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Method for detecting tightening flaws

A detection method and defect technology, applied in the direction of material magnetic variables, etc., can solve the problems of no strangulation defect detection method, non-destructive detection method is difficult to work, strangulation and other problems

Inactive Publication Date: 2009-05-27
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the interference fit parts are pressed in, if the parts have local shape defects or are not centered, the parts with greater stress on the mating parts may be violently deformed, resulting in strangulation
The strength of the parts in the state of strangulation is much smaller than that of similar parts, and accidents such as root fractures are prone to occur, leading to serious consequences
Since strangulation is an internal defect, it is not only invisible to the naked eye at the junction of the mating parts, but also other non-destructive testing methods (such as ultrasound) are also difficult to be effective
Through the search of existing scientific and technological literature, no research on detection methods for strangulation defects was found

Method used

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  • Method for detecting tightening flaws
  • Method for detecting tightening flaws
  • Method for detecting tightening flaws

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] A detection method for strangulation defects

[0030] (1) Measure the magnetic field intensity distribution data of the end face of the accessory hole of the mating component

[0031] (1.1) Use a single-probe magnetic probe with a sensitivity of 0.2ut to measure the magnetic field strength PHa at the height of the mating part relative to the end face of the hole at a=1mm;

[0032] (1.2) Keeping the height of a=1mm unchanged, measure along the end surface (annular surface) with a stepping distance of b=1.5mm, and measure the magnetic field strength value PH of one circle of the matching component hole;

[0033] (2) Processing the data

[0034] Plot the data measured in step (1): take the circumference as the x-axis and the PH value as the Y-axis to obtain the magnetic field intensity distribution diagram of the height a matching the part for one cycle, such as figure 2 ;

[0035] (3) Analyze the data and get the result: Is there any strangulation defect?

[0036] In the abo...

Embodiment 2

[0039] A detection method for strangulation defects

[0040] (1) Measure the magnetic field intensity distribution data of the end face of the accessory hole of the matching component

[0041] (1.1) Use a dual-probe differential magnetic probe with a sensitivity of 2ut to measure the magnetic field strength PHa at the height of the mating part relative to the end face of the hole at a=0.01mm;

[0042] (1.2) Keeping the height of a unchanged, measure along the end surface (annular surface) with a stepping distance of b=1.5, and measure the magnetic field strength value PH of one circle of the matching component hole;

[0043] (2) Processing the data

[0044] Plot the data measured in step (1): take the circumference as the x-axis and the PH value as the Y-axis, and obtain the magnetic field intensity distribution diagram of the height a matching the component for one cycle;

[0045] (3) Analyze the data and get the result:

[0046] Build a database based on the PH status of the mag...

Embodiment 3

[0049] A detection method for strangulation defects

[0050] (1) Measure the magnetic field intensity distribution data of the end face of the accessory hole of the mating component

[0051] (1.1) Use a magnetic probe with a sensitivity of 2ut to measure the magnetic field strength PHa at the height of the mating part relative to the end face of the hole at a=0.01mm;

[0052] (1.2) Keep the height of a unchanged, measure along the end surface (annular surface) with a stepping distance of less than b=1.5mm, and measure the magnetic field strength value PH of one circle of the matching component hole;

[0053] (2) Processing the data

[0054] Plot the data measured in step (1): take the circumference as the x-axis and the PH value as the Y-axis, and obtain the magnetic field intensity distribution diagram of the height a matching the component for one cycle;

[0055] (3) Analyze the data and get the result: Is there any strangulation?

[0056] By comparing the measured peak-to-peak ...

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Abstract

The present invention relates to a nondestructive detection method of tightened damage defect, belonging to the field of nondestructive electromagnetic detection of ferromagnetic material. Said method mainly includes the following several steps: using magnetic probe to measure magnetic field intensity of fitting piece and its magnetic field intensity distribution data, making data processing and analyzing data so as to obtain the data processing result, utilizing said result to judge that said fitting piece has tightened damage or not.

Description

Technical field [0001] The invention relates to a nondestructive detection method for strangulation defects, belonging to the field of nondestructive electromagnetic detection of ferromagnetic materials. Background technique [0002] Interference fit is generally produced by the fit between the shaft and the hole. If the tolerance zone of the hole is completely below the tolerance zone of the shaft, that is, there is an interference fit. All kinds of bearings and axles belong to the interference fit. When the interference fit part is pressed in, if the part has a partial shape defect or is not aligned, the part of the mating part that is more stressed may be severely deformed, resulting in strangulation. The strength of the strangled component is much smaller than that of similar components, and it is prone to accidents such as root breakage, which can lead to serious consequences. Because strangulation is an internal defect, it is not only imperceptible to the naked eye at the j...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N27/82
Inventor 李路明陈钘杨德智郝红伟邓远辉
Owner TSINGHUA UNIV