摘要
一次铝硅合金(含铁5wt%)加锰并在电磁场中进行定向凝固去除合金中的富铁相,主要通过改善富铁相的形态和降低合金中的铁含量减弱富铁相对铝硅合金性能的影响,研究了不同锰添加量下铝硅合金的电磁除铁效率、锰对富铁相形态改善的影响及电磁加锰分离富铁相的机理。结果表明,随锰添加量增大,铝硅合金中的富铁相逐渐从有害的针状转变为骨骼状、块状。加锰并经电磁定向凝固处理后,铝硅合金中绝大部分富铁相的形态变得规则,并在电磁力驱动下富集至合金底部。当锰铁摩尔比为1.2时,铝硅合金中残留的铁含量降至0.39wt%,加锰电磁除铁的效率高达90%。
Iron-rich phases mainly existing in the form of acicular-like in coarse Al-Si alloy has detrimental effects on the mechanical property of the alloy,which is urgently needed to be solved before used as materials for producing casting Al-Si alloys.Based on the traditional metal impurity removal theory,iron-rich phases in the coarse Al-Si alloy(Fe content 5 wt%)can be removed by adding manganese during the electromagnetic directional solidification process,which mainly improves the structure and shape of iron-rich phases and reduces iron content to decrease the harmful influence of iron-rich phases on mechanical properties of Al-Si alloy.The effects ofMn addition on the removal rate of iron-rich phases from Al-Si alloy,influence of Mn on the improvement of morphology of iron-rich phases,and the separation mechanism were studied.The results showed that with the moderate increase of manganese addition,iron-rich phases in Al-Si alloy combined with Mn to form some complex intermetallic compounds with larger shape factors,decreasing the migrating resistance of iron-rich phases when conducting the electromagnetic directional solidification.The migrating velocity of iron-rich phases could be improved as the majority of iron-rich phases in the Al-Si alloy got regularized in shape and structure,therefore the separation efficiency of iron-rich phases was enhanced as well.Eventually,iron-rich phases could be enriched at the bottom of the alloy by the electromagnetic force as a result of larger magnetic susceptibility than that of Al melts.This new technology to remove iron-rich phases from coarse Al-Si alloy had the characteristics of high-efficiency,cost saving,environmental-friendly and energy conservation.It could hopefully become the substitute for preparing casting Al-Si alloy after the electro-thermal process,because not only iron-rich phases in Al-Si alloy were removed,but also primary silicon was accumulated at the bottom of the alloy.In other words,impacted by electromagnetic directional solidification and Mn addition,the purified alloy was divided into two parts:the upper Al-Si alloy with low iron and silicon contents,and the bottom impurity accumulating parts of Si and Fe.The residual iron content in Al-Si alloy was reduced to 0.39 wt%,with the iron removal efficiency reaching 90%.
作者
鲍雨
赵世民
吕国强
王毅博
肖庭
马文会
Yu BAO;Shimin ZHAO;Guoqiang Lü;Yibo WANG;Ting XIAO;Wenhui MA(State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province,Kunming,Yunnan 650093,China;Faculty of Metallurgical and Energy Engineering,Kunming,University of Science and Technology,Kunming,Yunnan 650093,ChinaNational Engineering Laboratory for Vacuum Metallurgy,Kunming University of Science and Technology,Kunming,Yunnan 650093,China;Kunming Green Island Environmental Technology Co.,Ltd.,Kunming,Yunnan 650228,China)
出处
《过程工程学报》
CAS
CSCD
北大核心
2019年第2期309-316,共8页
The Chinese Journal of Process Engineering
基金
国家自然科学基金资助项目(51466005)
关键词
铝硅合金
富铁相
电磁定向凝固
形态
除铁
Al-Si alloy
iron-rich phase
electromagnetic directional solidification
shape
iron removal
