Classification by chemical composition:

Carbon steel: It is an alloy of iron and carbon. In addition to iron and carbon, it contains elements such as silicon, manganese, phosphorus and sulfur. According to different carbon content, it can be divided into low carbon (C<%), medium carbon (C:%%) and high carbon (C>%) steels

Steel with carbon content less than% is called industrial pure iron

Ordinary low alloy steel: add a small amount of alloy elements (such as silicon, calcium, titanium, nickel, boron and rare earth elements, the total amount of which shall not exceed 3%) on the basis of low-carbon plain carbon steel. The steel grades with better comprehensive properties are obtained

Alloy steel: It is a kind of steel containing one or more appropriate alloy elements, with good and special properties. It can be divided into low alloy according to the total content of alloy elements

(total amount< 5%), medium alloy (total amount of alloy is 5% - 10%) and high alloy (total amount> 10%) steels