PURPOSE: To bend an extruded shape of a tubular member consisting of aluminum and its alloy and having a hollow part for which severe bending is requested and which has an intricate sectional shape.
CONSTITUTION: The elongation and strength of the extruded shape consisting of the aluminum and its alloy are improved when the extruded shape is cooled. The consumption of liquid nitrogen is reduced if the extruded shape injected with water in the hollow part is immersed in the liquid nitrogen and is cooled down to a temp. range of -20 to -196°C. In addition, there is no need for molding a core, inserting this core into the hollow part and drawing out the core from the hollow part after bending and, therefore, the bending of the extruded shape at a low cost is possible.
OKA TAKASHI
YASUNAGA SHIGENOBU
HIRANO MASAKAZU
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