Gridding ultrasonic tomography detection method for defects of shaft workpieces

Abstract

The invention discloses a gridding ultrasonic tomography detection method for defects of shaft workpieces. The method comprises the following steps: meshing an end surface area at one end of a workpiece; adopting a grid center as an ultrasonic probe sampling point, adopting an ultrasonic pulse echo method is used for sequentially collecting time domain signals of all sampling points and then converting the time domain signals into spatial depth signals, echo amplitudes corresponding to all depths are obtained, the position where defect echoes are located is clearly located, and detection of internal defects of shaft workpieces is achieved. According to the invention, acoustic beam diffusivity is also considered; superposing all reflection signal amplitudes which can be diffused to a certain position; echo amplitudes of cross sections at different depths in the workpiece are reconstructed by adopting amplitude data after superposition processing, and information of the cross sections inthe workpiece is displayed by tomography, so that the depth and two-dimensional distribution of defects are effectively identified, and the defect detection rate is greatly improved. According to themethod, a complex scanning array does not need to be arranged, comprehensive, visual and effective detection and positioning imaging of the internal defects of the shaft workpiece are achieved. The detection operation difficulty is reduced, and the operation efficiency, the detection rate and the reliability of a detection result are improved.

Description

technical field [0001] The invention relates to the technical field of ultrasonic non-destructive testing, in particular to a gridded ultrasonic tomographic detection method for shaft workpiece defects. Background technique [0002] Shaft workpieces are one of the most commonly used parts and vulnerable parts in various mechanical equipment. Defects in shaft workpieces will cause a series of problems such as severe vibration and noise of the machine, and even cause damage to the equipment. Ultrasonic testing has strong penetrating power, high sensitivity, low cost, and fast speed. It can detect large steel forgings up to several meters long. Therefore, ultrasonic nondestructive testing methods are suitable for testing shaft workpieces. [0003] However, the traditional ultrasonic testing of shafts mostly adopts the method of radial detection and continuous scanning along the circumference. The assumption of straight radiation from the axis of the probe, however, in actual t...

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Problems solved by technology

[0003] However, the traditional ultrasonic testing of shafts mostly adopts the method of radial detection and continuous scanning along the circumference. The assumption of straight radiation from the axis of the probe, however, in actual testing, the beam radiated by the ultrasonic wave source is not radiated straight from the wave source, but diffused outwards at a certain angle, so the above assumptions lead to the processing of the obtained echo data fundamentally. It is impossible to accurately reflect the defect on the

In addition, the traditional imaging of defect detection is displayed through A, B, C, and D scans, which cannot traverse and present the detection situation of each detection surface to intuitively judge the defect position and range

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