Inclusions come
from two broad sources:
- Indigenous
- Exogenous
Indigenous - These inclusions are determined by the chemistry of
the steelmaking system. Here, the 'steelmaking system' is defined as
the secondary steelmaking ladle and inputs to the ladle. The
continuous caster tundish may also be regarded as an extension of
the steelmaking system. It should be noted that the chemistry in the
ladle is often not in an equilibrium state due to kinetic factors,
and as such prediction of the prevailing indigenous inclusion
species can prove very difficult. An example of indigenous inclusions are those that are introduced to
improve machining, click here
for further information.
Exogenous - Such inclusions are introduced to the steel from
external sources. The most common source of exogenous inclusions is
particles of refractory material which detach from their parent
material and are entrained in the steel. e.g. erosion of
refractories.
To review where these inclusions can originate from we need to
analyse the components of the ladle steelmaking system.
