( 1. 東北大學(xué) 材料電磁過程重點(diǎn)實(shí)驗(yàn)室，沈陽 110004;
2. 沈陽航空工業(yè)學(xué)院 航空宇航工程學(xué)院， 沈陽 110034)
摘 要: 采用異相位電磁連鑄技術(shù), 制備d290 mm×35 mm的鋁合金空心管坯， 研究異相位電磁場對鑄錠凝固組織及表面質(zhì)量的影響。 結(jié)果表明： 異相位電磁場通過改變金屬熔體的流動(dòng)狀態(tài)， 減少原子團(tuán)簇上角隅的形成， 降低熔體及凝固前沿的溫度梯度等機(jī)制， 可使Al熔體內(nèi)產(chǎn)生爆發(fā)式形核， 增加晶核數(shù)量， 抑制枝晶生長， 從而可細(xì)化、 球化晶粒， 改善鑄錠凝固組織， 避免裂紋的產(chǎn)生; 同時(shí)， 異相位電磁場通過作用于初凝殼內(nèi)液態(tài)金屬熔體以及初凝殼本身的電磁力， 降低了結(jié)晶器與初凝殼的接觸壓力、 減小了鑄錠表面的摩擦并抑制了偏析瘤的形成， 從而提高鋁合金空心管坯的內(nèi)外表面質(zhì)量。
關(guān)鍵字: 鋁合金； 電磁鑄造； 凝固組織； 表面質(zhì)量
casting of hollow billet
（ 1. Key Laboratory of Electromagnetic Processing of Materials,
Northeastern University, Shenyang 110004, China)
2. Institute of Aeronautical Engineering, Shenyang Institute of Aeronautical Engineering, Shenyang 110034, China）
Abstract: Under the out-phase electromagnetic field, Al alloy hollow billet of d290 mm×35 mm was semi-continuously cast, the effect of out-phase electromagnetic on as-cast microstructures and surface quality were investigated. The results show that the out-phase magnetic field changes the flow of metal melt, reduces the corner, reduces the temperature gradient of melt and solidification front, which gives rise to fulminic nucleation, increases the magnitude of crystal nucleus, restraines the growth of dendritic crystal in melt aluminium, the refines crystal grain, improves solidification structure, and eliminates phenomenon of crack. Simultaneously, Lorentz force that acts on the metal melt and initial skull reduces the contact pressure between the crystallizer and the initial skull, decreases the friction of ingot surface, restrains the form of segregation burl, and improves the surface quality of Al alloy hollow billet.
Key words: aluminum alloy; electromagnetic casting; solidification structure; surface quality
