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Manganese
being analogous to iron and
exhibiting unlimited solubility in
iron, is present to some degree in
all iron ores and is thus found in
hot metal and steel. Manganese, like
iron, solidifies in a cubic lattice.
In the liquid state, the oxides of
iron and manganese are completely
soluble in one another. Oxides of
manganese, like oxides of iron, can
combine with calcium oxides to form
low melting point compounds (calcium
magnates).
Consequently, it affects not only
the properties of the finished
metals but also the melting process.
The
original austenitic manganese steel,
containing about 1.2% C and 12% Mn,
was invented by Sir Robert Hadfield
in 1882. Hadfield`s steel was unique
in that it combined high toughness
and ductility with high
work-hardening capacity and,
usually, good resistance to wear.
Consequently, it rapidly gained
acceptance as a very useful
engineering material. Hadfield`s
austenitic manganese steel is used
extensively, in the fields of
earthmoving, mining, quarrying, oil
well drilling, steelmaking,
railroading, dredging, lumbering,
and in the manufacture of cement and
clay products.
Austenitic manganese steel is used
in equipment for handling and
processing earthen materials (such
as rock crushers, grinding mills,
dredge buckets, power shovel buckets
and teeth, and pumps for handling
gravel and rocks). Other
applications include fragmentizer
hammers and grates for automobile
recycling and military applications
such as tank track pads.
Higher
Manganese Content Steel austenitic
steels with higher manganese
contents (>15%) have recently been
developed for applications requiring
low magnetic permeability, low
temperature (cryogenic) strength and
low temperature toughness. This
applications stem from the
development of superconducting
technologies used in transportation
systems and nuclear fusion research
and to meet the need for structural
materials to store and transport
liquefied gases.
Another
class of austenitic steels with high
manganese additions has been
developed for cryogenic and for
marine applications with resistance
to cavitation corrosion.
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