Various mixture of heating and cooling to give necessary
characteristic to steel.

Heat treatment is done in a protective environment to prevent
high-temperature oxidization and de-carburization, as well as
to maintain brightness on surface.
bright annealing
bright normalizing
bright hardening
bright tempering

General term for all heat treatment in vacuum.
vacuum annealing
vacuum hardening
vacuum tempering

Surface treatment in a decompressing environment,
where glow discharge is created between anode and
treatment from the electrode.

Heat treatment where treated materials from either electrolyte
or salt bath, and where electricity is allowed to flow with the
anode are heated followed by cooling.

Treatment to change steel into an austenite composition
by heating over transforming temperature. Also know as
complete austenitizing. Austenitizing within transforming
temperature is known as partial austenitizing.

Treatment to increase hardness by aging, heating and cooling.
Includes aging hardening, extraction hardening, quenching hardening and surface hardening

When particles that are transformed with cold working are
heated, the nucleus of new particle with no internal
transformation are formed and multiplied after the process
of reduction of internal stress.

As the nucleus become greater in size, it is substituted
with theoriginal particle.
The temperature that induces recrystalization is called the
recrystallization temperature.
This temperature varies according to the purity of metal or
alloy, transformation of particles, and heating time.

When steel is heated in an environment where it reacts
with carbon, this process will lead to a phenomenon of
losing carbon.
The layer that is decarburized is called the decarburized
layer and it is measured in overall decarburized depth,
ferrite decarburized depth,
certain remaining carbon decarburized depth, and
decarburized depth for actual use

Treatments to harden steel's surface including carburized
hardening, induction hardening, spark hardening.

Hardening process where hard frequency electricity
induces heating.
It is used to harden unspecified areas of surface.
This treatment is prescribed in KS B4902
(Induction hardening and tempering treatment).

Treatment to increase carbon in surface of steel by
heating in carburizing agents.
They are divided into hard, liquid and gas carburizing
depending on the agent. It is usual for carburizied
steel to be used after hardening tempering.
This treatment is also known as case hardening.