Brazing Private
2 years ago - Multimedia - San Antonio - 109 views -$ --
What is vacuum brazing?
Brazing is a metal-joining process in which two or more materials are joined when a filler metal (with a melting point lower than those of the materials themselves) is drawn into the joint between them by capillary action.
Vacuum Brazing Euipments have many advantages over other metal-joining techniques, particularly welding. Since the base metals never melt, brazing allows much tighter control over tolerances and produces a cleaner connection, normally without the need for secondary finishing. Because components are heated uniformly, brazing consequently results in less thermal distortion than welding. This process also provides the ability to easily join dissimilar metals and non-metals and is ideally suited to cost-effective joining of complex and multi-part assemblies.
How does vacuum brazing work?
High Temperature Vacuum Brazing Furnace is carried out in the absence of air, using a specialized furnace, which delivers significant advantages:
Extremely clean, flux-free joints of high integrity and superior strength
Improved temperature uniformity
Lower residual stresses due to slow heating and cooling cycle
Significantly improved thermal and mechanical properties of the material
Heat treating or age hardening in the same furnace cycle
Easily adapted for mass production
In order to obtain high-quality brazed joints, parts must be closely fitted and the base metals must be clean and free of oxides, normally accomplished by either chemical or mechanical (abrasive) cleaning. In the case of mechanical cleaning, proper surface roughness must be maintained as the capillary action of the filler material occurs much more readily on a rough surface than a smooth surface.
Temperature and time are also important factors that contribute to the quality of brazed joints. As the temperature of the braze alloy is increased, the alloying and wetting action of the filler metal increases as well. In general, the temperature selected must be above the melting point of the filler metal, though there are several other factors that influence temperature selection.
