Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Toshiki Nonaka

Koichi Sato

Nobuhiro Fujita

Satoshi Kato

Kaoru Kawasaki

Toshimasa Tomokiyo

Hirokazu Taniguchi

Toshio Ogawa

Koichi Goto

Yoshihiro Suwa

Noriyuki Suzuki

Masafumi Azuma

Hiroshi Takebayashi

Yoshifumi Kobayashi

Manabu Naruse

Masaaki Mizutani

Yasunori Iwasa

Shinichiro Watanabe

Akihiro Miyasaka

Kazuhiko Honda

Kenichiro Matsumura

Akihiro Sengoku

Yasuhide Morimoto

Toru Yonebayashi

Kojiro Akiba

Naoki Matsutani

Hiroki Murayama

Koji Yanaba

Yuki Yasuda

This steel sheet for a can is a steel sheet for a can containing, by mass %, C: 0.010% to 0.050%, Si: 0.020% or less, Mn: 0.10% to 0.60%, P: 0.020% or less, S: 0.020% or less, Al: 0.050% or less, N: 0.0100% or less, Nb: 0% to 0.03%, Ti: 0% to 0.03%, B: 0% to 0.0020%, and a remainder including Fe and unavoidable impurities, in which, when the number of carbides having an equivalent circle diameter of 2 μm or more and 5 μm or less is indicated by a, and the number of carbides having an equivalent circle diameter of 0.1 μm or more and less than 2 μm is indicated by b, a/b satisfies a range of the following formula (1), a fracture strain is 1.6 or more, and a sheet thickness is 0.10 to 0.30 mm<0.12  . . . (1).

Steel sheet for can and manufacturing method thereof

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.

Hot stamped component

A cold-rolled steel according to the present invention has a predetermined chemical composition, satisfies (5&#xd7;[Si]+[Mn])/[C]&#x3e;10 when [C] is the amount of C by mass %, [Si] is the amount of Si by mass %, and [Mn] is the amount of Mn by mass %, includes 40% to 95% ferrite and 5% to 60% martensite in area fraction, and optionally further includes 10% or less pearlite in area fraction, 5% or less retained austenite in volume fraction, and less than 40% bainite in area fraction. The total of the area fraction of ferrite and the area fraction of martensite is 60% or more, the hardness of martensite measured with a nanoindenter satisfies H2/H1&#x3c;1.10 and &#x3c3;HM&#x3c;20.

Cold-rolled steel sheet

A hot-dip galvanized steel sheet includes a steel sheet and a hot-dip galvanized layer arranged on the steel sheet, in which the Si content and the Al content by mass % of components of the steel sheet satisfy a relationship 0.5&#x3c;Si+Al&#x3c;1.0, and a metallographic structure of the steel sheet satisfies a relationship of {(n)&#xd7;d}/{(n)&#xd7;d}&#xd7;ln(H/H)&#x3c;0.3 when the nis the number of a MnS of a surface portion of the steel sheet, the d&#x3bc;m is an average equivalent circle diameter of the MnS in the surface portion of the steel sheet, the HGPa is a hardness of a martensite of the surface portion of the steel sheet, the nis the number of the MnS of a center portion of the steel sheet, the d&#x3bc;m is an average equivalent circle diameter of the MnS in the center portion of the steel sheet, and the HGPa is the hardness of the martensite of the center portion of the steel sheet.

Hot-dip galvanized steel sheet and manufacturing method thereof

A hot-stamped steel according to the present invention has a predetermined chemical composition, satisfies (5&#xd7;[Si]+[Mn])/[C]&#x3e;10 when [C] is the amount of C by mass %, [Si] is the amount of Si by mass %, and [Mn] is the amount of Mn by mass %, includes 40% to 95% ferrite and 5% to 60% martensite in area fraction, and optionally further includes 10% or less pearlite in area fraction, 5% or less retained austenite in volume fraction, and less than 40% bainite in area fraction. The total of the area fraction of ferrite and the area fraction of martensite is 60% or more, the hardness of martensite measured with a nanoindenter satisfies H2/H1&#x3c;1.10 and &#x3c3;HM&#x3c;20, and TS&#xd7;&#x3bb; which is product of tensile strength TS and hole expansion ratio &#x3bb; is 50000 MPa&#xb7;% or more.

Hot-stamped steel, cold-rolled steel sheet and method for producing hot-stamped steel

A cold-rolled steel sheet has a predetermined chemical composition, in which a structure before and after a hot-stamping includes ferrite: 30 area % to 90 area %, martensite: 0 area % or more and less than 20 area %, pearlite: 0 area % to 10 area %, retained austenite: 5 volume % to 20 volume %, and rest structure: bainite, a hardness of the retained austenite measured with a nano indenter before and after the hot-stamping satisfies relations of H/H&#x3c;1.1 and &#x3c3;HM&#x3c;20, and a relation of TS&#xd7;El&#x2265;20000 MPa&#xb7;% is satisfied.

Cold-rolled steel sheet and method for manufacturing same, and hot-stamp formed body

A hot stamped steel according to the present invention satisfies an expression of (5&#xd7;[Si]+[Mn])/[C]&#x3e;11 when [C] represents an amount of C by mass %, [Si] represents an amount of Si by mass %, and [Mn] represents an amount of Mn by mass %, a metallographic structure after hot stamping includes 40% to 90% of a ferrite and 10% to 60% of a martensite in an area fraction, a total of an area fraction of the ferrite and an area fraction of the martensite is 60% or more, a hardness of the martensite measured with a nanoindenter satisfies an H2/H1&#x3c;1.10 and &#x3c3;HM&#x3c;20, and TS&#xd7;&#x3bb;, which is a product of a tensile strength TS and a hole expansion ratio &#x3bb; is 50000 MPa&#xb7;% or more.

Hot stamped steel and method for producing hot stamped steel

A cold rolled steel sheet according to the present invention satisfies an expression of (5&#xd7;[Si]+[Mn])/[C]&#x3e;11 when [C] represents an amount of C by mass %, [Si] represents an amount of Si by mass %, and [Mn] represents an amount of Mn by mass %, a metallographic structure before hot stamping includes 40% to 90% of a ferrite and 10% to 60% of a martensite in an area fraction, a total of an area fraction of the ferrite and an area fraction of the martensite is 60% or more, a hardness of the martensite measured with a nanoindenter satisfies an H2/H1&#x3c;1.10 and &#x3c3;HM&#x3c;20 before the hot stamping, and TS&#xd7;&#x3bb; which is a product of a tensile strength TS and a hole expansion ratio &#x3bb; is 50000 MPa&#xb7;% or more.

Cold rolled steel sheet and method for producing cold rolled steel sheet

In a hot stamped steel, when [C] represents an amount of C (mass %), [Si] represents an amount of Si (mass %), and [Mn] represents an amount of Mn (mass %), an expression of 5&#xd7;[Si]+[Mn])/[C]&#x3e;10 is satisfied, a metallographic structure includes 80% or more of a martensite in an area fraction, and optionally, further includes one or more of 10% or less of a pearlite in an area fraction, 5% or less of a retained austenite in a volume ratio, 20% or less of a ferrite in an area fraction, and less than 20% of a bainite in an area fraction, TS&#xd7;&#x3bb;, which is a product of TS that is a tensile strength and &#x3bb; that is a hole expansion ratio is 50000 MPa&#xb7;% or more, and a hardness of the martensite measured with a nanoindenter satisfies H2/H1&#x3c;1.10 and &#x3c3;HM&#x3c;20.

Hot stamped steel and method for producing the same

When the amount of C, the amount of Si and the amount of Mn are respectively represented by [C], [Si] and [Mn] in unit mass %, the cold rolled steel sheet satisfies a relationship of (5&#xd7;[Si]+[Mn])/[C]&#x3e;10, the metallographic structure contains, by area ratio, 40% to 90% of a ferrite and 10% to 60% of a martensite, further contains one or more of 10% or less of a pearlite by area ratio, 5% or less of a retained austenite by volume ratio and 20% or less of a bainite by area ratio, the hardness of the martensite measured using a nanoindenter satisfies H20/H10&#x3c;1.10 and &#x3c3;HM0&#x3c;20, and TS&#xd7;&#x3bb; representing the product of TS that is a tensile strength and &#x3bb; that is a hole expansion ratio is 50000 MPa&#xb7;% or more.

Cold rolled steel sheet and manufacturing method thereof

Provided is a galvanized steel sheet having a tensile strength of 770 MPa or more including a steel sheet portion, and a plated layer formed on the surface of the steel sheet portion, in which the plated layer is a galvanized plated layer or an galvannealed plated layer, the steel sheet portion has a soft layer that directly adjoins the interface with the plated layer and an inside layer that is other than the soft layer, the thickness D of soft layer is 0.001% to 5% of thickness t of the steel sheet portion, and, when the hardness of the soft layer measured by nano-indentation method is indicated by H1, and the representative hardness of the steel sheet portion measured by the nano-indentation method is indicated by Ha in cross section that goes along the thickness direction of the steel sheet portion, H1 is 5% to 75% of Ha.

High-strength galvanized steel sheet and method of manufacturing the same

Exemplary embodiments of a facility or an arrangement capable of producing a high strength steel sheet or a hot dip zinc coated high strength steel sheet according to the present invention are provided which can make a quenching facility and tempering facility continuous treatment facilities. For example, an improvement in the material quality can be effectuated due to tempering enable improvement of the hole expandability. In addition, an elongation of the sheet can be improved. For example, an exemplary production facility/arrangement for high strength steel sheet or hot dip zinc coated high strength steel sheet excellent in elongation and hole expandability can be provided by arranging in a continuous annealing facility or a continuous hot dip zinc coating facility or their joint facility or continuously with the same, (i) a quenching facility able to cool steel sheet after recrystallization or after recrystallization and after hot dip zinc coating down to a temperature region of the martensite transformation point or less, (ii) a tempering facility for tempering the steel sheet and holding its temperature, and (iii) a recooling facility for cooling the steel sheet to about 100&#xb0; C. or less.

Facility for production of high strength steel sheet or hot dip zinc coated high strength steel sheet excellent in elongation and hole expandability

The high-strength steel sheet includes, by mass %: C: 0.01% to 0.10%; Si: 0.15% or less; Mn: 0.80% to 1.80%; P: 0.10% or less; S: 0.015% or less; Al: 0.10% to 0.80%; Cr: 0.01% to 1.50%; N: 0.0100% or less; and a balance consisting of iron and inevitable impurities, in which a metallic structure is composed of ferrite and a hard second phase, the area fraction of the ferrite is 80% or more, the area fraction of the hard second phase is 1% to 20%, the fraction of unrecrystallized ferrite in the ferrite is less than 10%, the ferrite grain sizes are 5 &#x3bc;m to 20 &#x3bc;m, and the fraction of the ferrite crystal grains having an aspect ratio of 1.2 or less in the entire ferrite crystal grains is 60% or more.

High-strength steel sheet having excellent processability and paint bake hardenability, and method for producing of high-strength steel sheet

A high strength steel sheet excellent in formability which has a chemical composition in mass %: C: 0.03 to 0.20%, Si: 0.005 to 0.3%, Mn: 1.0 to 3.1%, P: 0.001 to 0.06%, S: 0.001 to 0.01%, N: 0.0005 to 0.01%, Al: 0.2 to 1.2%, Mo&#x2266;0.5%, and the balance: Fe and inevitable impurities, with the proviso that the values of mass % for Si and Al satisfy the following formula (1):(0.0012&#xd7;[objective value of TS]&#x2212;0.29&#x2212;[Si])/2.45&#x3c;Al&#x3c;1.5&#x2212;3&#xd7;[Si]&#x2003;&#x2003;(1)wherein [objective value of TS] represents a design strength value for the steel sheet in an Mpa unit, and has a metal structure containing ferrite and martensite. The above high strength steel sheet is also excellent in formability and the capability of being chemically treated and that of being hot-dip zinc sheeted.

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Tokyo, Japan

Toshiki Nonaka