An evaluation of ultrasonic and electrical resistance methods for the non-destructive testing (NDT) of resistance spot welds in low carbon steel sheet

TWI Industrial Member Report Summary  415/1990

By S A Westgate

Scope

The work reported covers an extensive study of the non-destructive testing (NDT) of resistance spot welds in both laboratory made samples and production components using conventional ultrasonic and electrical resistance measurements. Aspects of procedure development have been studied, followed by detailed testing of welds in uncoated low carbon steel sheet, with limited tests on zinc coated steel. Ultrasonic work included the assessment of various probe types and operating frequencies including attenuation studies. Investigation of the electrical resistance method covered an assessment of the factors influencing the measurements, such as impacting the welds prior to testing, edge distance and weld spacing and the distribution of voltage measurements across the weld.