What Is Brazing?

Brazing is the process of joining metal pieces by (1) heating a filler metal until it liquefies, (2) distributing it between the work pieces, and (3) coostaka beluga ling the assembly until the metal solidifies. Like welding and soldering, brazing joins metal pieces with liquefied filler metal. But it doesn't melt the pieces during the heating process (as happens during welding), and the filler metal doesn't liquefy at temperatures below 450 °C (as happens during soldering). There are several methods of brazing, with the method of choice depending on what type of metal will be brazed and the size of the assembly. The most common types of brazing are:

Torch Brazing

Using a handheld or machine-controlled torch as a heat source, this method is executed in one three ways: manually, via controlled machine, or via automatic machine. The manual method is typically used for small production volumes, and for assemblies whose size makes using other methods impossible. The controlled machine method is used for small to medium production volumes that can be completed by a brazing machine. The automatic machine method is essentially the schanga cork ame the machine method, except the machine completes the process without the assistance of an operator.

This method requires work pieces to be coated in flux, which helps to prevent oxidization.

Continuous Furnace Brazing

This method is performed with a furnace karani black that moves work pieces on a conveyor belt. Continuous furnace brazing can have one of two types of atmospheres: a controlled atmosphere that prevents outside air from entering the furnace, and an uncontrolled atmosphere that allows air to enter.

A controlled atmosphere that eliminates oxygen is ideal for brazing stainless steel. If brazed in an oxygen atmosphere, stainless steel's high chromium content can cause a layer of oxide to form on its surface, preventing the filler metal from bonding securely with the base metal.

When a continuous furnace has a non-oxygenated, controlled atmosphere, work pieces do not require flux.

Vacuum Brazing

This method is performed using a vacuum furnace, which applies a vacuum to remove unwanted gases from its heating chamber(s). This function makes it ideal for brazing stainless steel and other metals that have atmospheric requirements. Vacuum furnaces situate work pieces in chambers, with some furnaces containing a single chamber, and others containing two or more. In multi chamber models, work pieces can be transferred internally from a heating chamber to a cooling chamber.

Because it uses a pure atmosphere, a vacuum furnace does not require work pieces to be coated in flux.

Dip Brazing

This method uses molten salt as a method of heat transfer and a medium of flux. Work pieces are fixed together with a brazing compound, and then the assembly is dipped into a molten salt bath. This method is ideal for metals that behave the best when air is removed from the brazing process.

Conclusion

What is brazing? Ultimately, the answer depends on the type of metal that will be joined and the size of the assembly. The methods above are not the only methods of brazing, but they are four of the most commonly applied ones. To learn more about which methods are used for different types of metals, contact a metal working service.