Silver Brazing

- Jan 19, 2019-

Silver brazing, sometimes referred to as brazing, is performed using a silver alloy based filler. These silver alloys are composed of many different percentages of silver and other metals such as copper, zinc and cadmium.

Brazing is widely used in the tool industry to secure "hard metal" (hard alloy, ceramic, cermet and similar) tips to tools such as saw blades. "Pre-plating" is often performed: the brazing alloy is melted onto the tip of the hard metal, and the tip of the hard metal is placed next to the steel and remelted. Pretinning solves the problem that hard metals are difficult to wet.

Brazed carbide joints are typically 2 to 7 mils thick. The brazing alloy joins the material and compensates for the difference in expansion ratio. It also provides cushioning between the carbide tip and hard steel to reduce shock and prevent tip loss and damage - because the vehicle suspension helps prevent damage to the tires and the vehicle. Finally, the brazing alloy combines with the other two materials to form a composite structure that, like the wood and glue layers, forms a plywood. The standard for brazed joint strength in many industries is that it is stronger than either base material, so when under stress, one or the other substrate fails before the joint.

One special silver brazing method is called pinbrazing or pin brazing. It has been developed especially for connecting cables to railway track or for cathodic protectioninstallations. The method uses a silver- and flux-containing brazing pin, which is melted in the eye of a cable lug. The equipment is normally powered from batteries.

Braze welding.
Brazing is the use of a bronze or brass filler rod coated with flux to join steel workpieces. The equipment required for brazing is essentially the same as that used for brazing. Since brazing generally requires more heat than brazing, acetylene or methyl acetylene-propadiene (MAP) gaseous fuels are commonly used. The name comes from the fact that no capillary action is used.
Brazing has many advantages over fusion welding. It allows the joining of different metals, minimizes thermal deformation, and reduces the need for large amounts of preheating. In addition, since the added metal does not melt during the process, the assembly retains its original shape; it does not erode or change the edges and contours by forming rounded corners. Another effect of brazing is to eliminate the storage stresses that often occur in fusion welding. This is very important for the repair of large castings. The disadvantage is that it loses strength when subjected to high temperatures and cannot withstand high stresses.
Carbide, cermet and ceramic tips are plated and then joined to steel to make tipped band saws. The plating acts as a braze alloy.

Cast iron "welding"
The "welding" of cast iron is usually a brazing operation using a filler rod made primarily of nickel, although cast iron rods can also be used for true welding. Ductile iron pipes can also be "snap-mounted", a process of joining joints by small copper wires that are melted into iron when previously ground into bare metal, parallel to the formation of a hub tube with a neoprene gasket The iron joint is sealed. The goal behind this action is to use electricity along copper wires to keep underground pipes warm in cold climates.