GB/T 7991.9-2014 "Test methods for vitreous and porcelain enamel—Part 9: Determination of tensile strength" specifies the apparatus, test specimens, procedures, calculation of results, and reporting for determining the tensile strength of vitreous enamel layers at room temperature (10°C to 35°C). It is applicable to the vitreous enamel layers of enameled equipment. The test involves using a tensile strength testing machine to pull bonded test columns away from the substrate, recording the peeling force value to calculate the strength. The detection requires the use of a tensile strength testing machine, an electromagnetic thickness gauge, and an analytical balance. The loading speed is set to (5 ± 1) mm/min, and the test is used to evaluate the bonding strength between the vitreous enamel layer and the metal substrate.