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Electromagnetic on-line detection method of retained austenite of rolling bearing

A technology of residual austenite and detection method, applied in the direction of material magnetic variable, etc., can solve the problems of slow sample preparation, large phase difference, and large measurement error

Inactive Publication Date: 2014-04-23
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These methods have the disadvantages of slow sample preparation and large measurement errors, which are quite different from the results of traditional X-ray methods.

Method used

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  • Electromagnetic on-line detection method of retained austenite of rolling bearing
  • Electromagnetic on-line detection method of retained austenite of rolling bearing
  • Electromagnetic on-line detection method of retained austenite of rolling bearing

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0083] roller test

[0084] Fig. 3 is the comparison result of measuring the residual value of the roller according to this method and the X-ray method.

[0085] Take a bearing roller with a diameter of φ=20mm, and the measurement results are shown in Table 1 and Figure 4.

[0086] Table 1 Paralympic content of rollers

[0087]

[0088] Figure 3(a) is the relationship between the test unbalanced current and the paralyzed content, and Figure 3(b) is the relationship between the tested unbalanced current and the paralyzed content. From Fig. 3, we can get the comparison results of the method of the present invention to measure the paralyzed value of the roller and the paralyzed value (■) of the X-ray method.

Embodiment 2

[0090] bearing ring

[0091] Table 2 Parallel content of bearing rings

[0092]

[0093] Take a bearing ring with a diameter of φ=78mm, and its measurement results are shown in Table 2 and Figure 4. remnants

[0094] When the tenite content is less than 18.5%, the difference with the X-ray method is less than 1%.

[0095] Figure 4(a) is the relationship between the test unbalanced current and the paralyzed content, and Figure 4(b) is the relationship between the tested unbalanced current and the paralyzed content. From Fig. 4, the comparison result of the paralyzed value of the ferrule measured by the method of the present invention and the paralyzed value of the X-ray method (■) can be obtained.

Embodiment 3

[0097] Field measurements

[0098] In Luoyang Bearing Research Institute and Luoyang Bearing Roller Factory, various types of bearing rings and rollers were measured by Paralympic electromagnetic method and X-ray method, and the results are shown in Table 3-6.

[0099] It can be seen from the X-ray results that for the same type of sample, the same sample is measured multiple times, and the dispersion is relatively large. The maximum difference between the three samples of 7011 is 3.9%, and the difference between the two samples of 7215 is 2.2%. The magnetic test result 7010 has a maximum deviation of 0.15% from the mean value.

[0100] table 3

[0101]

[0102] Table 47010 bearing outer ring

[0103]

[0104] Table 57011 bearing outer ring

[0105]

[0106] Table 67521 bearing roller

[0107]

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PUM

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Abstract

The invention discloses an electromagnetic on-line detection method of retained austenite of a rolling bearing. The electromagnetic on-line detection method comprises the steps that: (1) an alternating current bridge type circuit is established to build an equivalent circuit of a magnetic loop; (2) a constant current source provides exciting current signals; (3) the constant current source inputs the exciting current to an excitation loop; (4) resistors, a reference probe and a measuring probe compose four arms of the alternating current bridge type circuit, and the reference probe and the measuring probe detect a material to be detected; (5) the resistors are connected with a mutual inductor to send output current signals to a data acquisition card and then to a computer; (6) another mutual inductor is connected between the reference probe and the measuring probe to send unbalanced current signals to the data acquisition card and then to the computer; and (7) the computer adjust the alternating current bridge type circuit to a maximum sensitivity according to the input exciting current, and the unbalanced current signal calculates content of the residual austenite of the detected piece. The electromagnetic on-line detection method, disclosed by the invention, has the advantages of high sensitivity, good repeatability, convenient operation and fast detection speed, is relatively well matched with a result of an X-ray method and is suitable for on-line detection and popularized use.

Description

technical field [0001] The invention relates to a new method for detecting the residual austenite content of bearing products by using a U-shaped sensor and an AC bridge circuit, in particular a method for characterizing the change of the residual austenite volume according to the change of the reluctance of the strong magnet in the magnetic circuit of the test piece. Background technique [0002] The amount of retained austenite in bearing steel has a decisive influence on the mechanical properties and dimensional stability of the bearing. There is often a corresponding relationship with the tensile strength, impact toughness and fatigue strength of the bearing material. In order to ensure the quality of bearings, foreign countries have clear regulations on the content of residual austenite in bearing products. If the content exceeds the specified range, the bearing will become a substandard product. At present, the domestic requirements for bearing products are becoming m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N27/72
Inventor 董光能张相臣王振山雷建中高元安李建忠关志刚
Owner XI AN JIAOTONG UNIV