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

Abstract:

The present invention provides a steel material, and a method of manufacturing the same. The steel material comprises, by weight %, 0.02 to 0.07% of carbon, 0.1 to 0.5% of silicon, 0.2 to 0.7% of manganese, 0.05% or less of phosphorus, 0.02% or less of sulfur, 0.07% or less of aluminum, 0.1 to 0.5% of chromium, 0.3 to 1.0% of molybdenum, 0.05% or less of vanadium, 50 ppm or less of boron, 0.01 to 0.5% of nickel, 0.5% or less of copper, 0.02% or less of titanium, 0.05% or less of niobium, and 2 to 100 ppm of calcium, 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. 260.ltoreq.1589.times.[C]+228.ltoreq.340 [Relational Expression 1] [C]/[Mo].ltoreq.0.250 [Relational Expression 2]