The invention relates to high-
toughness cold-hot-fatigue-resistant cast steel for a high-speed
train brake disc and a preparation method thereof, belongs to the field of
metal materials and preparation thereof, and solves the problem of matching of room-temperature
toughness, high-temperature mechanical properties and cold and hot fatigue failure resistance of the cast steel for the high-speed
train brake disc in the prior art. The high-
toughness cold-hot-fatigue-resistant cast steel for the high-speed
train brake disc comprises the following chemical components, in percentage by
mass, of 0.20%-0.40% of C, 0.30%-0.70% of Si, 0.50%-2.00% of Mn, 0.50%-2.00% of Cr, 0.50%-2.00% of Ni, 0.40%-1.80% of Mo, 0.01%-0.30% of V, smaller than or equal to 0.015% of P, smaller than or equal to 0.010% ofS, smaller than or equal to 0.010% of O, smaller than or equal to 0.015% of N, and the balance Fe and inevitable impurities, wherein the total content of the Mn, the Cr and the Ni is 2.00%-6.00%, andthe total content of the Mo and the V is 0.41%-2.00%. Through reasonable composition, organization structure and preparation process regulation and control, excellent room-temperature toughness, high-temperature
mechanical property and cold and hot fatigue failure resistance of the cast steel are matched, the requirements for comprehensive
mechanical property and long service life of the cast steel brake disc of a high-speed train are met, and the cast steel is suitable for being used as a material for the cast steel brake disc of the high-speed train.