Observation of Hot Tearing in Sr-B Modified A356 Alloy
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Dosyalar
Tarih
2017
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Polska Akad Nauk, Polish Acad Sciences
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
In this work, T-shaped mould design was used to generate hot spot and the effect of Sr and B on the hot tearing susceptibility of A356 was investigated. The die temperature was kept at 250 degrees C and the pouring was carried out at 740 degrees C. The amonut of Sr and B additions were 30 and 10 ppm, respectively. One of the most important defects that may exist in cast aluminium is the presence of bifilms. Bifilms can form by the surface turbulence of liquid metal. During such an action, two unbonded surfaces of oxides fold over each other which act as a crack. Therefore, this defect cause many problems in the cast part. In this work, it was found that bifilms have significant effect over the hot tearing of A356 alloy. When the alloy solidifies direetionally, the structure consists of elongated dendritic structure. In the absence of equiaxed dendrites, the growing tips of the dendrites pushed the bifilms to open up and unravel. Thus, leading to enlarged surface of oxide to become more harmful. In this case, it was found that these bifilms initiate hot tearing.
Açıklama
Anahtar Kelimeler
A356, Casting, Melt quality, Grain refinement, Hot tearing
Kaynak
Archives Of Foundry Engineering
WoS Q Değeri
N/A
Scopus Q Değeri
Q3
Cilt
17
Sayı
4
