◇ Introduction to the Designation Method of Steel Grades in China (GB)
The current system for designating steel product grades in China is based on two recommended national standards: GB/T 221-2008 "Designation Method of Steel Products" and GB/T 17616-2013 "Unified Numerical Code System for Steels and Alloys". The former employs a naming method that combines Chinese pinyin, chemical element symbols, and Arabic numerals. The latter, on the other hand, has established a systematic numerical coding system. The standard stipulates that all steel and alloy products listed in national or industry standards should be assigned both a brand name and a unified numerical code, which are used in parallel and correspond to each other.
◇Commonly Used Query Comparison Table:
1. Common Chemical Element Symbols in Steel Materials (GB/T 221-2008) are shown in Table 1.
2. Boundary Values of Specified Element Contents for Non-alloy Steels, Low-alloy Steels and Alloy Steels (GB/T 13304.1-2008) are shown in Table 2.
3. Symbols for the Names, Uses, Characteristics and Process Methods of Steel Products (GB/T 221-2008) are shown in Table 3.
Table1. Common Chemical Element Symbols
元素名称Element Name | 化学元素符号 Symbols | 元素名称Element Name | 化学元素符号Symbols | 元素名称Element Name | 化学元素符号Symbols |
铁 | Fe | 锆 | Zr | 硫 | S |
锰 | Mn | 锡 | Sn | 磷 | P |
铬 | Cr | 铅 | Pb | 铝 | Al |
镍 | Ni | 铋 | Bi | 铌 | Nb |
钴 | Co | 铯 | Cs | 钽 | Ta |
铜 | Cu | 钡 | Ba | 镧 | La |
钨 | W | 钐 | Sm | 铈 | Ce |
钼 | Mo | 锕 | Ac | 钕 | Nd |
钒 | V | 硼 | B | 氮 | N |
钛 | Ti | 碳 | C | 氧 | O |
锂 | Li | 硅 | Si | 氢 | H |
铍 | Be | 硒 | Se | 混合稀土 | RE |
镁 | Mg | 碲 | Te |
|
钙 | Ca | 砷 | As |
Table 2 Specified Content Limits for Elements in Non-alloy Steel, Low-alloy Steel and Alloy Steel
Alloy element | The specified content limits for alloying elements % |
Non-alloy steel | Low-alloy steel | Alloy steel |
ΑΙ | ＜0.10 | No regulations | ≥0.10 |
B | ＜0.0005 | No regulations | ≥0.0005 |
Bi | ＜0.10 | No regulations | ≥0.10 |
Cr | ＜0.30 | 0.30～<0.50 | ≥0.50 |
Co | ＜0.10 | / | ≥0.10 |
Cu | ＜0.10 | 0. 10～<0.50 | ≥0.50 |
Μn | ＜1.00 | 1.00～< 1.40 | ≥1.40 |
Μo | ＜0.05 | 0.05～<0.10 | ≥0.10 |
Νi | ＜0.30 | 0.30～<0.50 | ≥0.50 |
Nb | ＜0.02 | 0.02～< 0.06 | ≥0.06 |
Pb | ＜0.40 | No regulations | ≥0.40 |
Se | ＜0.10 | No regulations | ≥0.10 |
Si | ＜0.50 | 0.50～< 0.90 | ≥0.90 |
Te | ＜0.10 | No regulations | ≥.010 |
Ti | ＜0.05 | 0.05～< 0.13 | ≥0.13 |
W | ＜0.10 | No regulations | ≥0.10 |
V | ＜0.04 | 0.04～< 0.12 | ≥0.12 |
Zr | ＜0.05 | 0.05～< 0.12 | ≥0.12 |
The La series (for each element) | ＜0.02 | 0.02～<0.50 | ≥0.05 |
Other specified elements (Except for Ρ, S, C, and Ν) | ＜0.05 | No regulations | ≥0.05 |
Note 1: The content of La series elements can also refer to the total content of mixed rare earths. |
Note 2: When Cr, Cu, Mo, Ni (Nb, Ti, V, Zr) are among the four elements, and two, three or all four of these elements are specified in the steel, for low alloy steel, the specified content of each of these elements should be considered simultaneously. The total of the specified contents of all these elements should not exceed 70% of the sum of the highest limit values of each of the two, three or four specified elements. If the total of the specified contents of these elements exceeds 70% of the sum of the highest limit values of each of the specified elements, even if the specified content of each element is lower than the highest limit value, it should still be classified as alloy steel. |
Table 3: Names, Uses, Characteristics and Main Process Symbols of Steel Products
Product Name | Letter | Product Name | Letter |
Carbon structural steel, low alloy structural steel | Q | Weather-resistant steel | NH |
Hot-rolled plain steel bar | HPB | High weather-resistant steel | GNH |
Hot-rolled ribbed steel bar | HRB | Steel for automotive beams | L |
Fine-grained hot-rolled ribbed steel bar | HRBF | High-performance building structure steel | GJ |
Cold-rolled ribbed steel bar | CRB | Low weld crack sensitivity steel | CF |
Reinforcing steel for prestressed concrete | PSB | Steel for ensuring full hardening | H |
Steel for welding gas cylinders | HP | Mining steel | K |
Pipeline steel | L | Ship steel | International symbol |
Ship anchor chain steel | CM | Boiling steel | F |
Coal mining steel | M | Semi-static steel | b |
Steel for boilers and pressure vessels | R | Static steel | Z |
Steel for boilers (tube) | G | Special static steel | TZ |
Steel for low-temperature pressure vessels | DR | Quality grade | A/B/C/D/E |
