Carbon is the main alloying element of steel materials, so steel materials can also be called iron-carbon alloys. The main functions of carbon in steel are:
1) Form a solid solution structure to improve the strength of steel, such as ferrite and austenite structures, both of which contain dissolved carbon elements;
2) The carbide structure formation can improve steel’s hardness and wear resistance. For example, cementite, namely Fe3C, is a carbide structure.
Therefore, the higher the carbon content in steel, the higher the strength and hardness of the steel, but the plasticity and toughness will also decrease; conversely, the lower the carbon content, the higher the plasticity and toughness of the steel, and its strength. , the hardness will also decrease accordingly.
Therefore, the carbon content determines the use of steel:
Low carbon steel (carbon content <0.25%), generally used as profiles and stamping materials;
Medium carbon steel (carbon content <0.6%), generally used as mechanical parts;
High carbon steel (carbon content >0.7%) is generally used as tools, cutters, molds, etc.
