What material is structural steel?

Structural steel is steel that meets specific strength and formability grades. Formability is expressed as the elongation after interruption of the tensile test. Structural steel is often used for bearings and other applications where the strength of the steel is an important design criterion.
The carbon content is about 0.05%~0.70%, and in some cases can be as high as 0.90%. It can be divided into ordinary carbon structural steel and high-quality carbon structural steel. The former has many impurities and is low in price. Used in places where performance requirements are not high. Most of its carbon content is below 0.30%, and its manganese content does not exceed 0.80%. Its strength is low, but its plasticity, toughness and cold deformation properties are good.
Except for rare cases, it is generally used directly without heat treatment. Most of them are made into bars, special-shaped steel, steel plates, etc. It has many uses and many uses. It is mainly used in railways, bridges and various construction projects to manufacture various metal components that bear static loads, mechanical parts and generally weldments that are not heavy or require heat treatment.
High-quality carbon structural steel is pure, has few impurities, and has good mechanical properties. It can be used after heat treatment. According to the manganese content, it is divided into two groups: ordinary manganese content (less than 0.80%) and high manganese content (0.80%~1.20%). The carbon content is less than 0.25%, and it is often used directly without heat treatment, or it is carburized or carbonitrided.