关于热顶铸造6082合金圆铸锭表层成分偏析的研究  

Study on Surface Composition Segregation of 6082 Alloy Round Ingots Cast by Hot Top Casting

作　　者：沈国新 刘金辉 周桂山 张迪 曹威 SHEN Guo-xin;LIU Jin-hui;ZHOU Gui-shan;ZHANG Di;CAO Wei(Guangdong Xingfa Aluminum(Henan)Co.,Ltd.,Jiaozuo 454550,China)

机构地区：[1]广东兴发铝业(河南)有限公司

出　　处：《铝加工》2019年第6期30-34,共5页Aluminium Fabrication

摘　　要：通过大量生产实践及严谨的实验,发现大直径规格6082圆铸锭表层存在宏观偏析层。Si、Mg、Mn主要合金元素都存在成分偏析,Si、Mg偏析规律及偏析程度高度一致。偏析层的形成是热顶铸造这种生产方式造成的,其形成机理是:铸锭在凝固结晶过程中,表层经历了急剧冷却凝固-晶界重熔-溶质在晶界网络流动-再凝固过程。晶界重熔引起溶质流动,溶质流动导致表层不同区域出现成分偏析,最终形成“勺子”形状的表层偏析层。Through a large number of production practice and rigorous experiments,it was found that macroscopic segregation layer exists on the surface of the large diameter specification 6082 round ingots.Composition segregation exists in the main alloy elements of Si,Mg and Mn,and the segregation rules and degree of Si and Mg are highly consistent.The formation of segregation layer is caused by hot top casting.During solidification and crystallization of ingots,the surface layer underwent rapid cooling solidification-grain boundary remelting-melting in grain boundary network flow-resolidification.Grain boundary remelting leads to molten flow,which leads to composition segregation in different zones of the surface and eventually forms"spoon-shaped"surface segregation.

关 键 词：热顶铸造 6082合金 圆铸锭 表层 成分偏析 

分 类 号：TG292[金属学及工艺—铸造]