Abstract
After the energy crisis the steel industry is required to minimize its energy consumption. Direct connection with a hot rolling process in continuous casting is one of the solutions for this problem. Furthermore along with the developments of the continuous casting process, new casting processes are presently under development with the objective of eliminating most parts of the rolling and heating processes.
As the solidification rate of the rapidly solidified plate in the new casting processes is 100103°C/s, the properties of the cast plate are expected to be improved. As the first step in our experiment, the properties of cast iron and high carbon steel were investigated.
Thin sheets of cast iron were made by the twin roll test caster and cold rolling. Cold rolling was attainable due to the fine spheroidal graphite structure formed by the rapid solidification and the following annealing.
Furthermore, rapid solidification of high carbon steel was investigated by using the water-cooled chill block apparatus, which was supposed to function similarly to a caterpillar type caster. The rapid solidification promoted less macrosegregation and finer MnS inclusions.
It is well known that in the high carbon steel, the heat treatment is necessary for spheroidizing the cementite structure. It was proved, however, by the rapid cooling at eutectoid temperature, the spheroidal cementite structure was obtained in a relatively shortened annealing time.
