Whose hardness is higher, No.20 steel or No.45 steel?

Whose hardness is higher, No.20 steel or No.45 steel?

No.20 steel and No.45 steel are high-quality carbon structural steel. According to the characteristics of high-quality carbon structural steel, its carbon content determines the performance of the steel. The higher the carbon content, the higher the hardness and strength of the steel, the lower the plasticity and toughness.

The carbon content of No.20 steel and No.45 steel are 0.20% and 0.45% respectively, which shows that the hardness of No.45 steel is higher under the same process.