Cast iron is one of the initial products in the manufacturing process, and its flow chart shows the importance of cast iron in the steel industry. Cast iron belongs to the family of ferroalloys and is one of the most widely used alloys in the industry.
Iron, carbon and silicon are the main elements of this alloy. Of course, certain amounts of metals and other elements (such as manganese, phosphorus, sulfur, etc.) can also be used in this alloy, their existence is not permanent and they are added to the casting depending on various factors and conditions. iron
Cast iron is available in the market in various forms and types. Each of these types has its own properties and characteristics. These features allow the use of cast iron in various industries
Cast iron is an iron alloy with a higher percentage of carbon and silicon than steel. This alloy is produced in white, gray, brittle, malleable and compact graphite.
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What is cast iron? Its difference with steel
Cast iron and steel are both iron alloys, but the presence of silicon in the cast iron mixture creates a difference between cast iron and steel and the characteristics and properties of both. First, we will cover cast iron completely, then we will examine its difference with steel.
History of cast iron production
Today, cast iron is less used in the construction industry, but there are still some cast iron tools that are used in the petrochemical and oil refining industries and have a reasonable price.
For example, due to its quality and strength, the price of cast iron valves in the market is very reasonable compared to other types of valves used in the petrochemical industry.
But about its history, it can be said that the main element of cast iron is more than 1000 years old. When iron was discovered in human life, it was used by people for various purposes.
Humans use iron to make agricultural tools, war weapons and other powerful tools they need. This made blacksmithing an important job at that time. Gradually, people thought of using iron in other ways.
For this reason, iron is melted and mixed with various materials. One of the materials that combine with molten iron is carbon. Years later, they added a new element called silicon to this composition and called it cast iron.
Cast iron was very popular and widely used in the 18th century, and in England, due to the large use of cast iron in building and construction, a style called cast iron construction was created.
Chemical composition of cast iron
As we said from the beginning, cast iron consists of three main elements and several secondary elements.
But when these elements are combined with each other, a certain amount of elements must be included in the composition so that cast iron maintains its properties and does not contain large amounts of impurities.
In this composition, iron has the largest share with about 92%. After that, carbon, which makes up about 2-4% of the composition of cast iron, and then 1-3% silicon, lead to the difference between steel and cast iron.
which remains about one percent, which is specific to less common elements in cast iron compounds.
Manganese
phosphorus
sulfur
Sometimes other elements (in different amounts) are added to cast iron to change its structure and properties. These elements are:
aluminium
magnesium
copper
sodium
Chrome alloy
vanadium
Other metals
Features of cast iron
The uniqueness and specialness of cast iron has made it popular and attention of many people. The following are among the most important properties of this alloy:
It turns from a solid to a liquid instead of a paste.
It can be hammered.
It is hard and fragile.
Rust happens later.
It is resistant to heat.
There are many types to cover a wide range of applications.
It has a reasonable price.
Your weight is heavy
Melting point of cast iron
The melting point of cast iron is lower than its constituent elements due to the presence of impurities in cast iron and the amount of impurities that enter its composition.
The melting point of cast iron is about 1420 to 1470 Kelvin. Used for its low melting point, flowability, castability, machinability and wear resistance, this compound has become an engineering material for a wide range of applications.
The difference between cast iron and steel
The main difference between steel and cast iron is in their composition. At first glance, steel and cast iron seem close because they are made from the same basic material called iron and have the same properties.
Silicon is a cast iron only ingredient that makes a big difference between cast iron and steel. The next point is the amount of carbon used in each alloy.
The percentage of carbon used in steel is less than 2%, while in cast iron this amount reaches 2 to 4%. Cast iron is also less flexible than steel.
One of the most important ways to distinguish between cast iron and steel is to perform a spark test. In this test, if the spark is low and red, the metal involved must be cast iron. But if the spark is white and long, the metal you are testing is steel.
This method is for beginners, but for professionals there are other inspection methods such as chip testing and bimetal surface observation.
cast iron flow chart
The pig iron flow chart provides a wide range of prices and price volatility. Among its various types, cast iron offers a variety of connections, each of which can exist and be effective in different sectors of the industry depending on the connections and capabilities they have.
white cast iron
White cast iron is produced by accelerating the cooling process of the metal and having a lower carbon content. Therefore, most of the carbon is deposited in a semi-stable form (cementite), which increases the hardness of cast iron.
If you look at white cast iron in broken form, it is silver. White cast iron is too brittle to be used in many industries. The only place you can see it is the windmill propeller.
White cast iron is not as good or as good as other types of cast iron. The reason for this is its higher freezing temperature than other types of cast iron. White cast iron is corrosion resistant and very economical.
gray cast iron
This cast iron is called gray cast iron because of the presence of flaky graphite inside it, gray can be seen after crushing. Gray cast iron is one of the most important and widely used alloys in cast iron.
There are two famous gray cast iron alloys named GG-20 and GG-25, which are used in automobile manufacturing, making pipes, valves and fittings, making pumps, making engine bodies and parts, equipment and industrial production. . device
In addition to the iron element used in it, the approximate percentage of gray cast iron elements is as follows:
Carbon: 3.5% to 4%
Sulfur: 0.06% or less
Silicon: 0.5 to 1.5%
Manganese: 0.2% to 0.8%
Phosphorus: 0.1 percent or less
Cast iron flow chart
