Nippon Steel Corporation

Kojiro Akiba

Satoshi Kato

Koichi Sato

Yoshiaki Nakazawa

Masafumi Azuma

Kiyokazu Ishizuka

Hiroshi Takebayashi

Takuya Nishio

Takeshi Yasui

Koki Tanaka

Akihiro Sengoku

Toshiki Nonaka

Yusuke Kondo

Yoshitaka Kikuchi

Yoshimasa Narita

Kotaro Ohno

A hot stamped component, includes: a base material; and a Zn-based plating layer provided in contact with the base material as an upper layer of the base material and containing Zn and Ni. A region of the Zn-based plating layer on a base material side is a Fe—Zn solid solution containing Ni, and two or more twins exist in 10 crystal grains of the Fe—Zn solid solution containing Ni adjacent to an interface between the base material and the Zn-based plating layer.

Hot stamped component

A plated steel sheet for hot stamping including a base metal and a galvanized layer that is formed on a surface of the base metal, wherein the galvanized layer includes a galvannealed layer, a solidified zinc layer, and an oxide layer containing Al, in this order from the base metal, and a proportion of a content of Zn (g/m) in the solidified zinc layer to a content of Zn (g/m) in the galvanized layer is 10 to 95%.

Plated steel sheet for hot stamping

A hot stamped component, includes: a base material; and a Zn-based plating layer provided in contact with the base material as a layer above the base material and containing Zn. A base material side of the Zn-based plating layer is a Fe—Zn solid solution, and two or more twins exist in 10 crystal grains of the Fe—Zn solid solution adjacent to an interface between the base material and the Zn-based plating layer.

This high-strength cold-rolled steel sheet has a predetermined chemical composition, wherein a microstructure at a &#xbc; position of a sheet thickness from a surface includes predetermined ranges of volume percentages of tempered martensite, residual austenite, ferrite and bainite, and martensite, wherein a microstructure at a position 25 &#x3bc;m from the surface includes, predetermined ranges of volume percentage of ferrite and bainite, and martensite and tempered martensite, wherein in the position 25 &#x3bc;m from the surface, an average grain size of the martensite and the tempered martensite is 5.0 &#x3bc;m or less, a tensile strength is 1,310 MPa or more, and a uniform elongation is 5.0% or more, and R/t is 5.0 or less, the R/t being a ratio of a limit bend radius R in 90&#xb0; V-bending to a sheet thickness t.

High-strength cold-rolled steel sheet and manufacturing method therefor

[Object] To provide a method of manufacturing a plate-like molded body having a thickened portion in a region spaced apart from an edge in a substantially flat plate-like portion. [Solution] Provided is a method of manufacturing a plate-like molded body having a plurality of thickened portions, including at least a drawing step of obtaining by a drawing process a cylindrical drawn molded body including a flat plate portion and a cylindrical drawn portion that swells in such a manner as to project from the flat plate portion and has a circular top portion. The drawing step includes a first step of pressing a region spaced apart from an edge in a plate-like member having a flat plate shape, with a first mold and a second mold, to form a concave curved portion in the plate-like member, and a second step of holding an outer circumferential section of the plate-like member between a third mold and a fourth hold while a region containing the concave curved portion in the plate-like member is held between the first mold and the second mold, and moving the first mold and the second mold relative to the third mold and the fourth mold to cause the region containing the concave curved portion to project with respect to the outer circumferential section and to obtain the cylindrical drawn molded body.

Method of manufacturing plate-like molded body having a plurality of thickened portions, and plate-like molded body having a plurality of thickened portions

A hot stamp molded body that can be produced highly efficiently without causing sticking of plating to a mold, when an electrogalvanized steel sheet with a light plating weight is hot-stamped using a rapidly heating method such as Joule heating and induction heating, and can secure favorable paint adhesiveness without a posttreatment such as shotblasting after hot stamping, as well as a method for producing the same. A hot stamp molded body is produced by hot-stamping an electrogalvanized steel sheet which is composed of predetermined components, and is electrogalvanized on each face with a plating weight not less than 5 g/mand less than 40 g/m; and therein a galvanized layer of the hot stamp molded body is configured with 0 g/mto 15 g/mof a Zn&#x2014;Fe intermetallic compound and a Fe&#x2014;Zn solid solution phase as a balance, and in the galvanized layer of the hot stamp molded body 1&#xd7;10 pcs to 1&#xd7;10pcs of particulate matter with an average diameter of from 10 nm to 1 &#x3bc;m are present per 1 mm length of the galvanized layer.

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Tokyo, Japan

Kojiro Akiba