Classification Of Structural Steel

Compared with ordinary carbon structural steel, high-quality carbon structural steel has a lower content of sulfur, phosphorus and other non-metallic inclusions. According to the different carbon content and use, this type of steel can be roughly divided into three categories:

1. Less than 0.25% C is low carbon steel, especially 08F, 08Al, etc. with carbon content less than 0.10%. Because of their good deep drawability and weldability, they are widely used as deep drawing parts such as automobiles and manufacturing. Tanks...etc. 20G is the main material for making ordinary boilers. In addition, low carbon steel is also widely used as carburizing steel for machinery manufacturing.

2. 0.25～0.60%C is medium carbon steel, which is mostly used in quenched and tempered state to make parts for machinery manufacturing industry. Quenching and tempering is 22~34HRC, which can obtain comprehensive mechanical properties and is also convenient for cutting.

3. High carbon steel greater than 0.6% C is used to make springs, gears, rolls, etc. According to the different manganese content, it can be divided into ordinary manganese content (0.25 ~ 0.8%) and higher manganese content (0.7 ～1.0% and 0.9～1.2%) two steel groups. Manganese can improve the hardenability of steel, strengthen ferrite, and increase the yield strength, tensile strength and wear resistance of steel. Usually, “Mn” is added to the grade of steel with high manganese content, such as 15Mn, 20Mn to distinguish it from carbon steel with normal manganese content.

The carbon content of carbon tool steel is between 0.65 and 1.35%. After heat treatment, high hardness and high wear resistance can be obtained. It is mainly used to manufacture various tools, cutting tools, molds and measuring tools (see tool steel).