PRODUCT CATEGORIES

Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Vacuum brazing of refractory metals

When are refractory metals combined with vacuum brazing?

Due to the oxidation or inherent contamination of active metals, vacuum brazing is often used when connecting refractory metals to active metals, such as titanium and aluminum. Refractory metals refer to metals with very high melting temperatures. For example, the melting temperature of tungsten is as high as 3410°C, which is more than twice that of titanium (1668°C). Refractory metals have high corrosion resistance and wear resistance, as well as excellent thermal strength and mechanical strength. Although there are as many as 12 such metals, only 5 are widely used: tungsten, molybdenum, niobium, tantalum and rhodium.

What are reactive metals and why is vacuum brazing the perfect method for reactive metals?

Reactive metals are a group of metals that undergo chemical reactions when exposed to air, water, acids, and inorganic acids. Since these reactions may produce surface oxides or inherent contamination during the brazing process, this can cause numerous problems for both material joining and brazing, and lead to joint brazing failure. Therefore, vacuum brazing is the preferred process. Aluminum, for example, reacts quickly in air and produces harmful surface oxides that must be chemically cleaned and removed before vacuum brazing and then sealed in a bag.

Vacuum brazing process

Vacuum brazing does not use protective and deoxidizing inert gases, such as the common hydrogen process, nor does it use flux, and it is usually performed in a high temperature and ×10^-5~10^-6 pressure environment. This cleaning process also deoxidizes the metal being brazed, but more importantly it eliminates reactions that would otherwise occur in hydrogen and helps evaporate or remove high vapor pressure materials that are considered contaminants.

Vacuum firing can even be used to remove hydrogen from materials like stainless steel, which were previously brazed with hydrogen. Many of the same alloys that are brazed with hydrogen (such as fillers or die-cut preforms) can also be used with this process, and we can add common materials such as Silver, Copper, and Stainless Steel.

Vacuum brazing furnace technology

Our high-efficiency vacuum furnace is a cold-wall distillation furnace with a graphite or molybdenum hot zone. Most vacuum furnace brazing techniques use ultra-clean cryopumps, while a few use very clean turbine pumps in order to achieve consistent results. Currently, we have 14 vacuum furnaces of different sizes, the largest one has a hot zone of 48″.

Furnace vacuum degree: ×10^-5~10^-6;

Hot zone size: 48″×28″×28″.