The extrusion temperature of industrial aluminum profiles is an important process parameter in the extrusion production process. In order to reduce the deformation resistance of the metal and reduce the extrusion force, it is necessary to increase the extrusion temperature of the industrial aluminum profile. However, when the extrusion temperature is raised to a certain temperature, hot brittleness is likely to occur, and defects such as cracks are generated. In order to avoid this phenomenon, in order to increase the extrusion speed, it is necessary to lower the extrusion temperature. These two conditions are contradictory. In order to reduce the deformation resistance and the larger extrusion speed, a metal plasticity* temperature range must be selected.
However, during the extrusion process of industrial aluminum profiles, the friction between the metal and the lining of the extrusion cylinder, the mold and the gasket, and the deformation of the metal itself cause the temperature of the metal to rise, which often breaks through the pre-selected extrusion temperature. range. The experiment proves that the extrusion temperature is gradually increased during the whole extrusion process, and the extrusion speed is gradually accelerated as the ingot metal is reduced. Therefore, the tail end of the industrial aluminum profile product often cracks due to an increase in the extrusion temperature and an increase in the extrusion speed. The increase in extrusion temperature during extrusion is related to the nature of the industrial aluminum profile and the extrusion conditions. For industrial aluminum profiles, the temperature difference between the metal at the exit of the die is between 10 and 60 °C.
In order to make the extrusion temperature in the extrusion process of industrial aluminum profiles constant in the temperature range of metal plasticity*, * isothermal extrusion is performed. This is a new process explored by engineers and technicians for many years. To achieve isothermal extrusion, there are many conditions that can be adjusted automatically during the extrusion process. For example, the temperature of the ingot and the temperature of the extrusion tube can be heated in a gradient. The mold can be cooled and the temperature can be adjusted. The extrusion speed can be automatically changed. Or use constant velocity extrusion. In addition, after the mold is changed, the above conditions can be adjusted accordingly due to the change of the extrusion coefficient. It can be seen that achieving isothermal extrusion of industrial aluminum profiles is a very complicated process. At present, the method of gradient heating of the ingot is adopted, and the similar isothermal pressing can be performed, and the extrusion speed and the product quality can be greatly improved.
With the gradual development of computer and digital programming technology in the industry, modern extruders have also been upgraded, equipped with FI controlled constant velocity extrusion and TIPS controlled isothermal extrusion. The operator can select the required constant velocity or isothermal extrusion by means of the device's automated programming technique.