Some Study on Cooling Capacity Analysis of Walking Bar Indirect Cooling Type Curvilinear Continuous Casting Machine and Quality of the Slab

Abstract

The Kobe Steel has built a W. B.*-curvilinear type continuous casting machine at Kakogawa plant; this machine has a special indirect cooling system named W. B. in it's upper part of the secondary cooling zone.
Solidification constants, K's of this machine are as follows:
(i) Mold zone K_M=-29.8 (mm min^-1/2)
(ii) W. B. zone K_W.B.=23.9 (mm min^-1/2)
(iii) Roller zone K_R=21.9 (mm min^-1/2)
An analytical simulation of cooling capacity has been made by a computer.
As a result, the average heat transfer coefficient of W. B. zone is found about 320 kcal/m² hr°C, and the average heat transfer coefficient of W. B. is 360 kcal/m²hr°C when it contacts with the slab surface. The components of them are as follows:
(i) Radiation 270 kcal/m²hr°C
(ii) Convection (gas) 48 kcal/m² hr°C
(iii) Contact 42 kcal/m²hr°C
Concerning the quality of the product, the following characteristics are obtained:
(i) The slab is kept in good uniformity, so the error in the weight per unit length is within a 0.5% deviation.
(ii) The equiaxial crystal zone occupy about 30% of the slab width in a usual slab.
(iii) The centerline segregation is slight.
(iv) Few large inclusions can be found.