Method of manufacturing a cold-rolled steel plate

A method of manufacturing a cold-rolled steel plate, comprising the steps of:

• smelting a steel slab having the chemical composition containing on the basis of percent by mass, C from 0.03 to 0.12%, Si from 0 to 1.0%, Mn from 0.2 to 0.8%, P at 0.03% or less, S at 0.03% or less, Ti from 0.04 to 0.3%, and Al at 0.05% or less, with a residue being formed of Fe and unavoidable impurities, the chemical composition satisfying 5*C %−Si %+Mn %−1.5*Al %<1, and an average diameter of particles of a Ti-based carbide as a precipitate is from 20 to 100 nm;
• heating the steel slab to 1200° C. or more and hot rolling to form a hot-rolled steel plate;
• winding the hot-rolled steel plate from 500 to 700° C. to form a hot-rolled coil;
• and
• at least one of cold rolling or annealing and cold rolling the hot-rolled coil obtaining cross-sectional hardness from 200 to 400 HV.