What does steel and alloy grade mean?

Structure of alloys

If you look at a metal with a powerful electron microscope, you can see the densely packed structure of the crystal lattice. In addition to the atoms of the base metal, there are also atoms of alloying additives throughout the structure of the alloy.

Substitution Alloys

If the atoms of the alloying element replace the atoms of the base metal within the crystal lattice, we get substitution alloys. An alloy is formed only when the atoms of the base metal and the atoms of the alloying agent are about the same size. In most substitution alloys, the alloying elements are close together in the periodic table. Brass, for example, is a copper-based alloy in which 10-35% of copper atoms are substituted for brass atoms Brass works as an alloy because copper and zinc are close together, in the periodic table, and have atoms of approximately the same size.

Interstitial alloys

Also, alloys are obtained if the alloying agent or agents have atoms that are much smaller than those of the base metal. In this case, the atoms of the alloying agent fall into the gaps as well, giving an interstitial alloy. Steel is an example of such an alloy in which a relatively small number of carbon atoms are arranged in the gaps between the larger iron atoms in the crystal lattice.

Steel Alloy Labeling

The grade of a steel alloy can be designated by an alphanumeric abbreviation. Each of the letters denotes a specific element included in the alloy.

Identification	Element	Name
Б	Nb	niobium
В	W	tungsten
Г	Mn	manganese
Д	Cu	copper
Е	Se	selenium
Л	Be	beryllium
М	Mo	molybdenum
Н	Ni	nickel
Р	Ce	cerium
С	Si	silicon
П	P	phosphorus
Ф	V	vanadium
Х	Cr	chromium
Ц	Zr	zirconium
Ю	Al	aluminum

Ion implantation - technology of introducing atoms of alloying elements into a surface layer of a tape or foil by bombarding the surface with a high energy beam (10-2000 keV); it is used to produce semiconductors with required properties, donor or acceptor sites and low-resistance contacts. Ion implantation is also used for metal alloying in order to make the surface layer hard and wear resistant.

Thermal diffusion is a technology of introducing atoms of alloying elements into the alloy under the influence of temperature gradient. This phenomenon was discovered in 1856 by the German chemist K. Ludwig and studied by the Swiss scientist S. Saure.

For the newcomer to the rolled metal market, the question "what does steel grade mean?" is one of the first questions. In the enormous variety of iron-carbon alloys, the brand serves as one of the simplest reference points in the field of application of each specific product. Thus, the following steel grades are distinguished:

-for castings;

-for castings; -constructional;

-instrumental;

-special purpose;

-fireproof;

-Rustproof; -Stainless;

-precision;

-electrotechnical.

The easiest way to find out what an alloy grade means is to refer to GOST standards (regarding domestic products, of course). Thanks to the approved standards it is possible to find out not only the composition of the alloy, but also its relevant characteristics.

To get general information about rolled metal of foreign production, it is necessary to have access to AISI standards or their analogues. If you are interested in heat-resistant stainless steel pipe, sheet, bar, plate or circle, the manager of Auremo will be happy to answer all your questions.