Human communication with metals began a very long time. Already 4 thousand years BC. Enterian and ancient Egyptian civilizations used iron products. Scientists believe that it was an alloy of iron obtained from meteorites, and nickel. Since then, iron in one form or another began to play a huge role in the life of the inhabitants of the planet. People learned to find iron ore deposits and process it into metals with different properties.
And it is the possibility of obtaining materials with various properties, based on iron and various additives, that determined the dominant role of this metal by importance for humanity. Most often in our time, iron and carbon alloys are used. If the percentage of carbon in the gland is 2.14 % – this metal is called steel. The difference between this metal and others is that it has a specific property – steel can be hardened. The result of this action is that the properties and texture of the metal change in its process. The principle here is this – steel is heated to a certain temperature and cooled. If cooling passes quickly, in water or oil, then the steel is very solid and practically unable to process. If it is cooled slowly, then it becomes viscous, plastic and ready to change the form, that is, capable of processing tools. There are various ways of hardening steel. You can make surface hardening by strengthening only the upper layer of the product. You can act on steel with chemical ingredients, adding various beneficial properties to it. You can harden steel gradually, with a stepped method – this allows you to reduce the voltage inside the metal and saves it from cracks and warping. Metallurgists seek and find new methods of processing metal with the name steel to obtain more interesting properties in the interests of science and industry.
