方坯直轧工艺下连铸坯温度场均匀性及切坯工艺优化

Uniformity of Temperature Field and Cutting Process Optimization for Continuously Cast Billet under Square Billet Direct Rolling Process

对方坯直轧工艺下连铸坯温度场和初生晶粒演化进行数值模拟,并根据计算结果对连铸坯切坯顺序进行优化。结果表明:随着连铸拉速的提高,连铸方坯表面温度和心表温差逐渐增大,心部等轴晶区也逐渐扩大;拉速对连铸坯初生晶粒取向的影响较小;连铸坯定尺对铸坯头尾温差的影响较大,在拉速不变的情况下,连铸坯定尺每增加1 m,头尾温差增大约10.5℃。方坯直轧工艺生产采用非定尺切坯策略,可以有效减小连铸拉速波动对出坯生产节奏的影响。

Numerical simulations of temperature field and primary grain evolution in continuously cast billet under square billet direct rolling process were carried out,and the cutting sequence of continuously cast billet was optimized based on the calculation results.The results showed that(a)with the increase of continuous casting speed,the surface temperature and temperature difference between center and surface of the casting square billet gradually increased,and the central equiaxed crystal area also gradually increased;(b)the casting speed had a little effect on the orientation of primary grains in continuously cast billet;(c)the fixed length of the continuously cast billet had a great influence on the temperature difference between head and tail of the billet;(d)when the casting speed was constant,the temperature difference between head and tail increased by about 10.5℃for each 1 m increase in the fixed length of continuously cast billet.The non-fixed length cutting strategy can be used in the square billet direct rolling,which can effectively reduce the impact of casting speed fluctuations on the production rhythm of discharging billet.