In the ASTM, SAE, AISI standard, the representation method of carbon steel and alloy steel grades are basically the same. Generally use (a) four digits method, sometimes in the middle or the end of the letters. For example: 1005 hanjie xuebao/transactions B15, 3140, etc. Four digits in the first two digits said steel type and the main content of alloy elements. After the two figures show that the steel, the value of average carbon content is very few.

　　1. The first digit (or the first and second digits) said the following categories: 1, carbon steel, 2 - nickel steel, 3 - nickel chrome steel, 4 - molybdenum steel, 5 - chromium steel, chrome vanadium steel 61 -, 8 - low nickel chrome steel, 92, silicon manganese steel, 93, 94, 97, 98 - nickel chrome molybdenum steel.

　　2. The second digit (category number is 2 digits without the) said steel or alloy element content as follows:

　　Carbon steel: 0 - general carbon steel, 1 - free cutting steel, 3 - manganese steel.

　　Molybdenum steel: 1, chrome molybdenum steel, 3 and 7 - nickel chrome molybdenum steel, 6 and 8 - nickel molybdenum steel, 0, 4, 5 - Mo content different molybdenum steel.

　　Nickel and nickel chrome steel, expressed in percentage of the average nickel content.

　　Chrome steel: 0 - chromium content is low, 1 - chromium content is higher.

　　Low nickel chrome steel: 6, 7, 8, 1 must be nickel and chromium content, molybdenum content is different. 6 said molybdenum content is 0.15 ~ 0.25, 7 said molybdenum content is 0.2 ~ 0.3, eight said molybdenum content is 0.3 ~ 0.4, 1 molybdenum content is 0.08 ~ 0.15.

　　3. The third and fourth digits said the average carbon content, with a few per said.

　　Some steel grade intermediate inserted into the B/L: B - boron steel, L - steel with lead.

　　Add at the end of "H", said steel grade of hardenability have certain requirements. Some add lead letter "M" or "MT" : M - mechanical level, MT - mechanical tubing.

　　(2) stainless steel and heat resistant steel grades

　　This kind of steel mainly adopts AISI standard numbering system, brand is composed of three digits, the first digit the category of the said steel. The second and third digit serial number.

　　Steel category number: 1, precipitation hardening stainless steel, 2 - Cr - Mn - Ni - N austenitic steel, austenitic steel, 3 - CrNi 4 - high chromium martensitic and low carbon ferrochrome ferrite steel, 5 - low carbon martensitic steel.

　　(3) the ASTM/SAE tool steel grades

　　ASTM and tool steel grades in the SAE standard is composed of materials letters add digital serial number. For example, D7 and A10 F2, etc. See the category letter meaning in this section, the section "Britain and the United States" in the standard tool steel material categories.