PURPOSE: To decrease considerably the amt. of inclusions in the surface layer part of a stainless steel billet by charging molten steel having a specified amt. of inclusions contained therein into a casting mold and applying a specified flow rate under specific conditions thereto in the specific range under the surface of the molten steel in the casting mold.
CONSTITUTION: The amt. of inclusions of ≥25μm diameter in molten steel 4 prior to charging into a casting mold 3 is specified to ≤15mg for each 10kg of the molten steel in casting continuously a Cr-contg. or Cr-Ni-contg. stainless steel. Such molten steel 4 is charged into the mold 3, and is cast while 10W 30cm/sec flow rate is applied to the molten steel within 3mm from the forward end of the solidified layer 5 in each 30cm width region from the center in the transverse direction of the mold 3 to both sides within the range of 5cm below the surface of the molten steel in the mold 3. For example, a blowing jig 3 of an inverted shape formed with many blow holes 1 is inserted into the prescribed position of the steel 4 and an inert gas is blown at a prescribed flow rate. The stainless steel having the clean surface layer contg. less non-metallic inclusions is thus obtd.
EMI TOSHIHIKO
KOSHIKAWA TAKAO
TANAKA SADAJI
