CN108267502B - Eddy current detection system and method for depth of hardened layer - Google Patents
Eddy current detection system and method for depth of hardened layer Download PDFInfo
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- CN108267502B CN108267502B CN201611255456.8A CN201611255456A CN108267502B CN 108267502 B CN108267502 B CN 108267502B CN 201611255456 A CN201611255456 A CN 201611255456A CN 108267502 B CN108267502 B CN 108267502B
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Abstract
The invention provides an eddy current detection system and an eddy current detection method for detecting the depth of a hardened layer on a metal surface. The eddy current detection system comprises eddy current detection equipment for performing eddy current detection on a detection target part and a standard sample for calibrating the eddy current detection equipment; the accuracy and the stability of the standard sample are improved by improving the preparation process of the standard sample, and the influence of interference factors on equipment is reduced by improving the detection method, so that the precision and the stability of eddy current detection are improved.
Description
Technical Field
The invention relates to an eddy current non-destructive inspection system and method for detecting the depth of a metal hardfacing layer.
Background
For critical components of torque transmission, such as camshafts, gears, etc., the mechanical properties of the components are significantly influenced by the properties of the force surface-hardening layer. Therefore, it is necessary to effectively detect the depth of the surface hardening layer of the part during the production process. The traditional metallographic and microhardness analysis methods are destructive testing methods performed on the extracted samples, with obvious disadvantages: high cost, low efficiency, poor reliability and incapability of timely tracing the production quality. The eddy current detection method is used for analyzing the metal surface by utilizing the action rule of the change of the physical characteristics of the metal surface, such as conductivity, magnetic permeability and the like, on eddy current signals, and is an important method for carrying out nondestructive detection on the metal surface.
Patent document CN200620098397.3 discloses an eddy current tester for measuring the depth of a metal surface hardening layer, which works according to the following principle: the method comprises the steps of respectively placing a metal material to be detected and a standard metal material between primary and secondary stages of two groups of identical induction coils of an eddy current sensor, exciting the eddy current sensor by using signals with certain frequency and amplitude, and analyzing and processing output signals of the secondary induction coils of the eddy current sensor to obtain an evaluation value of the depth of a surface hardening layer of the metal to be detected.
Patent document CN201320013358.9 discloses a double-station eddy current sensor testing device for constant velocity universal joint, which utilizes the principle of current magnetic effect to perform nondestructive testing of the depth of a hardened layer of a rod part of a workpiece. Before the workpiece is detected, the device needs to be calibrated, namely, a standard part which is manufactured in advance is placed in the eddy current sensor to form an initial oscillogram, and then relevant parameters of an analysis system are adjusted to corresponding values. And then, positioning and measuring the workpiece to be measured, and comparing the similarity of a waveform diagram formed by the measured value and a waveform diagram of the standard part to judge whether the depth of the hardened layer of the workpiece is qualified.
However, in the actual production detection process, due to many factors such as personnel, environment and standard samples existing in the eddy current detection equipment, the eddy current detection method cannot accurately and reliably measure the depth of the metal surface hardening layer.
Therefore, how to prepare a more reliable standard sample and how to reduce the interference to the eddy current test, and to improve the accuracy and stability of the eddy current test are the current subject to be solved.
Disclosure of Invention
In order to solve the technical problems, the invention provides an eddy current testing system for testing a metal surface hardening layer, which improves the preparation process of a standard sample so as to ensure that the prepared standard sample has better reliability; on the other hand, the detection method for detecting the metal surface hardening layer is provided, and the influence of interference factors on the measurement result in the test process is reduced through improving the detection process, so that the accuracy and the stability of the detection result are improved.
The eddy current detection system for detecting the depth of the metal surface hardening layer comprises eddy current detection equipment for performing eddy current detection on a piece to be detected and a standard sample for calibrating the eddy current detection equipment.
Wherein, the preparation process of the standard sample is as follows:
step 1, selecting a series of hardening process parameter values C1 according to the same production process to prepare a series of samples D1 with different hardening layer depths;
step 2, determining the depth of a hardened layer of the series of samples D1 by a metallographic method and a microhardness method;
step 3, determining a series of hardening process parameter values C2 according to the detection results of the series of samples D1, and obtaining a series of samples D2 with different hardening layer depths according to the series of hardening process parameter values C2, wherein n samples are respectively manufactured by using each hardening process parameter in C2;
and step 5, determining the hardened layer depth of the standard sample in D2.
The process of determining the hardened layer depth of the standard sample in D2 is as follows, firstly, m (m < n) samples are selected from the same group of D2 samples with consistency, the hardened layer depth values are determined by a metallographic method and a microhardness method, and the average value of the hardened layer depth values is used as the nominal hardened layer depth of the group of standard samples.
An eddy current inspection method for detecting the depth of a hardened layer on a metal surface according to the present invention, wherein the method comprises the steps of: preparing a standard sample, carrying out initial calibration on eddy current testing equipment by using the standard sample, testing a piece to be tested by using the eddy current testing equipment, and carrying out intermediate calibration on the eddy current testing equipment by using the standard sample.
Wherein, the initial calibration of the equipment comprises the following steps:
s1: selecting a standard sample according to the detection target range;
s2: inputting a standard sample value in eddy current detection equipment;
s3: calibrating an eddy current detection program;
s4: and judging whether the measured value of the standard sample is correct or not.
The initial calibration of the device may further comprise the steps of:
s5: and judging whether the measured value of the sample to be measured is reliable or not.
Wherein, whether reliable judgement is passed through right to the sample measured value that awaits measuring the sample is measured with metallography and microhardness method and is measured the sclerosis layer depth value that obtains and measure with the eddy current method and carry out the contrast and obtain.
The eddy current testing method for the metal surface hardening layer comprises the following steps of:
s2: inputting a standard sample value in eddy current detection equipment;
s3: calibrating an eddy current detection program;
s4: judging whether the measured value of the standard sample is correct or not;
the intermediate calibration process for the equipment is performed periodically.
By using the eddy current detection system, particularly by improving the standard sample preparation process and the test method, the accuracy and stability of the detection of the depth of the metal surface hardening layer by using eddy current are improved, the product quality is effectively ensured, and the production efficiency is improved.
Drawings
FIG. 1 schematically shows a flow of the method for detecting the depth of a hardened layer on a metal surface according to the present invention.
FIG. 2 schematically shows a flow of determining a standard sample in the method for detecting the depth of a hard-facing layer of a metal according to the present invention.
FIG. 3 schematically shows a series of samples D1 and D2 in the determination of a standard sample according to the method of the present invention.
FIG. 4 schematically shows a consistent screening of the same set of samples in the determination of standard samples according to the method of the invention.
Fig. 5 schematically shows the calculation of the depth of the hardened layer for the same set of samples during the determination of the standard sample according to the method of the invention.
Fig. 6 schematically shows a method for determining the depth of a hardened layer of a workpiece to be measured by fitting a standard measurement curve to the measurement values of a standard sample when the workpiece is measured by the method of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantages obtained by the present invention more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings and embodiments.
Fig. 1-6 show a preferred embodiment of the present invention.
Before using the eddy current apparatus for measurement, as shown in fig. 1, an appropriate eddy current test coil or test probe is first selected according to the surface geometry and the surface physical properties of the sample to be measured. And a proper positioning mode is selected for the sample to be tested so as to improve the testing precision and efficiency.
FIG. 2 shows a process for preparing a standard sample according to the present invention.
When preparing the standard sample, a series of hardening process parameters C1 can be obtained according to the empirical values and the allowable range of the surface parameters of the sample to be measured, such as the upper and lower limits of the depth of the surface hardening layer. Here, as shown in fig. 3, when the metal surface is hardened using the electron beam, C1 may be a current value of the electron beam hardening apparatus (a1, a2, A3, a4, a5, a6, …, Ax, Ay). Accordingly, a series of test specimens D1 were prepared by using the hardening process parameter C1 described above. By measuring D1 by metallographic and microhardness methods, a series of depth values of the hardened layer of D1 (D1, D2, D3, D4, D5, D6, …, dx, dy) were obtained. Wherein, above-mentioned a series of sclerosis layer depth values have covered the sample sclerosis layer depth upper and lower limits that awaits measuring.
Then, a series of samples D2 having depth values (D1, D2, D5, …, dy) of the hardened layers are selected from the series of samples D1 according to the specific needs of the measurement. The samples were prepared using the same electron beam curing equipment and the same curing method according to the curing process parameter C2(A1, A2, A5, …, Ay) corresponding to D2. A set of n test specimens was prepared using each of the hardening process parameters in C2. By respectively carrying out eddy current detection on each group of samples, a corresponding hardened layer depth eddy current detection value D _ WL can be obtained. As shown in fig. 4, the hardened layer depth eddy current detection values of the 10 samples in the group are D _ WL _1 to D _ WL _10, respectively. The measurement values D _ WL _1 to D _ WL _9 included in the dashed circles in the figure have good consistency, and D _ WL _10 has insufficient consistency with other measurement values, and therefore, are not excluded.
As shown in fig. 5, samples No. 4, 6, 8 and 9 selected from the samples corresponding to D _ WL _1 to D _ WL _9 were measured by metallographic method and microhardness method, and depth values of the hardened layer as shown in the figure were obtained. The average value of 0.33 was set as the hardened layer depth of the group of remaining samples satisfying the requirement for consistency. Thus, a set of standard samples having a depth of the hardened layer of 0.33 was prepared.
After all of the desired standard samples have been prepared, they can be used to initially calibrate the eddy current testing apparatus. As shown in fig. 6, a standard test curve was fitted through the measurement values of the standard sample after calibration.
In order to reduce errors, the calibrated eddy current testing equipment is also checked by using a standard sample. As shown in fig. 1, if the detection result by the standard sample does not match the depth value deviation of the hardened layer of the standard sample, the measurement preparation process is restarted. Preferably, the test piece is also used to test the measurement reliability of the eddy current test device after the test of the standard test specimen has been passed. Wherein, whether reliable judgement is passed through right to the sample measured value that awaits measuring the sample is measured with metallography and microhardness method and is measured the sclerosis layer depth value that obtains and measure with the eddy current method and carry out the contrast and obtain. The measurement preparation process is restarted if the deviation is too large.
After the test of the measurement reliability of the eddy current testing equipment by the piece to be tested is passed, the formal testing of the piece to be tested can be started. As shown in fig. 6, the depth value of the hardened layer of the workpiece to be measured can be determined by the detection signal of the workpiece and the standard test curve.
Because of the sensitivity of the eddy current inspection apparatus to the environment, especially to the temperature and the electromagnetic field, in order to reduce the error caused by the environment, periodic intermediate calibration of the eddy current inspection apparatus is also required in the inspection process. The calibration steps are as follows:
s2: inputting a standard sample value in eddy current testing equipment;
s3: calibrating an eddy current detection program;
s4: and judging whether the measured value of the standard sample is correct or not.
The period of the intermediate calibration of the eddy current test device is preferably 1 hour.
Besides the eddy current testing method, the invention also provides an eddy current testing system for testing the depth of the metal surface hardening layer, which comprises eddy current testing equipment for carrying out eddy current testing on a testing target piece and a standard sample for calibrating the eddy current testing equipment; wherein the standard sample is prepared according to the method.
Although specific embodiments of the present invention have been described herein with reference to the accompanying drawings, it will be understood by those skilled in the art that the foregoing examples are illustrative only and not limiting, and that various equivalent modifications and changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this invention.
Claims (9)
1. An eddy current testing method for detecting the depth of a metal surface hardening layer comprises the steps of initially calibrating eddy current testing equipment by using a standard sample, and testing a sample to be tested by using the initially calibrated eddy current testing equipment, wherein the standard sample is prepared according to the following method:
step 1, selecting a series of hardening process parameter values C1 according to the same production process to prepare a series of samples D1 with different hardening layer depths;
3, selecting a series of samples with specific hardened layer depth values from the series of samples D1 with different hardened layer depths, and preparing a series of samples D2 with different hardened layer depths according to a series of hardening process parameter values C2 corresponding to the series of samples;
step 4, performing consistency screening on the prepared sample D2 through eddy current testing, and excluding samples which are not in the consistency range;
and 5, determining the hardened layer depth of the sample in the consistency range in D2, and taking the hardened layer depth as the hardened layer depth of the corresponding standard sample.
2. The eddy current inspection method for inspecting the depth of a hardened layer on a metal surface according to claim 1, wherein the process of determining the depth of the hardened layer of the standard specimen in D2 is performed by first selecting m specimens from the same group of D2 specimens having consistency, determining the depth values of the hardened layers of the m specimens by a metallographic method and a microhardness method, and taking the average value of the depth values of the hardened layers of the m specimens as the depth of the hardened layer of the group of standard specimens.
3. The eddy current inspection method for inspecting the depth of a hardened layer of a metal surface according to claim 1 or 2, wherein the step of preparing the standard specimen further comprises:
step 2, determining the hardened layer depth of the series of samples D1 with different hardened layer depths by a metallographic method and a microhardness method;
wherein n samples were made using each of the hardening process parameters in C2, where n > m.
4. An eddy current inspection method for detecting the depth of a metal surface hardening layer according to claim 1 or 2, wherein the initial calibration of the eddy current inspection apparatus includes the steps of:
s1: selecting a standard sample according to the detection target range;
s2: inputting a standard sample value in eddy current detection equipment;
s3: calibrating an eddy current detection program;
s4: and judging whether the measured value of the standard sample is correct or not.
5. An eddy current inspection method for detecting the depth of a metal hardfacing layer in accordance with claim 4, wherein initial calibration of said eddy current inspection apparatus further comprises the steps of:
s5: and judging whether the measured value of the sample to be measured is reliable or not.
6. The eddy current inspection method for detecting the depth of a hardened layer on a metal surface according to claim 5, wherein said judgment as to whether the measured value of the specimen is reliable is made by comparing the depth value of the hardened layer measured by the metallographic method and the microhardness method with the depth value of the hardened layer measured by the eddy current method for said specimen.
7. An eddy current inspection method for detecting the depth of a metal hardfacing layer according to claim 1 or 2, further comprising an intermediate calibration of said eddy current inspection apparatus with said standard specimen, said intermediate calibration of said eddy current inspection apparatus comprising the steps of:
s2: inputting a standard sample value in eddy current testing equipment;
s3: calibrating an eddy current detection program;
s4: and judging whether the measured value of the standard sample is correct or not.
8. An eddy current inspection method for detecting the depth of a hardened layer on a metal surface according to claim 7, wherein the intermediate calibration process for the eddy current inspection apparatus is periodically performed.
9. An eddy current detection system for detecting the depth of a metal surface hardening layer comprises eddy current detection equipment for performing eddy current detection on a sample to be detected and a standard sample for calibrating the eddy current detection equipment; wherein the standard sample is prepared according to the eddy current testing method of claim 1 or 2.
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| CN111413244A (en) * | 2019-01-04 | 2020-07-14 | 国电锅炉压力容器检验有限公司 | Calibration method of oxide skin detector |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101915685A (en) * | 2010-07-12 | 2010-12-15 | 贾真甲 | Method for preparing standard sample for detecting impact toughness of superhard material |
| CN202974182U (en) * | 2013-01-10 | 2013-06-05 | 浙江欧迪恩传动科技股份有限公司 | Double-station eddy-current transducer detecting device of constant velocity joint |
| CN103286144A (en) * | 2012-02-22 | 2013-09-11 | 宝山钢铁股份有限公司 | Ultrasonic resonance spectrum detection method for fatigue hardening layer of roll |
| CN103615965A (en) * | 2013-12-20 | 2014-03-05 | 爱德森（厦门）电子有限公司 | Eddy-based method for measuring thickness of covering layer on surface of cambered metal with variable curvature |
| CN104865310A (en) * | 2015-06-29 | 2015-08-26 | 中国矿业大学 | Gear and shaft part carburization depth pulse eddy current detection apparatus and gear and shaft part carburization depth pulse eddy current detection method |
| CN105486214A (en) * | 2015-12-14 | 2016-04-13 | 南京泰祺瑞新材料科技有限公司 | Method for measuring heat processing seeping layer thickness |
| CN105509630A (en) * | 2015-11-27 | 2016-04-20 | 爱德森（厦门）电子有限公司 | Nonuniform-conductivity conductive material coating thickness measurement apparatus and method |
-
2016
- 2016-12-30 CN CN201611255456.8A patent/CN108267502B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101915685A (en) * | 2010-07-12 | 2010-12-15 | 贾真甲 | Method for preparing standard sample for detecting impact toughness of superhard material |
| CN103286144A (en) * | 2012-02-22 | 2013-09-11 | 宝山钢铁股份有限公司 | Ultrasonic resonance spectrum detection method for fatigue hardening layer of roll |
| CN202974182U (en) * | 2013-01-10 | 2013-06-05 | 浙江欧迪恩传动科技股份有限公司 | Double-station eddy-current transducer detecting device of constant velocity joint |
| CN103615965A (en) * | 2013-12-20 | 2014-03-05 | 爱德森（厦门）电子有限公司 | Eddy-based method for measuring thickness of covering layer on surface of cambered metal with variable curvature |
| CN104865310A (en) * | 2015-06-29 | 2015-08-26 | 中国矿业大学 | Gear and shaft part carburization depth pulse eddy current detection apparatus and gear and shaft part carburization depth pulse eddy current detection method |
| CN105509630A (en) * | 2015-11-27 | 2016-04-20 | 爱德森（厦门）电子有限公司 | Nonuniform-conductivity conductive material coating thickness measurement apparatus and method |
| CN105486214A (en) * | 2015-12-14 | 2016-04-13 | 南京泰祺瑞新材料科技有限公司 | Method for measuring heat processing seeping layer thickness |
Non-Patent Citations (1)
| Title |
|---|
| 确定D2中标准试样的硬化层深度的过程如下，首先，在同一组具有一致性的D2试样中选取m个试样，通过金相法和显微硬度法确定所述m个试样的硬化层深度值，并且，将所述m个硬化层深度值的平均值作为该组标准试样的硬化层深度。;伞晶超等;《热加工工艺》;20120831;第41卷(第16期);摘要、第224页第1栏第1段-第225页第2栏最后1段 * |
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