| 摘要 |
The procedure of this invention for non-destructive testing of spot welds is based partly in the creation of a low-frequency electromagnetic primary field in the zone in front of the spot welding core. The field induces eddy currents in this zone, and in part determines the phase of the resulting low-frequency electromagnetic field's strength in this zone, and also creates a high-frequency electromagnetic primary field in the spot-welding zone. The field induces eddy currents in this zone, and in part determines the phase of the resulting high-frequency electromagnetic field's strength in this zone, and thereafter determines a difference between the resulting high-frequency electromagnetic field's strength phase and the resulting low-frequency electromagnetic field's strength phase and appreciates the quality of the spot welding core as directly dependent on the phase difference.The device for non-destructive testing of spot welds includes a current converter (1), a low-frequency measurement channel (22), a high-frequency measurement channel (18), and an indicator (28). The device also includes a directional coupling device (30) which is designed to alternately couple the converter (1) into the low-frequency measurement channel (22) and the high-frequency measurement channel (18), a memory unit (26) which is designed to store the output signal from the high-frequency measurement channel (18), a comparator (27) and control (29). The comparator (27) is designed to compare a signal stored in the memory unit (26) with the output signal from the low-frequency measurement channel (22), while the control (29) is designed to alternately create signals to simultaneously couple the converter (1) into the high frequency measurement channel (18) and lower signal from the measurement channel (18) in the memory unit (26) as well as signal to simultaneously couple the converter (1) into the low frequency measurement channel (22) and compare the signal from the low frequency measurement channel (22) with the signal stored in the memory unit (26).This invention can be used in the machine, ship, construction, aviation, and automotive industries for fault tracing and a non-destructive testing of a change in properties in the material of metal constructions of varioustypes. |
