Silver Brazing

A joining process, silver brazing allows alloy, a non-ferrous filler metal, to be heated at a melting temperature above 800°F later distributed between two or more close-fitting parts by capillary attraction. The filler metal interacts with a thin layer of the base metal at liquidus temperature, the molten filler metal interacts with a thin layer of the base metal. The grain structure interaction leads to the formation of a strong, leak-proof, sealed joint. The silver brazed joint becomes a sandwich of different layers, each metallurgically linked to each other.

Forms of Heat Sources
Making use of filler metals & alloys as silver, copper, zinc, cadmium to name a few in solid forms like rings, wires, slugs, washers, powder & paste, silver brazing applies varied forms of heat sources such as :

The joints produced due to silver brazing beautifully meet the specifications touching upon varied aspects as mechanical performance, electrical conductivity, pressure tightness, corrosion resistance, and service temperature. Employment of silver brazing by high production, metal joining operations is the common practice. Used for joining or bonding ferrous and non-ferrous base metals like steel, stainless steel, copper, and brass, silver brazing process are generally done on automatic machines for cost-efficient metal joining at high production rates.

Silver Brazing Alloys
Silver brazing alloys are available in varied forms & their chemical composition is another point to be taken into consideration, since, the silver content in them differ in terms of the silver content, melting temperature and in flow temperature.

Chemical Composition
The most widely used silver alloys consists of 40 to 50% silver while 25 to 15% zinc is commonly used. The typical chemical composition for an alloy with a 607°C melting point & 618°C flow point consists of :

Availability of Silver Brazing Alloys
Silver brazing alloys are available as:

Requirement of Flux in Silver Brazing Alloys
Flux forms an important part of silver brazing finer alloys. Available in a powder or paste form, flux is mainly applied either by dipping or spraying or brushing the filler rod end into it. The requirement for flux is for three main reasons which are :

The flux residues should be removed after they are brazed from the assemblies, since, it prevents corrosion. The residues are removed by applying either of the these options.

Silver Brazing Methods
Silver brazing methods make use of almost varied methods specially the torch brazing and furnace brazing method. Furnace brazing method though have additional advantages, since, that achieves high production rates in order to provide a high degree of reproducibility of results etc.

While oxyacetylene torch method used in silver brazing procedure are mentioned in details.

Advantages
Though being quite costly, silver brazing filler alloys as well have some real vital plus points which are mentioned below :

Application
Used to be known as silver soldering earlier, silver brazing allows silver alloy fiber rod to be used for brazing purposes. Applied mainly for arts and in jewelry manufacturing, not many industries have silver brazing applications.

The varied applications of silver brazing method are as follows :

The varied other usages of silver brazing are :