Carburizing and quenching enhances hardness and rigidity.

Carburizing and quenching is a surface treatment process for metals, involving the diffusion of carbon atoms into the surface layer of steel.
This process imparts a high-carbon steel surface layer to low-carbon steel components.
Following quenching and low-temperature tempering, the surface layer achieves high hardness and wear resistance,
while the core retains the toughness and ductility of low-carbon steel.

Aging Treatment for Impact Resistance

Aging treatment refers to a heat treatment process where metal or alloy components, after solution treatment, high-temperature quenching,
or significant cold working deformation, are held at elevated temperatures or room temperature to allow their shape,
dimensions, and properties to change over time.
After 24 hours of aging, hardness and strength increase. For higher-carbon steels, very high hardness is achieved immediately after quenching.