Abstract:In order to evaluate the proficiencies of testing chemical compositions of Al alloys among the laboratories in Henan province, the CDMQI organized the interlaboratory comparisons for testing the contents of Si and Fe in aluminum alloys. Twenty laboratories took part in the interlaboratory comparisons. GB/T7999-2007《optical emission spectrometric analysis method of aluminum and aluminum alloys》was recommended. Other national standards were also permitted to be used. The results showed that 80% participating laboratories had satisfactory results, 15% had dissatisfactory results and 5% had questionable results. So it concluded that the majority of the participating laboratories were capable of accurately inspecting chemical compositions of Al alloys.