The outer surface has a cylinder with a spiral groove or a cone with a tapered cone. The screw has a different head. For example, large flat screw, hexagonal bolt and so on. The screw of the extrusion process is in high temperature, corrosion, intense wear and high torque, so the screw must:
1) high temperature and non-deformation under high temperature;
2) wear and tear, long life;
3) corrosion resistant and corrosive materials;
4) high strength, high torque, high speed;
5) have good cutting performance;
6) small residual stress after heat treatment and small thermal deformation.
The outer surface has a cylinder with a spiral groove or a cone with a tapered cone. The screw has a different head. For example, large flat screw, hexagonal bolt and so on.
