Technical Paper
Accelerated Corrosion Test Methods for Evaluating External Corrosion Resistance of Vacuum Brazed Aluminum Heat Exchangers
1991-02-01
910590
A program to develop an aluminum tube stock alloy for vacuum-brazed heat exchangers with improved external corrosion resistance necessitated the use of accelerated laboratory corrosion tests to rank trial materials and ultimately qualify an alloy for production and sale. Brazed radiator sections and sheet samples were exposed to a variety of ASTM standard corrosion test environments. Metallographic examination of samples thus exposed demonstrated that the SWAAT test (ASTM G85:A3) closely replicated the air-side corrosion morphology found in aluminum radiators from the field. Samples exposed in test environments other than SWAAT did not generally exhibit the mixed intergranular/pitting morphology found in field retrievals. In neutral salt spray (ASTM B117), for instance, smooth-sided hemispherical pitting was the corrosion mode observed.
