热轧全流程带钢温度场数值模拟

为精确预测轧件的温度场、优化轧制工艺和提高最终产品的质量水平,通过对钢坯的加热和轧件轧制过程传热关系的分析,采用有限差分法建立了热轧全流程各环节轧件三维温度场的数值计算模型。结合钢厂实际生产条件,利用该模型模拟了各环节轧件的温度场,并与实测结果进行了比较,验证了计算结果的准确性。研究表明,轧制速度和终轧厚度对轧件温度影响较大,压下率和轧辊温度对轧件温度有一定的影响,其他工艺因素的影响较小。     

薄板坯连铸工艺因素对结晶器非稳定流场特征参数的影响

利用波高仪和粒子示踪法在1∶1的水力学模型中研究了薄板坯连铸工艺参数对结晶器内非稳定流场特征参数的影响.结果表明:流场特征参数随时间变化具有一定的周期性.随着拉坯速度增加,平均射流撞击位置下降,平均回流区中心深度下降,平均波高增加;同时,撞击点、回流区中心深度和波高的变化范围增大,周期减小,结晶器内流动不稳定程度增大.随着水口浸入深度增加,平均射流撞击位置下降,平均回流区中心深度下降,平均波高减小;同时,撞击点、回流区中心深度和波高的变化范围减小,周期增加,流场不稳定程度减小.随着水口出口角度增加,平均射流撞击位置下降,平均回流区中心深度下降,平均波高减小;对于较大的水口出口角,尽管结晶器内流场非稳定流动范围较大,但是流场的运动周期较大,液面波动的非稳定程度却较小.     

Static and Metadynamic Recrystallization of Low Carbon Steels During Mechanical Deformation

Static and metadynamic recrystallization models were developed with the coefficients determined by multiple nonlinear regression analyses to describe microstructure evolution in low carbon steels.The effects of initial grain size, deformation temperature, strain, and strain rate on the austenitic recrystallized volume fraction and grain size were studied using a Gleeble machine. The results show that deformation reduces the grain size when the recrystallized volume fraction is large. The static recrystallized volume fraction increases with increasing deformation temperature, strain, and strain rate, and decreasing initial grain size. The grain size during metadynamic recrystallization is independent of the deformation strain and the initial grain size. The recrystallized volume fraction, the grain size, and the grown grain size calculated by the correlations are consistent with the measured values.