Method for judging delamination flaws of flat metal plate by using ultrasonic single-crystal straight probe

Abstract

The invention relates to a method for judging the delamination flaws of a flat metal plate by using an ultrasonic single-crystal straight probe and belongs to the technical field of plate ultrasonic flaw detection. The ultrasonic single-crystal straight probe is adopted to detect the internal delamination flaws of a flat metal plate with a thickness of 20mm or more. The method includes the following steps that: 1) an ultrasonic single-crystal straight probe is selected; 2) an ultrasonic flaw detector which is examined as a qualified one is calibrated; 3) the ultrasonic flaw detector is adoptedto detect flaw positions, and after a user observes flaw waves on the screen of the ultrasonic flaw detector, the user should pay attention to the waveform characteristics of first-time flaw waves F1and first-time bottom waves B1, and sensitivity is reduce when it is necessary, until the user can see the peaks of the first-time flaw waves F1 and the first-time bottom waves B1; and 4) judgment and characterization are performed, if the wave height of the F1 is larger than 50% of the wave height of the B1, it can be judged that a current point is a delamination point. With the method of the invention adopted, the delamination flaws of the plate can be quickly identified. The method has the advantages of high speed, high accuracy and high work efficiency.

Description

technical field [0001] The invention relates to a method for judging delamination defects of flat metal plates by using an ultrasonic single-crystal straight probe, and belongs to the technical field of plate ultrasonic detection. Background technique [0002] At present, the ultrasonic testing of hot-rolled flat metal sheets is carried out with single-crystal straight probes, but the internal defects are only judged, quantified and rated. In actual use, after flame cutting, welding and other processing for unqualified plates found by ultrasonic testing, some can achieve the intended purpose of use, while some will directly crack along the 1 / 2 of the thickness of the plate, that is, "partition". layer", which eventually leads to the scrapping of the workpiece. Consult the relevant European and American ultrasonic testing standards, and there is no clear description of the severity of the internal defects of the plate. 5.3.9.2 of the current NB / T47013.3-2015 standard only p...

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Problems solved by technology

5.3.9.2 of the current NB / T47013.3-2015 standard only points out that "during the inspection process, if the inspector confirms that there are defects such as white spots and cracks in the plate, it should be rated as level IV", which does not clearly state How to identify defects such as points and cracks

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