| 摘要 |
<p>A continuous cast slab includes the following component: by mass%, C: 0.01 ˆ¼ 0.3%, Si: 0.05 ˆ¼ 0.5%, Mn: 0.4 ˆ¼ 2%, P: 0.03% or less, S: 0.03 or less, Al: 0.005 ˆ¼ 0.03%, Ni: 0.2 ˆ¼ 2%, O: 0.006% or less, and N: 0.006% or less; wherein the balance is composed of Fe and inevitable impurities; wherein a structure in steel in a region within at least 2 mm from a broad surface is composed of ferrite and pearlite and a equivalent circular diameter of ferrite grains in the region is equal to or shorter than 30 µm.</p> |
