Study On Ultrasonic Testing Technology For Motor Bolt In Service

The quality of bolts used in pole fasten piece of motor is very important for motor safe operation, so it is necessary to do some non-destructive testing on bolt on line. The ultrasonic testing technology for motor bolts in service has been researched in this paper. By analyzing the structure and application characteristics of motor bolts, a kind of effective and feasible ultrasonic testing schemes in service was proposed, a special ultrasonic transducer was designed. The crack like defect on bolt's can be effective tested.Based on the motor bolts characteristics and working conditions, two testing methods were researched, one is testing in the hex bolt space on bolts with double crystal transducer, the other is testing in the narrow space on bolts end with ultra-thin transducer. The experimental results was showed that the former one is sensitive to bolt root crack defects, but not good to defect inside the screw; the latter one is well in the screw of crack testing, but not well in the root of bolt crack testing. If the two methods were combined,1 mm depth crack defects above the bolt surface can effectively detected, The methods meet the bolt detection requirements. The results is valuable to the research and development of relevant testing.