| 摘要 |
A steel sheet according to the present invention has a specified chemical composition, and also has a carbon equivalent (CE) of 0.30 to 0.40% by mass and a SOLB value of -0.0015 to +0.0015% by mass, wherein the metallic structure of the steel sheet is a mixed structure containing a ferrite and a bainite or a mixed structure containing the ferrite, a pearlite and the bainite, the area ratios of the ferrite and the bainite are 50 to 90% and 10 to 50%, respectively, the weighted average value (DAVE) of the particle diameters of the crystal grains is 3 to 17 μm, the area ratio of {100} plane is 2 to 20%, the sum total of the particle number densities of TiN particles, MnS particles and composite particles is 20 to 200 particles/mm2, the particle number density of oxide particles each having an equivalent circle diameter of 1 to 10 μm is 20 to 200 particles/mm2, and the thickness of the steel sheet is 10 to 35 mm. |
