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Collision‐controlled growth of composites in casting nozzles
Author(s) -
Fix Wolfdietrich,
Jacobi Hatto,
Wünnenberg Klaus
Publication year - 1993
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199300985
Subject(s) - nozzle , ladle , tundish , materials science , metallurgy , composite material , continuous casting , airlift , liquid steel , chemistry , mechanical engineering , engineering , organic chemistry , bioreactor
Like the open‐stream nozzles and submerged entry nozzles on c.c. tundishes, ladle nozzles can also become blocked. Accumulations of Al 2 O 3 , CaO · 2Al 2 O 3 , CaO · Al 2 O 3 , MgO · Al 2 O 3 and Ti 3 O 5 particles were observed on five sleeves removed from rotary ladle nozzles. The type of particles suspended in the steel depends on metallurgy. Growth takes place in bushy ramification in a coral‐shaped structure and is controlled by flow separation, interfacial turbulence and gradient collision. Heat transfer on the nozzle wall is impaired. Steel which has infiltrated freezes if a heat sink is present. A stable composite of steel and oxide is formed. CaS depositions in c.c. tundish submerged entry nozzles are also examined. These CaS deposits become coated with viscous aluminates of the (C 12 A 7 + CA) type, prior, here too, to impregnation with steel. The overall result is a reduction in interfacial energy.