Jfe Steel Corporation

Kyoko Fujimoto

Satoshi Kinoshiro

Hiroshi Kajiyama

Yoichi Makimizu

Masayasu Nagoshi

Hiroyuki Masuoka

Katsuya Hoshino

Naoto Yoshimi

Shinji Ootsuka

Toshiyuki Ito

Wataru Tanimoto

Masao Inose

Masahiko Tada

Sakae Fujita

Yoichi Tobiyama

Makoto Shimura

Ryo Kawabata

Toshiro Ishige

Susumu Satoh

Takashi Kawano

Shigeru Unami

Yukiko Ozaki

Kazuaki Kyono

Tomoshige Ono

Kazutoshi Hanada

A method for desulfurizing molten steel comprising taking a sample out from molten steel after tapping from a converter or during secondary refining and analyzing the sample rapidly with high accuracy by a method comprising a high frequency induction heating step wherein the sample is combusted and oxidized under the high frequency induction heating in an oxygen atmosphere having an oxygen purity of 99.5 vol % or more to convert S in the sample into SOand an analyzing step wherein SO-containing gas produced in the high frequency induction heating step is analyzed through an ultraviolet fluorescence method to quantify S concentration of the sample.

Molten steel desulfurization method, molten steel secondary refining method, and molten steel manufacturing method

A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)&#xb7;ZnSO&#xb7;xHO is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)&#xb7;ZnSO&#xb7;3-5HO.

Zinc-based metal plated steel sheet

In a method for desulfurizing hot metal by analyzing S concentration of a sample taken out from the hot metal, the S concentration is analyzed rapidly and precisely by a method comprising a high frequency induction heating step of oxidizing the sample under a high frequency induction heating in a pure oxygen atmosphere to convert S in the hot metal to SOand an analysis step of analyzing SO-containing gas generated in the high frequency induction heating step through an ultraviolet fluorescence method to quantify S concentration in the sample, whereby S concentration after the desulfurization is controlled precisely and hence fault of S concentration is prevented but also the increase of the cost due to the excessive addition of a desulfurization agent and step disruption at steel-making step are prevented.

Method for desulfurizing hot metal

An analyzing method which enables highly precise and rapid quantitative analysis of sulfur contained in a metal sample, includes: combusting a metal sample containing a sulfur component under pure oxygen gas atmosphere to oxidize the sulfur component into sulfur dioxide; and quantitatively analyzing sulfur in the metal sample through analysis, according to a UV fluorescence method, of a sulfur dioxide containing gas containing the sulfur dioxide generated by combustion of the metal sample.

Method and device for analyzing sulfur in metal sample

A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH).ZnSO.xHO is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH).ZnSO.3-5HO.

Flowability-improving particles containing 50 to 100% by mass of carbon black are adhered to surfaces of iron powder through a binder to provide an iron-based powder for powder metallurgy which has excellent flowability and which is capable of uniformly filling a thin-walled cavity, compaction with high ejection force, and maintaining sufficient strength of a sintered body in subsequent sintering.

Iron-based powder for powder metallurgy

An alloyed hot-dip galvanized steel sheet is obtained by forming a hot-dip galvanized layer on the surface of the steel sheet and then alloying the steel sheet. The steel sheet exhibits a potential of &minus;850 mV or less when it is immersed in a zinc sulfate-sodium chloride electrolyte. Alternatively, when it is electrolyzed according to constant potential electrolysis process in a zinc sulfate-sodium chloride electrolyte at a potential in a range from &minus;940 mV to &minus;920 mV, the quantity of electricity consumed is less than or equal to 0.5 C/cm . The steel sheet exhibits excellent processability and particularly excellent sliding property.

Alloyed galvanized steel plate having excellent slidability

A method for determining a quantity of each of alloy phases in the plating layer includes subjecting each alloy phase in the plating layer to constant potential electrolysis in each of a plurality of ranges of potentials obtained on the basis of the immersion potential of each alloy phase and the immersion potential of a basis metal, by using a plated metal material having different kinds of alloy phases in the plating layer as the anode, to determine the quantity of each alloy phase in the plating layer on the basis of the quantity of electricity consumed in each range of the potentials during the electrolysis.

Method for determining alloy phase in plating layer and method for evaluating sliding property of alloy galvanized steel plate

Growing community of inventors

Chiba, Japan

Kyoko Fujimoto