1. The representation of cast steel grades

Cast steel grades can be represented in two ways: the content of major elements and the intensity grades, and for cast steel for special purposes, some countries add specific letters for distinction on the basis of the two ways. 

2. China's cast steel brand representation (according to GB/T5613-1995)

Except for the cast carbon steel and high-strength steels for general engineering and structural use, China cast steel grade are expressed by the main element content method. And regardless of which method is adopted, ZG is used before grade to indicate the cast steel. 

(1) The cast carbon steel and high-strength steel used for general engineering and structures: add two groups of figures after ZG. The first group represents the yield strength and the second group represents the tensile strength. The two groups are separated by "一".

(2) Cast alloy steel: A set of figures is used behind ZG to indicate the nominal carbon content (per ten thousand). Cast steel with an average carbon content of more than 1% is not marked with average carbon content; cast steel with an average carbon content of less than 0.1% is marked with “0” in nominal content; only the upper limit of carbon content is given, cast steel without a lower limit uses upper limit to express the nominal carbon content. Thereafter, the major alloy element symbols are arranged in order, and the nominal percentage content of each element is represented by an integer after the corresponding element symbol.

When the average content of manganese element is less than 0.9%, the symbol of the element is not marked; when the average content is 0.9% to 1.4%, only mark the symbol but not indicate the content.

When the average content of molybdenum is less than 0.15%, and when the average content of other elements is less than 0.5%, the symbol of the element is not marked; when the average content of molybdenum is 0.15% to 0.90%, and when the average content of other elements is 0.5% to 0.90%, only mark element symbol without content; when the average content is 0.9% to 1.4%, the number 1 is added after the symbol of the element.

When the average content of titanium and vanadium is less than 0.9%, when the average content of trace elements such as niobium, boron, nitrogen, and rare earth is less than 0.5%, only the symbols of other elements are marked, and the content is not marked.

When there are more than three kinds of major alloying elements, can only mark the nominal content of the first two or the first three elements.

For example:

ZG: Cast steel 

15: Carbon content

Cr: Chromium

1: Chromium content

Mo: Molybdenum

1: Molybdenum content

V: Vanadium (V<0.9%)