High-carbon alloy cast steel softening method

The invention discloses a high-carbon alloy cast steel softening method. The method comprises the following steps that the high-carbon alloy cast steel is treated by the aid of a vacuum furnace, and solution treatment and spheroidizing annealing are performed in sequence; the treatment temperature of solution treatment is 1100 DEG C, heat preservation is conducted for 2-3 h, and discharging and oil cooling are conducted; and the spheroidizing annealing comprises the following steps that the high-carbon alloy cast steel subjected to solution treatment is placed into the furnace to be slowly heated to 850 DEG C along with the furnace, heat preservation is conducted for 4-5 h, then the steel is cooled to 750 DEG C along with the furnace, heat preservation is conducted for 6-8 h, the steel is cooled to 500 DEG C or below along with the furnace, and discharging and air cooling are performed. By means of the method, the high-carbon alloy cast steel can be reduced to 52 HRC or below from 67-68 HRC, and the machining