The for absorber which is superior in tenacity are low the yield point steel and its production

摘要

PROBLEM TO BE SOLVED: To provide low-yield point steel for a damper as an energy absorbing device at a big earthquake and also to provide its manufacturing method.;SOLUTION: The steel has a composition containing 0.001 to 0.050% C, ≤0.80% Si, 0.1 to 2.0% Mn, ≤0.020% P, ≤0.015% S, Ti in an amount 4 times that of C and not larger than 0.30%,≤0.060% Al and ≤0.006% N and further containing, if necessary, one or more among Nb, V, B, Ni, Cu, Cr, Mo, Ca and REM each in a specific amount and also has a microstructure composed of ferrite single phase and shows no clear upper/lower yield point at a tensile test. A cast slab or steel slab, having the above components, is heated to 1,000 to 1,300°C and then subjected, after the completion of hot rolling at ≥900°C, to natural cooling or subjected, after hot rolling, to holding at 900 to 1,000°C for ≥10 min and then to natural cooling.;COPYRIGHT: (C)2009,JPO&INPIT