电磁驱动力对金属铸坯凝固的影响

利用低熔点 Sn+3.5 wt% Pb合金模拟钢的凝固末端电磁搅拌的实验条件 ,研究了电磁驱动力对铸坯凝固进程的影响。研究表明 :在电磁驱动力作用下 ,半固态区存在一个边界层 ,边界层表征电磁驱动力作用的极限区域 ,边界层以内熔体的流速随着搅拌器线圈电流的增大而增大 ,电磁场对边界层以外的熔体影响不大 ;电磁搅拌驱动力使固 -液界面或边界层向外推移 ,铸坯凝固坯壳变薄 ;电磁搅拌力对半固态的金属熔体具有熔蚀、冲刷作用 ,阻碍柱状晶生长 ,使凝固壳生长均匀 ,且内表面光滑无突起。

电磁场作用下材料加工新技术

材料电磁加工已成为金属材料基础研究和开发制备新技术的重要领域 .在材料制备过程中施加电磁场 ,不仅改善了金属铸坯的外部质量 ,而且细化了铸坯内部的凝固组织 .随着超导强磁场技术的发展 ,电磁场在控制金属凝固、改善电镀质量及防止金属腐蚀等方面将越来越重要 .

Area Method Analysis and Thermodynamic Behavior of Nonmetallic Micro-Inclusions in Casting Slab of GCr15 Bearing Steel

The distribution and characteristics of nonmetallic micro-inclusions of GCr15 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope.The results show that the micro-inclusions,of which the average value is 0.032%,are mainly the compounds formed via the adsorption/aggregation of multielement deoxidized compounds and secondarily deoxidized products on tundish liquid level.The micro-inclusions of diameters from 0 to 5 μm are 92.5% in total,which basically determines the characteristics of inclusions distribution in casting slab.The inclusions of diameters more than 10 μm only account for less than 1% in total,which have little influence on steel quality.The relationship between equilibrium compositions of the first deoxidation products and molten steel compositions was also calculated based on thermodynamic theory.