The QB/T 1901.2-2006 specifies the testing methods for gold alloy overlays in watch cases and their Accessories, focusing on the testing requirements for purity, thickness, corrosion resistance and adhesion. This standard is applicable to the mass evaluation of gold alloy overlays in the watch industry and covers the physical and chemical performance testing of metal surface overlays. Specific test methods, such as chemical analysis, thickness measurement, corrosion testing and adhesion evaluation, ensure that the overlays meet the design and use requirements. The standard provides a unified technical basis for manufacturers and testing agencies to help improve product mass, enhance durability and aesthetics, and meet consumer demand for high-quality case products.