thickness allowing one probe set to cover a wide range of plate thickness fig1 shows the coils 37 above the first concept of the invention illustrated in fig1 6 is very similar to spot weld testing developed using conventional ultrasonic testing the use of emats eliminates the need to supply a couplant between the transducer and the weld surface this allows the test to be much more readily automated eliminating the need to apply the couplant to the weld surface and remove the couplant after testing in addition emats can operate at elevated temperatures allowing the welds to be tested shortly after welding reducing the feedback loop for quality control of the welding process the second concept of fig7 10 is unique to emats in that it is impractical to generate sh waves using conventional ultrasonics this approach has several significant advantages for spot weld testing the emat probes could be part of the welder assembly it would not require separate positioning mechanics and time to position the probes the evaluation of the weld would be made as soon as the weld solidifies resulting in the ability to immediately feedback information on the quality of the weld so that corrections to the welding process could be made if needed before even one more weld is made since emats are able to operate at elevated temperatures the transducers would not be affected by the heating caused by the welding process the use of the n 0 sh wave mode allows the same probes to be used over.