| 摘要 |
PROBLEM TO BE SOLVED: To provide a controlled rolling method for a sheet pile having excellent toughness. SOLUTION: A slab having a composition comprising, by mass, 0.05 to 0.20% C, 0.05 to 0.20% Si and 0.50 to 1.60% Mn, suitably containing one or more kinds selected from 0.3 to 1.0% Cu, 0.2 to 1.0% Ni, 0.3 to 0.7% Mo and 0.2 to 0.7% Cr, and/or one or two kinds selected from 0.005 to 0.040% Nb and 0.05 to 0.10% V, and further comprising≤0.005% N, and in carbon equivalent equation Ceq=C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4+V/4, the componential contents satisfy the Ceq of 0.28 to 0.45, and the balance Fe with inevitable impurities is reheated at 1,100 to 1,300°C, hot rolling is started, and is finished in such a manner that the cumulative draft at≤900°C is controlled from 20 to 40%, and, suitably, accelerated cooling is performed in such a manner that the average cooling rate in the steel average temperature from 750 to 550°C is controlled from 0.8 to 10.0°C/s so as to produce a steel pile having the 0°C impact absorption energy of≥100 J. COPYRIGHT: (C)2006,JPO&NCIPI |
