Jfe Steel Corporation

Tomoharu Ishida

Kaoru Sato

Katsumi Yamada

Tetsuya Yamamoto

Satoshi Kinoshiro

Yuji Miki

Norichika Aramaki

Toru Inoue

Hisato Noro

Masamichi Kikuchi

Tomoyoshi Ogasahara

Yoshie Nakai

Kohei Furumai

Takeshi Murai

Shuji Kuyama

Yukio Usui

Keisuke Mizobata

Kohei Tandokoro

Sara Arakawa

A decarburization end point determination method includes: estimating the carbon concentration and oxygen concentration of the molten steel and carbon dioxide gas concentration of exhaust gas in the vacuum chamber by using measurement values of the carbon concentration and the oxygen concentration of the molten steel, a measurement value of internal pressure of the vacuum chamber, and a model formula; correcting a parameter included in the model formula to reduce at least one of a difference between an estimate value and a measurement value of the oxygen concentration and a difference between an estimate value and a measurement value of the carbon dioxide gas concentration of the exhaust gas; estimating the carbon concentration of the molten steel by using the model formula in which the parameter is corrected; and determining timing when an estimate value reaches a target value as the completion time point of the vacuum decarburization treatment.

Decarburization end point determination method, decarburization end point determination device, secondary refining operation method for steel making, and method for producing molten steel

A method of producing a steel material includes a step of adding Ca to molten steel with an amount of Ca adjusted within a range satisfying the formula (1) below: where Ca is the amount [kg] of Ca added, y is an yield [%] of Ca, [S] is a concentration [% by mass] of S in the steel before addition of Ca, [AlO] is an amount [% by mass] of AlOin the steel before addition of Ca, and W is a weight [kg] of the molten steel.

Method of producing steel material

A method for analyzing a metal material includes electrolyzing a metal sample in an electrolytic solution, immersing a remaining portion of the metal sample taken out of the electrolytic solution in a dispersible solution to separate at least one substance selected from the group consisting of precipitates and inclusions attached to the remaining portion of the metal sample, filtering the dispersible solution containing the at least one separated substance through filters having straight pores and a porosity of 4% or more to obtain residues trapped on the filters and filtrates, and analyzing at least one of the residues and the filtrates.

Method for analyzing metal material

A method for analyzing a metallic material includes the steps of electrolyzing a metal sample in an electrolyte; removing the electrolyzed metal sample from the electrolyte; immersing the metal sample removed from the electrolyte into a dispersive solution that is different from the electrolyte to separate at least one selected from the group consisting of a precipitate and an inclusion deposited on the metal sample; and analyzing the at least one selected from the group consisting of a precipitate and an inclusion extracted into the dispersive solution.

Method for analysis of metal inclusions in steels by partial electrolysis

A method for analyzing a metal specimen includes an electrolysis step of electrolyzing a metal specimen containing a reference element and a target element in an electrolytic solution, a sampling step of sampling a portion of the electrolytic solution, an analysis step of analyzing the sampled electrolytic solution, a concentration ratio-calculating step of calculating the concentration ratio of the target element to the reference element in the electrolytic solution on the basis of the analysis results, and a content-calculating step of calculating the content of the target element present in the form of a solid solution by multiplying the content of the reference element in the metal specimen by the obtained concentration ratio.

Method for analyzing metal specimen

Growing community of inventors

Tokyo, Japan

Tomoharu Ishida