Abstract
In the coupling of oilfield tubes bonded by the amorphous bonding method, quality assurance techniques have been studied in process after process. During the bonding, an ultrasonic wave was propagated toward the bonding interface and the changes in the amplitude of reflection were monitored. As a result, the bonding processes including a phase transformation of the mother materials and the dissolution of filler material were identified. Using the information, measurement errors of a radiation thermometer can be corrected in real time and the bonding states of the local area of the bond can also be observed by the convergence nature of the ultrasonic beam. After the bonding, height of the steps at the interface, grain size and hardness of the heat-affected zone were evaluated by an ultrasonic method in addition to the conventional pulse echo inspection. As a result, 100% of defective joints, in which breakage had occurred by the expansion test, were distinguished.
