| 摘要 |
PROBLEM TO BE SOLVED: To enable medium and high carbon steel to be certainly produced even without using fluorite.SOLUTION: A method of producing medium and high carbon steel is provided in which: a basicity of slag is set to be 0.8 or higher and 1.2 or lower and an oxygen feeding speed is set to be 1.8 Nm/min/t or less at the start of blowing; the oxygen feeding speed is changed to 2.2 Nm/min/t or higher and 3.2 Nm/min/t or lower while the oxygen amount during the blowing is 3%-10% of the total oxygen amount of whole blowing after starting the blowing; a CaO source is charged two times or more while the oxygen amount during the blowing is 40%-70% of the total oxygen amount, where the CaO source is charged at 16 kg/t or less each time and at an interval of one minute or more; the oxygen feeding speed during CaO source charge is set to be 2 Nm/min/t or less; the basicity of slag is set to be 2.5 or higher and 4 or lower at the end of the blowing; and the CaO source of 0.7 kg/ton or more and 5.7 kg/ton or less in a unit consumption is charged after the blowing. |
