QUALITY CONTROL IN THE CONTINUOUS CASTING OF STEEL BY ELECTROMAGNETIC STIRRING

摘要

PURPOSE:To reduce segregation, make steel quality soft and reduce strain aging embrittleness during working by subjecting molten steel to electromagnetic induction stirring by the magnetic field induced by the AC of specific frequencies and magnetic flux densities. CONSTITUTION:Molten steel is charged together with heat insulation type flux into a mold for casting, and is subjected to electromagnetic induction stirring by the magnetic field induced by the AC of frequency f=1.5-10Hz and of the magnetic flux density (gauss) G on the mold surface kept within the 268Xe-0.18f=G=745X e-0.20f range. It is continuously drawn out in the downward direction of the mold, and in the intermediate period when the molten steel solidifies, it is subjected to secondary electromagnetic induction stirring by the magnetic field induced by the AC of the same intensity as the above in the magnetic flux density G on the ingot surface at frequency f=1.5-10Hz, and by the AC of the frequency f=50-60Hz and of the magnetic flux density G kept in the range defined by 750,000/(D- 107)2=G=750,000/(D-100)2 where the thickness of the solidified shell layer is defined as Dmm..