Common Misconceptions about Vacuum Brazing

In our fact check, we clarify

High-temperature brazing refers to brazing at temperatures above 900°C under vacuum or protective gas atmosphere. The applications are diverse: ranging from household appliances to highly stressed machine parts and extreme applications in aerospace. Although extremely versatile and efficient, the benefits of this process are still relatively unknown. In this blog post, we help to clarify the most common misconceptions:


Misconception #1: Brazed joints have low strength

This assumption is a widespread misconception. Typically, it’s not the joint itself that is weak, but rather the design of the joint is inadequate. This is because in the DIY applications, sufficient overlap lengths are rarely used or the components are brazed bluntly together. This naturally leads to insufficient strength of the joint. In contrast, in professional brazing, there are generally accepted strength estimates and suitable design guidelines. When brazing according to these guidelines, the brazed joint corresponds can keep up with the strength of the base material.

Misconception #2: Vacuum brazing requires flux

A common mistake is the assumption that flux is necessary for vacuum brazing. In fact, the surfaces of the brazing materials remain metallically clean during vacuum brazing, as the vacuum prevents oxidation during the brazing process. Therefore, flux is not required and extensive cleaning steps after brazing are not necessary.


Misconception #3: High-temperature brazing in a vacuum is expensive

High-temperature brazing in a vacuum is technically demanding but not necessarily expensive. The crucial factor for the cost of the brazing process is the size of the vacuum furnace. Therefore, at REUTER TECHNOLOGIE, we attach great importance to the efficient use of our furnaces. On the one hand, several components can be brazed at the same time, and on the other hand, we ensure that the furnace size matches the components. The result is an extremely efficient brazing at a competitive price.


Misconception #4: The brazing material remains unchanged in its properties after brazing

A common misconception is the assumption that the properties of the brazing material do not change after brazing. In fact, the brazing material diffuses into the base materials and vice versa during the brazing process, leading to changes in chemical composition as well as mechanical properties such as strength, elongation, and conductivity. For this reason, “brazed joint” is spoken of after brazing, and the strengths of brazing materials are always specified in connection with the base material used.


Misconception #5: The success of brazing is determined during the brazing process

The brazing result is not decided only during the brazing process in the vacuum furnace, but already beforehand. Crucial for a successful batch are the parameters set and tested before the furnace cycle, as well as a precise preparation of the brazing surfaces. The actual brazing process is merely the result of the pre-set values.


Curious? Then feel free to contact us, we are happy to advise you.

Published on 21.04.2024

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