Expanding diameter spinning is a spinning forming method in which a hollow rotating body container or a tubular blank is increased in diameter (middle or end) by a spinning tool. The limitation of this method is mainly the material properties of the workpiece, such as tensile strength. Strength, yield limit, elongation rate, section shrinkage rate, etc.; depending on the degree of expansion of the workpiece, it is often divided into several passes. The stress during the molding process cannot exceed the tensile strength of the material, otherwise it will cause cracking. If the material has a large tendency of work hardening, the number of passes should be less, and the amount of expansion per pass should be as large as possible. Otherwise, due to severe hardening, intermediate heat treatment needs to be performed earlier, otherwise it cannot be carried out;