Pretreatment of Superalloy Vacuum Brazing

Superalloy refers to high alloyed shackle-based, drill-based or iron-based austenitic metal materials that can resist oxidation or corrosion above 600 °C, can work for a long time under certain stress, and have surface stability. The key material for the hot end components of aerospace engines is also the high-temperature corrosion-resistant component materials required by industrial gas turbines, energy and chemical industries and other industrial sectors. High-temperature alloy parts have complex structures, difficult manufacturing and processing, and high prices. Due to the extremely harsh working environment, the traditional fusion welding method has shortcomings and shortcomings such as large deformation and easy cracking. Vacuum brazing can not only be applied to difficult-to-weld superalloys (especially cast superalloys), but also has the advantage of mass production. It is a common processing technology for high-temperature intermetallic parts.

Vacuum brazing is an important process for processing superalloy parts. The use of scientific and reasonable pre-brazing technology, especially cleaning technology, is the premise and guarantee for obtaining high-quality brazing joints.

High-temperature brazing mainly includes four processes: pre-brazing, brazing application, brazing cycle and post-brazing. First, the parts should be thoroughly cleaned to remove oxides; then the parts should be coated with brazing filler metal and brazed in a vacuum atmosphere.

According to the characteristics of superalloy parts and their high-temperature protective coatings, a series of chemical cleaning, salt bath cleaning, hydrogen reduction treatment, vacuum cleaning, high-pressure water cleaning, laser cleaning, thermal ion cleaning and mechanical polishing have been researched and developed at home and abroad. The high-temperature brazing pre-treatment technology can better meet the requirements of high-temperature brazing on the cleanliness of parts, and can obtain brazed joints with good structure and performance.

In addition to good pre-soldering techniques, the chosen brazing furnace for vacuum brazing is also crucial. The RHVB vacuum high temperature brazing furnace produced by SIMUWU is an excellent product for handling such processes. After a suitable pretreatment process, with its excellent temperature control accuracy and temperature uniformity, the workpiece can be brazed evenly.