GB1255870A - Method and system for ultrasonic weld inspection - Google Patents

Abstract

1,255,870. Ultrasonic inspection devices. COMMISSARIAT A L'ENERGIE ATOMIQUE. 5 Sept., 1969 [13 Sept., 1968], No. 44097/69. Heading H4D. In a system for inspecting a circular weld ultrasonically the weld is scanned helically by a transducer and time-gated echo signals from the weld are fed to an echo amplitude recorder having a recording head which is moved along a spiral path, each turn of the spiral corresponding to a complete rotation of the transducer about the weld axis. In the Fig. 3 embodiment for inspecting the circular weld 28 between a sleeve 23 and a plate 24, plug 33 provides a seal for water couplant in which transmit/receive transducer 30 is rotated and raised to give a helical scan of the weld. The X and Y deflections of a plotter stylus are synchronized with the transducer rotation by means of sine/cosine potentiometer 46 and the plotter trace is expanded by means of linear potentiometer 44 as the transducer is raised, thereby giving a spiral record. Echo signals are applied to a time gate 40 to select weld echoes and the weld echoes may be fed to a four-channel amplitude-analyser 42 whereby only echoes above a threshold amplitude (i.e. indicating weld flows) are recorded and whereby such echoes are recorded at the appropriate one of four tonal values. The transducer rotation rate may be programmed such that the plotter stylus speed does not vary with diameter of the plotted trace. A polar co-ordinate plotter or an oscilloscope may be used instead of the X-Y plotter. Constructional details of the transducer scanning mechanism are given (Figs. 8 and 9, not shown).