This standard specifies the technical requirements and test methods for tin _ lead alloy platings containing 50% to 70% tin. It is suitable for electronic, electrical and Miscellaneous metal products to prevent corrosion and improve welding performance. The standard specifies the classification of platings, the conditions of use and the thickness requirements of platings. It does not apply to threaded parts, bearings and raw materials. The standard also covers the requirements of the base metal, the appearance, thickness, composition, bonding strength and porosity of platings, and provides instructions for handling platings before and after to ensure platings mass and performance.