Patent ID: 11970758
Assignee: NIPPON STEEL CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 1:
2. The hot-rolled steel sheet according to claim 1,
wherein in a case where area fractions of residual austenite in metallographic structures, in the sheet width cross section parallel to the rolling direction,
at the sheet thickness ¼ depth from the surface and at the center position in the sheet width direction,
at the sheet thickness ¼ depth from the surface and at a position 300 mm from the center position in the sheet width direction to one end side in the sheet width direction,
at the sheet thickness ¼ depth from the surface and at a position 600 mm from the center position in the sheet width direction to the one end side in the sheet width direction,
at the sheet thickness ¼ depth from the surface and at a position 300 mm from the center position in the sheet width direction to the other end side in the sheet width direction, and
at the sheet thickness ¼ depth from the surface and at a position 600 mm from the center position in the sheet width direction to the other end side in the sheet width direction
are respectively denoted by γ, γD1, γD2, γW1, and γW2 in terms of area %, γ/γD1, γ/γD2, γ/γW1, and γ/γW2 are each 0.8 or more and less than 1.2, and
in a case where C concentrations in the residual austenite in the metallographic structures,
at the sheet thickness ¼ depth from the surface and at the center position in the sheet width direction,
at the sheet thickness ¼ depth from the surface and at the position 300 mm from the center position in the sheet width direction to the one end side in the sheet width direction,
at the sheet thickness ¼ depth from the surface and at the position 600 mm from the center position in the sheet width direction to the one end side in the sheet width direction,
at the sheet thickness ¼ depth from the surface and at the position 300 mm from the center position in the sheet width direction to the other end side in the sheet width direction, and
at the sheet thickness ¼ depth from the surface and at the position 600 mm from the center position in the sheet width direction to the other end side in the sheet width direction
are respectively denoted by CγC, CγD1, CγD2, CγW1, and CγW2 in terms of mass %, CγC/CγD1, CγC/CγD2, CγC/CγW1, and CγC/CyW2 are each 0.8 or more and less than 1.2.