Abstract: Casting under pulsating
electromagnetic field is a process in which a mould is put in a
copper coil to which pulsating current is connected, after
pouring liquid metal into the mould, to produce a pulsating
electromagnetic field which exerts pulsating electromagnetic
pressure on the liquid metal, so that defects in the casting are
eliminated and the cast crystal structure refined. It has been
found that solidification under the pulsating electromagnetic
field can completely eliminate the macro dispersed shrinkage and
micro dispersed shrinkage of Al-5% Cu alloy, increase the
compactness of Al alloy by 0.9% and shorten the relative
intrusive depth of shrinkage in pure aluminium sample from 0.56
to 0.05. Washing the channel repeatedly between dendrites in
liquid-solid region by the metal liquid, caused by the
electromagnetic pressure is the main factor in eliminating
dispersed shrinkage, and the facilitating of the settling of
grains is the reason for the shortening of intrusive depth of
shrinkage. The practical experiments were carried out in Harbin
Steam Turbine plant and some perfect results were gained.
Key words:
Pulsating electromagnetic field Casting technique principle Dispersed shrinkage
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