THICK STEEL PLATE HAVING EXCELLENT BEND PROPERTY FOR TOWER OF WIND POWER GENERATOR AND METHOD OF MANUFACTURING THE SAME

摘要

The present invention relates to a thick steel plate for a wind power generator tower with excellent bending properties capable of improving arrest properties of a crack generated during bending; and a method to manufacture the same. According to an embodiment of the present invention, the method to manufacture a thick steel plate for a wind power generator tower with excellent bending properties comprises: a step of reheating a slab comprising: 0.08-0.18 wt% of C, 0.1-0.45 wt% of Si, 1.0-1.6 wt% of Mn, 0.01-0.05 wt% of Al, 0.005-0.02 wt% of Ti, more than 0 wt% and 0.03 wt% or less of Nb, more than 0 wt% and 0.05 wt% or less of V, more than 0 wt% and 0.05 wt% or less of Ni, more than 0 wt% and 0.05 wt% or less of Cu, more than 0 wt% and 0.02 wt% or less of P, more than 0 wt% and 0.008 wt% or less of S, more than 0 wt% and 0.004 wt% or less of N, and the remainder consisting of Fe and inevitable impurities, wherein the carbon equivalent (Ceq) is 0.36-0.42, and a crack susceptibility composition (Pcm) is 0.21-0.23 wt% at 1050-1200°C for a heating time of 1 minute per 1 mm thickness of the slab; and a step of air-cooling the slab to a room temperature after the reheated slab is extracted at 1140-1160°C, control rolled in the accumulated reduction ratio of 30% or more at a temperature of Ar3 or more, and finishing at 820°C or less.