A Quantitative Method for Defect Location and Quantification in Billet Ultrasonic Detection

Abstract

The invention relates to a method for positioning and quantifying ultrasonic inspection defects of billets and belongs to the field of inspection and detection. The method comprises the following steps: classifying abnormal waveform states of large / medium-sized cylindrical extrusion billets or electroslag ingots in a contact-method ultrasonic longitudinal wave testing process, fully considering the similarity of diameters of acoustic beams and acoustic transmission performances of materials, and respectively positioning and quantifying the defects. The technical problem that the conventional defect positioning and quantifying method is not applicable is solved, and a reliable basis is provided for subsequent treatment of the billets.

Description

technical field [0001] The invention relates to a defect location and quantification method for ultrasonic detection of billets, in particular to a method for defect location and quantification of large and medium-sized cylindrical extrusion billets or electroslag steel ingots by contact method ultrasonic longitudinal wave detection using a conventional pulse reflection ultrasonic flaw detector. It belongs to the field of inspection and testing. Background technique [0002] Because the ultrasonic inspection of the billet state belongs to the process control, if the defect is found, it will be used after sawing, and the outer surface will not be processed generally. Therefore, the surface roughness of the circumference is poor, the two ends are not even, there are many obvious shrinkage holes in the riser, and there is a dummy plate at the end of the ingot. etc. It is impossible to test on the end face. In order to meet the requirements of ultrasonic testing coupling, two br...

AI Technical Summary

Problems solved by technology

Large and medium-sized cylindrical extrusion billets or electroslag steel ingots are still cast structures, without forging or extrusion deformation, the internal structure is not dense, the dendrites are developed, the grains are coarse and extremely uneven, the signal-to-noise ratio is very low, and the ingot tail The sound transmission performance varies greatly within the longitudinal length of the riser. The riser generally has looseness or even shrinkage cavities, and there may be secondary shrinkage cavities or shrinkage cracks in the middle of the billet. The shape of the defect changes significantly. During the detection process, the probe moves slightly, including The waveform including the bottom wave and the defect wave will change greatly. In this case, the comparison test block method cannot be used, and only the bottom surface reflection method can be used. Waves often disappear, so the conventional method of defect location and quantification is not suitable, and a more suitable method needs to be studied, so as to provide a reliable basis for the sawing process of the billet

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