Q345E钢Φ600mm大圆坯连铸凝固数值模拟

Numerical simulation of solidification in continuous casting process of Φ600 mm Q345E steel round billet

建立了Q345E钢Φ600 mm大圆坯凝固传热模型,利用Procast软件对其连铸凝固过程进行了数值模拟,并通过射钉试验结果验证。研究结果表明:浇铸温度对铸坯的表面与中心温度以及固液相分布影响很小;拉速每增加0.02 m/min,铸坯表面温度无明显变化,糊状区向前移动,凝固末端离结晶器液面距离增加约1.75 m;二冷比水量每增加0.01 L/kg,其二冷区表面温度约降低30℃,糊状区向后移动少量,凝固末端后移0.3 m左右;适宜的工艺条件为浇铸温度1 539℃、拉速0.22 m/min、二冷比水量0.08 L/kg。实际生产的Q345E钢Φ600 mm大圆坯中心缩孔0.5级,中心疏松1.0级,碳偏析指数不大于1.09,完全满足标准要求。

A mathematical model of solidification and heat transfer process was established for the 0600 mm round billet of Q345E steel. The result generated by software Procast was in agreement with the nail test. The simulation results showed that casting temperature had little impact on the surface, central temperature of the round billet and the distribution of solid-liquid phase; as the casting speed increased by 0. 02 m/min, the surface temperature almost remained unchanged and the mushy zone moved ahead, the distance from the mould to the solidification end increased by around 1.75 m; as the specific water flow of secondary cooling zone raised by 0.01 L/kg, the surface temperature of secondary cooling zone decreased by about 30℃ and mushy zone moved back slightly, the distance from the mould to the solidification end raised by around 0. 3 m. Therefore, the proper conditions were as follows： casting temperature l 539 ℃, casting speed 0. 22 m/min and water ratio in secondary cooling zone 0. 08 L/kg. The practical product of φ600 mm round billet of Q345E steel could reach the national standard, with central shrinkage of grade 0. 5, central porosity of grade 1.0 and central carbon were not greater than 1.09.