WHAT IS METAL BRAZING?
Brazing is the joining of metals through the use of heat and a filler alloy or pure metal whose melting temperature is below the melting point of the metals to be joined.
It works since it create a metallurgical bond, at molecular level, between the filler and the surfaces of the metals to be joined. The capillary action is the principle by which the filler metal is drawn to the joint.
Conventional processes and technology of brazing are one of the oldest civilization art. However in the last 50 years it as been applied to a much larger number of material combinations an, therefore, become more and more complex.
Several variation of brazing are now well known and established: dip-brazing, exothermic brazing, brazing under an electric blanket, induction brazing etc.
One of the latest, most powerful and innovative way of brazing is Brazing in Vacuum , where no flux is needed. These technology allow to join together metals and non metallic materials which can't be joined in atmosphere environment.
High temperature vacuum brazing, is particularly well suited for joining Titanium, Molibdenum, Tungstenum, Tantalum, etc. A list of metals, which can be joined by VLT high temperature vacuum brazing techniques is included in the Tab. 1 Brazing Chart.
We should underline that some of these joints required the development of specific techniques and cannot be provided by all suppliers.
Outstanding characteristics of brazed joints are
High mechanical strength.
High working pressure, over the limit of basic metals.
Vacuum tightness better than 1X10-10 mbar/lt/sec.
Temperature resistant; joints may reach an operating temperature up 1000°C and over.
High vacuum brazing is the best technology to have high quality joint even in a very complex geometry, between metals and metals to ceramics.
VLT can supply any type of component on client request and for a wide range of applications.
TABLE 1 - Referring card for brazing in high vacuum:
- Not suitable for all applications. Limitations may apply depending on shape, dimension, etc..
- Brazing is possible, but todate no practical application.
- C.F.C. Carbon Fiber Carbon.