Solidification of Steel Billets in the Mold of a Synchronized Rotary Type Continuous Caster

Abstract

A high speed continuous billet caster where casting speed matches the rolling speed has been developed. The caster consists of a copper wheel with a groove and an endless steel belt, both strongly cooled by water. There is almost no friction between mold and billet because of the mold moving simultaneously with the billet. In the course of development two studies were performed to establish the optimum casting and operating conditions. The first was to investigate the effect of casting temperature on the shell thickness. The second was with heat transfer characteristics of rotating wheel. The results are summarized as follows.
(1) The shell thickness of belt side was smaller than that of wheel side when the molten steel with large superheat was poured.
(2) Water modelling test revealed that downward flow with high velocity existed along belt side and upward flow along wheel side.
(3) The allowable superheat was estimated to be 50 C by computer calculation on solidification.
(4) Tension casting where the pinch rollers were controlled at a slightly higher rate than the wheel was effective to straighten the billets without any trouble.
From these results the optimum conditions were established and the belt wheel type continuous caster was finally practised.