METHOD FOR MAKING HOLLOW SHAPES IN NITROGEN MEDIUM AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 2002 - IPC

FIELD: extrusion in nitrogen medium, possibly manufacture of hollow products of metals, mainly aluminum hollow sections and tubes for building, aircraft manufacture, chemical machine engineering and so on. SUBSTANCE: method comprises steps of supplying nitrogen to die and also to splitter forming inner surface of article. Apparatus for performing the method includes distribution duct in splitter for supplying liquefied nitrogen, additional throttles, controlled solenoid valves and electronic unit with program controlled feedback of nitrogen consumption by temperature of die and splitter. Invention provides extrusion rate increased by 2-5 times, useful life period of die increased by 1.5 times, enhanced quality of surface of product, yield increased by 10-20%. EFFECT: enhanced quality of product surface, increased extrusion rate, improved yield. 2 cl, 3 dwg