A three-dimensional transient heat transfer model has been developed to simulate the solidification process of strand in a continuous casting. The temperature distribution of a typical beam blank from the meniscus to the unbending point was investigated by the numerical simulation method, which is justified by the in situ test data. Based on the temperature distribution of the beam blank, improvement on the layout of spray nozzles and water consumption in the secondary cooling zone is proposed. When the improved cooling scheme was employed, the temperature of the beam blank in the secondary cooling zone was controlled in a suitable range determined by the metallurgical criteria, and the transverse surface temperature on a crosssection of the strand became more uniform, which was assessed by the standard deviation of temperature. Moreover, the macrostructure defects are greatly decreased and the quality of the beam blank product is enhanced.

Two-dimensional finite element heat transfer models have been developed to predict temperature distribution in beam blank moulds with large and small hole water cooling channels. The effects of water channel design and grinding thickness on transverse temperature profile in meniscus region were analysed in detail. The effects of both moulds during plant trials are also compared. The results show that the peak temperature is found in the fillet area of the large hole mould and is 20uC higher than that of the small hole mould. With increasing grinding thickness, peak temperature in both moulds decreases linearly, and when the grinding thickness reaches 9 mm, the peak temperature of the small hole mould exceeds that of the large hole mould. The transverse temperature uniformity of the hole mould is superior to that of the large hole mould. It is also found that longer mould life, better strand surface quality and more homogeneous surface microstructure are obtained when using the small hole mould.List of symbols c w specific heat of cooling water, c w 54178 J kg 21 uC 21 D hydraulic diameter of water channel, m h w coefficient of heat transfer, W m 22 uC 21 k thermal conductivity of copper, W m 21 uC 21 q heat flux density between mould copper plate and cooling water, W m 22 T temperature, uC T s surface temperature of water channel, uC T w temperature of cooling water, uC x, y rectangular coordinates, m l w thermal conductivity of cooling water, l w 50?614 W m 21 uC 21 m w viscosity of cooling water, m w 50?792610 23 Pa s 21 r w density of cooling water, r w 5998?2 kg m 23 u w velocity of cooling water, m s 21

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