PURPOSE: To melt an Cr-containing dead soft steel with low Cr loss and in a short time by adding H2-containing material after executing vacuum decarburization or oxygen top-blowing decarburization to reduce the carbon concn. in the Cr-containing steel within a prescribed range and executing hydrogen addition treatment.
CONSTITUTION: The Cr-containing steel is decarburized to the extremely low carbon zone by using a vacuum degassing apparatus. In the melting of the Cr-containing dead soft steel, after executing the vacuum decarburization or the oxygen top-blowing decarburization to the prescribed carbon concn. in the steel, the H2-containing material is added to execute the hydrogen addition treatment. This hydrogen addition treatment can be executed, e.g. by top-blowing the H2-containing gas or by blowing this gas below the bath surface. Further, after oxygen concn. in the steel reaches a critical oxygen concn. (%O) cwt% obtd. with the equation: log (%O) C=-(146.80/T)+0.0126 (%Cr) +0.03 (in the equation, (%Cr): Cr concn. in steel %, T: molten steel temp. K), the hydrogen additional treatment is desirably started to prevent excess oxidation of Cr and retardation of the decarburization.
| JPS56162394 | REMOVAL OF SLAG |
| JPH0192314 | LADLE REFINING METHOD |
HARA YOSHIAKI
SAKURATANI TOSHIKAZU
TAKEUCHI HIDEJI
