METHOD AND DEVICE FOR NONNDESTRUCTIVELY MEASURING REAL TIME OF WELDING

摘要

Spot welds are evaluated using stress-wave emission techniques by measuring the stress-wave energy emitted from the weld area during n time intervals of the weld cycle, where n/=4. Each of the time intervals corresponds to a different aspect of the weld cycle such as, for example, the initiation of heating, the separate solid-to-liquid phase transformation in each of the articles being welded, material combination within the weld nugget, cooling stresses occurring during resolidification, and post-weld cracking. The energy values obtained for each of the time interval can be compared with predetermined acceptable energy value ranges for corresponding ones of the intervals and/or compared with predetermined ratio values between two or more of the obtained interval values to determine the quality of a weld.