45# steel refers to 45 steel; 45 steel is the name in the national standard, also called "oil steel". Most of the spot hot rolling in the market; 1.0~4.0mm (mm). The cold plasticity of this steel is general, the annealing normalization is slightly better than the quenching and tempering, and it has higher strength and better machinability.

Extended data:

Uses of 45# steel:

45 # steel is widely used in machinery manufacturing, and its mechanical properties are very good. But this is medium carbon steel with poor quenching performance, and 45 # steel can be quenched to HRC42~46. Therefore, if the surface hardness is needed and the superior mechanical properties of 45 # steel are expected to be exerted, the surface of 45 # steel is often carburized and quenched, so that the required surface hardness can be obtained.

In the field of mold maintenance:

The die welding material model of 45 # steel is CMC-E45, which is the only medium hardness steel covered electrode with good combination. It is suitable for air-cooled steel and cast steel, such as ICD5, 7CrSiMnMoV…, etc. The repair of stretching parts of automotive sheet metal panel dies and large sheet metal stamping dies can also be used for hard surface production.

References:

Baidu encyclopedia -45 steel