铸造速度对半连续铸造过共晶Al-Si合金管坯的影响  

Effects of Casting Speed on Hypereutectic Al-Si Alloy Hollow Billet Fabricated by Direct-chill Casting

作　　者：左克生[1] 张海涛[1] 林兆伟[1] 秦克[1] 崔建忠[1] 

机构地区：[1]东北大学材料电磁过程研究教育部重点实验室

出　　处：《特种铸造及有色合金》2016年第4期407-411,共5页Special Casting & Nonferrous Alloys

基　　金：国家重点基础研究发展计划(973计划)资助项目(2012CB723307-03);国家自然科学基金资助项目(51204046);中央高校基本科研业务费专项资金资助项目(N130409003)

摘　　要：采用半连续铸造制备了尺寸为φ106mm/φ60mm的过共晶Al-Si合金管坯。结合数值模拟和铸造试验,研究了铸造速度对半连续铸造过程和组织的影响。结果表明,随着铸造速度的增加,A390合金管坯中的液穴深度逐渐增加,内壁处重熔层的高度和最高温度逐渐增加。当铸造速度达到240mm/min以上,管坯内壁出现了明显的贫Si层,这是由于熔体的对流作用所致。当铸造速度增加至使Si原子或原子团簇在内侧凝固前沿的附着能力小于冲刷作用时,即在内壁处形成贫Si层。Hypereutectic Al-Si alloy hollow billets with φ106mm/φ60mm in diameter were fabricated by direct-chill casting.Combined numerical simulation with casting experiments,effects of casting speed on casting process and microstructures of the hollow billet were analyzed.The results reveal that with increasing in the casting speed,the sump depth is increased,and the height and the maximum temperature of remelting layer at the inner wall are increased gradually.When the casting speed reaches 240 mm/min,a significant Si-deplete layer is formed at the inner wall,which is attributed to the melt convection at the solidification front.When the casting speed reaches a certain value that the absorption ability of Si atoms or cluster is the lower than that of breaking away at the solidification front,the Si-deplete layer can be formed.

关 键 词：过共晶AL-SI合金 初生SI 数值模拟 铸造速度 管坯 

分 类 号：TG292[金属学及工艺—铸造]