Carburized alloy steel having improved durability and method of manufacturing the same

A method of manufacturing a carburized alloy steel, the method comprising steps of:

• carburizing an alloy steel comprising, based on a total weight of the carburized alloy steel,
• 0.1 to 0.35 wt % carbon,
• 0.1 to 2.0 wt % silicon,
• 0.1 to 1.5 wt % manganese,
• 1.5 to 3.0 wt % chromium,
• 0.2 to 0.5 wt % molybdenum,
• greater than 0 to 0.07 wt % niobium,
• 0.1 to 0.6 wt % nickel,
• more than 0 to 0.3 wt % vanadium,
• more than 0 to 0.2 wt % titanium,
• more than 0 to 0.015 wt % nitrogen,
• 0.00002 to 0.00005 wt % boron, and
• a balance of iron,
• at 880 to 940° C. for 1.5 to 2 hours;
• oil-quenching the carburized alloy steel at 80 to 120° C.;
• and
• tempering the oil-quenched alloy steel at 170 to 200° C. for 1 to 3 hours.