It can be seen from the extrusion process that the screw works under high temperature, certain corrosion, strong wear, and high torque. Therefore, the screw must:
1) High temperature resistance, no deformation under high temperature;
2) Wear resistance and long life;
3) Corrosion resistance, the material is corrosive;
4) High strength, can withstand large torque and high speed;
5) Has good cutting performance;
6) After heat treatment, the residual stress is small, and the thermal deformation is small.