Steel is the most common metallic material in industry, on the basis of which structures and tools with specified properties are made. Many of its physical properties, including density, change depending on the purpose of this material. In this article, we consider the density of steel in kg / m3.
What is steel, and what is it?
Before we give the table, the density of steel in kg / m3, get acquainted with the material itself. Steel in metallurgy is an alloy of iron with carbon, the content of which does not exceed 2.1 atomic percent. If there is more carbon, then graphite begins to form in the system, which leads to a sharp change in the properties of the alloy. In particular, its hardness and brittleness increase, and ductility decreases. If there is more carbon than 2.1%, then the alloy is called cast iron.
The main thing to understand is that steel is an alloy of iron with other elements that act as impurities. If iron is not the main component, then such an alloy is not steel.
They have become very different. Thus, a low carbon content leads to the formation of a class of structural materials. Its higher content forms a class of tool steels. In addition to carbon, there are materials doped with various elements. For example, the addition of more than 13% chromium leads to the formation of stainless materials, and the high content of molybdenum and tungsten forms a class of cutting steels.
What determines the density of steel?
There are a number of factors that determine the density of steel in kg / m3. These include the following:
- the density of iron proper for a given crystal lattice;
- amount and type of impurities;
- the presence of phases.
Of these factors, the first is the most important, since it is iron that is the basis of the alloys under consideration. As is known, it can exist in two crystal lattices: bcc (volume-centered cubic) and fcc (face-centered cubic).
The first type of lattice forms the so-called ferritic steels, the second - austenitic. The fcc lattice is close packed, while the bcc lattice is a more loose packing of atoms. However, the density of ferritic steels is usually higher than austenitic. The reason for this is simple, the fact is that fcc is a stable structure only at high temperatures for pure iron, and all metals expand strongly when heated. The latter leads to a decrease in density.
Carbon steel
What is the density of carbon steel? In general, we can say that it is slightly lower than the density of pure bcc iron (7874 kg / m 3 ). This insignificant decrease is due to the fact that the carbon in the bcc lattice occupies the octahedral pores. The density of carbon itself in the structures of diamond and graphite is very low, so its addition to iron reduces its average density. Since carbon atoms occupy large octahedral pores, they slightly increase the average lattice parameter, which affects a small decrease in the considered parameter. The table below shows the density of steel in kg / m3 depending on the grade and temperature.
Alloy steels
As was said, these include any iron-based alloys that, in addition to carbon, contain other elements, for example, chromium, nickel, tungsten, vanadium, and so on. Thus, the density of stainless steel 12X18H9, containing, in addition to chromium, nickel, at room temperature is 7900 kg / m 3 , which is higher than that of pure bcc iron. If there is no nickel in the stainless steel, then its density will be lower than that of pure iron, since the chromium atom is lighter than iron.
The most dense are high-speed steels. They contain large quantities of heavy metals such as molybdenum and tungsten. Their density can reach 8800 kg / m 3 .