Initial Solidification Control of Continuous Casting Using Electromagnetic Oscillation Method

Abstract

An initial solidification control technology, called the Electromagnetic Oscillation Method, intermittently applying high frequency magnetic field was developed aiming to reduce the friction between mold and initial solidified shell and to perform high speed casting for producing cast having excellent surface properties. According to the method, a high frequency magnetic field is applied synchronizing with the mold oscillation, applying a horizontal and inward electromagnetic force from outside the mold during the positive strip period, while applying a downward electromagnetic force from above the mold during the negative strip period. The method was investigated in terms of influence on the surface properties of cast and other variables by applying the method to laboratory scale continuous steel casting. The experiment was given by casting round billets having 100 mm in diameter at casting speeds of 0.5 to 1.6 mm/min, applying high frequency magnetic fields of 1 to 9.8 kHz. The flux film thickness in the mold increased by applying horizontal electromagnetic force during the positive strip period, and the surface properties of the cast improved. By applying downward electromagnetic force during the negative strip period, the strength of initial solidified shell increased to prevent the occurrence of breakout.

Effect of Agitation on Crystallization Behavior of CaO^|^ndash;SiO2^|^ndash;R2O (R = Li, Na, or K) System Characterized by Electrical Capacitance Measurement

“…Reported thicknesses of the mold flux film are in the range of a few hundreds of microns to a few millimeters. [16][17][18][19][20][21][22][23][24][25][26][27][28] Hanao et al developed mold fluxes for high-speed continuous casting of a hypo-peritectic steel slab, and investigated the thickness of the mold flux based on CaF2-and Na2O-containing calcium silicates below the meniscus. They reported that the film thickness of the mold fluxes was found to be 0.8-1.6 mm.…”

Effect of exciting current of high frequency electromagnetic field on initial solidification of steel during electromagnetic continuous casting

“…It is clear that the solidified shell thickness is almost decreased linearly with increasing exciting current density. Under the condition that the exciting current density is less than 4?62610 7 A m 22 , if the exciting current density is increased by 6?6610 6 A m 22 , the solidified shell is thinned 1?2-1?4 mm. Whereas if the exciting current density exceeds 4?62610 7 A m 22 , the solidified shell is thinned 2?2-2?3 mm with exciting current density increased by 6?6610 6 A m 22 .…”

“…1,2 Electromagnetic continuous casting minimises the occurrence of casting defects on the surface and subsurface of billets by exerting an alternating electromagnetic field in the initial solidification region of molten steel in the mould to form a thin and uniform early solidified shell. 3,4 This is achieved by the electromagnetic force and induction heat of electromagnetic field at the meniscus in the mould. 5 The electromagnetic force can decrease the contact pressure between the mould wall and molten steel or initial solidified shell so that the adverse effects of mould oscillation on billet surface quality are reduced.…”

“…5 The electromagnetic force can decrease the contact pressure between the mould wall and molten steel or initial solidified shell so that the adverse effects of mould oscillation on billet surface quality are reduced. 6 On the other hand, the induction heat retards the solidification process and a more uniform early solidified shell is formed. 7 For the past few years research on EMCC was mainly focussed on the design of the electromagnetic field and mould, optimising the distribution of electromagnetic force in mould and improving the billet surface quality.…”

Experimental Study on Mould Oscillation-less Continuous Casting Process under High Frequency Amplitude-modulated Magnetic Field

“…1,2) Several kinds of alternative magnetic field in terms of their amplitude have been tested in this technology, such as, intermittent, [3][4][5][6] half-triangle 7) and quasi-sinusoidal 8) ones. On the base of these studies, a novel technology named Mould Oscillation-Less Electromagnetic Continuous Casting (MOLECC) Process 4,9) has been proposed in order to substitute the huge and heavy mechanical mould oscillation system by a small and light electromagnetic one.…”