| 摘要 |
The present invention relates to an inverted angle steel capable of obtaining excellent low-pressure impact toughness; excellent ability to weld; a tensile strength (TS) of 460-590 MPa; a yield strength (YP) of 315 MPa or greater; an elongation percentage (EL) of 18% or greater; an impact toughness of 300 J or greater at a temperature of -60°C through a grain refinement process cooling a material with an accelerated cooling device after rolling with a continuous rolling mill; and to a method to manufacture the inverted angle steel. According to the present invention, the method to manufacture the inverted angle steel is characterized by comprising: (a) a step of reheating bloom comprising 0.06-0.08 wt% of C, 0.15-0.25 wt% of Si, 1.3-1.5 wt% of Mn, 0.015 wt% or less of P, 0.005 wt% or less of S, 0.035-0.040 wt% of V, 0.015-0.020 wt% of Ti, 0.20-0.25 wt% of Ni, 0.02-0.05 wt% of Al, 0.007 wt% or less of N, and the remainder consisting of Fe and inevitable impurities at a slab reheating temperature (SRT) of 1100-1200°C; (b) a step of hot-rolling the reheated bloom at a finish rolling temperature (FRT) of 850-900°C; and (c) a step of cooling the hot-rolled bloom at a finish cooling temperature (FCT) of 600-700°C. |
