutch assemblies, crankshafts, camshafts with cams, which, interacting with the pushers, operate the unit in a certain cycle, chain links, pawls, ridges, knife heads, brake drums and etc.

These products operate under the influence of static and dynamic loads and abrasion. The advantages of pearlitic cast iron are strength, wear resistance, high fatigue strength, resistance to high temperatures, and elimination of vibration.

CC is used in the automotive industry in the manufacture of thin-walled domestic castings operating under the influence of dynamic alternating loads.

Drives, gearboxes, wheel hubs, gears, gear housings, differentials, steering systems, engine and spring brackets, brake pads, rollers, linings, plugs, balancers, wings, cardan shafts, manifolds, etc. are made from the alloy. KCh is widely used in shipbuilding in the production of equipment for ships. It is used to make portholes, mast brackets, rowlocks, bridges, and models of steam and water fittings.

In the carriage industry they are used in the manufacture of spare parts for air brakes, bearings, brackets, traction couplings, shock-traction devices, brackets; These parts work under loads of impacts, bending, and wear.

Application of CP in various fields of industry

Cast collapsible chain made of malleable cast iron: a – design; b – method of assembly and disassembly.

In the electrical industry, CPs are used to produce terminals, insulator hooks, caps, and wire holders. Products are subject to bending and shock loads. In the machine tool industry and textile engineering, CP are used to produce gears, forks, spokes and all kinds of parts for paper spinning machines, i.e. those parts that are subject to static and dynamic loads, wear, and friction. They use grades of anti-friction gray malleable cast iron, which ensures minimal friction at the points of contact of the parts.

Decarbonized CC grades are used in the production of sanitary and construction equipment and various parts. Plumbing products can be: bends for water supply and sewerage, flange adapters for connecting cast iron systems with plastic ones, valves, pipes, heating radiators. These products are exposed to aquatic environments. In gas systems, CN is used when producing fittings for connecting pipes at branching points.

Also, various brands of KCh can be used in the defense industry, landscape design when creating decorative elements: elaborate hedges, benches, gates, wickets; in the manufacture of decorative furniture exposed to atmospheric precipitation: tables and chairs for terraces, gazebos of country houses; in the manufacture of household and industrial equipment: bathtubs, gas stoves, washing machines, dishes (pots, pans).

Due to its high-strength properties, ductile cast iron is used as a structural material in many industries.

Source: https://moyakovka.ru/izdeliya/kovkii-chugun-primenenie.html

Gray cast iron products

An alloy of iron containing carbon is called cast iron. In some cases, alloying additives are added to the composition, affecting its consumer qualities. Cast iron is a metal that is used primarily in ferrous metallurgy. It is not only used to produce steel, it is also in demand in the manufacture of forged artistic parts.

Gray cast iron

For mechanical engineering, gray cast iron containing graphite is mainly used. Parts made from such material do not react to stresses; they absorb vibrations that occur when mechanisms vibrate. Critical parts are made from it

1. Bushings;
2. Machine beds;
3. Heavy bases.

It began to be used as a structural material in almost all enterprises of the mechanical engineering industry. The following industries became the largest consumers of gray cast iron

1. Automotive industry;
2. Machine tool industry;
3. Metallurgy;
4. Sanitary.

Tractor parts made from gray cast iron reach 20% of the total number of parts. This use of this alloy is associated with high wear resistance. It does not lift up in case of high friction and lack of lubrication, in other words, it has damping ability . It is made from:

1. Blocks;
2. Bearing caps;
3. Brake discs;
4. Ferrado;

To manufacture the cylinder head of various engines, of low-alloy alloy :

The main requirements for the midrange during the production of liners were:

1. Pearlite structure;
2. Graphite;
3. High hardness.

For car engines of any design, cylinder liners made of a special alloy are used. In most cases, its phosphorous fraction is used.

Diesel engines during operation create a large load on the cylinder block , so alloy cast iron is used for them. Cylinder heads are made from high carbon alloy grades,

The same requirements are observed in the manufacture of liner castings, the material of which is a low-alloy alloy. The chemical composition of this material depends on several technological characteristics:

1. Melting method;
2. Casting dimensions;
3. Manufacturability of form.

Cars are equipped with cast iron camshafts, which are highly wear-resistant. This parameter is achieved thanks to surface hardening to which the metal is subjected.

When a part is operated at high speeds, when dry friction occurs, it is necessary to have increased wear resistance of the material and a high coefficient of friction. It is in such conditions that this alloy is simply irreplaceable.

Brake drums operating in such conditions are made from SCh20. When a part experiences high loads and thermal cracks may appear, a special heat-resistant alloy with a high carbon content and a high level of alloying is used.

For particularly severe conditions, parts made of pearlitic cast iron are installed. It contains vermicular graphite.

The rotation of the flywheel during operation reaches 7000 rpm. This speed causes tensile stresses to appear. The rotating surface of the flywheel constantly touches the working surface of another part. Such friction causes a strong release of heat, resulting in thermal cracks that negatively affect the strength of the part.

To increase strength , given the large weight of the flywheel and the size of its cross-section, it is made from various grades:

It must provide a workpiece strength above 250 N/mm2. Sometimes SCh 35 has strength that is not enough to ensure normal operation of the flywheel. In this case, cast iron is used, to which nodular graphite is added.

Passenger cars boast cast iron caps covering the main bearings . This design is found in most cases on cars with a carburetor engine. To ensure a pearlite structure, as well as high hardness exceeding 200 HB, SCh25 is used for the manufacture of bearing caps.

Manufacturing of collectors

In a car, the exhaust manifolds are exposed to exhaust gases, the temperature of which reaches 90 degrees. Collectors under the influence of an aggressive environment oxidize, deform and crack.

The use of gray cast iron ensures durability of such parts and high efficiency. Due to the fact that the thickness of the collector walls is very small, less than 7 mm, SCh15 is used for their manufacture. To increase its heat resistance, cast iron is alloyed with chromium or nickel additives.

For the manufacture of collectors experiencing high thermal loads, the following is used:

1. Ductile iron;
2. With additives of spherical graphite;

All of the above materials have high heat resistance and resistance to aggressive environments, alkalis and oxides.

Machine tool industry

In the machine tool industry, a large number of cast parts are made from gray cast iron, operating in various conditions, the weight of which can reach 100 tons , with a maximum wall thickness of 200 millimeters.

The classification of such cast parts in the machine tool industry, depending on the designs and the operating conditions created, corresponds to the current standard.

For each part, a special grade of cast iron is selected . It depends on the following parameters:

1. Class of the workpiece;
2. Wall thickness;
3. Hardness;
4. Microstructures.

  How to distinguish cast iron from steel visually?

Considering the specifics of many machine-tool parts, which work mainly on rigidity, for their manufacture they prefer to use cast iron, which has increased hardness and fairly low ductility.

The chemical composition of such cast irons is high in manganese and low in carbon. To obtain high hardness of cast iron, alloying and other technological processes are used.

SSP blanks are widely used in metallurgical equipment:

1. Sheet rolls;
2. Molds;
3. Slag bowls.

Plumbing

A lot of cast iron products are used in plumbing. Made from cast iron:

1. Heating radiators;
2. Pipes;
3. Fitting;
4. Sinks;
5. Kitchen sinks.

And today cast iron bathtubs remain in demand, which are distinguished by high strength , durability and reliability. Such products can be used for decades. They retain their original appearance and do not require replacement.

Craftsmen make artistic masterpieces from cast iron. For example, the embankments of St. Petersburg are decorated with cast iron parts. Walking along the streets of the city you can see openwork gates and original cast-iron fences. In the parks you can see cast iron monuments.

Application of Ductile Iron

This material has excellent damping properties and is capable of excellent performance at very low temperatures. This type of cast iron is used in the production of critical parts for tractors, as well as cars, which will have to perform their work in difficult climatic conditions.

Parts made of malleable cast iron have also found their application in the electrical industry . It is made from:

1. Terminals;
2. Insulator hooks;
3. Wire holders.

Such products cope well with force loads; they can bend under mechanical stress.

In textile engineering , ductile iron is used in the manufacture of:

1. Gears;
2. Forks
3. Spokes;
4. Parts for paper spinning machines.

In other words, for parts experiencing large static loads, subject to friction and rapid wear. For such products, anti-friction malleable cast iron is used, which is capable of creating minimal friction where there is maximum contact between the parts.

Source: https://varimtutru.com/izdeliya-iz-serogo-chuguna/

Properties of cast iron

Cast iron is an alloy of iron with carbon, as well as other elements.

Characteristics of cast iron

An important factor in the production of cast iron is that the minimum amount of carbon in the alloy is 2.14% or more. If the carbon content in the alloy is below the specified amount, then this alloy is not cast iron, but is called steel. The production process for steel and cast iron is approximately the same. The main difference between these two alloys is the quantitative carbon content in their composition.

Since cast iron contains more carbon than steel, cast iron is a very strong but brittle material. While steel is very flexible. It is the high carbon content in cast iron that gives this material its exceptional hardness, which is as much as 7.5 on the Mohs scale.

This indicator is significantly higher than that of quartz, however, less than that of diamond, but only by 2.5 points.

The carbon in cast iron can be cementite and graphite. It is the shape of graphite and the quantitative content of cementite in the alloy that determines the type of cast iron. Thus, cast iron is divided into white, gray, malleable and high-strength. The chemical composition of cast iron, which contains impurities such as silicon, manganese, sulfur and phosphorus, is almost always constant.

However, in some cases, cast iron may also contain the following alloying elements: chromium, nickel, aluminum, vanadium and others. These components are introduced into the alloy in order to give it greater strength, wear resistance, heat resistance, corrosion resistance, and non-magneticity. Cast iron containing these impurities is called alloy cast iron.

The quantitative content of these impurities in the alloy determines the degree of alloying. Depending on this, there are:

• low alloy cast iron. It contains less than 2.5% of all alloying impurities;
• medium alloy cast iron. Here the impurities are about 2.5 - 10%;
• highly alloyed, containing more than 10% alloying elements.

The chemical characteristics of alloy cast irons are the main factor for their classification. Thus, among alloyed cast irons there are:

• aluminum cast iron. It contains aluminum in amounts from 0.6 to 31%. This cast iron is stronger, more heat-resistant, corrosion-resistant, and also has high wear resistance. The use of this alloy is appropriate where work is carried out in an aggressive environment and at high temperatures - thermal furnaces, chemical equipment, gas engines.
• nickel cast iron. It contains nickel in amounts ranging from 0.3-0.7% to 19-21%. nickel directly affects the shape of graphite precipitates in the structure of nickel cast iron. This alloy has such properties as high resistance to corrosion, high resistance to the effects of both high and fairly low temperatures on the material (heat resistance and cold resistance), and is also able to withstand exposure to such an aggressive environment as sea water. The latter property of nickel cast iron determines the high demand for this material in shipbuilding, as it is used for the manufacture of parts operating in sea water.
• chromium cast iron. This alloy contains about 32% chromium. This type of alloy cast iron has the following properties: heat resistance, corrosion resistance, wear resistance.

It is worth noting that in general the cost of alloy cast iron is significantly lower than the cost of stainless steel. In addition, they have good casting properties. In this regard, products made from this alloy are very durable, high quality, and at the same time economical.

Pig iron is extracted through the process of smelting iron ore in blast furnaces at temperatures ranging from 1150 to 12000C.

History of cast iron

Cast iron has been known to mankind since ancient times, which go back to the era BC. This is evidenced by numerous archaeological finds, among which there are both cast iron objects and the cheese furnaces themselves, in which, in fact, people received this material.

However, iron is far from the first historical metal with which humanity became acquainted. Initially, people used native copper, which was mined in shallow mines. However, despite the appearance of metal in people's lives, stone remained very popular for quite a long time.

Later, people learned to make bronze, and only in VI-V BC iron appeared in people's lives, and with it steel and cast iron.

The birthplace of cast iron products is China. It was there that the technology of cast iron was first mastered and this term was born, which later came to Russia through Tatar-Mongol mediation. Thus, the first cast iron products also appeared in China. It was a wide variety of everyday items, kitchen utensils, as well as coins.

The wok frying pan, quite popular today, was one of the first to be made in China from cast iron. In those distant times, it was a vessel whose diameter reached one meter. This frying pan also had very thin walls.

Its cost was quite high, however, despite this, this kitchen equipment was extremely popular and in demand in large Chinese families.

In addition, archaeologists find unique things cast from cast iron, among which we should note a cast iron lion, which is 6 meters high and 5 meters long. According to scientists, this statue was cast in one go. This indicates that in those distant prehistoric times, in the absence of modern high-quality technologies, Chinese metallurgists achieved enormous skill in working with metals, in particular with cast iron.

A rather interesting and somewhat unusual fact is that it is believed that malleable cast iron began to be produced only in the 19th century AD, despite the fact that archaeologists have found cast iron swords made in the pre-Christian era.

Russia and Europe became acquainted with cast iron more than a century later, namely only in the 14th – 16th centuries. At this time, cast iron was the main material for the production of artillery shells and weapons. And only in the 17th century the use of cast iron expanded significantly. This was facilitated by the development of the metallurgical industry.

Gradually, the era of artillery use of cast iron ended and the era of artistic casting began - the new capital of the Russian Empire was decorated everywhere with cast fences, benches, and other elements of fine cast iron.

Cast iron also caused changes in the stove business, as cast iron valves and stove doors were replaced, which had the significant advantage of resistance to high temperatures, as well as tightness, which did not allow stove smoke to escape from the stove and fill the room with smoke.

Russian metallurgists were considered the best in those days. They mastered many cast iron processing technologies, which were constantly adopted by English, French and German craftsmen.

Today, in the era of nanotechnology and technological progress, when new materials appear every year, the development of metallurgy does not stop and continues to move forward. And after more than two thousand years, humanity has not been able to find a material that could replace cast iron. It continues to be used to make various objects that surround people.

Use of cast iron

The properties of cast iron are so unique that to date no more suitable material has been found that could replace this alloy. In addition, cast iron is a fairly cheap material.

In this regard, the use of cast iron remains wide and varied. The use of cast iron is especially appropriate where parts with complex shapes and high strength must be manufactured.

In this regard, cast iron has found its wide application in the following areas of human activity:

• Automotive industry. In this case, cast iron with vermicular graphite is used. It is the main material for the manufacture of crankshafts of diesel engines, as well as cylinder blocks of internal combustion engines. Due to the graphite content, the strength of the alloy increases significantly, which is the main reason for the popularity of cast iron in this industry.
• plumbing equipment. As with the automotive industry, graphite cast iron is also used. This material is perfect for the production of pipes used for both drainage and water supply. It is also actively used in the production of bathtubs, sinks, washstands, fittings and much more. In this case, the products are highly reliable, do not require any specific care, and retain their original appearance for a long period.
• Oil and gas industry. Not only water pipes are made from cast iron, but also pipes for transporting, injecting and pumping out oil and gas. The main reason for using cast iron in this industry is that cast iron products have fairly high performance qualities.
• heating. Pipes and heating radiators are made from cast iron. The use of the material in this case is due to its high heat transfer, as well as good heat-storing properties, which is very important and beneficial. After turning off the heating, after an hour, cast iron pipes are able to continue to radiate heat at a third of their original power. And here cast iron completely prevails over steel, which cannot boast of such qualities, because steel pipes cool twice as fast.
• kitchen tools. The material has large pores, due to which it has the ability to absorb fat during cooking. In this regard, pots, cauldrons and frying pans are made from cast iron, the non-stick properties of which become better and better over the years. In addition, scientists have proven that when cooking in cast iron cookware, food is enriched with beneficial nutritional properties. In addition, cast iron cookware can prevent carcinogens during further storage of food.

Fences and gratings, spiral staircases, balconies, gazebos, fireplaces, lamps, pillars, lanterns, sculptures, etc. are made from cast iron.

How to identify cast iron

Knowing the material from which certain objects are made is very important. For example, it is necessary to carry out repair work on certain automotive components, individual parts or other items. This is due, first of all, to the fact that different materials lend themselves to different types and methods of processing (for example, welding, drilling, etc.).

So, cast iron can in some cases be determined visually. However, this method is suitable if there are any cracks, chips or tears in the material. If any such defects are present, it should be carefully inspected. A cast iron part that is broken or cracked will be painted dark gray and have a matte surface. While steel will have a light gray, closer to white, color and glossy shine.

If you look closely at the surface defects, cast iron will have characteristic hemispherical small grains. Unfortunately, this method is not an accurate determination of the material, since it is possible to determine “by eye” whether it is cast iron or not only if the alloy (in this case cast iron) was poured into the mold at a low temperature, was not further processed and was not coated no paints and varnishes.

It is the characteristic small hemispherical grains that indicate the pouring of the alloy at high temperatures.

The mechanical method can provide more information in determining cast iron. To do this, it is necessary to obtain alloy shavings. This can be done by drilling to a shallow depth in some area of ​​the non-working part. For high-strength cast iron, the shavings will be characteristic - they will crumble, grinding into dust in the hands and leaving a mark on the fingers, similar to the lead of a simple pencil. Cast iron shavings are not able to wrap themselves in a twisted rope. This is due to one of the properties of cast iron - fragility.

If you try to cut a cast iron product with a grinder, then short sparks will fly from it, having a reddish tint on the star at the end of the track.

All of these options are valid for determining cast iron at home. However, they cannot give a 100% determination. To more accurately determine the alloy, spectral analysis, microscopic analysis, as well as weighing and volume determination are used.

Cast iron

Source: http://mining-prom.ru/rud/zhelez/svoystva-chuguna/

Cast iron

Cast iron began to be used many decades ago. This material has special performance characteristics that differ from those characteristic of steel. The production of cast iron, despite the emergence of a large number of different alloys, is established in many countries. In order to determine the properties of cast iron, one should consider the features of its chemical composition, on which certain physical qualities depend.

Cast iron

The chemical composition of cast iron is an important factor that largely determines the mechanical properties of the resulting castings. In addition, many properties are influenced by the mechanisms of primary and secondary crystallization.

carbon in cast iron can vary from 2.14 to 6.67 percent. Modern production technologies make it possible to control the concentration of all elements in the composition with high precision, thereby reducing the fragility index and increasing other performance characteristics.

Considering the chemical composition of cast iron, it should be noted that, in addition to iron and carbon, it necessarily includes the following elements:

1. Silicon (concentration no more than 4.3%). This element has a beneficial effect on cast iron, making it softer and improving its casting properties. However, too high a concentration may make the material more susceptible to plastic deformation.
2. Manganese (no more than 2%). By adding this element to the composition, the strength of the material increases significantly. However, too high a concentration can cause the structure to become brittle.
3. Sulfur is a harmful impurity that can significantly impair the performance of the material. As a rule, the concentration of sulfur in cast iron does not exceed 0.07%. Sulfur causes cracks to appear when the composition is heated.
4. Phosphorus is contained in the composition in a concentration of less than 1.2%. An increase in the concentration of phosphorus in the composition causes cracks to appear when the composition cools. In addition, this element causes deterioration of other mechanical properties.

As with many other compounds, the most important chemical element in cast iron is carbon. The type of material depends on its concentration and type. The structure of cast iron can vary significantly depending on the production technology used.

Physical properties

Cast iron has become widespread due to its attractive physical properties:

1. The cost of the material is significantly lower than the cost of other alloys. That is why it is used to create a wide variety of products.
2. Considering the density of cast iron, we note that this indicator is significantly lower than that of steel, due to which the material becomes much lighter.
3. The melting point of cast iron can vary slightly depending on its structure, but in most cases it is 1,200 degrees Celsius. Due to the inclusion of various additives in the composition, the melting point of cast iron can significantly increase or decrease.
4. When choosing a material, many pay attention to the fact that the color of cast iron may differ slightly depending on the structure and chemical composition.

The boiling point of cast iron also largely depends on the chemical composition. In order to consider the physical properties of a material, attention should be paid to each of its varieties. A different structure and chemical composition cause different physical and mechanical properties to be imparted.

Production technology

Cast iron has been smelted for several decades, which is due to its unique performance qualities. The large number of varieties of alloys determines the application of special marking rules. Marking of cast iron is carried out as follows:

1. Foundries are designated by the letter L.
2. Gray has become widespread; the combination of letters “SCH” is used to designate it.
3. Malleable is designated KCH.
4. Extreme or white is designated by the letter P.
5. Anti-friction or gray indicate ASF.
6. Alloy cast irons can have a wide variety of chemical compositions and are designated by the letter “C”.

The technology of cast iron production involves several stages that make it possible to obtain the required structure. Considering the process of producing cast iron, we note the following points:

1. Production is carried out in special blast furnaces.
2. Alloyed and heat-resistant cast iron can be obtained by using iron ore as a raw material.
3. The technology is presented in the reduction of iron oxides ore. As a result of the restructuring of the crystal lattice and changes in the structure, the output is a material called cast iron.
4. Considering production methods, we note that the features of the technology also lie in the materials used - cokes. Coke refers to natural gas or thermoanthracite, which acts as fuel.
5. The production of cast iron involves tempering iron in solid form using a special furnace. At this stage, liquid cast iron is obtained.

Equipment for the production of cast iron can vary significantly. In addition, the production technology used largely determines what kind of material will be obtained. An example is the production of ductile iron, which involves giving the structure an unusual shape.

https://www.youtube.com/watch?v=Wj3yX7R9dE4

There are quite a large number of varieties of the material in question. The classification of cast iron largely depends on the structure and chemical composition. The following types of cast iron are distinguished:

1. Grey. This type of material is characterized by low ductility and high viscosity, as well as good machinability. Carbon is contained in the form of graphite. Area of ​​application – mechanical engineering; production of wear parts. As practice shows, phosphorus concentration can vary over a fairly wide range: from 0.3 to 1.2%. Due to its special chemical composition, the material has high fluidity and is often used in artistic casting. Anti-friction cast iron is relatively inexpensive, which also determines its widespread use.
2. White. Due to the fact that in this composition carbon is presented as cementite, the structure is characterized by extreme fragility and increased hardness, as well as low casting properties and poor machinability. It is worth considering that white cast iron is used for conversion into steel or for the manufacture of malleable iron. Very often it is called the limit.
3. Half-type is characterized by increased wear resistance, which is associated with the distribution of carbon into a cementite and free base. Often this type of material is used in mechanical engineering and machine tool building.
4. Alloy. In order to give special properties to cast iron, alloying is also carried out. Alloy cast iron has increased wear resistance and corrosion resistance due to the inclusion of nickel and chromium, as well as copper. Such versions of cast iron get their name depending on how the alloying element was used in their manufacture.
5. Ductile iron is produced by introducing various elements, such as magnesium and calcium, into liquid gray cast iron. As a result of alloying, the shape of graphite changes - it resembles a sphere and does not change the crystal lattice. It is worth considering that in its properties this metal resembles carbon steel and is used mainly in the manufacture of various wear-resistant parts.
6. Malleable. It is obtained by melting white cast iron, which should be heated to a high temperature and maintained in this state. In some cases, alloying elements are added to impart special qualities to the composition. The main properties include high viscosity and an increased degree of plasticity. Widespread in the engineering industry.
7. Special. It is an alloy that contains a large amount of manganese and silicon. It is often used to remove oxygen from steel during its production or remelting, thereby lowering the melting point.

Iron casting

Each type of cast iron has its own special structure and chemical composition, which determine the scope of application.

Due to its special physical and mechanical qualities, the use of cast iron has become possible in a wide variety of areas:

1. For the production of various parts in the mechanical engineering industry. For many years, this alloy has been used in the manufacture of a wide variety of parts for internal combustion engines. At the same time, automakers change the basic properties of the material by alloying it, which is necessary to achieve unique qualities. In addition, brake pads made of this alloy have become widespread.
2. Cast iron products can withstand low temperatures. Therefore, the material is used in the production of equipment and tools that are used in harsh climatic conditions.
3. Cast iron is valued in the metallurgical field. This is due to the low cost, which largely depends on the carbon concentration and the characteristics of the resulting structure. High castability also makes the material more attractive. The resulting products are characterized by high strength and wear resistance.
4. Over the past few decades, the alloy in question has been widely used in the manufacture of sanitary equipment. This is due to high anti-corrosion abilities, as well as the possibility of obtaining products of a wide variety of shapes. Examples include cast iron bathtubs and radiators, various pipes, radiators and sinks. Despite the emergence of materials that could replace cast iron, such products are very popular. This is due to the fact that they retain their original appearance over a long period of use.
5. The alloy is also used for the manufacture of various decorative elements, which is associated with high casting qualities. An example is a railing grid, various figurines and much more.

Cast iron frying pansCast iron radiators

In addition, the scope of application depends on the following properties of the material in question:

1. Some brands have high strength, which is characteristic of steel. That is why the material is used even after the advent of modern alloys.
2. Cast iron products can retain heat for a long period. In this case, thermal energy can be distributed evenly throughout the material. These qualities began to be used in the manufacture of heating radiators or other similar products.
3. It is generally accepted that cast iron is an environmentally friendly material. That is why it is often used in the manufacture of various dishes, for example, cauldrons.
4. High resistance to acid-base environments.
5. High hygiene, since all contaminants can be easily removed from the surface.
6. The material in question is characterized by a fairly long service life, provided that the operating recommendations are followed.
7. The chemicals included in the composition cannot cause harm to health.

In conclusion, we note that the long-discovered production technology of the material in question has remained virtually unchanged for many years. This is due to the fact that a large volume of molten alloy could be obtained at relatively low cost. Today, material is often produced from scrap, which makes it possible to further reduce the cost of the resulting product.

Source: https://stankiexpert.ru/spravochnik/materialovedenie/chugun.html

Cast iron alloy composition: difference from steel, melting point of cast iron and steel

Cast iron is an alloy of iron and carbon. The percentage of iron contained is more than 90%. The amount of carbon ranges from 2.14-6.67%. Thanks to this element, the material has high hardness, but becomes brittle. This entails a deterioration in ductility and ductility. In some types, alloying elements are added to improve characteristics: aluminum, chromium, vanadium, nickel.

Characteristics of types of carbon metal

The iron-carbon diagram shows what cast iron is made of. In addition to iron, carbon is present in the form of graphite and cementite.

The composition of the cast iron alloy has varieties:

• White. The carbon present here is in a chemically bound state. The metal is strong, but brittle and therefore difficult to machine. In industry it is used in the form of castings. The properties of the material allow it to be processed with an abrasive wheel. The welding process causes difficulty, since there is a possibility of cracks due to the heterogeneity of the structure. Found application in areas related to dry friction. Has increased heat resistance and wear resistance.
• Half-hearted. It has increased fragility, so it is not widely used.
• Grey. GOST 1412–85 indicates what percentage of impurities this metal contains: 3.5% carbon, 0.8% manganese, 0.3% phosphorus, 0.12% sulfur and up to 2.5% silicon. The carbon present in the platelet form creates low impact strength. The characteristics of the type indicate that the material works better in compression than in tension. When heated sufficiently, it has good weldability.
• Malleable. A ferrite base of this type provides it with high ductility. When broken, it has a black, velvety color. It is obtained from white, which languishes for a long time at a temperature of 800-950 degrees.
• Highly durable. The difference from other types is the presence of spherical graphite. It is obtained from gray after adding magnesium to it.

Individual properties of metal

The material is characterized by certain characteristics. These include:

• Physical. Values ​​such as specific gravity or expansion coefficient depend on the carbon content of the metal. The material is heavy, so cast iron bathtubs can be made from it.
• Thermal. Thermal conductivity allows you to accumulate heat and retain it, distributing it evenly in all directions. This is used in the manufacture of frying pans or radiators for heating.
• Mechanical. These characteristics vary depending on the graphite base. The most durable is gray cast iron with a perlite base. A material with a ferrite component is more malleable.

Depending on the presence of impurities, a difference in the properties of the material appears.

These elements include sulfur, phosphorus, silicon, manganese:

• Sulfur reduces the fluidity of the metal.
• Phosphorus reduces strength, but makes it possible to manufacture products of complex shapes.
• Silicon increases the fluidity of the material, lowering its melting point.
• Manganese gives strength, but reduces fluidity.

Differences between cast iron and steel

To understand the difference between steel and cast iron, you need to consider their characteristics. A distinctive feature of cast iron is the amount of carbon. Its minimum content is 2.14%. This is the main indicator by which this material can be distinguished from steel.

iron in steel is 45%, and the percentage of carbon is up to 2. To determine the differences by eye, you need to pay attention to the color. Steel is light in color and cast iron is dark.

Only chemical analysis can determine the percentage of impurities. If we compare the melting point of cast iron and steel, then for cast iron it is lower and amounts to 1150-1250 degrees. For steel - around 1500.

To distinguish the material, you need to do the following:

• The product is lowered into water and the volume of displaced water is determined. Cast iron has a lower density. It is 7.2 g/cm3. For steel - 7.7−7.9 g/cm3.
• A magnet is applied to the surface, which attracts the steel better.
• The chips are rubbed using a grinder or file. Then it is collected in paper and wiped on it. Steel will not leave marks.

Pros and cons of the material

Like any material, cast iron has positive and negative sides. Positive qualities include:

• a wide variety of conditions.
• some types are highly durable;
• the ability to maintain temperature for a long time;
• environmentally friendly, which allows you to make dishes from it;
• resistance to acid-base environment;
• high hygiene;
• long service life and durability;
• harmlessness of the material.

However, there are also disadvantages. These include:

• when kept in water for a long time, the surface becomes covered with rust;
• high cost of material;
• low ductility of gray cast iron;
• fragility.

Cast iron is a metal characterized by a high carbon content. Thanks to this, it has qualities that are necessary for industrial and domestic purposes.

Source: https://obrabotkametalla.info/stal/sostava-splava-chuguna-i-otlichie

Cast iron - composition, properties and characteristics

The term “cast iron” can mean both a structural material based on iron and a metal vessel, a round pot for cooking. The latter is rare. Modern dishes are crowding.

The word “cast iron” is completely outdated. This is what the railway was called in the 19th and early 20th centuries.

What is cast iron

This is an alloy of iron and carbon with a carbon content of 2.14%. Ideally. In fact, in addition to those indicated, there are always impurities and alloying elements. So the distinction “floats”.

Depending on the carbon content relative to the eutectic, metal varieties are distinguished. Eutectic is the composition of an alloy with a minimum melting point.  

For cast iron, the carbon content is approximately 4.3%. Why “approximately” has already been said. Therefore, it is customary to divide cast iron into:

• hypoeutectic - 2.14 - 4.3% carbon;
• eutectic - 4.3% carbon;
• hypereutectic - from 4.3 to 6.67% carbon. 

Types of cast iron

In the generally accepted classification, they are divided according to the form of carbon they contain.

White

It is called so because of the characteristic color of the chip. Carbon C is contained in the form of cementite (formula Fe3C), which is formed when the melt cools. Hard refractory material.

In hypoeutectic alloys - in the composition of pearlite and ledeburite. In eutectic ones - in ledeburite. In hypereutectic - primary cementite and ledeburite.

In its original form, such cast iron is practically not used. Cannot be processed with high-speed steel tools. Only with carbide nozzles (VC), and even then with difficulty.  

It is used as a raw material for producing malleable.

Grey

Also named after the shade on the chip. Contains graphite fractions of various shapes. Carbon precipitation is facilitated by the addition of silicon.  

Properties and structure strongly depend on cooling conditions after crystallization.

Rapid cooling will give a predominance of perlite. Alloy of ferrite and carbide. A kind of “hardening” will increase strength and hardness. And fragility, which is not always acceptable.

Gentle cooling determines the increase in ferrite content. An alloy of iron with oxides, mainly Fe2O3. Plasticity will improve. Therefore, modes are selected based on the required parameters.

Gray cast iron is suitable for cast structures. It has a low curing temperature and good fluidity. Not prone to shell formation.

With all this, carbon inclusions cause low crack resistance. The material confidently withstands compressive forces, but is completely unsuitable for stretching/bending.

The marking indicates the symbols SCh and the ultimate strength in kg/mm2: SCh25. The most common cast irons are those with a C content below 3.7%.

Malleable

To produce white cast iron, it is heated to the required temperature, kept for a sufficient time and cooled slowly (“annealing”). The process provokes the decomposition of Fe3C with the release of graphite and the appearance of ferrite.

The shape of carbon inclusions is not similar to those in gray cast iron. This explains the appearance of some tensile strength and toughness.

Marked “KCh” with the addition of permissible tensile strength in MPa x 10-1 and maximum elongation. Example: CC 35-11.

High strength

A type of gray cast iron, only the graphite formations are shaped like balls. The roundness of the inclusions makes the crystal lattice not prone to cracks.

As a result, the initially valuable properties of cast iron (resistance to compression, ease of casting, etc.) are supplemented by a tensile yield strength comparable to steel, and crack resistance and ductility appear. 

They are marked similarly to malleable ones, but with the designation “HF”.

Peredelny

Used as a raw material for steel smelting. Often it does not even leave the enterprise where it was made.

Special

The production of such brands is small, up to 2% of the total volume. May contain significant amounts of alloying elements. Designed for limited purposes and specific conditions. Corrosion and chemically resistant ferroalloys are common.

One of the varieties is anti-friction cast iron. Used for the manufacture of rubbing parts. Alloyed primarily with chromium. Nickel, titanium, copper and others are also added.

It is characterized by high hardness (up to HB 300) and low coefficient of friction (up to 0.8 in the absence of lubricating emulsions).

Base materials: gray, ductile and high-strength cast iron. The markings are respectively AChS, AChK, AChV. The digital components are described above.

Advantages and disadvantages of the material

It is worth discussing in comparison with steel, although low-quality carbon steel is essentially the same as cast iron.

In some parameters (density, magnetic properties, typical chemical reactions) ferroalloys are almost identical. There are significant differences in the technology of use.

Advantages:

1. Moderate cost. Carbonation is part of the smelting process from ore. A decrease in its content will inevitably increase the price of the metal.

2. Excellent casting qualities. The melt is fluid. With low crystallization shrinkage, which minimizes defects. Relatively low melting point.

3. The products are durable, have a hard surface, and are wear-resistant.

4. The compositions used in mechanical engineering can be processed by cutting.

5. Durable. Including plumbing and sewer parts.

6. Items that have become unnecessary are easy to recycle. Any reception point with hands will be torn off.

Flaws:

1. Due to the high carbon content it is fragile. Not very suitable for pressure treatment. Certain brands produce forged products of excellent quality. But this is rather piece work and unprofitable on an industrial scale.

2. Welding is allowed only in extreme cases. The technology is quite complex, and the risk of defects is high.

3. The products are always massive. A thin-walled structure will not work, since it will not support its own weight and will not be able to be manufactured.

4. Easily oxidizes in a humid environment. It will not rust through due to its inevitable monumentality, but it will take on an unkempt appearance. Parts located outdoors require a corrosion-resistant coating.

Iron production

People mastered the rudiments of ferrous metallurgy already in the 2nd millennium BC. e. To obtain steel. But blast furnaces appeared in Europe only in the 14th and 15th centuries. Pig iron was obtained as a waste by-product.

They appreciated it when they noticed its outstanding casting qualities. It is convenient for making cannonballs, and it is also more convenient to obtain steel from it.

Technology reached Russia in a meaningful way in the 17th century. This happened under Peter I, when they were looking for material for weapons.

Iron ore is usually used as a raw material. The highest yield is obtained from magnetic and red, abundantly containing Fe.

Coke is used to maintain temperature. Combustion air is supplied forcibly. Flux (limestone) is designed to supply carbon dioxide. Main reaction:

.

The reduced Fe is lowered into the furnace, where it is saturated with carbon. The furnace operating cycle is continuous.

Getting steel

About 85% of cast iron is used for further steel production. An open hearth furnace is used for smelting.

During the melting process of the loaded raw material, a significant mass of FeO oxide is formed. As it heats up, the following reaction occurs:

.

Excess carbon is removed.

Electric arc and induction furnaces are also used. 

Areas of use

Due to the modern tendency to make equipment as light as possible, cast iron is used less and less. 

But there are areas where it is still indispensable and cost-effective:

1. In mechanical engineering it is used for large body parts with low tensile loads. Beds for machine tools, cylinder blocks for internal combustion engines. Flywheels, pulleys, gears, hydraulic cylinders, gear housings, electric motors, pistons.

2. Plumbing fittings, sewer pipes.

3. Decorative elements: fences, grilles, gates.

4. Stoves for houses, baths.

Source: https://nauka.club/materialovedenie/chugun.html

Cast iron - properties, classification, types

Surely many have encountered cast iron products in everyday life or at work. This material has good strength 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 from 2.14% to a maximum of 6.67% and can be included in the composition as cementite or graphite. Cast iron, by definition, is an engineering material that is inexpensive and easy to manufacture and serves as the basis for steel smelting. Its production refers to complex chemical processes occurring at certain stages of production.

Main characteristics and composition

In addition to iron and carbon, this alloy includes additional impurities that affect its properties. The diverse composition of cast iron provides it with high hardness, fluidity, and increases fragility. It includes: sulfur, silicon, manganese, phosphorus.

Due to the incoming carbon, the cast iron alloy has high hardness, but at the same time the malleability and ductility of the substance are reduced. To give the metal special characteristics, certain additives are added. The following alloying components are used: nickel, vanadium, as well as chromium and 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, which is why 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 fluidity state, significantly improves casting qualities, and also makes it softer.

Manganese is used to enhance strength. The addition of sulfur reduces the refractoriness and reduces 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, but allows the casting of objects of complex shapes.

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

The melting point ranges from a minimum of +1160 °C to a maximum of +1250 °C. It has high anti-corrosion properties and actively counteracts both dry (chemical) and wet corrosion. Thanks to him, stainless steel was born - a steel alloy with a high content of chromium component.

Application area

Cast iron is widely used in mechanical engineering for casting various parts. Used for the manufacture of crankshafts and engine blocks. In addition, high-quality pads are produced that are highly resistant to friction.

  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 that use a cast iron alloy for operation 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 parts are also made from a cast iron base. These are radiators, heating radiators, pipes, bathtubs, 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 when preparing many dishes.

Varieties

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

A special variety includes nickel-chromium alloys (nihards). These include low-carbon and high-carbon cast iron. The first is characterized by increased strength, and the second by 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.

Alloy

Alloyed cast iron alloy contains additional impurities. The composition includes high levels 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 and aggressive environments, as well as those operating under the influence of aqueous solutions.

Advantages of metal

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

• environmentally friendly material that is used in the production of household items, including dishes;
• resistant to acid-base environment;
• hygienic;
• ability to maintain temperature for a long time;
• some types have strength comparable to steel;
• duration of operation, during which its quality indicators only improve;
• Completely harmless to the body.

Production

The production of 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 point is about +1200 °C, which requires specific melting equipment. To obtain mass, ore is required, where the mass fraction of iron contained 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 the carbon in it. After the interaction, a cast iron mass is obtained, which falls down in liquid form. Unmelted impurities are pushed to the surface and subsequently removed. This slag is used to produce numerous materials.

After removing unnecessary particles from the melt, additives are added to obtain certain grades of cast iron alloys.

Source: https://oxmetall.ru/metalli/chugun/svojstva-klassifikatsiya-vidy

Classification of cast iron - types

“Iron casting” has been known to mankind since time immemorial. Nowadays, it is widely used in many areas of the national economy and is called cast iron. And while the average person may not know about crankshafts, gear housings, wheel hubs, fittings, everyone knows about frying pans, cast iron pots, radiators, bathtubs, grates and other cast iron products.

The metallurgical industry produces various simple and special types of cast iron, each of which has its own scope of application.

Features of cast iron

Cast iron is an iron-carbon alloy, smelted using fuel from magnetic, red or brown iron ore, with the addition of special inorganic substances - fluxes.

Many people do not see the fundamental differences between steel and cast iron, mistakenly assuming that they are the same thing. 

Both metallurgical products are alloys - they consist of several components, one of which is iron.

Cast iron is the raw material for steel production.

Technological properties:

• for steel – deformation (stamping, rolling, forging); 
• for cast iron - foundries.

Presence of carbon:

• steel – 0.02 – 2.14%; 
• cast iron - 2.14 - 6.67%.

External differences: 

• cast iron is dark and matte; 
• the steel is silvery and shiny.

Various physical characteristics

For cast iron:

• higher casting qualities; 
• easy to cut;
• has less weight;
• lower melting point.

The disadvantages of cast iron include:

• low plasticity;
• fragility;
• weakly susceptible to forging and welding.

Cast iron has a low cost and is cheaper than steel.

Additives and impurities

All supplied cast iron is regulated by GOSTs in terms of its chemical composition and impurity content. Cast iron casting, in addition to iron, contains some “ingredients” that affect the final product and add certain features:

• carbons – increase the hardness of the alloy;
• silicon – improves casting qualities;
• manganese – gives strength;
• sulfur - “thickens” and limits the fluidity of cast iron.
• Phosphorus causes cracks to form when cold and reduces mechanical parameters.

In order to improve the starting material, cast iron is alloyed, that is, various alloying additives are introduced that change the physical and/or chemical properties. 

Alloying additives:

• zirconium;
• aluminum;
• molybdenum;
• titanium;
• vanadium;
• copper;
• chromium.

Cast irons with a high content of silicon and manganese in their composition are classified as alloyed.

Classification of cast irons

The metallurgical industry produces different types of cast iron. The grade depends on the forms of graphite or cementite and other components involved in the alloy.

Gray cast iron (GC)

Designated by the letters SCH. In cross-section it is grayish-black, which is due to the presence of graphite, this natural color. The composition also contains various impurities, including silicon. This type of cast iron, which can be easily cut and is often used in the engineering industry for “minor” parts, becomes fluid when phosphorus is added. Suitable for all types of casting, including artistic.

White cast iron

The cut is light due to the presence of iron carbide. Subject to further processing into ductile iron and steel. That's why the variety is called reprocessing. Properties – brittleness and hardness, poorly processed, not suitable for independent use. Hard, poorly processed, fragile - these properties make it unsuitable for independent use.

Malleable iron

Designation - KCH. With prolonged annealing, white cast iron becomes malleable.

Properties - not amenable to pressure treatment, but at the same time it has increased impact resistance and tensile strength. Malleable cast iron is suitable for the manufacture of parts with complex configurations.

High strength 

Marked with the letters HF. It is obtained by introducing special additives into gray liquid cast iron to give the graphite a spheroidal shape. High-strength cast iron is used for the manufacture of critical parts - gears, crankshafts, pistons, which must have high wear resistance.

The form of production of conversion and foundry types is special forms - ingots. Modern technologies make it possible to obtain semi-finished products, square, sheet, plate, and bar blanks of various types of cast iron.

Depending on the purpose and chemical composition, the following types of cast iron are distinguished:

1. ferroalloys 
2. alloyed.

They have names corresponding to the metal additives:

• zirconium;
• chromium;
• vanadium; 
• copper;
• titanium.

Alloyed types are most in demand in the production of units, mechanisms, components and parts operating in particularly unfavorable environments and conditions.

Cast iron, characterized by an increased percentage of ferromanganese or ferrosilicon, is classified as a special ferroalloy. They are added in steelmaking for the release of oxygen - deoxidation.

Alloyed cast irons include:

1. Antifriction;
2. Heat resistant;
3. Heat resistant;
4. Corrosion resistant.

Antifriction types are marked with the first letters АЧ. For example, ASF is anti-friction gray cast iron. You can also see the markings AChV - anti-friction high-strength cast iron and AChK - anti-friction malleable.

The heat-resistant type is marked with the letters ZhCh. Next, the letter indicating the alloying element is indicated. For example, ZHCH-2.5. This is heat-resistant cast iron with the addition of 2.5% chromium.

Heat-resistant brands include: ChN19ХЗШ.

Corrosion-resistant: marking CHNHT, CHN1MHD

They are also called special cast irons.

Advantages of "iron casting"

Cast iron, like any materials, has certain pros and cons when using various products made from them - spare parts for cars, machine parts, plumbing equipment and other products.

Advantages

• environmental friendliness;
• ability to maintain temperature;
• high heat transfer;
• resistance to temperature changes;
• resistance to acids and alkalis;
• corrosion resistance;
• some types are of increased strength, which allows comparison with steel;
• wear resistance;
• durability.

Flaws:

• fragility, care should be taken during assembly;
• heavy weight of products;
• rusts with prolonged contact with water.

The basis of ferrous metallurgy in our country is the production of cast iron, steel and rolled products. The largest consumers of “iron casting” are such strategically important industries as metalworking, mechanical engineering, construction, transport, light industry, chemical and others.

Iron casting is not losing its position in the production of consumer goods - cast iron boilers, frying pans, duck pots, fences. Skilled craftsmen use this metal to create real works of art - fireplace grates, fences, benches, railings, decorating them with openwork cast iron lace.

Source: https://prompriem.ru/chugun/vidy.html