Patent ID: 7270720

Claim:
A method of imparting a planar or a spatial curvature of a predetermined form to a rod or band-like unfinished workpiece of a superelastic single-crystal Cu-alloy, and conserving the curvature, said method comprising the steps of heating the unfinished workpiece to be bent to a bending temperature of 700 to 900° C., heating at the same time a bending tool of a thermally sufficiently resistant material which is provided with the desired curvature to a temperature not exceeding the bending temperature at which the predetermined curvature can be successively imparted to the workpiece to be bent without fracture, when the predetermined curvature has been fully imparted to the workpiece, permitting the workpiece to cool down, removing the workpiece from the bending tool, and, for re-establishing the superelasticity which has been lost during heating and bending, placing the workpiece, after it has been cooled to ambient temperature, into an oven which has been preheated to 750 to 900° C. for at least one hour for tempering the workpiece, and then removing the workpiece from the oven and immediately quenching the workpiece in a cooling medium.