Several common acoustic methods

such as pulse reflection ultrasonic testing

time difference of diffraction ultrasonic testing

conventional linear array ultrasonic phased array and fully focused phased array

are effective means to detect buried defects in butt welds of pressure equipment.However

there are many differences in application scope

detection sensitivity

resolution and defect measurement accu-racy. In view of the above differences

this paper first expounds the detection principle

compares the differences and advan-tages and disadvantages of several methods

then compares the detection results of 43 mm thick butt weld simulation test plate

and analyzes the results

so as to clarify the application of these methods

which provides certain technical support for the detection of buried defects in butt weld of pressure equipment in the future.