STEEL MATERIAL FOR BRAKE DISC OF MOTOR VEHICLE HAVING EXCELLENT WEAR RESISTANCE AND HIGH TEMPERATURE STRENGTH AND METHOD OF MANUFACTURING THE SAME

摘要

One embodiment of the present invention provides a steel material for a brake disc of a motor vehicle having excellent wear resistance and high temperature strength, and a method of manufacturing the same. The steel material comprises, by weight%, 0.02 to 0.07% of carbon (C), 0.1 to 0.5% of silicon (Si), 0.2 to 0.7% of manganese (Mn), 0.05% or less (excluding 0) of phosphorus (P), 0.02% or less (excluding 0) of sulfur (S), 0.07% or less (excluding 0) of aluminum (Al), 0.1 to 0.5% of chromium (Cr), 0.3 to 1.0% of molybdenum (Mo), 0.05% or less (excluding 0) of vanadium (V), 50 ppm or less (excluding 0) of boron (B), 0.01 to 0.5% of nickel (Ni), 0.5% or less (excluding 0) of copper (Cu), 0.02% or less (excluding 0) of titanium (Ti), 0.05% or less (excluding 0) of niobium (Nb), 2 to 100ppm of calcium (Ca), and the balance of Fe and other unavoidable impurities, and satisfies relational expressions 1 and 2 mentioned below, wherein the microstructure thereof contains, by area%, 90% or more of martensite and 10% or less of bainite. [Relational expression 1] 260 ≤ 1589×[C]+228 ≤ 340 [Relational expression 2] [C]/[Mo] ≤ 0.250 (wherein [C] and [Mo] in relational expressions 1 and 2 are in weight%.)