Panel
AssigneeNippon Steel Corporation
InventorsMai NAGANO, Yasunori SAWA, Shigeru YONEMURA
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Abstract
A panel that is excellent in both appearance and dent resistance after being formed from a starting material is provided. The panel has a steel sheet including martensite, and a surface roughness parameter (Sa) at a flat part of a center-side portion of the panel is Sa≤0.500 μm. In laths of the martensite, the panel has precipitates having a major axis of 0.05 μm to 1.00 μm and an aspect ratio of 3 or more in an amount of 15 precipitates/μm2 or more. A ratio YS1/YS2 between a yield stress YS1 measured in a tensile test specimen cut out from the flat part of the center-side portion of the panel and a yield stress YS2 measured in a tensile test specimen cut out from an end part of the panel is 0.90 to 1.10.
Claims16
A panel having a steel sheet including martensite, wherein:
- a surface roughness parameter (Sa) at a flat part of a center-side portion of the panel is Sa≤0.500 μm;
- in laths of the martensite, a number density of precipitates having a major axis of 0.05 μm to 1.00 μm and an aspect ratio of 3 or more is 15 precipitates/μm2 or more;
- and
- a ratio YS1/YS2 between a yield stress YS1 measured in a tensile test specimen cut out from the flat part and a yield stress YS2 measured in a tensile test specimen cut out from an end part of the panel is 0.90 to 1.10.
Dependencies are inferred from the claim text.