6013 aluminium alloy ingot with 210 mm in diameter was prepared by low frequency electromagnetic field semi-continuous casting. The effects of electromagnetic field frequency on microstructures and mechanical properties of the ingot were investigated by optical microscope

scanning electron microscope

electron probe micro analysis and tensile testing machine. The results reveal that the low frequency electromagnetic field can refine the α-Al grains in the aluminum alloy ingot and increase the number of fine second phases as well as increasing the content of elements in the grain

so improving tensile properties of the ingot. With increasing in electromagnetic field frequency

the α-Al grains are converted gradually from coarse dendrites to fine grains

and the grain size and the second phase are gradually uniform distribution

so tensile properties of the ingot edge are improved gradually. Compared with the ingot without low frequency electromagnetic field

tensile strength

yield strength and elongation of the ingot edge are increased by 9.62%

8.36% and 62.89%

respectively

when the frequency of electromagnetic field is increased to 40 Hz.