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US 12,674,226 B2Granted
Steel sheet and enameled product
AssigneeNippon Steel Corporation
InventorsNobuo Yoshikawa, Takashi Aramaki, Tetsuji Fukuzato, Kazuhisa Kusumi, Hisayoshi Yatoh, Yoshinari Yano
Life of this patent
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Abstract
This steel sheet has a predetermined chemical composition, and, on a surface parallel to a surface at a ¼ position of a sheet thickness in a sheet thickness direction from the surface, with respect to a total area of three types of oxides of MnO, Cr2O3 and Al2O3 having a major axis of more than 1.0 μm, a total area ratio of the MnO and the Cr2O3 is 98.0% or more, and an area ratio of the Al2O3 is 2.0% or less.
Claims7
A steel sheet comprising, as a chemical composition, by mass %:
- C:
- 0.0050% or less;
- Si:
- 0.050% or less;
- Mn:
- 0.007% to 1.00%;
- P:
- 0.003% to 0.050%;
- S:
- 0.005% to 0.050%;
- Al:
- 0.002 to 0.010%;
- O:
- 0.0300% to 0.1000%;
- Cu:
- 0.010% to 0.060%;
- N:
- 0.0050% or less;
- Cr:
- 0.01% to 1.00%;
- and
- a remainder of Fe and an impurity,
- wherein, on a plane parallel to a surface at a ¼ position of a sheet thickness in a sheet thickness direction from the surface,
- included oxides consist of one or more oxides consisting of any one of Mn, Cr, Al, Si, and Ca, and O, and
- with respect to a total area of three types of oxides of MnO, Cr2O3 and Al2O3 having a major axis of more than 1.0 μm, a total area ratio of the MnO and the Cr2O3 is 98.0% or more, and an area ratio of the Al2O3 is 0.5 to 2.0%,
- wherein a total number density of the MnO and the Cr2O3 having a major axis of more than 1.0 μm and 10 μm or less is 5.0×102/mm2 or more and 5.0×104/mm2 or less, and
- wherein a number density of MnO having a major axis of 0.1 to 1.0 μm is 1.0×10/mm2 or more and 5.0×102/mm2 or less.
24 more elements
A steel sheet comprising, as a chemical composition, by mass %:
- C:
- 0.0050% or less;
- Si:
- 0.050% or less;
- Mn:
- 0.007% to 1.00%;
- P:
- 0.003% to 0.050%;
- S:
- 0.005% to 0.050%;
- Al:
- 0.002 to 0.010%;
- O:
- 0.0300% to 0.1000%;
- Cu:
- 0.010% to 0.060%;
- N:
- 0.0050% or less;
- Cr:
- 0.01% to 1.00%;
- and
- a remainder of Fe and an impurity,
- wherein, on a plane parallel to a surface at a ¼ position of a sheet thickness in a sheet thickness direction from the surface,
- included oxides consist of one or more oxides consisting of one or more of Mn, Cr, Al, Si, and Ca, and O, and
- with respect to a total area of three types of oxides of MnO, Cr2O3 and Al2O3 having a major axis of more than 1.0 μm, a total area ratio of the MnO and the Cr2O3 is 98.0% or more, and an area ratio of the Al2O3 is 0.5 to 2.0%,
- wherein a total number density of the MnO and the Cr2O3 having a major axis of more than 1.0 μm and 10 μm or less is 5.0×102/mm2 or more and 5.0×104/mm2 or less, and
- wherein a number density of MnO having a major axis of 0.1 to 1.0 μm is 1.0×10/mm2 or more and 5.0×102/mm2 or less.
24 more elements
Dependencies are inferred from the claim text.