Method for preparing gear blank by using blank with ultrahigh diameter ratio

The invention discloses a method for preparing a gear blank by using a blank with an ultrahigh diameter ratio, which comprises the following steps of: (1) hammering the blank placed on a workbench of forging and pressing equipment by using a hammer head of the forging and pressing equipment, keeping the axis of the blank vertical to the horizontal plane of the workbench of the forging and pressing equipment in the hammering process, when the hammerhead of the forging and pressing equipment hammers the blank every time, the height downward pressing amount of the hammerhead on the blank is 8-12 mm; or firstly, the upper end and the lower end of the blank are sleeved with the constraint molds, then the hammer head of the forging and pressing equipment hammers the blank placed on the workbench of the forging and pressing equipment, in the hammering process, the axis of the blank is kept perpendicular to the horizontal plane of the workbench of the forging and pressing equipment, and after the blank is upset to be