Forging forming method and die for unequal-thickness hollow part plate

The invention provides an unequal-thickness hollow part plate forging forming die which comprises a forming male die, an outer side female die, a female die base plate, a floating mandrel and a detachable core. The invention further provides an unequal-thickness hollow part plate forging forming method which comprises the steps that firstly, one end of an original pipe blank with the outer diameter equal to the outer diameter of a target part is placed in the female die; then the male die slowly moves downwards, a part with the required small-end appearance is extruded through upsetting, and then the floating mold core is pushed upwards by the press machine to eject the part out; secondly, the other end of the part is placed on a female die base plate, a forming male die slowly descends, and ejection and demolding are conducted after reaming is completed; and thirdly, the part subjected to broaching in the last step is placed in the female die, then the male die moves downwards slowly, the inner portion of th