高强钢板坯凝固过程模拟与工艺优化

Solidification process simulation and process optimization of high strength steel slab

以凝固参数测定和铸坯表面温度测量结果为验证边界条件,应用ProCAST软件对960QT钢板坯连铸过程中的传热和凝固过程进行了模拟,分析了拉速、过热度对铸坯温度场、液芯长度的影响,得出在拉速为0.9 m/min,过热度为23℃工况下,960QT板坯的凝固终点位置距离弯月面18.43 m;在浇注温度为1 535℃时,拉速每增加0.1 m/min,凝固末端位置向后移动2.7 m左右;在拉速为0.9 m/min时,过热度每增加10℃,凝固末端位置向后移动0.4 m左右。此外,对轻压下系统的压下位置和压下量进行了优化,由3个扇形段压下改为2个扇形段压下,6、7段压下量改为2.0、2.5 mm。工艺优化后,铸坯中心偏析和中心疏松得到明显改善,中心碳偏析指数由1.85降至1.09。

Using solidification parameters and surface temperature measurements as boundary conditions,ProCAST software was applied to simulate the heat transfer and solidification process of 960QT steel slab during continuous casting.The effects of casting speed and superheat on the temperature fields of slab and liquid core length at the outlet of the copper mold were analyzed.It is concluded that under the conditions of the casting speed of 0.9 m/min and superheat of 23℃,the solidification end point is 18.43 m away from the meniscus.When the casting temperature is 1535℃,the position of solidification end moves forward about 2.7 m when the casting speed increases by 0.1 m/min.When the pulling speed is 0.9 m/min,the position of the solidification end moves back about 0.4 m with every 10℃ increase of superheat.In addition,the reduction position and amount of the soft reduction system were optimized,from 3 segments to 2 segments,and the reduction of sections 6 and 7 was changed to 2.0 and 2.5 mm respectively.After the process optimization,the central segregation and central porosity of slab were significantly improved,and the carbon segregation index at the slab center decreased from 1.85 to 1.09.