What is steel?

Steel metal is an alloy composed of iron and 2% of its composition is carbon. If the amount of carbon is less than this limit, its characteristics will be close to iron, and if it is more, it will be called cast iron. All this is provided that at least 50% of the alloy is iron, otherwise it is not called steel at all. Steel production is an old industry whose history in the world goes back to several centuries and even in some regions to several millennia. What is important is the extensive and advanced production of steel, which is related to the last few decades. In 2013, the production of crude steel in the world was 1.6 billion tons. Today, steel is so important in infrastructure and industrial development that it is considered as a main indicator of countries' development. Ease of production and processing The abundance of two main materials for its production, namely iron ore (sponge iron) and scrap Relatively low construction cost An unparalleled range of mechanical properties such as ultimate tensile strength Wide applications in various industries, including infrastructure structures, building construction, automobile manufacturing, and the construction of large vehicles, the manufacture of tools, equipment and machinery, military equipment, etc. All these things make steel one of the most metals produced by mankind. Different types of steel can be classified in terms of chemical and physical properties, one of the most important and widely used of which is stainless steel sheet. To get to know the types of steel, one must first see what are the characteristics of steel.

Steel is composed of iron and carbon. In general, the percentage of carbon in steel is about 0.2 to 2.1%, and the amount of iron is more than 98%. These two elements are combined with each other in the form of an alloy to improve the mechanical properties, hardness and strength of steel.

The specifications of steel include the physical, chemical and mechanical characteristics and properties of this metal. These specifications are used to define and distinguish different types of steel and generally include the following: Chemical composition: It includes the percentage of different elements in steel, based on which steel is divided into different groups. The main elements in steel are iron (Fe), carbon (C), manganese (Mn), sulfur (S), phosphorus (P) and other less common elements. Physical properties: It includes properties such as density, melting point, boiling point, heat-absorbing efficiency, electrical conductivity and volume of paste. Mechanical properties: It includes properties such as tensile strength (pressure tolerance), tensile strength, hardness, flexibility and deformability. Thermal properties: includes properties such as thermal efficiency, thermal expansion coefficient and heat resistance. Electromagnetic properties: includes properties such as electrical resistance and magnetic resistance. Corrosion properties: includes properties such as resistance to rust and other chemical effects. Also, depending on the type of steel (carbon steel, alloy steel, etc.), more precise and detailed specifications can be seen, depending on how steel is used in different industries (construction, automotive, marine industries, etc.), the number and importance of each group of possible specifications is different Iron has taken the largest share in the composition of steel. Iron in the solid state is a polycrystalline metal. In the sense that it consists of many crystals that are stuck together. Refined molten iron becomes steel by adding carbon and some other metals such as nickel, manganese, chromium, titanium and vanadium in a certain amount. Some special steels may contain molybdenum or tungsten or other elements in their composition. Other metals that may be present in steel are silicon, cobalt, niobium, sulfur, phosphorus, calcium and lead. Iron and carbon are given a high temperature and these two combine together. Iron carbide called cementite is formed from their combination. Steel is formed by rapid cooling of cementite. The characteristic of steel is hardness and luster. This metal melts at a temperature of 1510 degrees Celsius, so it has a very high melting point. Its density is equal to 7.9 grams per cubic centimeter. The hardness of steel is higher than its basic element iron and it has a high tensile strength, which makes it not lose its shape and properties against the pressures applied to such simplicity. For this reason, the use of steel in all kinds of industries is many and unique. Of course, the level of resistance and hardness is different in different types of steel, and it should be seen what the alloy composition is in the steel and how it is set. In general, the alloy composition of all types of steel is such that they have more or less these characteristics: Ability to work hard abrasion resistance Heat resistance Toughness and strength The fineness of the microstructure Machinability

Steel making is done in various ways. One of them is the method of using iron and electric arc furnace. We already knew what the two main materials of steel are. Scrap and sponge iron are placed in the electric arc furnace. First, scrap iron enters the furnace, and after it is melted by creating an electric arc, sponge iron is added to it in the furnace. The physical characteristics of the scrap must be standard in order for the arc operation to take place properly. Otherwise, the following events may occur: Break the electrodes Explosion Melting and overflowing of steel

The use of steel is very wide and diverse according to its characteristics and types. We said that the types of steel are different in terms of the percentage of alloy and the type of compounds. This variety of types also has an effect on the use of steel. If we consider the smallest and most detailed industries (such as making workshop and kitchen tools) to huge industries (such as ship and airplane construction, oil and petrochemical refining, or building construction), the essential and irreplaceable role of steel occurs in them.