Influence of the brazing process parameters on the microstructural characteristics of copper alloy jointsPaper Presented at the 4^th National Welding Day, Workshop: “Brazing” Genova, 25–26 October 2007.

Paper Presented at the 4^th National Welding Day, Workshop: “Brazing” Genova, 25–26 October 2007.

Abstract

This paper reports the results of microstructural characterization studies conducted on copper alloy joints obtained by different brazing processes. In particular, tests have been conducted on Cu–Ni–Zn ternary alloys (nickel silvers), traditionally used in the spectacle industry, in order to highlight the merits and any metallurgical and functional defects in samples obtained using two different heat input methods: induction and LASER beam welding.

Along with the metallographic analysis of joints made using the traditional induction brazing technique, the joints obtained by LASER brazing have been investigated. In particular, it has been evaluated as to how altering the process parameters pertaining to both the LASER beam (power and impact time) and base metal surface conditions (presence or absence of surface oxides) can significantly influence the formation of macroscopic defects in the joints or on deformation of the components themselves.

Hence, the main scope of the paper has been an attempt to identify the optimal process parameters for LASER beam brazing, so that the joints thus obtained have acceptable mechanical properties, while maintaining good aesthetic appearance, a decidedly essential requirement in components for spectacles.

Keywords:

• brazeability
• brazing fillers
• copper alloys
• induction brazing
• influencing factors
• laser brazing
• microstructure
• process parameters

Acknowledgements

We thank Mr M. Cartello and Mr P. Castelli, RTM S.p.A., for their collaboration in this study and for their help with the LASER beam brazing of joints.

Notes

Paper Presented at the 4^th National Welding Day, Workshop: “Brazing” Genova, 25–26 October 2007.