Steel sheet and manufacturing method therefor

A manufacturing method for a steel sheet, comprising:

• heating a steel ingot or slab, including by weight:
• 0.05 to 0.25% of C, 0.7% or less (excluding 0%) of Si, 0.46 to 1.8% of Mn, 0.7% or less (excluding 0%) of Al, 0.05% or less (excluding 0%) of P, 0.03% or less (excluding 0%) of S, 0.03% or less (excluding 0%) of N, 0.22% or less of a total amount of at least one of Ti, Nb, and V, with a remainder of Fe and other unavoidable impurities, at a temperature within a range of 1000 to 1350° C.;
• hot rolling the heated steel ingot or slab at a finish rolling temperature of 800 to 1000° C. to obtain a hot-rolled steel sheet;
• coiling the hot-rolled steel sheet at a temperature within a range of 300 to 600° C.;
• heat treating the coiled hot-rolled steel sheet at a temperature within a range of 650 to 800° C. for 600 to 1700 seconds;
• cold rolling the heat treated hot-rolled steel sheet at a cold rolling reduction rate of 30 to 90% to obtain a cold-rolled steel sheet;
• reheating the cold-rolled steel sheet at a temperature within a range of 720 to 860° C. and maintained for 50 seconds or more;
• primarily cooling the reheated and maintained cold-rolled steel sheet to a temperature within a range of 600 to 760° C. at an average cooling rate of 1° C./s or more;
• secondarily cooling the primarily cooled cold-rolled steel sheet to a temperature within a range of 450 to 550° C. at an average cooling rate of 2° C./s or more and maintained for 50 seconds or more;
• and
• tertiarily cooling the secondarily cooled and maintained cold-rolled steel sheet to room temperature.