Introduction of Low Cadmium Brazing Alloys

Abstract

Silver brazing alloys are generally divided in TWO categories, one with Cadmium where Cadmium contain is about 18 to 24% & other without Cadmium. In India, the practice was to use Cadmium Containing alloys, however, in order to comply with RoHS directives, many industries shifted for without Cadmium alloys. In this case either they have to increase Silver percentage to match the melting range with there existing alloys or train operators to work with high melting range without Cadmium alloys of same silver percentage. For such industries we have designed an alloy with Cadmium percentage of 2 to 4% which is much less toxic. This alloy worked extremely good as far as flow & wet ability was concern. Some companies, who do not have RoHS constraints have even adopted these alloys for regular brazing, as ill effects of Cadmium is reduced drastically. From the manufacturing point, these alloys can be hot rolled, unlike without Cadmium alloys and gives faster production rates. They melt at moderate temperatures and it becomes extremely easy to switch from high Cadmium alloys to without Cadmium alloys by using these as step or practice alloys to smoothen the process of change over.