Why There is an Increasing Importance of Brazing

By Benedette Cuffari, M.Sc.Dec 7 2018

Article updated on 12 January 2021

Image Credits: Stopped_clock/shutterstock.com

Brazing is a process by which two metals are joined together. During the brazing process, a filler metal, which is otherwise referred to as a solder, is brought to a liquidus temperature that is greater than 840 °F (450 °C)¹. Throughout this entire process, the joining metals remain protected by a suitable atmosphere, such as a flux.

Wetting, which involves the flowing of the filler metal over the base metal, then occurs, which is then followed by a cooling process that allows both metal workpieces to come together. While this process is closely related to soldering, the temperatures required to melt the filler metal in brazing are much higher than those which are used in common soldering procedures.

Advantages of Brazing

Brazing is considered to be one of the most versatile metal joining techniques, especially when compared to other metal-joining processes like welding and soldering. For example, the brazing of nonferrous metals and/or steel materials often produces brazed joints that exhibit significantly greater tensile strength that can reach up to almost 900 megapascals (MPa). This joint strength has also been associated with improved shock and vibration resistance in the final brazed product. Another key advantage that supports the widespread use of brazing is the ability of this metal-joining technique to maintain precision dimensional tolerances throughout the entire process

The process of brazing is a relatively easy and fast technique that can be easily adapted for mass production purposes. As a result, brazing is often a highly economic option for industries, especially when complex metal assemblies are required. The use of brazing has been shown to significantly reduce the amount of time and material required for the manufacturing and designing of complex molds and castings. These advantages associated with brazing account for the use of this technique to be found in a diverse range of applications, some of which include jewelry, high-temperature ceramics, kitchen cutlery, bathroom faucets, automotive engines, jet aircraft engines, and air-conditioning systems².

The Automation of Brazing

To put the ease of automating brazing into perspective, consider the limitations of soldering and welding processes. Although soldering can be conducted at lower temperatures that are typically below 450 °C³, the strength of soldered joints is not comparable to those which are achieved by brazing. Furthermore, welding, which is a high-temperature process, successfully fuses metals together; however, this process often requires a greater amount of heat energy in order to achieve strong welded joints.

When comparing metal-joining techniques, brazing emerges as a relatively fast and economic process that is highly adaptable to automation. The ease of automating brazing is attributed to the flexibility in this process since the pre-fluxing and pre-positioning stages of this process can be automatically set up to increase speed when high throughput requirements are set into place.

To this end, various companies have developed their own automated brazing solutions. For example, UltraFlex Power Technologies offers the RoboBraze, which is a mobile induction heating and brazing unit that can be equipped with robotic arms for its integration into automated production lines. Within the RoboBraze, special induction heating terminals allow for this system to be easily mounted to various custom heating coils⁴. The flexibility of the RoboBraze has allowed users to program various aspects of the brazing process, such as time, power and temperature while maintaining a high level of repeatability in applied industries. UltraFlex also offers the Dragon 15, which is another automated brazing system, that has been shown to successfully braze multiple joints at predefined positions within the assembly line. As a result, the Dragon 15 provides users with high quality brazed joints while also increasing the overall productivity of assembly lines.

References

1. “The Basics of Brazing” – Brazing Book
2. “Ten Reasons to Choose Brazing” – The American Welding Society
3. “The Brazing Guide” – GH Induction Atmospheres
4. “RoboBraze” – UltraFlex Power Technologies

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