| 摘要 |
PURPOSE: A method for designing mold powder is provided to secure optimum product quality by understanding carbon melting speed control mechanism clearly, thereby controlling content and grain size of coke in accordance with characteristics of steel type cast. CONSTITUTION: The method for preparing mold powder by controlling content and size of coke is characterized in that an average grain size of base material of the mold powder is 30 to 50 μm, grain size of coke added to control mold powder melting rate is controlled to R/r>2.0 in types of steel for requiring carburizing reduction of cast slab while content of coke is controlled to 2 wt.% or less, grain size of coke added to control mold powder melting rate is controlled to R/r<0.5 in types of steel for requiring heat reserving property and clean steel while content of coke is controlled to 6 wt.% or more, and grain size of coke added to control mold powder melting rate is controlled to 0.5<R/r<2.0 in types of steel for requiring both carburizing prevention and heat reserving property while content of coke is controlled to 2 to 6 wt.%, wherein R is an average grain size of mold powder base material (average diameter in case of spherical shape), and r is an average grain size of coke (average diameter in case of spherical shape).
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