The equivalent stress distribution of spiral bevel gear blank during final forging is shown in the figure. The maximum stress during final forging is 696Mpa.

The maximum stress occurs at the step of outer side and flash of spiral bevel gear blank, and the stress at the step of inner side and concave thin layer is also large. The stress at the step between the outer side of the spiral bevel gear blank and the flash is 400-696Mpa, the stress at the step between the inner side and the concave thin layer is 350-460Mpa, the stress at the flash and the concave thin layer is 280-340Mpa, and the stress at the main body of the spiral bevel gear blank is 149-340Mpa.

Therefore, during the final forging of the spiral bevel gear blank, the large stress occurs at the steps of the outer side and flash of the spiral bevel gear blank and the steps of the inner side and the concave thin layer. This is because the metal flow at the steps is difficult, resulting in the increase of stress.