Commonly used metal material grade representation (III)

Alloy structural steel and alloy spring steel grades are expressed

–Alloy structural steel grades using Arabic numerals and standard chemical element symbols

Two Arabic numerals to indicate the average carbon content (in parts per million), placed in the head of the grade. The alloying element content is expressed as follows: the average content of less than 1.50%, the grade is only marked elements, generally not marked content; average alloy content of 1.50% ~ 2.49%, 2.50% ~ 3.49%, 3.50% ~ 4.49%, 4.50% ~ 5.49%, ……, when the alloying element After the corresponding written 2, 3, 4, 5 ……. For example, if the average content of carbon, chromium, manganese, and silicon is 0.30%, 0.95%, 0.85%, and 1.05% respectively, the grade is “30CrMnSi” when the content of S and P is ≤0.035% respectively. High-quality alloy structural steel (S, P content ≤ 0.025% respectively), the symbol “A” is added at the end of the grade. For example: “30 CrMnSiA”. Premium quality alloy structural steel (S ≤ 0.015%, P ≤ 0.025%), add the symbol “E” at the end of the grade, for example: “30CrMnSiE”.

Special alloy structural steel grades should be added to the head (or tail) of the grade to represent the symbols of product use.

–Alloy spring steel grades are expressed in the same way as alloy structural steel

For example, the average content of carbon, silicon, and manganese is 0.60%, 1.75%, 0.75% of the spring steel, the grade is expressed as “60Si2Mn”. High-quality spring steel, the symbol “A” added to the end of the grade, the grade is “60Si2MnA”.

Commonly Used Metal Material Grades

Free-cutting steel grades are expressed

Free-cutting steel using standard chemical element symbols, the symbols specified in Table 1 and Arabic numerals. Arabic numerals indicate the average carbon content (in parts per million).

a, add sulfur free-cutting steel and add sulfur, phosphorus free-cutting steel, in the symbol “Y” and Arabic numerals after the symbol of free-cutting elements without. For example, the average carbon content of 0.15% of the free cutting steel, grade is shown as “Y15”.

b, higher manganese content of sulfur or sulfur, phosphorus free cutting steel in the symbol “Y” and the Arabic numerals followed by the symbol of manganese elements. For example, the average carbon content of 0.40%, manganese content of 1.20% ~ 1.55% of the free-cutting steel, the grade is expressed as “Y40Mn”.

c, containing calcium, lead, and other free-cutting elements of free-cutting steel, in the symbol “Y” and Arabic numerals followed by free-cutting elements symbol. For example: “Y15Pb”, “Y45Ca”.

–Non-hardened mechanical structural steel grades, the symbols “YF” and “F” are added to the head of the grade to indicate free-cutting non-hardened mechanical structural steel and Hot forging with non-quenched mechanical structural steel, the other elements of the grade representation and alloy structural steel the same. For example: “YF35V”, “F45V”.