ULTRA HIGH STRENGTH CARBURIZING STEEL WITH HIGH FATIGUE RESISTANCE

摘要

An ultra high strength carburizing steel with high fatigue resistance is provided to make carbonitride into 100% solution and to improve various fatigue resistances and temper softening resistance, thereby shortening carburization time. An ultra high strength carburizing steel with high fatigue resistance includes 0.15 to 0.25 weight% of C, 1.70 to 2.30 weight% of Cr, 0.50 to 0.70 weight% of Si, 100 to 200 weight% of N, 0.010 to 0.040 weight% of Al, 0.015 to 0.035 weight% of Nb, less than 50 weight ppm of Ti, less than 0.05 weight% of Ni, the remaining Fe, and unavoidable impurities. The steel is milled at 1,200 to 1,300°C. The steel also includes 0.45 to 0.75 weight% of Mn, less than 0.030 weight% of S, and 0.25 to 0.50 weight% of Mo. Carbonitride is made into solid solution, abnormal grain generated temperature of the steel is 1,010 to 1,150°C, and fatigue resistance limit is 3,660 x 10^6 to 6.822 x 10^6.