To control the distribution of nonmetallic inclusions in molten developed method, hot-top pulsed magneto-oscillation （HPMO）, steel is of highly commercial importance. A newly was employed to control nonmetallic incl...To control the distribution of nonmetallic inclusions in molten developed method, hot-top pulsed magneto-oscillation （HPMO）, steel is of highly commercial importance. A newly was employed to control nonmetallic inclusions in a medium-carbon steel ingot. The experimental results present that the position of nonmetallic inclusions of spinel （Al-Mg-O） and Mn-S inclusions is significantly influenced by HPMO. The number of nonmetallic inclusions gradually increased from the lateral wall to the center of ingot along the radial direction under the impact of HPMO treatment, whereas this distribution trend cannot be observed in the reference sample without HPMO treatment. In addition, the number of inclusions along vertical direction is proportional to the height of ingot, especially for the inclusions with the size of larger than 10 pro. It indicates that the application of HPMO can push away inclusions from lateral to center, and then the expelled inclusions aggregate and rise up to the top of ingot.展开更多
Heavy ingots,especially the ingot of more than 10 t,often contain detrimental heterogeneous defects,such as macrosegregation,shrinkage pipes,and cracks.Hot-top pulsed magneto-oscillation(HPMO)can refine the solidified...Heavy ingots,especially the ingot of more than 10 t,often contain detrimental heterogeneous defects,such as macrosegregation,shrinkage pipes,and cracks.Hot-top pulsed magneto-oscillation(HPMO)can refine the solidified structure of ingot and improve their homogeneity.However,it may exacerbate the positive segregation at the upper part of the ingot body.Thus,a round table HPMO riser with a feeding part was designed,and the microstructure and macrosegregation of Al–Si alloy ingots solidified with and without HPMO were investigated.The simulation and experimental results indicated that round table HPMO riser could enable fine and uniform solidified structures in the whole ingot body;in the meantime,feeding part allowed the melt with enriched solute to gather in the upper part of the riser until the last solidification stage of ingot.This provides an effective approach for obtaining highly homogenized ingots.展开更多
在传统热顶铸造基础上,开发了一种新的热顶铸造结晶器,并在铸造过程中施加了低频电磁场,得出了稳定铸造φ500 mm 7050高强铝合金铸锭的工艺条件;当电磁场频率为15 Hz、磁场强度为10000 At时,铸造出了表面光滑的铸锭.采用偏光显微镜(Leic...在传统热顶铸造基础上,开发了一种新的热顶铸造结晶器,并在铸造过程中施加了低频电磁场,得出了稳定铸造φ500 mm 7050高强铝合金铸锭的工艺条件;当电磁场频率为15 Hz、磁场强度为10000 At时,铸造出了表面光滑的铸锭.采用偏光显微镜(Leica DMI)观察试样,分析试样的微观组织.实验结果表明:铸造过程中施加低频电磁场能提高铸锭的表面质量,细化铸锭的内部组织,以及抑制铸锭内部裂纹的产生.总结了低频电磁铸造改善表面质量和细化组织的原因以及低频电磁场对液穴形状的影响.展开更多
基金Acknowledgements The authors acknowledge the financial supports from the National Natural Science Foundation of China （Grant Nos. U1760204 and 51504048）, the National Key Research Program of China （Grant No. 2017YFB0701800） and the Science and Technology Commission of Shanghai Municipality （Grant No. 15520710800）.
文摘To control the distribution of nonmetallic inclusions in molten developed method, hot-top pulsed magneto-oscillation （HPMO）, steel is of highly commercial importance. A newly was employed to control nonmetallic inclusions in a medium-carbon steel ingot. The experimental results present that the position of nonmetallic inclusions of spinel （Al-Mg-O） and Mn-S inclusions is significantly influenced by HPMO. The number of nonmetallic inclusions gradually increased from the lateral wall to the center of ingot along the radial direction under the impact of HPMO treatment, whereas this distribution trend cannot be observed in the reference sample without HPMO treatment. In addition, the number of inclusions along vertical direction is proportional to the height of ingot, especially for the inclusions with the size of larger than 10 pro. It indicates that the application of HPMO can push away inclusions from lateral to center, and then the expelled inclusions aggregate and rise up to the top of ingot.
基金This work was financially supported by the National Key Research and Development Program of China(Nos.2020YFB2008400 and 2017YFB0701800)the National Natural Science Foundation of China(No.U1760204)In addition,the authors would liketo thankHui Shaoand Zi-hao Yin from Centerfor Advanced Solidification Technology,Shanghai University for their help in the experiment and data analysis.
文摘Heavy ingots,especially the ingot of more than 10 t,often contain detrimental heterogeneous defects,such as macrosegregation,shrinkage pipes,and cracks.Hot-top pulsed magneto-oscillation(HPMO)can refine the solidified structure of ingot and improve their homogeneity.However,it may exacerbate the positive segregation at the upper part of the ingot body.Thus,a round table HPMO riser with a feeding part was designed,and the microstructure and macrosegregation of Al–Si alloy ingots solidified with and without HPMO were investigated.The simulation and experimental results indicated that round table HPMO riser could enable fine and uniform solidified structures in the whole ingot body;in the meantime,feeding part allowed the melt with enriched solute to gather in the upper part of the riser until the last solidification stage of ingot.This provides an effective approach for obtaining highly homogenized ingots.
