Jfe Steel Corporation

Jfe Chemical Corporation

Yusuke Fushiwaki

Yoshiyasu Kawasaki

Yoshitsugu Suzuki

Yasunobu Nagataki

Kenji Takahashi

Yoshihiko Ono

Akira Matsuzaki

Kaneharu Okuda

Yoshiharu Sugimoto

Michitaka Sakurai

Mikito Suto

Shoichiro Taira

Ryota Yamaji

Masahiro Yoshida

Satoshi Maeda

Mai Aoyama

Masaki Koba

Ryuta Haga

Hiroshi Hasegawa

Hiroshi Matsuda

Takeshi Matsuda

Takeshi Yokota

Shinjiro Kaneko

Tatsuya Nakagaito

Takashi Kawano

Daisuke Mizuno

Yoichi Makimizu

Saiji Matsuoka

Hiroyuki Masuoka

Nobusuke Kariya

Hayato Saito

Kazuhisa Okai

Shotaro Terashima

Daisuke Harako

Yasushi Madokoro

Provided is spherically-shaped coated graphite exhibiting excellent cycle capacity-maintaining property when used as a negative electrode material for a lithium ion secondary battery. The spherically-shaped coated graphite includes: spherically-shaped graphite in which primary particles with an equivalent spherical diameter of not more than 0.8 &#x3bc;m have a volume ratio of more than 40.0% and not more than 70.0%, and primary particles with an equivalent spherical diameter of not less than 1.5 &#x3bc;m and not more than 3.0 &#x3bc;m have a volume ratio of not less than 3.0% and not more than 17.0%, in a particle size distribution of primary particles obtained using X-ray computed tomography; and a carbonaceous substance covering the spherically-shaped graphite, and a pore volume of pores with a pore size of 7.8 nm to 36.0 nm is not more than 0.017 cm/g, and a mass of infiltrated dibutyl phthalate is less than 0.70 g/cm.

Spherically-shaped coated graphite, negative electrode for lithium ion secondary battery, and lithium ion secondary battery

Provided are carbonaceous substance-coated graphite particles that include: graphite particles; and carbonaceous coatings covering at least part of surfaces of the graphite particles, the carbonaceous substance-coated graphite particles have a maximum particle diameter of 30.0 to 90.0 &#x3bc;m, a pore volume Vof pores with a pore size of 7.8 to 36.0 nm is 0.009 to 0.164 cm/g, and in a pore size distribution graph with the pore size being plotted on a horizontal axis and a dV/dP value obtained by differentiating the pore volume with the pore size being plotted on a vertical axis, a pore size Pwith which the dV/dP value is maximized is 2.5 to 5.5 nm.

Carbonaceous substance-coated graphite particles, negative electrode for lithium ion secondary battery and lithium ion secondary battery

Provided is carbonaceous substance-coated graphite particles that exhibit excellent battery properties when used as a negative electrode material for a lithium ion secondary battery. The carbonaceous substance-coated graphite particles includes: graphite particles; and carbonaceous coatings covering at least part of surfaces of the graphite particles, and the carbonaceous substance-coated graphite particles have a specific surface area Sdetermined by BET method of 4.0 to 15.0 m/g, and a pore volume Vof pores with a pore size of 7.8 to 36.0 nm is 0.001 to 0.026 cm/g, and in a pore size distribution graph with the pore size being plotted on a horizontal axis and a dV/dP value obtained by differentiating the pore volume with the pore size being plotted on a vertical axis, a pore size Pwith which the dV/dP value is maximized is 2.5 to 5.5 nm.

Carbonaceous substance-coated graphite particles, negative electrode for lithium ion secondary battery, and lithium ion secondary battery

A surface-treated steel sheet includes a chemical conversion coating with a thickness of 3.0 &#x3bc;m or less, the chemical conversion coating being placed on a surface of a hot-dip Zn&#x2014;Al alloy coated steel sheet including a hot-dip Zn&#x2014;Al alloy coating film containing Al: more than 1.0 mass % and 15 mass % or less, a balance being Zn and inevitable impurities. The chemical conversion coating contains AlHPO.2HO and a compound containing one or more elements selected from Mg, Ca, and Sr such that a sum of contents of AlHPO.2HO and the compound is 3.0 mass % to 50 mass %.

Surface-treated steel sheet

A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2):(273+)&#xd7;(20+2&#xd7;log())&#x2265;8000&#x2003;&#x2003;(1)40&#x2264;&#x2264;160&#x2003;&#x2003;(2)

High-strength hot-dip galvannealed steel sheet and method for producing same

A method for manufacturing a high-strength galvanized steel sheet having excellent strength-elongation balance, coating adhesiveness, and surface appearance. The method includes: (i) a first heating process of heating a steel sheet having a predetermined chemical composition, (ii) a first pickling process of pickling the steel sheet which was subjected to the first heating process in an oxidizing acidic aqueous solution, (iii) a second pickling process of pickling the steel sheet which was subjected to the first pickling process in a non-oxidizing acidic aqueous solution, (iv) a second heating process of holding the steel sheet, which was subjected to the second pickling process, at a temperature range of 700&#xb0; C. or higher and 900&#xb0; C. or lower in a hydrogen-containing atmosphere for 20 seconds or more and 300 seconds or less, and (v) performing a galvanizing treatment on the steel sheet which was subjected to the second heating process.

Method for manufacturing high-strength galvanized steel sheet

There is provided a high-strength hot-dipped steel sheet having excellent coating adhesion and a method for manufacturing the steel sheet. The steel sheet has a chemical composition, and a coating layer is disposed on the steel sheet. The chemical composition includes, by mass %, C: 0.02% or greater and 0.30% or less, Si: 0.01% or greater and 2.0% or less, Mn: 0.2% or greater and 3.0% or less, P: 0.08% or less, S: 0.02% or less, and Al: 0.001% or greater and 0.40% or less, with the balance being Fe and incidental impurities. The coating layer has a coating weight per side of 30 to 90 g/mand contains exfoliated base steel in an amount of 0.3 to 1.5 g/m.

High-strength hot-dipped steel sheet having excellent coating adhesion and method for manufacturing same

Provided are a high-strength galvanized hot-rolled steel sheet and a method for manufacturing the steel sheet. A steel sheet has a chemical composition, and a galvanized layer is disposed on the steel sheet. The chemical composition includes, in mass %, C: 0.02% or greater and 0.30% or less, Si: 0.01% or greater and 2.5% or less, Mn: 0.3% or greater and 3.0% or less, P: 0.08% or less, S: 0.02% or less, and Al: 0.001% or greater and 0.20% or less. The galvanized layer has a coating weight per side of 20 to 120 g/m. A surface of the steel sheet has a specific surface area ratio, r, of 2.5 or less, and an amount of Si present in the galvanized layer and an amount of Mn present in the galvanized layer respectively satisfy: amount of Si&#xd7;r&#x2264;0.06, and amount of Mn&#xd7;r&#x2264;0.10.

High-strength galvanized hot-rolled steel sheet and method for manufacturing same

A method for manufacturing a high strength galvanized steel sheet and a high strength galvanized steel sheet are provided. A base steel sheet having a chemical composition comprising C: 0.03% to 0.35%, Si: 0.01% to 0.50%, Mn: 3.6% to 8.0%, Al: 0.001% to 1.000%, P&#x2264;0.10%, S&#x2264;0.010%, and the balance comprising Fe and incidental impurities, on a percent by mass basis, is subjected to annealing and galvanization treatment, wherein the maximum steel sheet temperature in an annealing furnace is 600&#xb0; C. or higher and 700&#xb0; C. or lower, the steel sheet transit time in a temperature region of the maximum steel sheet temperature of 600&#xb0; C. or higher and 700&#xb0; C. or lower is specified to be 30 seconds or more and 10 minutes or less, and the dew point in an atmosphere is specified to be &#x2212;45&#xb0; C. or lower.

Method for manufacturing high strength galvanized steel sheet and high strength galvanized steel sheet

A high-strength steel sheet and a method for manufacturing a high-strength steel sheet having excellent phosphatability and excellent corrosion resistance after electrodeposition coating has been performed, even in the case where the contents of Si and Mn are high. The method may comprise annealing a steal sheet by using a continuous annealing method, performing a heating process, controlling the maximum end-point temperature of a steel sheet in the annealing furnace, controlling the traveling time of the steel sheet, and controlling the dew point of the atmosphere.

High-strength steel sheet and method for manufacturing the same

A method for manufacturing a high strength galvanized steel sheet which has a zinc coating layer with an amount of deposition of coating of 20 to 120 g/mper one surface on the surface of a base steel sheet having a chemical composition comprising C: 0.03% to 0.35%, Si: 0.01% to 0.50%, Mn: 3.6% to 8.0%, Al: 0.001% to 1.000%, P&#x2264;0.10%, S&#x2264;0.010%, and the balance comprising Fe and incidental impurities, on a percent by mass basis, is provided. In annealing and galvanization treatment of the base steel sheet in a continuous galvanizing line, the maximum steel sheet temperature in an annealing furnace is 600&#xb0; C. or higher and 750&#xb0; C. or lower, the steel sheet transit time in a temperature region of the steel sheet temperature of 600&#xb0; C. or higher and 750&#xb0; C. or lower is specified to be 30 seconds or more and 10 minutes or less, and the dew point in an atmosphere is specified to be &#x2212;10&#xb0; C. or higher.

Method for manufacturing high strength galvanized steel sheet

Disclosed is a high-strength hot-dip galvanized steel sheet produced from a steel sheet containing Si and Mn as a base material and a method for producing the same. The method using the following conditions for a heating process for annealing: (1) The rate of temperature rise when the temperature inside an annealing furnace is in a temperature range of from 450&#xb0; C. to A&#xb0; C. inclusive (where A is an arbitrary value selected in a range of 500&#x2264;A) is 7&#xb0; C./sec. or more; (2) The maximum steel sheet temperature reached during the annealing is 600&#xb0; C. or higher and 750&#xb0; C. or lower; (3) When the temperature of the steel sheet is in a temperature range of from 600&#xb0; C. to 750&#xb0; C. inclusive during the annealing, the transit time of the steel sheet is 30 seconds or longer and 10 minutes or shorter, and the dew point of an atmosphere is &#x2212;45&#xb0; C. or lower.

High-strength hot-dip galvanized steel sheet and method for producing same

Provided is a high-strength steel sheet that has good chemical convertibility and good corrosion resistance after electro deposition painting despite high Si and Mn contents. Also provided are a method for producing the high-strength steel sheet, a high-strength galvanized steel sheet formed by using the high-strength steel sheet, and a method for producing the high-strength galvanized steel sheet. A steel sheet containing, in terms of % by mass, C: 0.03 to 0.35%, Si: 0.01 to 0.50%, Mn: 3.6 to 8.0%, Al: 0.001 to 1.00%, P&#x2264;0.10%, S&#x2264;0.010%, and the balance being Fe and unavoidable impurities is annealed under condition under which a dew point of an atmosphere in a temperature zone of 550&#xb0; C. or higher and A&#xb0; C. or lower (A is a particular value that satisfies 600&#x2264;A&#x2264;750) inside an annealing furnace is controlled to &#x2212;40&#xb0; C. or lower.

High-strength steel sheet and production method therefor and high-strength galvanized steel sheet and production method therefor (as amended)

A galvannealed steel sheet includes a zinc coating layer containing 7 to 15% Fe on the surface of steel sheet including, C: 0.02% to 0.30%, Si: 0.01% to 2.5%, Mn: 0.1% to 3.0%, P: 0.003% to 0.08%, S: not more than 0.01%, Al: 0.001% to 0.20%, one or more selected from Ti: 0.03% to 0.40%, Nb: 0.001% to 0.2%, V: 0.001% to 0.2%, Mo: 0.01% to 0.5% and W: 0.001% to 0.2%. In the zinc coating layer, carbides with average particle size of 1 nm to 20 nm including one or more selected from titanium, niobium, vanadium, molybdenum and tungsten are present with a density of five or more particles per segment that is defined by the thickness of the coating layer and also by dividing a cross section of the coating layer at intervals of 1 &#x3bc;m in a direction perpendicular to the thickness of the coating layer.

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Fukuyama, Japan

Yusuke Fushiwaki