| 摘要 |
<p>PURPOSE: A structural steel and a manufacturing method thereof are provided to obtain a yield strength of more than 450MPa, a tensile strength of more than 650MPa, an elongation of more than 20%, and an impact value of more than 45J by adding Nb and V and controlling cooling conditions. CONSTITUTION: A structural steel is composed of 0.14-0.16wt.% of C, 0.25-0.35wt.% of Si, 1.25-1.35wt.% of Mn, less than 0.03wt.% of P, less than 0.015wt.% of S, 0.05-0.15wt.% of Ni, 0.15wt.% of Cr, 0.1-0.2wt.% of Cu, 0.01-0.02wt.% of Al, 0.008-0.012wt.% of N, 0.02-0.04wt.% of V, 0.035-0.045wt.% of Nb, and the rest of Fe.</p> |
