METHOD OF CONTINUOUS CASTING OF HIGH-ALUMINUM STEEL AND MOLD POWDER

摘要

A method of continuous casting, in which even in the production of a high-aluminum steel with an Al content of 0.1% or higher through continuous casting, a cast piece excelling in surface quality can be produced while preventing the occurrence of depression and cast piece cracking. In the continuous casting of a high-Al molten steel with given chemical components using a mold powder, use is made of a mold powder composed of 35 to 55% T-CaO, 10 to 30% SiO<SUB>2</SUB>, 4.0% or less (not including 0%) Al<SUB>2</SUB>O<SUB>3</SUB>, 0.2 to 1.0% MgO, 7 to 13% Li<SUB>2</SUB>O, 7 to 13% F, 10.5 to 14% C and unavoidable impurities, satisfying the relationships 1.6=[T-CaO]/[SiO<SUB>2</SUB>]=5 and 0.2=[Li<SUB>2</SUB>O]/[SiO<SUB>2</SUB>] =1.1. Further, the operation is carried out while controlling the conditions of rate of melt surface level fluctuation within casting mold, angle of molten steel discharge to a direction of width of casting mold, amplitude stroke, negative strip time (tN) determined by given relationship formula, etc.