Patent ID: 6532784
Filing Date: 2003-03-18
Classification: B21D,C10M,C10N

Abstract:
A process for hydroforming a tube of a ductile solid material, said tube having an outer surface, an interior, and an interior surface, said process comprising operations of:(I) providing an openable die having an interior surface of a shape to which it is desired to have the hydroformed part of the outer surface of the tube of ductile solid material conform after said tube has been hydroformed; (II) forming, over at least such portion of the outer surface of the tube of ductile solid material as is intended to contact the interior surface of the openable die during hydroforming, a coating of a solid wax, so as to form a coated tube of ductile solid material; (III) emplacing the coated tube of ductile solid material within at least a part of said openable die and closing the die, so that a portion of the outer surface of the coated tube of ductile solid material that is desired to be hydroformed is within the closed openable die; (IV) providing within the interior of the coated tube of ductile solid material a hydraulic fluid that exerts equal pressure on all parts of the internal surface of the coated tube of ductile solid material with which the hydraulic fluid is in physical contact; and (V) applying the hydraulic fluid provided in operation (IV) as described immediately above, while the coated tube of ductile solid material remains emplaced within the closed openable die as recited in operation (III) above, a sufficient pressure to cause at least a portion of the outer surface of the coated tube of ductile solid material to conform to the inner surface of the closed openable die, wherein operation (II) is accomplished by spraying melted wax that is maintained at a temperature at least about 20Â° C. higher than the lower end of the drop melting range of the wax onto the outer surface of the tube of ductile solid material.