Jfe Steel Corporation

Hirohide Uehara

Yoichi Ito

Takashi Yamauchi

Tatsuro Katsumura

Kazuaki Hirakawa

Koichiro Hirata

Isao Shimoda

An operation method of ladle refining treatment by which ladle refining treatment of a molten steel is performed while continuously measuring a molten steel temperature during operation of the ladle refining treatment of the molten steel is provided. The operation method includes setting a time earlier than a scheduled ending time of the ladle refining treatment in a continuous measurement period of the molten steel temperature as a determination timing, and estimating the molten steel temperature at the scheduled ending time on the basis of a change with time of the molten steel temperature in continuous measured data of the molten steel temperature from a start of continuous measurement of the molten steel temperature to the determination timing.

Operation method of ladle refining treatment

A method of manufacturing a round steel billet by continuous casting includes a local cooling step where inhomogeneous forced cooling is applied to a cast product during the continuous casting, and a rolling reduction step where rolling reduction is applied to the cast product in the opposite directions of the polar opposites by reduction rolls in the course from the completion of solidification to the completion of the recuperation of the cast product so that rolling reduction r which is a reduction ratio of a distance between middle points of the polar opposites is set to a value exceeding 0% and 5% or less.

Method of manufacturing round steel billet

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Chiba, Japan

Hirohide Uehara