Specifications

The Patent Office Journal 17/12/2010
4622
(12) PATENT APPLICATION PUBLICATION (21) Application No.3803/KOLNP/2010 A
(19) INDIA
(22) Date of filing of Application :11/10/2010 (43) Publication Date : 17/12/2010
(54) Title of the invention : MODULATED ELECTROMAGNETIC STIRRING OF METALS AT ADVANCED STAGE OF
SOLIDIFICATION
(51) International classification :B22D 11/115
(31) Priority Document No :12/076,954
(32) Priority Date :25/03/2008
(33) Name of priority country :U.S.A.
(86) International Application No
Filing Date
:PCT/CA2008/001333
:22/07/2008
(87) International Publication No :WO 2009/117803
(61) Patent of Addition to Application
Number
Filing Date
:NA
:NA
(62) Divisional to Application Number
Filing Date
:NA
:NA
(71)Name of Applicant :
1)ABB INC.
Address of Applicant :8585 TRANS-CANADA HIGHWAY,
SAINT-LAURENT, QUÉBEC H4S 1Z6 CANADA.
(72)Name of Inventor :
1)BEITELMAN, LEONID S.
2)LAVERS, J. DOUGLAS
3)CURRAN, CHRISTOPHER P.
4)TALLBACK, GOTE
(57) Abstract :
A method and apparatus for electromagnetic stirring of molten metals at an advanced stage of solidification, as may be used in
continuous casting of steel billets and blooms, are disclosed. At least first and second stirrers are provided for generating first and
second rotating magnetic fields of a differing frequency about an axis of solidifying molten metal. The stirrers are arranged about the
molten metal in sufficiently close proximity to each other so that their respective magnetic fields superpose to produce a modulated
magnetic field. The magnetic fields of the respective stirrers may either have common or opposing rotational directions. The
modulated stirring produced by the magnetic fields results in oscillating primary and secondary flows and hence turbulence within the
melt bulk in the region wherein temperature of the melt on its central axis is below the liquidus level and at least 10% of substantially
solidified material is formed. Turbulent flow created by this stirring method disrupts formation of crystalline structures in the melt
bulk and mixes solute enriched melt of the central region with the bulk volume which subsequently results in improvements of the
solidification structure and overall internal quality of the cast products.
No. of Pages : 38 No. of Claims : 40