Ultra-high carbon steel

Ultra-high
carbon steel contains between 1 and 2 percent carbon. These steels are
thermomechanically processed to produce microstructures that consist of
ultrafine, equiaxed grains of spherical, discontinuous proeutectoid carbide
particles. Higher carbon
steels are used for special applications such as non-industrial knives or
axles.

Typically, ultra-high carbon steels are tempered to extreme hardness and are
often made using a process called powder metallurgy. This process is the
compacting of metal powder, which is then placed in an oven where it is sintered
at high temperatures.

The metals then form a solid. Steels that contain a carbon content above 2
percent are classified as cast iron.

Medium-carbon ultrahigh-strength steels are structural steels with yield
strengths that can exceed 1380 MPa. Many of these steels are covered by SAE/AISI
designations or are proprietary compositions. Product forms include billet, bar,
rod, forgings, sheet, tubing, and welding wire.