(东北大学 材料电磁过程教育部重点实验室,沈阳 110004)
摘 要: 研究了不同强度交变电磁场作用下,7075合金凝固壳高度及铸锭表面质量的变化规律。结果表明,随着磁场强度增加,熔体与结晶器的接触高度以及凝固壳高度减小,初凝壳形成位置点降低,铸锭表面质量提高。采用晶粒游离理论解释了电磁场作用下初凝壳的形成机制,认为电磁场作用下,晶粒从结晶器壁游离数量增加,稳定初凝壳难以形成,是延缓初凝壳形成时间和降低初凝壳形成位置的根本原因。
关键字: CREM法;半连续铸造;铝合金;初凝壳
intensity and initial solidified shell height of
aluminum alloy produced by CREM process
(Key Laboratory of National Education Ministry for Electromagnetic
Processing of Materials,Northeastern University,
Shenyang 110004,China)
Abstract:Under the effect of electromagnetic field with low frequency,the evolutions of solidified shell height and surface aspects,bearing on 7075-aluminum alloy produced by CREM process,have been investigated. The results show that t he gradual enhancement of the electromagnetic intensity allows a decrease in the height of solidified shell and in the contact height between melt and mold,which improve surface aspects of the ingot. Crystal-dissociating theory are used to explain the formation mechanism of initial solidified shell under the effect of electromagnetic field. It is pointed out that under the effects of electromagnetic field, the decrease of crystal particles dissociated from the crystallizer wall results in the difficulty of formation of solidified shell,which is the key reason that delay the time an ddecrease the position of forming the initial solidified shell.
Key words: CREM process; semi-continuous casting; aluminum alloy; initial solidified shell