PURPOSE: To form a defectless joining boundary between a cladding material and a molten steel by fixing the cladding material on the inside wall of a casting mold and suspending a charging pipe into the mold then adding continuously a specific amt. of Al grains at the same instant when a rimmed steel is charged through the charging pipe.
CONSTITUTION: A descaled cladding material 2 is preliminarily fixed on the inside wall of a casting mold 1. A charging pipe 3 for a molten steel is suspended in the central part of the space in the mold 1. The pipe 3, made in a square cylindrical shape, has about 1W3mm thickness and has the length at which the pipe is positioned upward by about 20W50mm from the base of the casting mold. The space between the inside surface of the material 2 and the inside surface of the mold 1 is maintained at about 150W 250mm. A rimmed steel kept at about 1,530W1,600°C is charged to the central part of the pipe 3 at about 5W20mm/sec in the rising speed of the molten metal surface; at the same time, granular Amm having a grain size of 0.3W3.0g/grain is added continuously at 10W100g per ton of the molten metal charged into the mold to said mold. The foam of the gaseous CO2 generated in the process of solidification cleans the inside surface of the material 2 on account of the flow A, thereby making the joining boundary defectless. The Al grains are added to control the vigorous generation of the gaseous CO2.
YASUMOTO KUNIO
NAKAMURA TAKESHI
