Its carbon content is 3%.

It is already high carbon steel. There is no need for surface carburization at all. Surface carburizing is mainly carried out on low carbon steel and medium carbon steel. His goal is to increase the surface hardness of parts while maintaining their toughness.

The hardness and strength of gray cast iron itself have reached the limit. Generally, its heat treatment is normalizing treatment, which can eliminate internal stress and improve its fatigue strength.