Designation and interpretation of steel grades according to GOST
Designation and interpretation of steel grades according to GOST
In Russia and the CIS, an alphanumeric system is adopted, numbers indicate the content of steel elements, and letters - the name of the elements. Letter designations are also used to indicate the method of deoxidation of steel; KP - boiling steel, PS - semi-calm steel, SP - calm steel. There are certain designation features for different groups of building steels, structural, stainless, tool steels, etc. Common designations for all are the letter designations of alloying elements: H - nickel, X - chromium, K - cobalt, M - molybdenum, B - tungsten, T - titanium, D - copper, G - manganese, C - silicon.
(GOST 380-94) denote the letters ST., for example ST. 3. The number after the letters conventionally indicates the percentage of carbon in steel. Structural unalloyed quality steels (GOST 1050-88) are designated by a two-digit number indicating the average carbon content in steel (for example, ST. 10). Quality steels For the production of boilers and pressure vessels, (GOST 5520-79), they are designated as structural unalloyed steels, but with the addition of the letter K (for example, 20K). Structural alloyed steels (GOST 4543-71), denoted by letters and numbers. The numbers after each letter indicate the approximate content of the corresponding element, however, if the content of the alloying element is less than 1.5%, the figure after the corresponding letter is not put. Qualitative additional indicators, the reduced content of impurities such as sulfur and phosphate are indicated by the letter - A or W, at the end of the designation, for example ( 12 X NZA, 18HG-Sh), etc. Cast structural steels (GOST 977-88), are designated as high-quality and alloyed, but at the end of the name they put the letter L. Construction steels (GOST 27772-88), denoted by the letter C and numbers corresponding to the minimum yield strength of steel. Additionally, the designations are used: T - heat-strengthened rolled products, K - increased corrosion resistance, (for example, C 345 T, C 390 K, etc.). Similarly, the letter D denotes an increased copper content. Bearing steels (GOST 801-78), are designated the same as alloyed, but with the letter Ш at the end of the name. It should be noted that for steels of electroslag remelting, the letter Ш is denoted by a dash (for example, ШХ 15, ШХ4 -Sh). Unalloyed tool steels (GOST 1435-90), are divided into quality, designated by the letter U and a number indicating the average carbon content (for example, U7, U8, U10) and high quality, designated by the additional letter A at the end of the name (for example, U8A) or an additional letter G, indicating an additional increase in the content of manganese (for example, U8GA). Alloyed tool steels (GOST 5950-73) are also designated as structural alloyed steels (for example, 4X2V5MF, etc.). High-speed steels They have the letter P in their designation (this is the starting point for the designation of steel), followed by a number indicating the average tungsten content, and then letters and numbers that determine the mass content of elements. The chromium content is not indicated, since it is stable about 4% in all high-speed steels and carbon, since the latter is always proportional to the vanadium content. It should be noted that if the vanadium content exceeds 2.5%, the letter F and the number are indicated (for example, steel R6M5 and R6 M5F3). Standard stainless steels (GOST 5632-72), marked with letters and numbers according to the principle adopted for structural alloy steels (for example, 08X18H10T or 16X18H12S4TUL). Non-standard stainless steels pilot batches denoted by letters - the indexes of the manufacturer's plant and serial numbers. EI, EP, EK - to the steels smelted at the Elektrostal plant, ChS - to the steels smelted at the Chelyabinsk plant Mechel, DI - to the steels smelted at the Dneprospetsstal plant. To indicate the method of smelting, finishing, the names of a number of steels are supplemented with letters (for example, 13X18N10-VI), which means vacuum induction smelting.