Jfe Steel Corporation

Takahiko Maeda

Yusuke Vincent Fujii

Naoki Kikuchi

Yoshie Nakai

Yuji Miki

Shinichi Nagai

Yusuke Fujii

Naoya Shibuta

Mikihiro Mori

Noritaka Nishiguchi

When performing dephosphorization treatment of hot metal by adding a refining agent as a lime source and an oxygen source (dephosphorizing agent(s) and a gaseous oxygen source into the hot metal accommodated in a hot metal holding container, the refining agent used is a refining agent having an Ig-loss value of from 4.0% by mass to 35.0% by mass and including 60% by mass or more of quicklime.

Method for dephosphorization of hot metal, and refining agent

A molten steel refining method includes throwing a powder to molten steel while heating the powder with a flame formed by combustion of a hydrocarbon gas at the leading end of a top blowing lance. The lance height of the top blowing lance (the distance between the static bath surface of the molten steel and the leading end of the lance) is controlled to 1.0 to 7.0 m, and the dynamic pressure P of a jet flow ejected from the top blowing lance calculated from equation (1) below is controlled to 20.0 kPa or more and 100.0 kPa or less. P=&#x3c1;&#xd7; U/2 . . . (1) wherein P is the dynamic pressure (kPa) of the jet flow at an exit of the top blowing lance, &#x3c1;the density (kg/Nm) of the jet flow, and U the velocity (m/sec) of the jet flow at the exit of the top blowing lance.

Method for refining molten steel in vacuum degassing equipment

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Tokyo, Japan

Takahiko Maeda