METHOD AND APPARATUS FOR THE REAL-TIME EVALUATION OF WELDS BY EMITTED STRESS WAVES

摘要

METHOD AND APPARATUS FOR THE REAL-TIME EVALUATION OF WELDS BY EMITTED STRESS WAVES Spot welds are evaluated using stress-wave emission techniques by detecting and measuring the stress waves emitted from a weld area during a first solid-to-liquid phase transformation period and a second liquid-to-solid phase transformation period of the weld. The stress waves emitted during the first transformation period provide an indication of the weld nugget size, while the stress waves emitted during the second transformation period provide an indication of the amount of post-weld cracking in the weld area. By subtracting the stress-wave energy measured during the second transformation period from the stresswave energy measured during the first transformation period, an indication of the strength of the weld is obtained.