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|1. (WO2018026014) STEEL SHEET AND PLATED STEEL SHEET|
|Applicants:||NIPPON STEEL & SUMITOMO METAL CORPORATION
|Title:||STEEL SHEET AND PLATED STEEL SHEET|
This steel sheet has a specific chemical composition and is provided with a structure represented by, in terms of area ratio, 30–95% ferrite and 5–70% bainite. When a crystal grain is defined as a region which is surrounded by grain boundaries having a misorientation of 15° or higher and for which the equivalent circle diameter is 0.3 μm or larger, the proportion of crystal grains having an intragranular misorientation of 5–14° relative to all of the crystal grains is 20–100% in terms of area ratio. The average aspect ratio of ellipses equivalent to the crystal grains is 5 or lower. The average distribution density of the total of Ti carbides and Nb carbides having a particle size of 20 nm or larger in the ferrite grain boundaries is 10 particles/μm or lower.