| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing an energy absorbing member in which areas of different strength are formed in one member. SOLUTION: When cooling a steel plate obtained by executing any one of hot rolling, cold rolling and continuous annealing of a slab having a composition containing, by mass, 0.19-0.35% C, 0.1-0.5% Si, 0.1-1% Mn,≤0.015% P,≤0.01% S, 0.005-0.05% Ai, and 0.001-0.003% N, also containing one or more kinds of Ti, Nb, V and Mo of 0.005-0.15% in total in a range of 0.005-0.1% Ti, 0.005-0.02% Nb, 0.01-0.1% V, and 0.01-0.1% Mo, and the balance Fe with inevitable impurities, after heating the slab to the temperature range equal to or higher than Ac3 point, the difference in strength (ΔTS) between a quenched portion which is cooled in the temperature range of Ar3 point to 300°C at the rate of 200°C/s and an annealed portion which is cooled at the rate of <150°C/s is≥490 MPa. COPYRIGHT: (C)2011,JPO&INPIT |
