Nondestructive detection and acceptance method for butt-jointed welding seams

Abstract

The invention provides a nondestructive detection and acceptance method for butt-jointed welding seams. The nondestructive detection and acceptance method comprises the following steps: carrying out PAUT (Phased-Array Ultrasonic Detection) and TOFD (Time-Of-Flight Diffraction) scanning, collecting images, and comprehensively analyzing the images collected on site to determine positions of reflectors; judging and recognizing whether reflected signals discovered by TOFD and PAUT are non-relevant display or relevant display; if the reflected signals are relevant display, further judging whether defects are area type or non-area type; when judging that the defects are area type, measuring the heights of the defects on TOFD images, and measuring the lengths of the defects on PAUT images; and when judging that the defects are non-area type, measuring the amplitudes and the lengths on the images obtained by PAUT scanning. The nondestructive detection and acceptance method provided by the invention has the advantages that for the conditions that the welding of welding seams of medium-thickness plates is more difficult and the welding defects such as cracks and the like are easy to generate and the like, the problems of difficult recognition and inaccurate positioning of relevant display in individual detection process of the TOFD or the PAUT are solved, and when the PAUT and TOFD detection and acceptance methods are combined for use, the false judgment and missed judgment of detection results are reduced and the missed-detection rate is reduced to be lowest.

Description

technical field [0001] The invention relates to the technical field of detection, in particular to a method for non-destructive detection and acceptance of butt welds. Background technique [0002] At present, the use of medium-thick (thickness 40-100mm) steel plates is inseparable from industries such as ships, nuclear power, petroleum, and pressure vessels. Medium-thick steel plates are difficult to weld and prone to cracks, incomplete fusion, pores, and slag inclusions. and other defects. To detect these defects, non-destructive testing is required. In the past, X-ray detection and ultrasonic detection were the main methods for the detection of medium and thick plate welds. Recently, due to the development of new technology, PAUT (Phased Array Ultrasonic Testing phased array ultrasonic testing) and TOFD (Time of Flight Diffraction time-of-flight diffraction ultrasonic testing) new technologies are applied to detect ship plate welds, and achieved good results. However, ...

AI Technical Summary

Problems solved by technology

[0003] (1) PAUT mainly uses the principle of reflection, which can accurately locate defects, but it is difficult to identify the types of hazardous defects of area type (such as cracks, incomplete fusion, incomplete penetration, etc.);

[0004] (2) TOFD detection mainly uses the endpoint diffraction method, which is particularly sensitive to area-type defects such as unfused, cracks, etc., and can effectively detect such defects, and judge the type of defect based on image features, but TOFD detection is not good at locating defects. Accurate, resulting in defects that cannot be removed during rework, and there are blind spots on the upper and lower surfaces of TOFD detection;

[0005] (3) Using PAUT acceptance or TOFD acceptance alone will lead to missed defect detection, difficulty in defect characterization, and unreliable acceptance results

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