MELTING FURNACES
Before pouring into the mold, the metal to be
casted has to be in the molten or liquid state.
Furnace is used for carrying out not only the basic ore refining process
but mainly utilizedย ย to melt the metal also. A blast furnace performs basic
melting (of iron ore) operation to get pig iron, cupola furnace is used for
getting cast iron and an electric arc furnace is used for re-melting steel. Different furnaces are employed for melting
and re-melting ferrous and non- ferrous materials. The following are the
factors which are responsible for the selection of furnace.
(i)ย
Considerations of initial cost and cost of its operation.
(ii)ย
Relative average cost of repair and maintenance.
(iii)ย ย
Availability and
relative cost of various fuels in the particular locality.
(iv)ย ย
Melting efficiency, in particular speed of melting.
(v)ย
Composition and melting temperature of the metal.
(vi)ย ย
Degree of quality control
required in respect
of metal purification of refining,ย
(vii)ย ย
Cleanliness and noise level in operation.
(viii)ย ย
Personnel choice or sales influence.
Heat in a melting
furnace is created by combustion of fuel, electric arc, electric resistance, etc. A furnace contains
a high temperature zone or region surrounded by a refractory wallย structure
which withstands high temperatures and being insulating minimizes heat losses
to the surroundings. For refining and melting the ferrous and non ferrous
materials, various furnaces are used.