Process for producing spectacle frames using an age-hardenable nickel-bronze alloy

In a process of making spectacle frames with high tensile strength and good resistance to permanent set of frame from a plurality of parts by brazing, the improvement comprising,

• preparing a precursor alloy shape capable of subsequent working to make spectacle frame parts, said shape characterized by softness and being of a nickel bronze alloy, the alloy consisting essentially of about 2-10 percent tin, from about 3-26 percent nickel, with the rest being copper, there being minor amounts of manganese to impart ductility to the alloy, and less than about 1 percent of other elements, said shape having been rendered soft by subjecting the alloy thereof to prolonged heating in the range of about 600.degree. C., to about 950.degree. C. for a time period sufficient to obtain the easily workable soft condition,
• forming a part of a spectacle frame from said alloy in the course of which said shape is reduced on the order of 10-75 percent in area to thereby impart cold working characteristics and thus some hardening to the frame part being made,
• brazing said part to another of said plurality of parts,
• heating said frame part to age it at a temperature in the range of about 300.degree. C. to about 450.degree. C. for about 1 to 6 hours in order to promote precipitation of a phase in the alloy, which phase is characterized by the chemical formula Ni.sub.2 Sn, to thereby obtain a spectacle frame part characterized by high tensile strength and good resistance to permanent set.