Current Status of Aluminium Brazing Technology

This technology offers the benefits of a flux for successful o9xide removal, working at atmospheric pressure while avoiding the disadvantages of postbraze treatments and corrosion susceptibility. The nonhygroscopic and noncorrosive potassium fluoroaluminates are used as fluxes [76]. 

The process in most brazing operations includes the following steps  

Success or failure in CAB production relies on several factors. The starting point is a good product fit up. Parts to be joined by metallurgy must have intimate contact at some points along the joint. An adequate but not excessive quantity of filler metal must be available to fill the joints. Capillary forces pull the filler into the joints. The gap tolerance is 0.1 to 0.15 mm for nonclad components. When clad products are used, intimate contact is recommended the clad layers will act as a gaping tool. 

Another essential for reliable brazing results is a uniform flux coating on all surfaces involved in the joint formation. The main focus for achieving this task is on the cleaning and fluxing procedure. 

Equally important are the fiimace conditions, i.e. temperamre profile, temperature uniformity and atmospheric conditions. 

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