razing is a joining process which involves heating the surfaces of two alloys (or filler metals) uniformly to a melting temperature above 450 °C (840 °F) so the flux melts and removes the surface oxides allowing the filler metal to form a joint between these two surfaces.

Brazing is often confused with soldering. A defining characteristic is that the braze melts while the material(s) being joined do not. The distinction between brazing and soldering is somewhat arbitrary; brazing occurs at a higher temperature than soldering.

One definition of brazing is “joining of two materials using a third, dissimilar material at higher temperatures than soldering.” While the exact temperature difference between brazing and soldering is often disputed, there are definite metallurgical reasons to use the 450 °C (840 °F) figure.

Braze alloy is often used to define an alloy that flows in thin joints while braze filler metal is used for thicker joints and for gap filling.

Brazing of Aluminium

Brazing of aluminium can be classified into two main areas:

  • Brazing in an enclosure i.e. Furnace brazing either Vacuum furnace (without flux) or Controlled Atmosphere Brazing CAB (with flux)
  • Brazing in the open air, either by Flame or by Induction