the manifold 126 a pair of ears 130 project from opposite sides of the manifold providing handles for carrying the transducer the handles include respective cooling medium inlet and outlet passages 132 and 134 respectively for flowing a cooling medium through the cavity for example a cooling medium such as water may be supplied from a suitable supply for flow through the inlet 132 into the cooling cavity and out through the outlet 134 for return to the supply to maintain the temperature of the transducer 120 within allowed temperature limits it will be appreciated that the transducer per se is conventional and includes an end 129 which transmits a signal through the high temperature delay 122 and into the ring 40 when the transducer is held against the outer surface of the ring as the rotor turns the ultrasonic signal is returned to the transducer and interpreted to determine the existence and location of any defects in the weld by using the manifold the use of a conventional transducer is permitted even at high temperature permitting the results to be directly correlated with final u t results in a cold condition referring to fig8 a similar type of weld head 70a may be provided for butt welding the ends of the ring sections to one another in order to butt weld however a pair of runoff blocks 100 having slots 102 are secured on opposite sides of the ring and wheel with the slots 102 in registration with the groove 98 between the end faces of.