Instruction
1
So, in the marking of steel are the following elements of the notation:

N – Nickel, X – chromium, M – molybdenum, T – titanium, cobalt, D copper, silicon, G – manganese.
2
To specify the methods of deoxidation of steel are also used letter designations: SP – quiet steel, SS – balanced, KP – boiling.
Your notation there are different types of steel depending on the composition and appointment.
3
Non-alloy structural steel of ordinary quality are indicated by the letters ST. (for example, ART.4, where figure 4 after the letters indicates the carbon content in percent).
4
Non-alloy structural steel high quality are indicated by a two-digit number that indicates the average content of carbon in steel (ST.10)
5
Quality steel for manufacturing high pressure vessels and boilers represent as well as structural and non-alloy steel, add the letter K (for example, 20K).
6
Alloy structural steel designate an alphanumeric code. The numbers after the letters indicate the approximate content of the element (but the content of alloying elements less than 1.5% figure is not put).
7
A low content of impurities (sulphur, phosphate) are denoted by the letters A or W at the end of the markings (e.g., 17ХГ-W).
8
To the designation of casting of structural steel in the end is added the letter L.
9
The designation of structural steel there is a letter and numbers that correspond to the minimum yield point of steel. Additionally, at the end put T for heat-strengthened rolled, for superior corrosion resistance, D to denote a high content of copper (for example, 354).
10
Non-alloy tool steel divided into qualitative (denoted by the letter U and the numeral indicating the average carbon content, for example, U9) and high-quality in the marking which is placed the letter a at the end of the labeling (e.g., U9A).
Alloy tool steels indicate in the marking the same as a structural alloy (for example, 3Х2В5МФ).
11
Marking high-speed steels starts with the letter R, then there is a digit indicating the content of tungsten. If the vanadium content exceeds 2.5%, indicated by the letter f and the corresponding digit (e.g., Р5М6Ф3).
12
Knowing these rules, you can easily determine the composition of a particular steel, and an experienced professional transcript grades of steel and is simple and intuitive.