STEEL PLATE FOR TORSION BEAM AND MANUFACTURING METHOD THEREFOR, AND TORSION BEAM AND MANUFACTURING METHOD THEREFOR

Disclosed are a steel plate for a torsion beam and a manufacturing method therefor, and a torsion beam and a manufacturing method therefor. The steel plate for the torsion beam has the following chemical components in percentages by mass: 0.04-0.085% of C, 0.02-0.5% of Si, 1.3-1.8% of Mn, 0.15-0.5% of Cr, 0.12-0.30% of Mo, 0.058% or less of Nb, 0.15% or less of V, 0.02% or less of Ti, 0.02-0.1% of Al, 0.02% or less of P, 0.005% or less of S, 0.005% or less of N, and the balance being Fe and inevitable impurities. The steel plate has one or two of Nb and V, and the amount of Nb and V satisfies 0.096%≤2Nb+V≤0.17%. The steel plate for the torsion beam of the present invention has an excellent elongation and excellent cold bending properties while ensuring high strength, and meets the requirement for producing lightweight torsion beams.