To prevent occurrence of defects, such as adhesion failure of joined surface, blow hole, sticking of impurity by making clean the joining surface of molten base steel and a joining material, applying a carburizing preventing treatment, applying a scum repulsing agent on the joining surface, preheating and drying, and immediately pouring the molten steel.
After setting the joining material 1 in a mold A, further, a scum repulsing agent preheating heater 7 is set at a prescribed position in a mold A. Successively, a preheating up to set temp. of a scum repulsing agent 2 is executed by the scum repulsing agent preheating heater 7. When immediately pouring the molten base steel (5) from a pouring hole 12 after taking out the scum repulsing agent preheating heater 7 from the mold A before casting, the sticking of the scum floating on the molten steel to the joining surface of the joining material 1 is prevented by the scum repulsing agent 2, and the scum is lifted by the molten base steel (5) poured successively. Therefore, the clad steel ingot excellent in press-stickiness in the joining surface can be obtd. and the occurrence of bulging flaw caused by the scum, etc., in the finish product can be restrained.
KUMASAKA MISAO
YASUOKA KAZUYOSHI
