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An extensive field study was made of the corrosion of aluminum alloy panels in over fifteen years of service in three regions of the USA. Panels removed from service exposed vehicles were subjected to further testing to determine the relationship between field service, accelerated laboratory corrosion testing, and marine environment exposure for two years at Daytona Beach, Florida. In addition, two 42 year old aluminum bodied Dyna Panhard vehicles were recovered in France, examined closely, and subjected to similar tests. Few examples of significant corrosion were found in the field, and only one example of filiform corrosion on aluminum sheet in service. Steel panels on the same vehicles frequently rusted through, and filiform corrosion was seen occasionally. Laboratory tested aluminum panel samples frequently showed filiform corrosion and severe intergranular corrosion.

Vacuum brazed aluminum automobile radiators have exhibited a susceptibility to intergranular corrosion on the external tube surfaces, induced by road salt splash high in chlorides. A novel brazing sheet material with greatly improved perforation resistance has been developed to address this problem. Relative external corrosion resistance of conventional and experimental alloy systems was determined by accelerated corrosion testing of brazed composites and radiator sections in SWAAT. The new material, designated K319, exhibits an order of magnitude improvement in time to perforation in this test. A subsurface layer, anodic to the core alloy, is developed during the brazing process and accounts for the material's greatly enhanced resistance to perforation.

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.