PURPOSE: To produce a hollow bloom for steamless steel pipe continuously and efficiently with simple stage at a low cost by subjecting the continuously case bloom to bloom piercing in succession to the continuous casting while keeping the bloom at the piercing temp.
CONSTITUTION: The bloom B which is obtained when the molten metal charged from a tundish 1 into a mold 2 solidifies during passing through curtain rolls 3 is kept at the piercing temp. in succession and in this state, the bloom is forced onto a plug 10 by means of thrusting pinch rolls 4 and rolling and piercing rolls 6, whereby a hollow bloom B' is formed. At the point of the time when the bloom B' attains a prescribed length, the bloom is cut with a movable round cutter 7, and the piercing is interrupted temporarily. The plug 10 is pulled down, and the hollow bloom B' is carried to the outside of the system by a carriage 8 for carrying out. The piercing is resumed upon resetting of the carriage 8 and the plug 10. The above-mentioned plug 10 is moved upward and downward and is held by driving of a plug cylinder 13 mounted to a holding frame 9.
NAKAGAWA KICHIZAEMON