METHOD FOR PRODUCING HIGH MANGANESE STEEL MATERIAL HAVING EXCELLENT ANTI-VIBRATION CHARACTERISTICS AND FORMABILITY, AND HIGH MANGANESE STEEL PRODUCED THEREBY
The present invention relates to a steel material used for a steel plate or the like for automobiles or construction and, more particularly, to a high manganese steel material having excellent anti-vibration characteristics and formability, which can be used where anti-vibration characteristics are required for noise reduction, and a method for producing same.
1 . A method of manufacturing a high manganese steel material having excellent anti-vibration characteristics and formability, the method comprising:
heating a steel slab including, in percentages by weight, 0.1% or less of carbon (C), 8 to 30% of manganese (Mn), 3.0% or less of silicon (Si), 0.1% or less of phosphorus, 0.02% or less of sulfur (S), 0.1% or less of nitrogen (N), 1.0% or less (excluding 0%) of titanium (Ti), 0.01% or less of boron (B), the balance iron (F) and other inevitable impurities at 1,150 to 1,350° C.;
finish hot-rolling the heated steel slab to manufacture a hot-rolled steel plate; and
cooling the hot-rolled steel plate to 700° C. or lower,
wherein the finish hot-rolling is performed at a finishing delivery temperature (FDT) (° C.) satisfying Relational Expression 1 below:
FDT(° C.)≥928+(480×C)+(450×N)+(0.9×Mn)+(65×Ti) [Relational Expression 1]
wherein each element represents content by weight.
2 . The method of claim 1 , wherein the finish hot-rolling is performed with a total rolling reduction ratio of 80% or more.
3 . The method of claim 1 , wherein the cooling is terminated at room temperature to 300° C.
4 . The method of claim 1 , wherein an epsilon martensite phase in an area fraction of 90% or more is included after the cooling.
5 . The method of claim 1 , further comprising performing coiling after the cooling.
6 . The method of claim 1 , wherein the steel slab further includes, in percentages by weight, one or more of 0.005 to 2.0% of nickel (Ni) and 0.005 to 5.0% of chromium (Cr).
7 . The method of claim 1 , wherein the steel slab further includes, in percentages by weight, one or more of 0.005 to 0.5% of niobium (Nb), 0.005 to 0.5% of vanadium (V), and 0.005 to 1.0% of tungsten (W).
8 . A steel material manufactured by the manufacturing method of claim 1 , comprising, in percentages by weight, 0.1% or less of carbon (C), 8 to 30% of manganese (Mn), 3.0% or less of silicon (Si), 0.1% or less of phosphorus (P), 0.02% or less of sulfur (S), 0.1% or less of nitrogen (N), 1.0% or less (excluding 0%) of titanium (Ti), 0.01% or less of boron (B), the balance iron (F), and other inevitable impurities,
wherein the steel material has a microstructure comprising an epsilon martensite phase in an area fraction of 90% or more and the rest austenite phase, being a fully recrystallized structure.
9 . The steel material of claim 8 , further comprising, in percentages by weight, one or more of 0.005 to 2.0% of nickel (Ni) and 0.005 to 5.0% of chromium (Cr).
10 . The steel material of claim 8 , further comprising, in percentages by weight, one or more of 0.005 to 0.5% of niobium (Nb), 0.005 to 0.5% of vanadium (V), and 0.005 to 1.0% of tungsten (W).