carbon in 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://steelfactoryrus.com/soderzhanie-ugleroda-v-chugune-i-stali/
How much alcohol does beer contain?
Beer is a low-alcohol drink with a long history; in addition, it is the most popular in the world. There are many types of alcohol, they all differ in production techniques, as well as in strength, that is, the percentage of ethyl alcohol.
What is beer
This is a foamy drink that is produced on the basis of malt wort (from barley), with the help of brewer's yeast and hops. The average alcohol content in beer is 3-5.5%.
Creating foam is a complex technological process that includes the production of beer wort - malt is brewed with hops for several hours, yeast is added, and its maturation occurs. The duration of ripening depends on the brand, and can be from several days to several months.
Next, the foam goes through filtration, preservatives are added, and it can already be consumed. The following are formed in the finished foam: alcohol, phytoestrogens, carbon dioxide, fusel oils.
The best and highest quality is considered to be traditional foam, which contains nothing but barley, hops, yeast and water. In some varieties, barley is partially or completely replaced by wheat, rice, corn and rye grains.
Bottom-fermented foam is the most popular and main product on the market, accounting for 90% of total sales turnover. It is usually called lager, and the production has the same name - lager. Bottom fermentation occurs due to special yeast, and for a long time due to low temperature of 5-10 °C. The taste becomes very rich.
The duration of top fermentation is much shorter. Occurs at a temperature of 15-20 °C due to top-fermenting yeast, and takes little time. Varieties of this method include ale and porter.
alcohol in beer
The indicator on the label of intoxicating drink indicates the lower limit of the ethanol content in it. The manufacturer does not have the right to indicate the number of % or revolutions lower than it actually is. Therefore, the real figure is often higher.
In Russia and Europe, alcohol is measured in percent by volume (% vol.) Therefore, if we say that beer is 5%, this means that in 100 liters of beer there are 5 liters of pure alcohol. In America, it is customary to calculate ethanol in weight fractions (% wt.). Knowing that the specific gravity of alcohol is 0.78, you can calculate how much pure ethanol is in beer. To do this, you need to divide the indicated percentage by 0.78.
For example, if the strength is 3.5%, then in percentage by volume it will be 3.5: 0.78 = 4.5%. If, for example, the figure is 6% (in weight fractions), again this figure must be divided by 0.78, and we get 7.7%.
If it is important for a buyer to know how much alcohol is in a drink, the country of origin should be checked on the label. If this is America, then the pure ethanol will be higher than what is stated on the label due to the units of measurement. And don’t forget that in most cases the % is always slightly higher.
Types of beer by strength
The percentage of ethanol depends on the production process. Main types:
- Non-alcoholic. Contains 0.5-0.7% alcohol.
- Light - up to 2% ethanol.
- Classic. 3.5 – 7%.
- Strong 8-14%.
- Very strong - from 14%.
During the manufacturing process, after fermentation, classic beer usually contains 3.5 - 4.5% ethyl alcohol. After filtering, the percentage decreases. This process is necessary to remove any remaining yeast. Some filtration methods destroy the microflora of beer, thereby extending its shelf life. Exposure to high temperatures can also reduce the number of revolutions. The alcohol is heated to a certain temperature, as a result of which some of the alcohol evaporates.
To increase the percentage of alcohol in the drink, sugar is added and frozen. Typically, a high percentage of intoxicants has a direct relationship with the calories it contains. Lovers of strong beer, those suffering from obesity, type 2 diabetes, and people watching their figure need to take this fact into account.
Excess weight is affected not only by caloric content, but also by the phytoestrogens contained in intoxicating drinks - these are substances similar to sex hormones. They affect a person's weight and appearance. In men who abuse foam, the figure begins to change according to the female type - an enlargement of the mammary glands and hips, as well as the abdomen, occurs. Women develop excessive hair on their bodies and their voice becomes rougher.
Nonalcoholic beer
A soft drink still has a small number of revolutions, this figure ranges from 0.15 to 0.7%. To preserve the familiar taste and aroma, manufacturers use standard ingredients, but stop the process before full fermentation, and special filtration in this production is used to filter out ethyl alcohol. But it’s impossible to filter it 100%, so “non-alcoholic” intoxicating drinks are gaining momentum.
People who struggle with alcohol addiction, including those who are coded, need to be especially careful. Even such a low percentage of ethanol can trigger cravings for alcohol. In addition, all other components are contained in the drink in standard quantities, especially phytoestrogens. As with drinking a seemingly harmless drink, the load on the liver, kidneys and cardiovascular system is high.
It is not recommended to consume more than one can of non-alcoholic foam before driving. Also, use is contraindicated for pregnant, lactating women and children.
Strong intoxication
To prepare strong foam, special yeast is used, since in standard production the strength does not exceed 5%. The technology is also different - alcohol is repeatedly frozen to reduce the liquid, as a result of which the degree increases.
What percentage of alcohol in beer is the most popular strong:
- Hakusekikan Brewery - “Hurricane”, 15%. Manufactured in Japan. Its special feature is aging with barley wine.
- Bruery - “Chocolate Rain”, 19.5%. Belgium. A high percentage is achieved through fermentation in a whiskey tub.
- De Struise Brouwers - “Five Squared”, 25%. Scotland.
Source: https://cafebabaluba.ru/alkogolnye-napitki/skolko-v-pive-soderzhitsya-alkogolya.html
carbon in cast iron as a percentage
Today there is almost no area of human life where cast iron is not used. This material has been known to mankind for quite a long time and has proven itself excellently from a practical point of view.
Cast iron is the basis for a great variety of parts, assemblies and mechanisms, and in some cases even a self-sufficient product capable of performing the functions assigned to it. Therefore, in this article we will pay close attention to this iron-containing compound.
We will also find out what types of cast iron there are, their physical and chemical characteristics.
Definition
Cast iron is a truly unique alloy of iron and carbon, in which Fe is more than 90%, and C is no more than 6.67%, but not less than 2.14%. Carbon can also be present in cast iron in the form of cementite or graphite.
Carbon gives the alloy a fairly high hardness, however, at the same time, it reduces malleability and ductility. In this regard, cast iron is a brittle material.
Also, special additives are added to certain brands of cast iron, which can give the compound certain properties. Alloying elements can be: nickel, chromium, vanadium, aluminum.
The density of cast iron is 7200 kilograms per cubic meter. From which we can conclude that the weight of cast iron is an indicator that cannot be called small.
Historical reference
Iron smelting has been known to man for quite some time. The first mention of the alloy dates back to the sixth century BC.
In ancient times, cast iron was produced in China with a fairly low melting point. In Europe, cast iron began to be produced around the 14th century, when blast furnaces were first used. At that time, such cast iron was used for the production of weapons, shells, and parts for construction.
In Russia, cast iron production began actively in the 16th century and then rapidly expanded. During the time of Peter I, the Russian Empire was able to surpass all the countries of the world in terms of pig iron production, but after a hundred years it began to lose its position in the ferrous metallurgy market again.
Iron casting was used to create a variety of works of art back in the Middle Ages. In particular, in the 10th century, Chinese craftsmen cast a truly unique figure of a lion, whose weight exceeded 100 tons. Starting from the 15th century in Germany, and then in other countries, cast iron casting became widespread. Fences, trellises, park sculptures, garden furniture, and tombstones were made from it.
In the last years of the 18th century, cast iron was used to the maximum in Russian architecture. And the 19th century was generally nicknamed the “cast iron age”, since the alloy was very actively used in architecture.
Peculiarities
There are different types of cast iron, but the average melting point of this metal compound is about 1200 degrees Celsius. This figure is 250-300 degrees less than what is required for steel smelting. This difference is due to the fairly high carbon content, which leads to less close bonds with iron atoms at the molecular level.
At the time of smelting and subsequent crystallization, the carbon contained in the cast iron does not have time to completely penetrate the molecular lattice of the iron, and therefore the cast iron ends up being quite brittle. In this regard, it is not used where constant dynamic loads occur. But at the same time, it is excellent for those parts that have increased strength requirements.
Production technology
Absolutely all types of cast iron are produced in a blast furnace. Actually, the smelting process itself is a rather labor-intensive activity that requires serious material investments. One ton of cast iron requires approximately 550 kilograms of coke and almost a ton of water. The volume of ore loaded into the furnace will depend on the iron content. Most often, ore is used, which contains at least 70% iron. A lower concentration of the element is undesirable, since it will not be economically profitable to use it.
First stage of production
Iron smelting occurs as follows. First of all, ore is poured into the furnace, as well as coking coal grades, which serve to pump and maintain the required temperature inside the furnace shaft. In addition, during the combustion process, these products actively take part in the ongoing chemical reactions as iron reducers.
At the same time, flux is loaded into the furnace, serving as a catalyst. It helps the rocks melt faster, which promotes the rapid release of iron.
It is important to note that the ore undergoes special pre-treatment before loading into the furnace. It is crushed in a crushing plant (small particles melt faster). Afterwards it is washed to remove particles that do not contain metal. After which the raw material is fired, due to this, sulfur and other foreign elements are removed from it.
Second stage of production
Natural gas is supplied to the loaded and ready-to-use furnace through special burners. Coke heats the raw material. This releases carbon, which combines with oxygen to form an oxide. This oxide subsequently takes part in the reduction of iron from the ore. Note that as the amount of gas in the furnace increases, the rate of the chemical reaction decreases, and when a certain ratio is reached, it stops altogether.
Excess carbon penetrates the melt and combines with iron, ultimately forming cast iron. All those elements that have not melted end up on the surface and are eventually removed. This waste is called slag. It can also be used to produce other materials. The types of cast iron obtained in this way are called foundry and conversion.
Source: https://crast.ru/instrumenty/soderzhanie-ugleroda-v-chugune-v-procentah
White cast iron
White cast iron is a type of cast iron that contains carbon compounds. In this alloy they are called cementites.
This metal got its name due to its characteristic white color and shine, which is clearly visible at the fracture. This shine is manifested due to the fact that such cast iron does not contain large inclusions of graphite.
In percentage terms, it is no more than 0.3%. Therefore, it can only be detected by spectral or chemical analysis.
White cast iron
Composition and types of white cast iron
White cast iron consists of the so-called cementite eutectic. In this regard, it is divided into three categories:
- Hypoeutectic. These are alloys in which carbon does not exceed 4.3% of the total composition. It is obtained after complete cooling. As a result, it acquires the characteristic structure of such elements as pearlite, secondary cementite and ledeburite.
- Eutectic. Their carbon content is 4.3%.
- Hypereutectic white cast iron. exceeds 4.35% and can reach 6.67%.
In addition to the above classification, it is divided into ordinary, bleached and alloyed.
The internal structure of white cast iron is an alloy of two elements: iron and carbon. Despite high-temperature production, it retains a fine-grained structure. Therefore, if you break a part made of such metal, a characteristic white color will be observed.
In addition, in the structure of a hypoeutectic alloy, for example, hard grades, in addition to pearlite and secondary cementite, cementite is always present. Its percentage can approach 100%. This is typical for a eutectic metal.
For the third type, the structure is a composition of eutectic (Ep) and primary cementite.
One of the varieties of such alloys is the so-called bleached cast iron. Its basis, that is, the core, is gray or high-strength cast iron. The surface layer contains a high percentage of elements such as ledeburite and perlite. The whitening effect up to 30 mm deep is achieved using the rapid cooling method. As a result, the surface layer is white, and then the casting consists of an ordinary gray alloy.
White cast iron structure
Depending on the percentage of alloyed additives, the following types of metal are distinguished:
- low-alloyed (they contain no more than 2.5% alloying elements);
- moderately alloyed (the percentage of such elements reaches 10%);
- highly alloyed (in them the amount of alloying additives exceeds 10%).
Quite common elements are used as alloying additives. The alloyed white cast iron obtained in this way acquires new, predetermined properties.
Properties of white cast iron
Any cast iron alloy, on the one hand, is very strong, but at the same time it is quite brittle. Therefore, the main positive properties of white cast iron include:
- High hardness. This greatly complicates the processing of parts, in particular cutting.
- Very high resistivity.
- Excellent wear resistance.
- Good resistance to increased heat.
- Sufficient corrosion resistance, including to various acids.
White cast irons, with a reduced percentage of carbon, are more resistant to high temperatures. This property is used to reduce the number of cracks in castings.
Appearance of white cast iron
The disadvantages include:
- Low casting properties. It has poor mold filling. During pouring, internal cracks may form.
- Increased fragility.
- Poor machinability of castings and parts made of white cast iron.
- Large shrinkage, which can reach 2%.
- Low impact resistance.
Another disadvantage is poor weldability. Problems in welding parts made of this material are caused by the fact that during welding, cracks form, both during heating and cooling.
Marking of white cast iron
To mark white cast iron, letters of the Russian alphabet and numbers are used. If it contains impurities, then the marking begins with the letter “H”. The composition of the available alloying additives can be determined by the following letters P, PL, PF, PVK.
They indicate the presence of silicon. If the resulting metal has increased wear resistance, then its marking will begin with the letter “I”, for example ICHH, ICH.
For example, the presence of the designation “Ш” in the marking means that the alloy structure contains spherical graphite.
The numbers indicate the amount of additional substances present in white cast iron.
Brand CHN20D2ХШ is deciphered as follows. This is a heat-resistant high-alloy metal. It contains the following elements: nickel - 20%, copper - 2%, chromium - 1%. The remaining elements are iron, carbon, and spherical graphite.
Application area
This alloy is used in the following industries: mechanical engineering, machine tool building, shipbuilding. Some elements of household products are produced from it. In mechanical engineering, it is used to make parts for trucks and cars, tractors, combines and other agricultural machinery. The use of alloying additives makes it possible to obtain specially specified properties. For example, they are used in the manufacture of slabs with different surface shapes.
White iron casting
Bleached cast iron has a fairly limited scope. It is used to produce parts of simple configurations. For example: balls for mills, wheels for various purposes, parts for rolling mills.
It is widely used in the production of parts for such large units as hydraulic and molding machines, and other industrial mechanisms in this area. A specific feature of their work is that they are constantly exposed to abrasive material.
Source: https://stankiexpert.ru/spravochnik/materialovedenie/beliy-chugun.html
Cast irons: the role of carbon and silicon
Cast irons are ternary alloys of iron-carbon-silicon.
The main types of cast iron are: – gray cast iron ;
– white cast iron ;
– high-strength cast iron with nodular graphite;
- malleable cast iron.
Carbon and silicon in cast irons
Carbon is found primarily in the form of graphite in gray and ductile cast irons, as well as in ductile cast irons with nodular graphite. In white cast iron, carbon is present in the form of cementite Fe3C.
The type and shape of the carbon phase in cast iron is influenced by the silicon content. Increasing the silicon content makes it more difficult for cementite to form and thereby promotes the formation of graphite in gray, ductile and ductile cast irons.
Carbon equivalent for cast irons
When working with cast iron, the concept of carbon equivalent is often used. For cast irons, the carbon equivalent CE has the following form:
The figure below gives a graphical representation of the ratio of carbon and silicon content in various types of cast iron.
Figure 1 – Carbon and silicon content ranges
for various types of cast iron and silicon-containing steels
Note that the dotted line at the top of the figure shows the composition of any type of cast iron for which CE = 4.3%. The dotted line at the bottom of the figure reflects the ratio CE = 2.0% - it separates silicon-containing steels from cast irons.
For clarity, let's consider an iron-carbon alloy - cast iron, which contains no silicon at all. Then this alloy contains only iron + carbon and its location on the graph will be limited to a carbon content of 4.3%. From the phase diagram in Figure 2, it can be seen that this composition is exactly the eutectic composition for iron-cementite alloys and is very close to the eutectic composition of iron-graphite alloys.
Figure - Combined phase diagram of iron-graphite and iron-cementite
The upper dashed line in Figure 1 is a good interpretation of the change in eutectic composition with increasing silicon content in iron-carbon alloys. In general, if cast iron has a composition that is close to eutectic, the proportion of austenitic dendrites in them will be very small.
This means that when the carbon equivalent CE in cast irons falls well below 4.3%, the volume fraction of the solid phase in the form of dendrites increases.
Similarly, when the carbon equivalent CE approaches 4.3%, the proportion of the eutectic mixture increases - either austenite + graphite in gray cast iron, or austenite + cementite in white cast iron.
Properties of various cast irons
Source: https://steel-guide.ru/chuguny/chuguny-rol-ugleroda-i-kremniya.html
