AbstractAn accelerated test for susceptibility to intergranular corrosion has been applied to a number of aluminium‐copper alloys whose service corrosion behaviour is known. In all cases, where intergranular corrosion occurred in service, the samples showed the same type of corrosion in the test solution. There was good correlation between the type of attack in the test solution and the K value (ml./cm.2/min.2) relating the volume of gas evolved in the test and the square of the time of effective attack. Factors which affect service performance are discusse