The use of iron by man amounts toa long history. Metal ores are fairly widespread. The content of iron in the earth's crust is 4.1 percent, that is, in this parameter it is on the second place among metals and on the fourth among all elements. Therefore, there is nothing surprising in the fact that even before our era (the second millennium), a method for obtaining and further processing was found. In the future, technologies were improved, new methods of obtaining iron were opened, and gradually this metal began to occupy a leading place in material production.
The importance of iron is not limited only to the fieldmaterial production. It as a microelement is a part of hemoglobin - red color our blood has thanks to the presence of iron in it. Iron is necessary for the normal growth and development of plants, it takes part in oxidative processes and is part of the protoplasm.
Any substance, including iron, has its owncharacteristics. If you put one kilogram of this metal and one kilogram of down on the scales, then they will have the same weight, but only the volume will be completely incommensurable. The thing is that the density of iron is much greater than that of down. By density we mean the mass enclosed in a unit of volume. Each substance has its own density. At the water, for example, one thousand kilograms / cubic meter, ice has nine hundred kilograms / cubic meter.
The density is defined as the mass ratio koccupied space. The density is affected by several factors. So, it depends on the temperature. For many substances, the following relationship is valid: as the temperature decreases, the density increases, and when it increases, it decreases. True, there are a few exceptions from this rule, and one of them is water. Here everything is the opposite, as the temperature is lowered, its density decreases.
Because of this exception on Earth, there is life.Ice is lighter than water, and it sticks to the surface. Otherwise, he would have sank to the bottom, lay there and did not melt. And over time, all the seas and oceans would completely freeze. So it turns out that the concept of the density of substances makes it possible to draw an extremely curious conclusion about the possibility of life on Earth.
Density is largely dependent on the chemicalcomposition of matter. The maximum effect on the density of iron is provided by silicon and carbon. They reduce the density of pure iron, which is 7800 kilograms / cubic meter at room temperature. At the same time, the properties of iron depend on the carbon content. In fact, iron is used in alloys, especially with carbon - in various steels and cast irons.
Cast iron usually contains more than 2.14 percentcarbon, the carbon content in steel is lower (0.8-1%). The density of iron in these cases will be different. Solid cast iron has a density of 7000-7200 kilograms / cubic meter at ordinary temperature, steel under the same conditions has a density of 7500-7600 kilograms / cubic meter. Thus, steel in density is located between the iron and iron.
According to its characteristics, cast iron is fragile:if you hit it, it splits. Steel is obtained by processing pig iron in an oxygen converter. With such processing, the carbon content decreases, it is said to burn down. In its properties, steel is very different from cast iron. You can forge it, make a rental. The steel acquires additional properties thanks to additives, giving it the necessary characteristics - strength, flexibility, hardness.
In the given material sucha concept like the density of iron. The features of the change in the density of certain substances under various external conditions are described. Some properties of iron itself and its significance in material production, as well as a trace element in the body, are considered.
