The standard "BS EN 29455-1-1994 Soldering solder. Test methods, Determination of non-volatile substances, Weighing analysis method" specifies the test method used to determine the content of non-volatile substances in solder solder solder solder. This method determines the residual solid composition of solder solder during heating, i.e. non-volatile substances, by means of weighing analysis. During the test, the sample is heated to a certain temperature so that the volatile components in it evaporate and the remaining solid substance is quantified by weighing. This test method helps to evaluate the compositional stability and quality control of solder solder solder, ensuring that it meets technical specifications and application requirements. This standard provides an effective means of mass inspection for the welding industry to ensure the performance and safety of welding materials during use.