Steel is in a state of mixture with iron and carbon. Steel can be considered as purified iron in essence. It retains the metal properties of iron but also has a carbon content ranging from 0.002% to 1.7%. Metal and non-metallic elements are often added in the production process. The addition of carbon and other alloying elements increases physical-chemical properties such as strength, resistance and variability. These developments make steel one of the most widely used materials in the world.

The History of Steel

The development of steel dates back about 4000 years ago. There is information that the blacksmiths of the Hittites obtained steel by forging the iron in the coal fire. Before the Renaissance, many ineffective methods were used in steel production. In parallel with the development of technology, steel production methods have also changed. In the light of these developments, pig iron with high carbon content started to be produced in Germany and England by increasing the amount of carbon in its content by applying surface hardening process. Modern steel production has developed in parallel with advances in technology.

How is Steel Produced?

Steel is basically made of carbonated iron and some other elements sprinkled into it. With the development of technology, today there are mainly two ways of producing steel: These are the Oxygen Furnace method and the Electric Arc Furnace (EAF) method. The Oxygen Furnace method uses raw material inputs to form steel. As the oxygen passes through the molten metal, it reacts with the carbon, releasing carbon dioxide and producing a purer iron. It reduces the carbon content and reduces the purity in iron, turning it into steel.

The EAF method uses recycled scrap steel, which is a more modern approach. Instead of using raw materials such as recycled steel, iron ore, it is fed from high-power electric arcs and melted into high-quality steel. Although the two methods are different, they give the same molten steel result.

After the steel is obtained, a second steel production process is entered. This includes the process of adding, removing certain elements and changing the temperature production environment. After this process is completed, the production, manufacturing and finishing stages can be completed. This includes techniques such as cold rolling, coating (galvanizing) or heat treatment (annealing), which give the steel its final shape and properties.

What are the Properties of Steel?

• The chemical composition of steel is suitable for welding.
• It is both harder and lighter than iron.
• Electrical, mechanical and physical properties can be gained by applying heat treatment.
• Its resistance and hardness to high temperatures can be increased by various processes.
• It can be molded into the desired shape by forging, pressing and rolling methods at a certain temperature.
• Steels with certain properties can also be cold formed.
• It can be coated with plastics and metals.
• When hot steel is suddenly quenched, it hardens by changing its crystalline properties.
• Stainless steels are resistant to corrosion and heat, 100% recyclable, easy to manufacture and clean.
• Alloy steels with high carbon content are called ’cast iron”. Steels with low carbon and iron slag are called ‘forged iron’.
• As the amount of carbon increases, the yield and tensile strength of steel increases, while its welding and forming capabilities decrease.