Significant Extrusion Speed Increase using Liquid Nitrogen to Eliminate Overheating of Dies During Extrusion Process

摘要

The use of nitrogen for improving output and quality in the extrusion of aluminum has been widely investigated in recent years. There are two different ways of using nitrogen: gaseous or liquid. In the past, creating an inert atmosphere at the die exit with gaseous nitrogen supplied via a ring equipped with a nozzle system or similar means enhanced the economy and the surface quality of the extrusion. The use of liquid nitrogen directly into the die opens the way to an even more significant improvement in output, while maintaining a consistently high level of surface quality. For this process, additional equipment has been developed with which the liquid nitrogen is fed in precisely controlled quantities. This method of operation is particularly efficient when long runs can be extruded, and when the peripheral conditions such as the section shapes, dimensional stability, die design, and the plant as a whole, permit the extrusion speed to be increased substantially. The use of liquid nitrogen has been successfully tested, even in small production lots or frequently changing shapes, by means of additional equipment.