Sergey Chugunov White and fluffy Funny
A funny novel about love and not only for animals. A collection of funny and tragic stories about the life of Varvara Rostopchina, her friend Alexander Kuzminsky, Aunt Lucy (godmother), and the white and fluffy cat Kuzi.
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Sergey Chugunov Women's health. Problems and their solutions
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Dontsova Daria Arkadyevna, Litvinova Anna Vitalievna, Litvinov Sergey Vitalievich He, she and the furry detective
How much joy our beloved pets bring us! They can listen, console, keep company and even help solve a complicated story! This is exactly what happens in the action-packed stories from the new collection “He, She and the Furry Detective.”
In them, shaggy and tailed four-legged pets, as best they can, help their owners not only discover a criminal secret, but also find their love and happiness! Recognized detective masters Daria Dontsova, Anna and Sergei Litvinov and their talented colleagues are revealed from a new side in this collection.
Here is a kind, lyrical and fascinating book.
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Chugunov Sergey Petrovich Women's health. Problems and their solutions
This book tells in an accessible form about the main women's diseases, symptoms and their treatment using traditional methods and traditional medicine. The second part of the book is devoted to such methods of treating and preserving women’s health as gymnastics, massage, physiotherapy, and aromatherapy. For a wide range of readers.
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Sergey Chugunov Flu and colds. Terrorists No. 1
In this book you will learn how the flu differs from a cold from a medical point of view. Recommendations from leading experts, folk recipes and recipes from healers will help you not only cope with these insidious ailments, but also, most importantly, prevent their occurrence.
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Sergey Chugunov When cleansing the body, do not forget about the soul. Removal of toxins, radionuclides and wastes
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Chugunov Vladimir Arkadevich Breath of Eternity. Priest Vladimir Chugunov
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Cast iron: gray and white: properties, production, casting, marking - Website about
Cast iron firmly entered our lives many years ago. It is relatively easy to produce and widely used in various fields. To have a clear understanding of this material, you need to know its features, disadvantages, advantages, chemical composition, properties, structure of cast iron and its alloys, their production and scope of application.
So, let's find out which iron-carbon alloys are called cast irons.
Concept
Cast iron is an iron-carbon alloy containing carbon, that is, it means a material that consists of an alloy of iron and carbon. The percentage of carbon in cast iron is more than 2.14%. The latter element can be included in cast iron in the form of graphite or cementite.
- This video talks about the features of cast iron:
- There are white and gray cast iron.
- The carbon in white cast iron is in the form of iron carbide. If you break it, you can see a white tint. White cast iron is not used in its pure form. It is added to the process of producing malleable iron.
- At a fracture, gray cast iron has a silvery tint. This type of cast iron has a wide range of uses. It lends itself well to processing with cutters.
In addition, cast irons are high-strength, malleable and with special properties.
- High-strength cast iron is used to increase the strength of the product. The mechanical properties of such cast iron allow this to be done perfectly. High-strength cast iron is obtained from gray cast iron by adding magnesium to the mass.
- Ductile iron is a type of gray iron. The name does not mean that this cast iron is easily forged. It has increased plasticity properties. It is obtained by annealing white cast iron.
- There is also a distinction between half cast iron. Some of the carbon in it is in the form of graphite, and the remaining part is in the form of cementite.
Special Features
The peculiarity of cast iron lies in the process of its production. The average melting point of different types of cast iron is 1200ºC. This value is 300 degrees less than that of steel. This is due to the very high carbon content. Carbon and iron atoms do not have a very close connection with each other.
https://www.youtube.com/watch?v=Wj3yX7R9dE4
When the smelting process takes place, carbon cannot be completely incorporated into the iron lattice. As a result, cast iron takes on the property of brittleness. It cannot be used for the manufacture of parts that will be subject to constant load.
Cast iron is a ferrous metallurgy material. Its characteristics are often compared to steel. Products made of steel or cast iron are widely used in our lives. Their use is justified. After comparing the characteristics, we can say the following about these two materials:
- The cost of cast iron products is lower than the cost of steel ones.
- Materials vary in color. Cast iron is a dark matte material, while steel is light and shiny.
- Cast iron is easier to cast than steel. But steel is easier to weld and forge.
- Cast iron is less durable than steel.
- Cast iron is lighter in weight than steel.
- Steel has a higher carbon content than steel.
Advantages and disadvantages
Cast iron, like any material, has positive and negative sides.
The advantages of cast iron include:
- Carbon in cast iron can be in different states. Therefore, this material can be of two types (gray and white).
- Certain types of cast iron have increased strength, so cast iron is sometimes placed on the same line as steel.
- Cast iron can maintain temperature for quite a long time. That is, when heated, the heat is evenly distributed throughout the material and remains in it for a long time.
- In terms of environmental friendliness, cast iron is a clean material. Therefore, it is often used to make dishes in which food is subsequently prepared.
- Cast iron is resistant to acid-base conditions.
- Cast iron has good hygiene.
- The material has a fairly long service life. It has been noticed that the longer cast iron is used, the better its quality.
- Cast iron is a durable material.
- Cast iron is a harmless material. It is not capable of causing even slight harm to the body.
The disadvantages of cast iron include:
- Cast iron will rust if it is exposed to water for a short time.
- Cast iron is an expensive material. However, this minus is justified. Cast iron is very high quality, practical and reliable. Items made from it are also high quality and durable.
- Gray cast iron is characterized by low ductility.
- White cast iron is characterized by brittleness. It is mainly used for smelting.
Properties and characteristics
Cast iron has the following properties:
- Physical . These characteristics include: specific gravity, coefficient of linear expansion, actual shrinkage. Specific gravity varies depending on the carbon content of the material.
- Thermal . The thermal conductivity of a material is usually calculated using the displacement rule. For solid cast iron, the volumetric heat capacity is 1 cal/cm3*oC. If cast iron is liquid, then it is approximately 1.5 cal/cm3*oC.
- Mechanical . These properties depend on the base itself, as well as on the size and shape of the graphite. Gray cast iron with a pearlite base is considered the most durable, and the most ductile is with a ferritic base. The maximum reduction in strength is observed with the “plate” shape of graphite, and the minimum – with the “ball” shape.
- Hydrodynamic . Viscosity in cast iron varies depending on the presence of manganese and sulfur. It also increases sharply when the temperature of cast iron passes the point where solidification begins.
- Technological. Cast iron has excellent casting properties, resistance to wear and vibration.
- Chemical . According to the electrode potential (in decreasing order), the structural components of cast iron are arranged in the following form: cementite - phosphide eutectic - ferrite.
Differences between cast iron and steel in chemical composition and properties
The properties of cast iron are affected by special impurities.
- Thus, the addition of sulfur can significantly reduce fluidity and reduce refractoriness.
- The addition of phosphorus simultaneously makes it possible to create a product of complex shape, but does not give it increased strength.
- The silicon impurity makes the melting point not so high and significantly improves the casting properties. Different percentages of silicon create different types of cast iron, from pure white to ferritic.
- Manganese worsens casting and technological properties, but increases strength and hardness.
In addition to the mentioned impurities, cast iron may also contain other components. Then such materials will be called alloyed. The most common materials added to cast iron are titanium, chromium, aluminum, nickel and copper.
Next, you will find out what elements are included in the chemical composition of cast iron.
The video below will show you how to weld cast iron using electric welding:
If we consider cast iron as a structural material, then it is a metal cavity with graphite inclusions. The structure of cast iron is mainly pearlite, ledeburite and ductile graphite. Moreover, for each type of cast iron these elements predominate in different proportions or are absent altogether.
According to the structure of cast iron there are:
- perlite,
- ferritic and
- ferritic-pearlitic.
Graphite is present in this material in one of the forms:
- Globular. Graphite takes on this shape when magnesium is added. The spherical shape of graphite is characteristic of high-strength cast irons.
- Plastic. Graphite is similar to the shape of petals. In this form, graphite is present in ordinary cast iron. This cast iron has increased ductility properties.
- Flaky. Graphite acquires this shape by annealing white cast iron. Graphite is found in flake form in malleable cast iron.
- Vermicular. The named form of graphite is found in gray cast iron. It was developed specifically to improve ductility and other properties.
Metal production
Cast iron is produced in special blast furnaces. The main raw material for producing cast iron is iron ore. The technological process consists of reducing the iron oxides of the ore and obtaining another material as a result - cast iron. The following fuels are used to make cast iron: coke, natural gas and thermal anthracite.
Once the ore is reduced, the iron is in a solid form. Next, it is lowered into a special part of the furnace (steam), where carbon is dissolved in the iron. The output is liquid cast iron, which falls into the lower part of the furnace.
The price of cast iron (per 1 kg) depends on the amount of carbon in it, the presence of additional impurities and alloying components. Approximately the price of a ton of cast iron will be 8,000 rubles.
Cast iron is common in many areas.
- It is used for the production of parts in mechanical engineering. Engine blocks and crankshafts are mainly made from cast iron. The latter require advanced cast iron, to which special graphite additives are added. Due to the resistance of cast iron to friction, it is used to make excellent quality brake pads.
- Cast iron can operate smoothly even at extremely low temperatures. Therefore, it is often used in the production of machine parts that will have to work in harsh climatic conditions.
- Cast iron has proven itself well in the metallurgical field. It is valued for its relatively low price and excellent casting properties. Products made from cast iron are characterized by excellent strength and wear resistance.
- A large variety of plumbing products are made from cast iron. These include sinks, radiators, sinks and various pipes. Cast iron bathtubs and heating radiators are especially famous. Some of them still serve in apartments today, although they were purchased many years ago. Cast iron products retain their original appearance and do not require restoration.
- Thanks to its good casting properties, cast iron produces real works of art. It is often used in the manufacture of artistic products. For example, such as beautiful openwork gates or architectural monuments.
Are you choosing a bath? Don't know which is better, cast iron or steel? Then this video will help you:
Source: https://nzmetallspb.ru/prochee/chugun-seryj-i-belyj-cvojstva-proizvodstvo-lite-markirovka.html
What is the difference between gray cast iron and white
The most common types of cast iron are gray and white. What does each one represent?
What is gray cast iron?
The corresponding type of cast iron is one of the most common in the field of mechanical engineering. This metal is characterized by the presence of plate-shaped graphite in the thin section. Its content in gray cast iron may vary. The larger it is, the darker the metal becomes at the fracture, and also the softer the cast iron. Castings from the type of metal in question can be produced in any thickness.
Main features of gray cast iron:
- minimum relative elongation - as a rule, not exceeding 0.5%;
- low impact strength;
- low plasticity.
Gray cast iron contains a small percentage of fixed carbon - no more than 0.5%. The remaining part of the carbon is presented in the form of graphite - that is, in a free state. Gray cast iron can be produced on a pearlitic, ferritic, or mixed ferrite-pearlite base. The metal in question usually contains a significant percentage of silicon.
Gray cast iron is quite easy to process using cutting tools. This metal is used for casting products that are optimal in terms of compression resistance. For example, various supporting elements, batteries, water pipes. The use of gray cast iron is also widespread in mechanical engineering - most often in the manufacture of parts that are not characterized by shock loads. For example, housings for machine tools.
What is white cast iron?
This type of cast iron is characterized by the presence of carbon, which is almost completely represented in the metal structure in a bound state. The metal in question is hard and at the same time quite fragile. It is resistant to corrosion, wear, and temperature effects. White cast iron is quite difficult to work with hand tools. When broken, this metal has a light tint and a radiant structure.
The main area of application of white cast iron is subsequent processing. As a rule, it is converted into steel, and in many cases into gray cast iron. In industry, its use is not very common due to its fragility and difficulty in processing.
The percentage of silicon in white cast iron is significantly less than in gray cast iron. The metal in question may also have a higher concentration of manganese and phosphorus (note that their presence is largely determined by the chemical composition of the ore from which the cast iron is smelted). Actually, an increase in the amount of silicon in a metal is accompanied by a decrease in the volume of bound carbon in its structure.
Comparison
The main difference between gray cast iron and white is that the former contains a small percentage of fixed carbon, while the latter, on the contrary, contains mainly fixed carbon. This feature determines the difference between the metals under consideration in terms of:
- hardness;
- colors on the break;
- wear resistance;
- fragility;
- machinability with hand tools;
- scope of application;
- percentage of fixed and free carbon;
- percentage of silicon, manganese, phosphorus.
To more clearly study the difference between gray and white cast iron in these aspects, a small table will help us.
Source: https://ostwest.su/instrumenty/chem-otlichaetsja-seryj-chugun-ot-belogo.php/
White cast iron
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White cast iron is a type of cast iron that has a white color when fractured and a characteristic metallic sheen. It contains carbon in the form of cementite. The presence of graphite in white cast iron is not visually detectable and is determined only chemically.
Unalloyed and alloyed white cast iron have different chemical compositions. Alloying of white cast iron is carried out in order to increase its wear resistance. For these purposes, carbide-forming elements are used - chromium, tungsten, molybdenum, etc.
Features of producing white cast iron
In the process of producing white cast iron of a given structure, it is necessary to suppress the graphitization process during the entire time of crystallization of the liquid mass. In this case, both the competent selection of source materials and adherence to the technology for cooling cast iron in the mold are important.
When castings are made from unalloyed cast iron in wet sand molds, there is a need to maintain the proportion of carbon and silicon: C (Si + log R) < 4.5. The cross-sectional area of the casting divided by the perimeter of the section is called the reduced thickness and is denoted in this case as R.
The high content of cementite in white cast iron seriously complicates their use as structural materials, since they are brittle and extremely difficult to machine.
On the other hand, white cast iron castings are characterized by corrosion resistance, resistance to high temperatures and open fire, and wear resistance. To maintain the above qualities, their composition must be as homogeneous as possible. The more carbides contained in white cast iron, the greater its hardness.
If coagulation of carbides occurs due to non-compliance with technology, the hardness of cast iron is significantly reduced. White cast iron with a martensitic structure has the maximum hardness.
Alloying elements of white cast iron
The hardness of white cast iron is most strongly influenced by carbon, which, in fact, determines the amount of carbides. The remaining elements that affect its hardness are arranged in the following order (in descending order): nickel, phosphorus, manganese, chromium, molybdenum, vanadium, silicon, copper, titanium, sulfur.
Elements such as Ni, Mn, Cr are directly involved in the formation of the martensite-carbide structure. If their total content is approximately equal to the proportion of carbon, the white iron casting has maximum hardness.
White cast iron is characterized by the absence of a direct relationship between hardness and wear resistance; in this case these are different qualities.
Wear resistance is a defining characteristic, and its best indicators are found in white cast iron with a special structure of the metal mass, in which carbides and phosphides are arranged in the form of separate uniform inclusions or a graphically regular grid.
White cast iron has found wide application in the production of machine parts, equipment and mechanisms operating under conditions of increased abrasive wear and in the absence of lubrication.
Alloyed white cast iron, in addition to heat resistance and corrosion resistance, also has electrical resistance.
These characteristics are determined by the structure of its metallic mass, which can be carbide-pearlite, carbide-austenitic, and contain alloyed ferrite.
In other words, the quality of casting directly depends on the composition of alloying elements and their concentration. In most cases, chromium is the main alloying element that forms chromium and iron carbides and binds carbon.
High chromium white cast iron
High-chromium white cast iron is characterized by maximum resistance to corrosion due to the formation of oxide films on its surface. In addition, chromium and iron carbides are characterized by a high electrode potential, comparable to the potential of chromium ferrite, the second component of the metallic mass of white cast iron. High-chromium white cast iron retains its corrosive properties in alkaline and saline solutions, sulfuric and nitric acid.
The process of complex alloying of white cast iron is fraught with coagulation of carbides under high temperature conditions. The presence of chromium in it increases the temperature resistance of carbides and helps slow down diffusion processes. If high-chromium white cast iron is additionally alloyed with elements such as Ni and Mo, its mechanical characteristics are further enhanced, and its strength approaches that of heat-resistant steel.
In areas where such qualities of cast iron as corrosion resistance and high electrical resistance are in demand, alloyed white cast iron is used.
White stainless and heat-resistant cast iron
In industry today, stainless white cast iron of the X28 and X34 grades is widely used. In addition to corrosion resistance, parts made from it have the ability to maintain their original dimensions during prolonged and cyclic heating. The improved characteristics of cast iron of these grades are due to additional alloying with the following elements:
N – 0.1%; Ti – 0.5%;
Cu – 0.5-2.0%.
White cast iron with high resistivity
Cast iron grade X34 is used for cast heaters capable of operating at temperatures of 800-900 ˚C. This type of white cast iron is called sormite and is distinguished by the following percentage of alloying elements:
carbon – 2.5-3.5%; silicon – 2.0-2.5%; manganese – 1.0-1.5%;
nickel – 3.0-5.0%.
Its resistivity is characterized by the following indicators: p = 1.4/1.5 ohm * m/mm2, σв = 35 kg/mm2; σben = 70 kg/mm2; HRC 48-50.
White cast iron castings are annealed to relieve internal stress and stabilize dimensions. The annealing temperature depends on the resistance of the carbides and in the case of white cast iron it rises to 850 ˚C. Heating and cooling processes should be slow for all grades of alloy cast iron. The result is durable parts that are much less prone to cracking.
See also:
Source: https://www.autowelding.ru/publ/1/1/belyj_chugun/4-1-0-532
Comparative characteristics of cast iron and steel (page 1 of 2)
Introduction
1. Characteristics of materials
1.1 Cast iron
1.2 Steel
2. Comparison of the properties of cast iron and steel
2.1 Physico-chemical properties of materials
2.2 Mechanical properties of materials
2.3 Specific properties
3. Conclusion
References
Introduction
Ferrous metallurgy is the basis for the development of most sectors of the national economy. Despite the rapid growth of products in the chemical industry, non-ferrous metallurgy, and building materials industry, ferrous metals remain the main structural material in mechanical engineering and construction.
Modern ferrous metallurgy has high technical potential. Significant progress has been achieved in production technology in certain sub-sectors and areas of ferrous metallurgy.
Thus, iron ore mining is mainly carried out using a progressive open-pit method; Smokeless charge and dry coke quenching have been introduced in coke production; in blast furnaces in furnaces with increased gas pressure under the top, 97% is smelted, and with natural gas injection - 84% of all cast iron; in the steelmaking industry, steel production in oxygen converters and electric furnaces is increasing, out-of-furnace processing of steel under vacuum, synthetic slag, inert gases, and remelting processes have been introduced; the share of continuous steel casting is increasing; in rolling production, heat treatment of metal products and non-destructive automatic testing means are effectively used; in the pipe industry, the technology for the production of large-diameter welded pipes and seamless pipes is being improved; Automated production lines are being introduced in hardware production. Industrial methods for the direct production of iron are being developed. Work is underway to create an automated control system for ferrous metallurgy.
The purpose of this work is to compare the properties of two products of ferrous metallurgy: cast iron and steel, so important for humanity.
Tasks:
1. Study the characteristics of materials.
2. Disassemble and compare the physicochemical, mechanical and specific properties of cast iron and steel.
3. Draw a conclusion.
When writing this work, educational and methodological literature was used.
1. Characteristics of materials
Cast iron (Turkic), an alloy of iron with carbon (usually more than 2%) also containing permanent impurities (Si, Mn, P and S). Widely used grades of cast iron usually contain 2.5-4% carbon, 1-5% silicon, up to 2% manganese, as well as impurities of phosphorus and sulfur. Special cast irons contain alloying additives: vanadium, molybdenum, nickel, titanium, chromium, etc. The melting point of cast irons depends on their chemical composition and is approximately 1200-1250oC.
Types: white, gray, malleable, high-strength, half-cast iron.
The structure of cast iron depends on the cooling rate and the content of carbon and alloying impurities in it. Based on their structure, cast iron is divided into white and gray.
White cast iron gets its name from the type of fracture that has a white or light gray color. The carbon in it is in a chemically bound state in the form of cementite Fe3C. Cementite is fragile and has high hardness, so white cast iron cannot be machined, is rarely used for the manufacture of products and cannot be welded.
Malleable cast iron is obtained from white cast iron through special heat treatment (long exposure at a temperature of 1000°C). In terms of mechanical properties, it is more ductile than white cast iron. The name “malleable” is a conditional name; cast iron is not used in the form of forgings, they are practically not forged.
High-strength cast irons are produced by adding some alloying elements (magnesium, cerium, etc.) to the alloy. Gray cast iron contains almost all carbon in the form of graphite, so its fracture has a silver-gray color.
Gray cast iron can be easily processed by cutting tools, so it is widely used as a structural material. Gray cast iron is cheaper than steel, has good casting properties, high wear resistance, the ability to dampen vibrations, and good machinability.
Its negative properties are reduced strength and high fragility.
Historical reference. The first information about cast iron dates back to the 6th century. BC. In China, cast iron containing up to 7% P and a low melting point was obtained from high-phosphorus iron ores, from which various products were cast. Cast iron was also known to ancient metallurgists of the 4th-5th centuries. BC. Iron production in Western Europe began in the 14th century.
with the advent of the first blast furnaces (stükofen) for smelting cast iron from ores . The resulting cast iron was used either for conversion into steel in a forge, or for the manufacture of various construction parts and weapons (cannons, cannonballs, columns, etc.). In Russia, cast iron production began in the 16th century.
; Subsequently, it continuously expanded, and under Peter I, Russia surpassed all countries in the production of cast iron, but a century later it lagged behind Western European countries. Appearance in the 2nd half of the 18th century. Cupola furnaces allowed foundries to separate from blast furnaces, i.e. marked the beginning of the independent existence of iron foundries (at machine-building plants). At the beginning of the 19th century. the production of malleable cast iron begins.
In the 2nd quarter of the 20th century. they began to use alloying of cast iron, which made it possible to significantly increase its properties and obtain special cast iron (wear-resistant, corrosion-resistant, heat-resistant, etc.). The development of methods for modifying cast iron also dates back to this period. At the end of the 40s. modified cast iron with spherical graphite inclusions was obtained instead of the usual lamellar one. In the 60s
in electric furnaces began to be obtained from steel waste with the addition of so-called carburizers. synthetic cast iron with high mechanical properties and lamellar graphite.
Marking. Cast iron is marked according to an alphanumeric system: the first letters (C, K and B) indicate gray, ductile and high-strength cast iron, respectively; the second letter (CH) stands for cast iron. In gray cast iron, two numbers indicate tensile strength.
For example, in the SCh10 brand, the letters SCH indicate gray cast iron, 10 - temporary resistance.
In the designations of malleable and high-strength cast iron, after the letter marking (KCh and VCh), the first two digits also indicate the tensile strength, and the second two - the relative elongation, for example, KCh 35-10 (ductile cast iron with a tensile strength of at least 350 MPa and a relative elongation of at least 10 %).
In industry, types of cast iron are labeled as follows:
· pig iron - P1, P2;
· pig iron for castings - PL1, PL2, pig iron - PF1, PF2, PF3, pig iron - high-quality pig iron - PVK1, PVK2, PVK3;
· cast iron with lamellar graphite - SCh (numbers after the letters “SCh” indicate the value of tensile strength in kgf/mm);
· anti-friction cast iron
o anti-friction gray - AChS,
o anti-friction high-strength - AChV,
o anti-friction malleable - ABC;
· cast iron with nodular graphite for castings - HF (the numbers after the letters “HF” mean tensile strength in kgf/mm and relative elongation (%);
· alloyed cast iron with special properties - Ch.
1.2 Steel
Steel (Polish stal, from German Stahl), a deformable (malleable) alloy of iron with carbon (up to 2%) and other elements. Steel is the most important product of ferrous metallurgy, which is the material basis of almost all industries. The scale of steel production largely characterizes the technical and economic level of development of the state.
Historical reference. Steel as a material used by man has a long history. The most ancient method of producing steel in a dough-like state is the cheese-blowing process, which was based on the reduction of iron from ores with charcoal in forges (later in small shaft furnaces).
To produce cast steel, ancient craftsmen used crucible melting - melting small pieces of steel and cast iron in refractory crucibles. Crucible steel was characterized by very high quality, but the process was expensive and inefficient. In particular, damask steel and its variety, Damascus steel, were produced in this way. The crucible process existed until the beginning of the 20th century.
and was completely replaced by electric smelting. In the 14th century a critical redistribution arose, which consisted of refining the previously obtained cast iron in a forge. At the end of the 18th century.
Pudding began to be used, in which, as with critical processing, the starting material was cast iron, and the product was dough-like metal (kritsa). The quality of the metal was higher, and the process itself was characterized by higher productivity. Pudding played an important role in the development of technology, but it could not meet the ever-increasing needs of society for steel.
Only with the appearance in the 2nd half of the 19th century. The Bessemer process and the open-hearth process, and then the Thomas process, made it possible to mass produce cast steel. At the end of the 19th century. steel smelting in electric furnaces began to be used. Until the middle of the 20th century.
The dominant position among steel production methods was occupied by the open-hearth process, which accounted for about 80% of the steel produced in the world. In the 50s The oxygen converter process was introduced, and in subsequent years its role increased sharply. Along with these methods of mass steel production, more expensive and less productive methods are being developed that make it possible to obtain high-quality, especially pure metal: vacuum arc melting, vacuum induction melting, electroslag remelting, electron beam melting, plasma melting.
Steels are divided into structural and instrumental. A type of tool steel is high-speed steel.
According to the chemical composition, steels are divided into carbon and alloy; including by carbon content - low-carbon (up to 0.25%), medium-carbon (0.3-0.55%) and high-carbon (0.6-0.85%); Based on the content of alloying elements, alloy steels are divided into low-alloy, medium-alloy and high-alloy.
Source: https://mirznanii.com/a/192055/sravnitelnaya-kharakteristika-chuguna-i-stali
Difference between iron and cast iron
Iron is an important metallic element. It is used in the production of many different useful metal alloys such as steel. The main problem with iron is surface rust. Various prevention methods are used to prevent rusting, such as galvanizing, painting, etc.
Metal alloys such as stainless steel are also produced to prevent rust. Cast iron is a form of iron that contains more carbon than other alloys. The main difference between cast iron and cast iron is that iron is a pure metal, while cast iron is a metal alloy.
Key areas covered
1. What is Iron
- Definition, Chemical Properties, Extraction
2. What is Cast Iron
- Definition, Properties, Different Types
3. What is the Difference Between Iron and Cast Iron
- Comparison of Main Differences
Key terms: cast iron, ductile iron, gray cast iron, iron, metal, malleable cast iron, metal alloy, rust, steel, white cast iron, wrought iron
What is iron
Iron is a metallic element with the symbol "Fe". The atomic number is 26 and the molar mass is about 56 g/mol. This chemical element belongs to block d of the periodic table. It is considered a transition element because it has partially filled d orbitals according to its electronic configuration ([Ar] 3d6 4s2).
Figure 1: Atomic structure of iron
Iron is solid at room temperature. The melting point is 1538°C and the boiling point is about 2862°C. It is very important as a metal and is also used in the production of various metal alloys.
When exposed to air and moisture, iron can deteriorate. This is called rust formation. This is a chemical reaction that involves oxidation of the surface of the iron.
Iron alloys are made with reduced or no corrosion by adding sufficient chromium to the iron; Stainless steel is the best example for this.
There are various types of iron alloys including steel, wrought iron, cast iron, anthracite, etc. Steel is one of the most used metal alloys in the world due to its various desirable properties such as strength, ductility, etc. Wrought iron is a low carbon metal alloy. It's tough and malleable. Cast iron consists of a large amount of carbon. It tends to be brittle.
Iron can be extracted from iron ores using a blast furnace. Generally, iron ore consists of iron in two forms as ferric and iron oxides. These forms can be reduced to iron in a blast furnace by heating the raw material with coke. Molten pig iron can be obtained from the bottom of the furnace. This molten pig iron can be used to make cast iron, steel and other forms of alloys.
What is cast iron
Cast iron is a hard, relatively brittle alloy of iron and carbon that can be easily cast into shape. It contains a higher proportion of carbon than steel. Cast iron is a metal alloy. carbon in this alloy is 2-4%. Cast iron has a relatively lower melting point than other iron alloys.
In addition to carbon and iron, cast iron also contains silicon, manganese and trace amounts of sulfur and phosphorus. Because the carbon content is high, cast iron solidifies as a heterogeneous alloy. Cast iron has about 1-3% silicon. Therefore, it is actually a metallic alloy of iron-carbon-silicon. Molten cast iron reacts less with the molding material. However, cast iron is not very ductile and is not suitable for rolling.
Cast iron is a good engineering material due to its low melting point, good fluidity, good machinability, etc. Below are several types of cast iron. This classification is based on the microstructure of the alloy.
- Gray cast iron
- Malleable iron
- Malleable iron
- White cast iron
Figure 2: Cast iron saucepan
These cast iron molds differ from each other depending on the shape and form of carbon present in the iron. In the production of gray cast iron , inoculants are used to control the type and size of graphite in the alloy. In the production of malleable iron, trace amounts of bismuth are used to improve ductility.
Malleable iron is produced by adding trace amounts of magnesium, which causes the formation of spheroidal graphite in the alloy. White cast iron has white cracks when broken. This is due to the presence of iron carbide impurities.
Likewise, the presence of certain other compounds can provide the desired properties of cast iron.
Definition
Iron: Iron is a metallic element with the symbol “Fe”.
Cast Iron: Cast iron is a hard, relatively brittle alloy of iron and carbon that can be easily cast into shape.
Nature
Iron: Iron is a pure metal.
Cast Iron: Cast iron is a metal alloy.
carbon
Iron: Pure iron is not composed of carbon, but iron alloys can have varying percentages of carbon.
Cast Iron: Cast iron consists of 2-4% carbon.
Melting temperature
Iron: Iron has a higher melting point of 1538°C.
Cast Iron: Cast iron has a relatively low melting point.
Rust formation
Iron: Rust forms on the surface of iron and iron alloys other than stainless steel.
Cast Iron: Cast iron is susceptible to rust.
stringiness
Iron: Iron and most iron alloys are malleable.
Cast Iron: Cast iron is less malleable and brittle (except for malleable cast iron).
Conclusion
Iron is a metal. It is used in the production of various types of metal alloys, which are used for various purposes depending on their favorable properties. Cast iron is one such form of iron. The main difference between iron and cast iron is that iron is a pure metal whereas cast iron is a metal alloy.
Recommendations:
1. “Understanding Cast Irons.” Atlas Foundry Company,
Source: https://ru.strephonsays.com/difference-between-iron-and-cast-iron
What is the difference between gray cast iron and white cast iron?
Cast irons are ternary alloys of iron-carbon-silicon. There are four main types of cast iron: - gray cast iron; - white cast iron; - malleable cast iron;
— cast iron with nodular graphite.
The chemical composition of these four types of cast irons is presented in the table below.
Table - Four main types of cast iron
Gray cast iron - graphite, white cast iron - cementite
In gray cast iron, a graphitic eutectic is formed - the carbon is mainly in the form of graphite, while in white cast iron a cementite eutectic is formed and the carbon is mainly in the form of cementite Fe3C.
The influence of silicon on the type of eutectic in cast irons
The addition of silicon allows graphite to form more easily, especially when formed directly from the liquid phase. It might even be more correct to say that the addition of silicon makes it more difficult for Fe3C to form cementite.
Figure 1 shows how silicon reduces the temperature of the austenite-cementite eutectic and at the same time raises the temperature of the austenite-graphite eutectic.
Figure 1 – Change in eutectic temperatures of graphite and cementite Fe3C
with increasing silicon content in cast iron from 0 to 2%
According to Figure 1, for an iron-carbon alloy with a silicon content of 2%, there are two eutectic temperatures: 1163 ºC for the formation of graphite and 1120 ºC for the formation of cementite. As the alloy cools, the liquid between the dendrites continues to become enriched in carbon until the temperature rises until one of these eutectics is formed.
Competition between graphite and cementite
There is a kind of competition between the two types of eutectics over which one is formed first. This competition involves three important factors:
1) Both types of eutectics require some undercooling below their eutectic temperatures, which are shown in Figure 1, before the eutectic begins to form. 2) The amount of undercooling increases with increasing cooling rate.
3) The amount of supercooling for the formation of austenite-cementite eutectic is less than that required for the formation of austenite-graphite eutectic.
Slow Cooling - Gray Cast Iron
Let us assume that the interdendritic liquid is cooled to 1130 ºС and that none of the eutectics have formed. Then the liquid is cooled by another 33 ºС – from 1163 to 1130 ºС. This supercooling is sufficient for the formation of graphite eutectic.
This cooling is not sufficient for the formation of cementite eutectic, since the temperature of the liquid has not dropped below 1120 ºС. Therefore, under these conditions, cementite eutectic cannot form.
Theoretically, supercooling of 33 ºС is sufficient for the formation of graphite eutectic and as a result, gray cast iron is obtained.
Fast Cooling - White Cast Iron
Let's imagine that the same iron-carbon alloy with 2% silicon is cooled faster, so that the required amount of supercooling for the formation of graphite eutectic increases from 33 to 53 ºС.
This means that graphitic eutectic will not form until the interdendritic fluid reaches 1110 ºC. However, at a temperature of 1110 ºС, the liquid is supercooled by 10 ºС, the temperature of the cementite eutectic is 1120 ºС.
Since a slight supercooling of less than 10 ºС is sufficient for the formation of cementite eutectic, this alloy will harden like white cast iron.
Cast iron production practice
These “theoretical” calculations confirm practical recommendations for the production of gray and white cast iron: 1) With the same chemical composition of cast iron, it will be white cast iron with rapid cooling or gray cast iron with slow cooling. 2) Increased silicon content in cast iron contributes to the formation of gray cast iron. The difference between the graphite and cementite eutectic temperatures decreases from 43 ºC for a silicon content of 2% to only 6 ºC in cast iron without any silicon.
3) In cast iron without silicon, as a rule, white cast iron is formed. This occurs because the interdendritic fluid reaches supercooling earlier for the “white eutectic” than for the “gray eutectic”.
Source: https://varimtutru.com/v-chem-otlichie-serogo-chuguna-ot-belogo/
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Cast iron
What is cast iron?
Cast iron is an alloy of iron and carbon obtained by smelting iron ore in blast furnaces.
Cast iron contains from 2 to 5% carbon. How are blast furnace cast irons divided depending on their chemical composition and purpose? Depending on the chemical composition and purpose, blast furnace cast iron is divided into pig iron, foundry cast iron and special cast iron.
How are cast irons separated depending on the nature of the carbon-iron compound?
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Depending on the nature of the combination of carbon with iron, cast iron is divided into white and gray.
What is characteristic of white cast iron?
The carbon in white cast iron is present in the form of cementite (FeO), so it is very hard and is practically not processed, but is used for conversion into steel and for other purposes. The fracture of white cast iron has a matte white color.
What is the state of carbon in gray cast iron?
In gray cast iron, all or part of the carbon is in a free state in the form of graphite, which gives it a gray or dark gray color when broken. Gray cast iron is the main foundry material; it has quite satisfactory mechanical properties, is cheap, has high casting properties and is well processed by cutting tools.
What is the designation for gray cast iron?
Gray cast iron is designated by two letters and two two-digit numbers separated by a dash. The letters SCH mean gray cast iron, the first two-digit number is the tensile strength, the second is the bending strength. For example, SCh 18-36 is gray cast iron, the tensile strength is 18, and the bending strength is 36.
How is modified cast iron different from regular gray cast iron?
Modified cast iron differs from ordinary gray cast iron in that it has improved mechanical and casting properties. It is obtained by adding graphitizing additives (ferrosilicon, elico-calcium or silicoaluminum) to liquid gray cast iron. Grades of modified cast iron: SCh 28-48, SCh 32-52, etc.
How is high-strength cast iron produced?
Ductile iron is produced from gray cast iron by ladle addition before casting into magnesium molds. The result is nodular cast iron, which has high mechanical and casting properties.
Grades of high-strength cast iron according to GOST 7293-54: VCh 45-0, VCh 45-5, VCh 40-10, VCh 50-1.5, VCh 60-2. The letters VCh mean high-strength cast iron, the first two digits indicate tensile strength , and the latter - the value of relative elongation during tension.
How is malleable cast iron obtained?
Malleable cast iron is produced by long-term annealing of white cast iron in special furnaces, after which graphite is formed in the cast iron instead of free cementite.
Grades of malleable cast iron according to GOST 1215-59: KCh 30-6, KCh 33-8, KCh 35-10, KCh 37-12, etc. The letters KCh mean malleable cast iron, the first two digits are the tensile strength, and the last are relative tensile elongation.
What parts are made from gray cast iron in crane construction?
In accordance with the “Rules for the design and safe operation of load-lifting cranes”, the following can be made from gray cast iron no lower than grade G4 15-42 according to GOST 1412-54 “Gray cast iron castings”: – gear, worm and running wheels of load-lifting cranes with manual drive; – worm wheels with a bronze rim, regardless of the type of drive and mode of operation of the crane; - drums, gearbox housings and blocks, with the exception of blocks of jib and tower cranes; – brake pads, drum brackets, bearing housings, etc.
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