(1) In extrusion production, there are two types of the most commonly used extrusion die: flat die and cone die.

When die angle a increases, the height of dead zone increases and the friction between metal flows increases. When die angle a = 900, the metal flow is the most uneven. Therefore, the metal flow in conical die extrusion is more uniform than that in flat die extrusion.

(2) When the extrusion ratio is small, the larger the die angle, the more uneven the metal flow. The influence of die angle on metal flow.

In recent years, a lot of theoretical and experimental studies have been made by scientists and technicians under different conditions. It is proved that the optimal die angle changes with different extrusion conditions. For large deformation and unlubricated hot extrusion, the optimal die angle for obtaining more uniform metal flow changes with the size of extrusion ratio. With the increase of extrusion ratio, the value of the optimal die angle increases.

(3) When the concave gasket is used for extrusion, the metal flow is more uniform than that when the flat gasket is used for extrusion, but the separation of the concave gasket is more difficult, and the general use is not much.

(4) The metal flow in porous die is more uniform than that in single hole die. The length of the die hole working belt has a great influence on the metal flow uniformity. The design of unequal length working belt used in actual production can be used as an important means to adjust metal flow. In addition, porous die extrusion can also increase the metal flow uniformity of non axisymmetric profiles.