Meaning of element symbols of alloy steel pipes

The steel grade is referred to as steel grade, which is the name of each specific steel product and a common language for people to understand steel. my country’s steel grade representation method generally adopts a combination of Chinese phonetic letters, chemical element symbols and numbers.

Below we will introduce the meaning of each element and symbol in alloy steel materials.

1. The first two digits of the steel grade represent the carbon content of the steel, expressed in ten thousandths of the average carbon content, such as 40Cr.
2. The main alloying elements in steel, except for individual micro-alloying elements, are generally expressed in percentages. When the average alloy content is <1.5%, the steel number generally only indicates the element symbol without indicating the content. However, in special cases where confusion is likely to occur, the number “1” can also be marked after the element symbol, such as the steel numbers “12CrMoV” and “12Cr1MoV”. The former has a chromium content of 0.4-0.6%, and the latter has a chromium content of 0.9-1.2%. The rest of the components are the same. When the average alloy element content is ≥1.5%, ≥2.5%, ≥3.5%, etc., the content should be indicated after the element symbol, which can be expressed as 2, 3, 4, etc. For example, 18Cr2Ni4WA.
3. Alloy elements such as vanadium V, titanium Ti, aluminum AL, boron B, and rare earth RE in steel are all micro-alloying elements. Although the content is very low, they should still be marked in the steel number. For example, the vanadium content in 20MnVB steel is 0.07-0.12%, and the boron content is 0.001-0.005%.
4. Steel should be marked with “A” after the steel number to distinguish it from general steel.
5. For special-purpose alloy structural steel, the steel number should be prefixed with (or suffixed with) a symbol representing the purpose of the steel. For example, the 30CrMnSi steel used for rivets and screws is represented by the steel number ML30CrMnSi.
6. For low-alloy high-strength steel, the steel number should be indicated. For example, 16Mn steel, the special steel used for bridges is “16Mnq”, the special steel used for automobile beams is “16MnL”, and the special steel used for pressure vessels is “16MnR”.