关键词: Q345E钢, ΦD600 mm圆铸坯, 凝固模拟计算, 射钉试验, 宏观碳偏析, 控制

Abstract: The metallurgical flow sheet of steel Q345E (/% ： 0. 13 ~0. 17C, 0.24 - 0.28Si, 1. 02 ~ 1. 40Mn, 0. 015 ~ 0,040Al, ≤0. 015P, ≤0. 015S) is 70 t converter-LF-VD- Φ600 mm round bloom casting process. By simulated calculation on solidification in condition with secondary cooling water ratio 0. 08 L/kg and casting speed 0. 18, 0, 20 and 0. 22 m/min and combined with pin-shooting test in conditions of casting speed 0. 22 m/min, liquid overheating extent 20 °C, mold cooling rate 4 600 l/min (water temperature difference between inlet and outlet 2. 7℃), secondary cooling water rate L₁-38, 1₂-6 and L₃-5 L/min, the position of end of liquid core- distance from meniscus 22. 4 m for Φ600 mm round bloom of steel Q345E with the casting speed is defined and based on this test the carbon macro-segregation of heavy round bloom improves obviously by application of optimized M-EMS \ (final) F-EMS combined electro-magnetic stirring (EMS) technology and adjustment of casting process. Results show that casting liquid overheating extent and EMS parameters are important factors to influence the carbon segregation of bloom ； with overheating extent 20 ~ 30℃ ，casting speed 0. 22 ~0. 24 m/min, M-EMS 200 A, 2 Hz and F-EMS 400 A, 8 Hz alternative stirring, the extreme difference of carbon content in steel Q345E at cross section of Φ600 mm round bloom is below 0. 04% C.