| 摘要 |
<p>PURPOSE: Environmentally-friendly lead-free speed-cutting steel is provided to improve the fracture toughness of a steel material and prevent the hardening during machining. CONSTITUTION: Environmentally-friendly lead-free speed-cutting steel comprises C 0.04~0.13 weight%, Si 0.1 weight% or less, Mn 0.7~2.0 weight%, P 0.05~0.15 weight%, S 0.2~0.5 weight%, B 0.002~0.01 weight%, Cr 0.08~0.5 weight%, Ti 0.003~0.35 weight%, N 0.005~0.015 weight%, O 0.03 weight% or less, and the rest Fe and inevitable impurities. The speed-cutting steel contains MnS inclusion with the density of 300~1000 per 1 mm^2 on the cross section.</p> |
