Acoustic detection method for defects of cast iron material

A detection method and technology for material defects, applied in the direction of using sonic/ultrasonic/infrasonic waves to analyze solids, etc., can solve problems such as difficult application, shrinkage, slag inclusion, etc., to avoid economic losses and reduce coupling pressure.

Active Publication Date: 2012-07-25
CHINA SPECIAL EQUIP INSPECTION & RES INST +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the inherent characteristics of cast iron materials and the particularity of the casting process make it inevitable that there will be defects in cast iron components and equipment.
Affected by the complexity of multiple propagation modes of ultrasonic waves and the existence of wave mode conversion (mutual conversion between transverse and longitudinal waves, mutual conversion between Lamb wave and Rayleigh wave, etc.), when it is applied to composite materials, in order to make The propagation mode of the sound wave is simple, and the emissi

Method used

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  • Acoustic detection method for defects of cast iron material
  • Acoustic detection method for defects of cast iron material
  • Acoustic detection method for defects of cast iron material

Examples

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Comparison scheme
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Embodiment 1

[0044] figure 1 It shows the configuration diagram of the acoustic detection system for cast iron material defects in this embodiment, 1 is the cast iron test plate, 2 is the acoustic emission detection module, 3 is the computer equipment, 4 is the pulse signal generation module, 5 is the amplifier, 6 is the excitation probe , 7 is the scanning probe, 8 is the couplant.

[0045] refer to figure 1 , the excitation probe 6 and the scanning probe 7 are fixed on the top of the cast iron test plate 1 by a clamp, wherein a coupling agent 8 is arranged between the excitation probe 6 and the cast iron test plate 1, and a coupling agent 8 is also arranged between the scanning probe 7 and the cast iron test plate 1 There is couplant 8. The pulse signal generation module 4 is connected with the excitation probe 6, and is used to transmit an ultrasonic excitation signal to the cast iron test plate 1 through the excitation probe 6, and the scanning probe 7 is used to receive the ultrason...

Embodiment 2

[0049] The applicant found in the research that when testing cast iron materials with crack defects, when the scanning probe is located in front of the defect, the attenuation characteristics are exactly the same as when there is no defect; when the scanning probe moves to the defect position and a certain range behind Within the range, the attenuation degree of the measured amplitude will be significantly larger than that of no defect; and after the scanning probe moves to a certain distance behind the defect, the amplitude will rise to the same attenuation level as that of no defect. degree; when the amplitude is raised to the normal attenuation level and continue to move the scanning probe backwards, the attenuation with defects and the attenuation without defects will be basically the same, specifically as figure 2 and image 3 shown.

[0050] refer to figure 2 and image 3 , the excitation probe 101 is fixed at the position of point O on the cast iron test plate 100 ...

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Abstract

The invention discloses an acoustic detection method for defects of a cast iron material. The method comprises the following steps of manufacturing a comparison test board and a maximum allowable defect test board; performing ultrasonic detection on the comparison test board and the maximum allowable defect test board respectively, and then performing ultrasonic detection on a board to be tested; performing normalization on amplitude attenuation of the comparison test board, the maximum allowable defect test board and the board to be tested to obtain a maximum difference value close to the end of a measurement range between a normalized amplitude attenuation curve of the maximum allowable defect test board and a normalized amplitude attenuation curve of the comparison test board; and comparing an attenuation variation value of the board to be tested relative to the normalized amplitude attenuation curve of the comparison test board with the maximum difference value, and judging whether a defect which is larger than a maximum allowable defect exists on the board to be tested. The defect detection method has the advantages of high detection speed and low cost.

Description

technical field [0001] The invention relates to the technical field of non-destructive testing, in particular to an acoustic testing method for defects in cast iron materials. Background technique [0002] Cast iron materials have been widely used in urban gas pipelines, paper drying cylinders, automobiles and other equipment or components due to their excellent castability, wear resistance and shock absorption, high yield and low cost. However, the inherent characteristics of cast iron materials and the particularity of the casting process make it inevitable that there will be defects in cast iron components and equipment. Common defects include: porosity, slag inclusion, cold shut, shrinkage cavity and porosity, cracks, etc. At present, the non-destructive testing techniques for internal defects of cast iron materials mainly include radiographic testing and pulse reflection ultrasonic testing. Radiographic testing can detect manufacturing defects such as porosity, porosit...

Claims

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Application Information

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IPC IPC(8): G01N29/11
Inventor 沈功田李丽菲吴占稳张峥
Owner CHINA SPECIAL EQUIP INSPECTION & RES INST
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