Effects of heat treatment on mechanical properties of base metal wrought wire clasps.

Abstract

The purpose of this study is to determine the effects of heat treatment and soldering on the change of shape and mechanical properties of cobalt-chromium-nickel alloy wrought wire clasps. The change of distance between the tips of the clasp arm was measured and mechanical properties were examined using the bending test. The following results were obtained. 1) By heat treatment at 500-700 degrees C for 10 minutes, bending rigidity and deflection at the proportional limit of the clasp arm increased significantly (p < 0.01), while permanent deformation after the bending test decreased considerably (p < 0.01). Concerning the deformation of clasp arms by heating, the distance between clasp tips increased remarkably above 500 degrees C (p < 0.01). 2) These mechanical properties of clasp arms were improved both by electric resistance soldering with silver solder and by heat treatment at 500 degrees C for 10 minutes after soldering. From these results, it was concluded that electric resistance soldering and adequate heat treatment were very effective to improve the mechanical properties of the clasp arm, especially to increase the deflection at the proportional limit and reduce the permanent deformation.