镁合金铸轧凝固过程与铸坯组织特征分析  

Solidification Process and Microstructures of Twin-roll Casting Magnesium Alloys Strip

作　　者：翁文凭[1] 盛敏奇[1] 许继芳[1] 王璟[1] 

机构地区：[1]苏州大学沙钢钢铁学院

出　　处：《特种铸造及有色合金》2015年第12期1245-1248,共4页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51204115);江苏省自然科学基金资助项目(BK20151221)

摘　　要：数值模拟了镁合金铸轧凝固中传热与流动过程,分析了铸轧速度对铸坯凝固温度场、流场的影响。制备了镁合金铸轧板坯,采用金相显微镜、扫描电镜等分析了板坯组织、形貌及成分分布特征。根据数值模拟结果与铸坯组织特征,分析了铸轧板坯中心线偏析形成过程。结果表明,镁合金铸轧速度显著影响铸轧区熔体的传热与流动过程,并决定铸坯全凝固点位置;铸轧区中熔体沿垂直轧辊面间存在强烈的热交换,铸坯沿传热反方向形成发达的柱状晶,溶质元素在凝固前沿固液界面处发生溶质再分配,Al、Zn元素在上下凝壳焊合位置富集,形成中心线偏析。Heating transferring and flow field during TRC strip were analyzed by numerical simulation to understand effects of rolling velocity on temperature field and flow field under various conditions.Microstructure,morphology and constituent of the TRC magnesium alloy strip were analyzed by OM（optical microscopy）,SEM（scanning electron microscopy）.Based on simulated results and microstructure observation,central-line segregations in magnesium alloys strip was described.The results indicate that the rolling-casting speed has the great effect on heating transferring and flow field of melt in casting-rolling zone,and controlled the full solidification point of the strip.The sharp heating transferring can be observed in the melt along perpendicular to roller surface,resulting in the formation of columnar grain along opposite direction of heating transferring.Solute redistribution occurs in the solid-liquid interface of solidification front,so the Al,Zn element can be enriched in the soldering joint of top-bottom solidified shell,which are responsible for the formation of central-line segregation.

关 键 词：镁合金铸轧 数值模拟 微观组织 中心线偏析 

分 类 号：TG335.9[金属学及工艺—金属压力加工]