Half shaft forming method and half shaft pre-forming die

The invention discloses a half shaft forming method and a half shaft pre-forming die. The method includes the steps that A100, first-time pre-pressing forming is conducted, wherein an oil sealing section of a half shaft part and part of raw materials needed in a flange plate are pre-pressed to be formed at the same time in a first pre-forming lower die; and S200, second-time pre-pressing forming is conducted, the rest of the part of the raw materials needed by the flange plate are pre-pressed to be formed in a second pre-pressing lower die, and the flange plate formed through pre-pressing is obtained. By means of the half shaft forming method, the lower die serves as a forming die, pre-pressing forming of the oil sealing section is completed while forming of the flange plate part is completed, subsequent punching is not needed, and therefore the forming defects of the oil sealing section are avoided; and in addition, by means of the half shaft forming method, pre-pressing forming of the flange plate is comple