METHOD FOR PRODUCING STEEL MATERIAL

摘要

A method for producing a steel material according to the present invention is characterized by adjusting the amount of Ca to a value falling within a range in which a specified equation is satisfied and then adding the adjusted amount of Ca to a molten steel. It is possible to analyze the amount of Al2O3 in the molten steel and then adding CaSi to the molten steel in a ladle after the secondary refining. It is also possible to: carry out the analysis of the amount of Al2O3 in the molten steel by a spark discharge atomic emission spectrometric analysis method; determine a light emission intensity ratio, i.e., the ratio of the intensity of light emitted upon the application of multiple times of electric discharge pulses in aluminum to that in iron, with respect to each of the electric discharge pulses; calculate an alumina fraction in accordance with a specific equation; arrange the light emission intensity ratios determined with respect to the electric discharge pulses in ascending order; determine, as a representative aluminum intensity ratio, a light emission intensity ratio at a certain position located within a range that is equal to or smaller than 30% of the total electric discharge pulse number; then calculate an alumina intensity ratio [= (alumina fraction) × (representative aluminum intensity ratio)] from the product of the calculated alumina fraction and the representative aluminum intensity ratio; and calculate the amount of alumina (in the steel) using the relational expression between the alumina intensity ratio and the amount of alumina (in the steel) calculated by chemical analysis.