| 摘要 |
<p>A boron steel for manufacturing 10T-grade automobile bolts is provided to omit a spheroidization annealing process requiring a long treatment time and reduce production time and cost accordingly by providing a composition in which Fe is used as a matrix, and accurate contents of C, Si, Mn, P and S and limit content values of Cr, Ti and N are prescribed, and into which B is added. A boron steel for manufacturing 10T-grade bolts comprises Fe as a matrix, and further comprises 0.17 to 0.22 wt.% of carbon(C), 0.15 to 0.35 wt.% of silicon(Si), 0.70 to 0.90 wt.% of manganese(Mn), 0.03 wt.% or less of phosphorous(P), 0.01 to 0.03 wt.% of sulfur(S), 0.70 to 0.90 wt.% of chromium(Cr), 0.02 to 0.05 wt.% of titanium(Ti), 0.01 to 0.02 wt.% of nitrogen(N), and 10 to 40 ppm of boron(B).</p> |
