Patent ID: 8939194
Filing Date: 2015-01-27
Classification: B22D,C22C

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