Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Nippos Steel Corporation

Tomohito Tanaka

Yuri Toda

Kazuo Hikida

Shingo Fujinaka

Takashi Kataoka

Masataka Iwaki

Kazutoshi Takeda

Daisuke Maeda

Jun Nakagawa

Hideyuki Hamamura

Yasunobu Miyazaki

Fuminori Watanabe

Seiji Furusako

Hideki Hamatani

Yasuaki Kawamura

Hatsuhiko Oikawa

Yuji Sakiyama

Tetsuya Toba

Shintaro Uemura

This grain-oriented electrical steel sheet includes a base steel sheet, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, in which, in the base steel sheet, a plurality of linear strain regions that extend continuously or intermittently in a direction intersecting with a rolling direction are present, the plurality of linear strain regions are each 210 μm or less in width in the rolling direction, the plurality of linear strain regions are parallel to each other, intervals of linear strain regions adjacent to each other in the rolling direction are 10 mm or less, and magnetostriction λin a unit of μm/m when the grain-oriented electrical steel sheet is excited up to 1.7 T and magnetostriction λin a unit of μm/m when the grain-oriented electrical steel sheet is heat-treated at 800° C. for 4 hours and then excited up to 1.7 T satisfy 0.02≤λ−λ≤0.20.

Grain-oriented electrical steel sheet and method for manufacturing same

This grain-oriented electrical steel sheet includes a base steel sheet having a predetermined chemical composition, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, on a front surface of the base steel sheet, a plurality of linear strains that extend continuously or intermittently in a direction intersecting with a rolling direction are present, intervals p in the rolling direction of the plurality of linear strains adjacent to each other are 3.0 to 9.0 mm, widths of the linear strains are 10 to 250 μm, and, in an X-ray topographic spectrum in a range of 1.50 mm in the rolling direction that is obtained from an X-ray topographic image of the front surface and includes the linear strain at a center, a full width at half maximum of a peak of the X-ray topographic spectrum including a maximum value of a spectral intensity is 0.02 mm or more and 0.10 mm or less.

A hot-dip plated steel sheet includes a hot-dip plated layer formed on a surface of a steel sheet, the hot-dip plated layer contains 4 to 22 mass % of Al and 1.0 to 10 mass % of Mg with a remainder including Zn and impurities. A pattern portion and a non-pattern portion are formed in the hot-dip plated layer. An element concentrated region containing an element M and an interface alloy layer containing Fe and Al are present at an interface between the steel sheet and the hot-dip plated layer in the pattern portion. An average concentration of the element M contained in the hot-dip plated layer present in the pattern portion and the element concentrated region is 0.0010 to 2 mass %. In the element concentrated region, the element M is concentrated two or more times the hot-dip plated layer present in the pattern portion, or the element M is unevenly distributed.

Hot-dip plated steel sheet

A hot-stamped article according to the present invention has a plating layer being attached in an amount of 10 g/mor more and 90 g/mor less and having a Ni content of 10 mass % or more and 25 mass % or less with a remainder including Zn and an impurity on a surface of a base steel sheet having a predetermined chemical composition, a surface layer region includes 90.0% or more of martensite in terms of area percentage, and a concentration of Ni in a prior austenite grain boundary in the surface layer region is 5.5 mass % or more.

Hot-stamped article

A hot-stamping formed body includes: a steel sheet having a predetermined chemical composition; and a plating layer provided on a surface of the steel sheet, the plating layer having an adhesion amount of 10 g/mto 90 g/mand a Ni content of 10 mass % to 25 mass %, and containing a remainder consisting of Zn and impurities. The hot-stamping formed body includes, in a surface layer region of the steel sheet, an average grain size of prior austenite grains to 10.0 μm or less, a Ni concentration per unit area at grain boundaries having an average crystal orientation difference of 15° or more is 1.5 mass %/μmor more.

Hot-stamping formed body

A hot stamped article having excellent shock absorption having a predetermined chemical composition, having a microstructure containing prior austenite having an average grain size of 3 &#x3bc;m or less and further containing at least one of lower bainite, martensite, and tempered martensite in an area ratio of 90% or more, and having a grain boundary solid solution ratio Z defined by Z=(mass % of one or both of Nb and Mo at grain boundaries)/(mass % of one or both of Nb and Mo at time of melting) of 0.3 or more.

Hot stamped article

A steel sheet for hot stamping use used as a material for a hot stamped article excellent in strength or bending deformability, having a predetermined chemical composition, having a microstructure containing at least one of lower bainite, martensite, and tempered martensite in an area ratio of 90% or more, having an X-ray random intensity ratio of {112}&#x3c;111&#x3e; of the crystal grains forming the above lower bainite, martensite, or tempered martensite of 2.8 or more, having a number density of grain size 50 nm or less cementite or epsilon carbides in the microstructure of 1&#xd7;10/cmor more, and having a grain boundary solid solution ratio Z defined by Z=(mass % of one or both of Nb and Mo at grain boundaries)/(mass % of one or both of Nb and Mo at time of melting) of 0.4 or more.

Steel sheet for hot stamping use

A hot stamped article excellent in strength having a predetermined composition, having an average crystal grain size of prior austenite of 3 &#x3bc;m or less, containing at least one of lower bainite, martensite, and tempered martensite in an area rate of 90% or more, and having a grain boundary solid solution ratio Z, defined by Z=(mass % of one or both of Nb and Mo at the grain boundaries)/(mass % of one or more of Nb and Mo at time of dissolution) of 0.3 or more.

A hot stamped article of high strength steel sheet excellent in bending deformability having a predetermined chemical composition, having an area rate of 90% or more of the microstructures of the steel sheet comprised of one or more of lower bainite, martensite, and tempered martensite, and having a ratio of the length of grain boundaries with a rotational angle about a rotational axis of the &#x3c;011&#x3e; direction of the crystal grains of the lower bainite, martensite, and tempered martensite of 15&#xb0; or more with respect to the length of grain boundaries with a rotational angle of 5&#xb0; to 75&#xb0; of 80% or more.

In a spot welded joint according to an aspect of the present invention, with respect to a rectangular planar region of 100 &#x3bc;m&#xd7;100 &#x3bc;m which is perpendicular to a sheet surface of the plurality of the steel sheets and which centers around an inner point spaced away by 100 &#x3bc;m in a direction parallel with the sheet surface from an edge of a nugget, in a case of measuring a P concentration at a pitch of 1 &#x3bc;m to obtain measured values of the P concentration at 100&#xd7;100 of measurement points, and in a case of repetitively calculating an average value of the measured values of the P concentration at 20 of the measurement points which are adjacent to each other and which are arranged in a row in the direction parallel with the sheet surface among the 100&#xd7;100 of the measurement points while shifting each one point to obtain 81&#xd7;100 of the average values, the number of the average values which are more than two times an average P concentration is 0 to 100.

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Tokyo, Japan

Tomohito Tanaka