材料期刊网

通过物理模拟实验研究板坯连铸流动控制结晶器(flow control mold II, 即FC Mold II)电磁制动过程中, 磁场强度和分布对结晶器内金属液流动的影响规律. 实验中, 以水银为模拟工质, 在模型拉速为0.41, 0.52和0.82 m/min(分别相当于生产拉速1.00, 1.30和2.00 m/min), 电磁制动的上区磁场强度B₁=0.18, 0.36和0.50 T, 下区磁场保持B₂=0.50 T不变的匹配(组合)条件下, 考察结晶器(模型)内的水银流态和流速分布, 并以此分析上、下区磁场强度匹配(组合)对水口出流、液面流动以及结晶器窄面模壁所受冲刷等的影响规律. 结果表明, 在上述拉速条件下, FC Mold II电磁制动的上、下区磁场强度匹配关系, 分别取B₁/B₂=0.36, 0.72和1.00时, 结晶器中金属液的制动效果最好.

Electromagnetic brake (EMBr) affects the flow field in mold during the slab continuous casting process. Flow control mold II (FC Mold II) has been developed to resolve the defects of the third generation (flow control mold) of EMBr which the braking effect on meniscus is too strong to make the surface flow excessively stabilize and it would be prone to freezing and related defects. To gain a fundamental understanding of FC Mold II, a mercury physical model was developed to investigate the influence of the magnetic field intensity match on metal flow in FC Mold II based on the\linebreak 1350 mm×230 mm slab continuous casting process in a factory. The flow regime and velocity distribution in mold were measured by ultrasound Doppler velocimeter (UDV) with the maximum magnetic field intensity of the upper pair of magnetic poles B₁=0.18, 0.36 and 0.50 T respectively and the maximum magnetic field intensity of the down pair of magnetic poles B₂=0.50 T, while the mold casting speed is 0.41, 0.52 and 0.82 m/min respectively corresponding to the practical casting speed 1.00, 1.30 and 2.00 m/min respectively. The influences of the magnetic field intensity match on the flow discharged from the nozzle, the flow near the meniscus and the washing intensity to the mold narrow wall were analyzed and studied. The results showed that, when the magnetic field intensity match of the upper and the lower pair of magnetic poles B₁/B₂≤1, with the continuous casting speed increasing, the value of B₁/B₂ should increase in order to get an ideal braking effect. The value of B₁/B₂ should be 0.36, 0.72 and 1.00 respectively when the model casting speed is 0.41, 0.52 and 0.82 m/min respectively. The increasing of the intensity of the magnetic field reduces the “flow passage” effect caused by EMBr, and is conducive to the formation of the plug flow under the electromagnetic braking region.