Brazing metals together is a process that is three centuries old. Its origin has been traced to Ancient Egypt. Archeologists have found small golden boxes and intricately formed jewelry made by brazing that dates back to 2975 B.C. These artifacts appear to be gifts made for Egyptian Pharaohs and are made mostly out of gold and silver.
Through the years, the Sumerians, Greeks, and Romans gave brazing their own touch and developed different heat systems to use in the “manufacturing” of their art objects. By the Middle Ages, brazing was used for copper, gold, and silver to create jewelry, stained-glass windows, dining utensils, and more.
This very old process is similar to soldering and welding but stands on its own as a separate specific process that is still used today to join certain types of metals and dissimilar metals. There are different methods of brazing, for example, furnace brazing, induction brazing, torch brazing, and vacuum brazing.
What Types of Metals Can be Used With This Process?
The best metals used for brazing are aluminum, copper, gold, nickel, silver, stainless steel, and zinc-coated steel. It is a process that works well for joining dissimilar metals.
Basics of How Brazing Works
In the brazing process, metal components are joined when molten filler metal flows into a joint. This is done at high heat, however, not higher than the melting point of the metals that will be combined. The molten filler metal, as it cools, will create a strong joint between the metals.
Capillary action required for brazing is the scientific process where the liquefied filler metal flows between the parts to be joined and thereby creates a bond between them. This creates a strong and leak-proof connection.
In welding, both pieces of metal that are being welded together have to melt at the same temperature. In brazing, only the filler melts, and it melts at a lower temperature than the metals that are being joined. This makes brazing a better process for industries where different types of metal are joined, such as for auto parts.
Common Applications of Brazing
Brazing is used across many industries including:
- Aerospace for jet engines and turbine blades as well as for satellites.
- Appliances, such as refrigerators and ice machines.
- Automobile manufacturing and repairing. Brazing works well for joining small auto parts. It is also used for vehicle air conditioning systems, radiator coils, and fuel lines.
- Construction industry. This includes almost everything, ranging from tools for cutting concrete and stone to carbide machine parts.
- Electrical industry, including fuses, motors, and packaging.
- HVAC systems. This includes rooftop units for industrial cooling to residential heating and air conditioning systems.
- Making fine jewelry.
Benefits of Brazing
Some advantages of brazing over welding are:
- It creates a strong joint. The joint is as strong or stronger as the metals that are being joined.
- Lower temperatures are used than for welding. Brazing temperatures range from 1150ºF (620ºC) to 1600ºF (870ºC). The average temperature needed for welding is 3000ºF (1650ºC).
- The base metals are never melted and generally retain their original properties.
- It is easier to join dissimilar metals.
- A brazed joint is smoother so it is more attractive.
- It is easier to learn brazing than to learn welding.
- It can be a fully automated procedure so takes less time than welding which makes it less expensive.
Drawbacks of Brazing
There are some drawbacks to brazing and there are industries for which welding is a better process than brazing. Some drawbacks are:
- For some metals, brazing may produce lower strength joints than welding.
- The color of the joint is often different from the base metals that are used. This may not be aesthetically pleasing.
- Materials to be joined must be very close together in order for capillary action of the molten filler material to occur.
- The process can only be used for smaller pieces of metal and won’t work for large pieces since they have to be close together for capillary action.
For More Information, Contact Vern Lewis Welding Supply, Inc.
We hope you found this information about Brazing useful. If you have any welding questions or are interested in purchasing welding equipment, contact Vern Lewis Welding Supply today! We offer a wide range of welding products as well as training classes, equipment repairs, maintenance, and more.