A simple and feasible method of preparing of semi-solid low alloy steel slurries at near liquidus temperature with medium-frequency induction furnance at holding is described. The effects of holding temperature

holding time and heating ways on the microstructure of the slurries are understood by observing water-quenched and air-cooled microstructures at different holding conditions. Few free nucleus are formed in the melt under the condition of large superheat or supercooling

resulting in coarse water-quenched microstructure

while amounts of free nucleus are created to uniformly distribute into the melt to greatly refine and homogeneousize the water-quenched microstructure at near liquidus temperature （1 508 ℃）

and it do so at air-cooled conditions. Electromagnetic stirring in medium-frequency induction furnace can greatly increase nucleus amounts at near liquidus temperature with short holding time and then keep the morphology and amounts of the nucleus. So change of the water-quenched microstructure of the semi-solid slurries can not be observed at holding for 5

5

0 min.