On the Unusual Columnar Zone near the Bottom of a Large Ingot

Akira SUZUKI, Takayasu NIIMI, Hiroyuki NAGATA, Shigeaki TANAKA, Yoshihiro IWATA, Isamu BESSHO
1975 Transactions of the Iron and Steel Institute of Japan  
Synopsis Unusual zones with columnar structure were observed near the bollom of the 100 t ingot. Nl etallographic examination of the unusual z ones has shown that the growth direction of one zone differs from those of other z ones. This means that unusual z ones originally solidify elsewhere and finally settle in the sedimental z one. A s it has p reviously bem prop osed that the tO j) surface of the ingot is the place where the unusual zones originally solidify, the existence of the frozen top
more » ... e of the frozen top crust was checked at the hot top oj a 120 t ingot. Some oj the top crust could be p icked up in the relatively early' stage oj solidification oj the ingot and their structure was also columnar. A small scale experiment using A I-O.2~o Cu alloy proved that the tOj) crust Jormed by jJU tting a chill block 011 the top surface oj the ingot sank to near the bollom of the ingot.
doi:10.2355/isijinternational1966.15.589 fatcat:lyd2q6z5ffhv7cbaagscrexaem