Hot-rolled steel sheet
AssigneeNippon Steel Corporation
InventorsHiroshi Shuto, Kazumasa Tsutsui, Koutarou Hayashi, Akifumi Sakakibara, Jun Ando, Mitsuru Yoshida
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Abstract
This hot-rolled steel sheet has a predetermined chemical composition, in a microstructure, in terms of area %, residual austenite is less than 3.0%, ferrite is 15.0% or more and less than 60.0%, and pearlite is less than 5.0%, an E value that indicates periodicity of the microstructure is 10.7 or more, and an I value that indicates uniformity of the microstructure is less than 1.020, a standard deviation of a Mn concentration is 0.60 mass % or less, and a tensile strength is 980 MPa or more.
Claims4
A hot-rolled steel sheet comprising, in terms of mass %, as a chemical composition:
- C:
- 0.050% to 0.250%;
- Si:
- 0.05% to 3.00%;
- Mn:
- 1.00% to 4.00%;
- one or more of Ti, Nb, and V:
- 0.060% to 0.500% in total;
- sol. Al:
- 0.001% to 2.000%;
- P:
- 0.100% or less;
- S:
- 0.0300% or less;
- N:
- 0.1000% or less;
- O:
- 0.0100% or less;
- Cu:
- 0% to 2.00%;
- Cr:
- 0% to 2.00%;
- Mo:
- 0% to 1.00%;
- Ni:
- 0% to 2.00%;
- B:
- 0% to 0.0100%;
- Ca:
- 0% to 0.0200%;
- Mg:
- 0% to 0.0200%;
- REM:
- 0% to 0.1000%;
- Bi:
- 0% to 0.020%;
- one or more of Zr, Co, Zn, and W:
- 0% to 1.00% in total;
- Sn:
- 0% to 0.05%;
- and
- a remainder comprising Fe and impurities,
- wherein, in a microstructure,
- in terms of area %, residual austenite is less than 3.0%, ferrite is 15.0% or more and less than 60.0%, and pearlite is less than 5.0%,
- an E value that indicates periodicity of the microstructure is 10.7 or more, and an I value that indicates uniformity of the microstructure is less than 1.020,
- a standard deviation of a Mn concentration is 0.60 mass % or less, and
- a tensile strength is 980 MPa or more.
Dependencies are inferred from the claim text.