Edge dam position control method and device in twin roll strip casting process

An edge dam position control method in a twin roll strip casting process for controlling the position of an edge dam to improve the quality of strip, said method comprising the steps of:

• calculating the position of a solidification point to a rolling force of twin rolls;
• measuring the rolling force of twin rolls upon casting by means of a load cell;
• determining whether the position of the solidification point of the measured rolling force of the twin rolls corresponds to a height of the bottom of the edge dam;
• and
• moving the edge dam to the position where the height of the bottom of said edge dam corresponds to the position of the solidification point of the measured rolling force of the rolls,
• wherein the step of calculating the position is comprised of the steps of:
• calculating the position of the solidification point to a reduction ratio of the twin rolls and
• calculating the rolling force of the twin rolls to the reduction ratio of the twin rolls by substituting the following expressions (5) to (8) for the following expression (4):
• Rolling Force=Km·Bm·Ld·Qp (4)
• wherein, the variable ‘Km’ designates mean hot deformation resistance (kg/mm2), ‘Bm’ mean strip width, ‘Ld’ length (mm) of contact arc, and ‘Qp’ geometric factor;
• and L d = α ⁢ D 2 ( 5 ) Q p = 0.8 + ( 0.45 ⁢ γ + 0.04 ) ⁢ D 2 ⁢ G - 0.5 ( 6 ) γ = ( G - G o ) / G = strain ( 7 ) K m = f ⁡ ( C , ϵ , ϵ ′ , T ) = C · ϵ n , ϵ ′ m · exp ⁡ ( A T ) ( 8 )
• wherein, the variable ‘C’ represents composition, the ‘ε’ strain, the ‘{acute over (ε)}’ strain ratio, the ‘T’ temperature (°K), and in case of stainless steel 304, in a general hot rolling process, C=0.24, n=0.07, m=0.05 and A=5700, and in a strip continuous casting, C=0.2, n=0.07, m=0.05 A=5300.