Casting method of thick-section wheel type casting with boss on outer tooth groove

The invention discloses a casting method for a thick-section wheel type casting with a boss on an outer tooth groove. The inclination of the hot spot inclining towards the interior of the shaft hole is set through a hot spot circle rolling method, a circular-truncated-cone-shaped shaft hole core is formed, and meanwhile an exothermic riser is used for feeding; a first chilling block is arranged on the outer side surface of the tooth groove boss; 0.3%-0.5% of rare earth ferrosilicon alloy is added in the later stage of smelting for modification and microalloy treatment; carrying out final deoxidation by adopting a composite deoxidation mode; and the pouring temperature is controlled to be 1540-1550 DEG C for pouring. The solidification sequence and time of the casting are adjusted through the method that the shaft hole optimization patch is arranged to be matched with the external chill, overall sequential solidification and local simultaneous solidification of the special-shaped casting are achieved, the feed