Comparison of Stationary and Movable Valves for Continuous Hot Extrusion

Continuous hot extrusion enables a constant profile velocity throughout all stages of the process, including the dead cycle time when reloading a billet. The processes direct and indirect hot extrusion are combined with a stationary or a movable valve. Both variants have different influences on the process and the profile properties. The movable and the stationary valve are directly compared with numerical and experimental methods. Continuous extrusion experiments are conducted using the method of similarity with a model material. The results show that a movable valve secures the functionality safely and a stationary valve reduces the length of the machine, the required ram forces and the amount of weld seams. The stationary valve also leads to a reduced profile temperature, which allows enhanced profile speeds and increases the productivity of the continuous extrusion process.