What are the marks of steels. Explanation of symbols

Steel is the most numerous group of metals used, and their labeling depends on the classification group.

What are the steel grades

The decoding of the brand begins with the definition of its main group by designation. The following groups of steels differ: structural, construction, tool, with special properties (heat-resistant, heat-resistant and high-strength).

From structural steels , machine parts, rolled products, welded structures are manufactured. Instrumental, as the name implies, is used to produce a machining tool. A special kind of tool steels are high-speed steels, they are designed for processing at higher loads. Structural steels, used mainly for welded structures, are characterized by low (up to 0.25%) carbon content. The composition is close to structural.

Structural steels

In their composition, they are divided into alloyed and carbonaceous, that is, with special impurities and without them. In alloy steel should contain at least 45% of iron. An important property is the presence of extraneous non-metallic impurities in the resulting alloy - sulfur, phosphorus and others. The less they are contained, the better metal is considered. There are 4 quality groups:

At the end of the designation, the type of deoxidation of the alloy (deoxidation-removal of oxygen from the steel composition) can be indicated: boiling (CP), half-quiet (PS), calm (SP). The SP index is usually not indicated.

In the general case, the decoding of the steels belonging to the doped group can be represented as follows:

- [carbon content] [alloying elements] [deoxidizing method] [additional characteristics], where the carbon content is written in hundredths of a percent.

Alloying elements are indicated as a combination of their letters and numbers in percent. If the content of the element in the alloy is less than a percent, its quantity is not indicated. At present, the following designations are used for inclusions: H - nickel, X - chromium, C - silicon, titanium - T, manganese - G, S - aluminum, etc. For example, 09G2S steel has 0.09% Carbon, 2% manganese and silicon in an amount of about 1%. In addition, there are some additional designations for the steel grade, their decoding is as follows:

1. "Sh" in the beginning - bearing steel.

2. "L" at the end - steel foundry.

3. "A" in the beginning - steel automatic.

4. "E" in the beginning - steel electrotechnical.

Separately distinguish the building marks of steels. The decoding looks like this: in the beginning, the letter "C" is put, after which the yield strength is indicated. The letter "K" means a variant of chemical composition, "T" means thermal hardening.

The marking of steels with special properties is similar to the marking of structural alloyed steels.

Tool steels

Before the designation is put the letter "Y", followed by the share of carbon (the minimum amount of carbon should be at least 0.7%). Tool steel as well as structural steel are divided into carbon and alloyed, but have only 2 quality groups - high-quality and high-quality. In the second case, the name is put the letter "A" at the end of the designation. The letter "G" indicates an increased content of manganese. Decoding of steel grades related to tool-cutting high-speed ones is somewhat different. In the first place is the designation of the whole group - the letter "P" (from the English word "rapid" - fast), then the amount of the basic alloying component - tungsten (its letter designation is skipped) is indicated.

Indication of the method of steel production

For high-quality alloys at the end of the designation, the method for producing steel grades is indicated, the decoding of the manufacturing methods is given below. These codes are placed at the end of the designation: VD - vacuum arc; Ш - electroslag; EL - electron beam; VI - vacuum induction.