| Sil-Fos 15 is the preferred alloy for general copper-copper brazing; the phosphorous in the Sil-Fos family serves as a fluxing agent, no flux is recommended. Sil-Fos 15 is the best alloy to use when joining metals where close fit-ups cannot be maintained and is well suited for use in refrigeration applications. Applications: HVAC/R Refrigerant systems, air conditioning coils, evaporator coils. Sil-Fos 15 and was developed primarily for use on copper, but its use has extended to other nonferrous copper base alloys. It is used extensively on refrigeration units, air conditioning apparatus, electrical conductors, copper and brass pipe fittings, and other copper and brass equipment. Brazing characteristics: Sil-Fos 15 is a copper rich, filler metal that is self-fluxing on copper by virtue of its phosphorus content. The self-fluxing property of this filler metals is effective on copper only. With copper-base alloys, such as brass or bronze, the joints should be fluxed with Handy Flux ®. Sil-Fos 15 should not be used on nickel-base and iron-base alloys, as the phosphorus reacts with the nickel or iron to form brittle compounds at the interface of the joints. Sil-Fos 15 has a strong tendency to liquate (i.e. to separate into low and high melting constituents) if heated slowly through its melting range, as normally occurs in furnace brazing. The results in leaving a “skull” of unmelted alloy behind may objectionable from the standpoint of appearance. In furnace brazing it is preferable to pre-place the alloys inside the joint where the skull is not visible. The properties of a brazed joint are dependent upon numerous factors including base metal properties, joint design, metallurgical interaction between the base metal and the filler metal. Normally the corrosion resistance of Sil-Fos 15 is of the same order as copper, but under certain conditions it may corrode more rapidly. Sil-Fos 15 should not be used where the joints are exposed to sulfur compounds, especially in gasses or oils at temperatures above normal room temperature. Exposure to pressured steam can also result in accelerated corrosion. Available forms: Wire, strip, engineered preforms, specialty preforms, powder and paste. Information provided by Lucas-Milhaupt. |
