HIGH STRENGTH THICK STEEL PLATE EXCELLENT IN CTOD(CRACK TIP OPENING DISPLACEMENT) CHARACTERISTIC, AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a high strength thick steel plate of ≥1 inch thick, having ≥700 MPa tensile strength and a critical CTOD value of ≥0.25 mm in heat affected zone as well as ≥0.5 mm in base material at -30°C, and provide its production method.;SOLUTION: This high strength thick steel plate has a composition containing 0.01-0.04% C, 0.50-2.00% Mn, 0.70-1.75% Cu, 0.50-3.50% Ni, 0.004-0.02% Ti, 0.0005-0.0015% B, ≤0.15% Si, ≤0.01% Al, ≤1.0% Cr, ≤0.80% Mo, ≤0.03% Nb, ≤0.10% V and ≤0.0030% Ca. Further, the value of M1* represented by M1*=5C+2Si+20Al+70N and the value of M2* represented by M2*=(Mn+2 Cr+Mo)/3Ni are regulated to ≤1.0% and ≤0.80, respectively.;COPYRIGHT: (C)2001,JPO