Recent Improvements in Aluminum Brazing Sheet for use in Heat Exchanger Applications, Especially Radiator Tube Stock

Several strategies can be employed for improving heat exchanger materials depending on the requirements of a specific heat exchanger component. One method would be to improve braze flow, thereby allowing a reduction in the amount of braze clad required, more core material and therefore a stronger radiator tube at a given gauge. Another means would be to strengthen the core material and still another way would be to improve air-side and water-side corrosion resistance. Improvements such as these are of interest in extending the life of radiators as well as other heat exchangers and are actively being pursued at Pechiney Rolled Products. Some of our ongoing R&D efforts towards improving radiator tube characteristics will be discussed in this paper. The evaluations include pre-braze and post-braze mechanical testing, internal corrosion testing, and SWAAT. For the internal corrosion testing, two different coolants (ASTM water and OY water) were used, and an internal corrosion testing apparatus that was designed and manufactured in-house was employed. Test results and discussion with respect to improved core material and improved liner material are presented herein.