Nondestructive testing method for tungsten alloy density and density distribution

Abstract

The invention discloses a nondestructive testing method for tungsten alloy density and density distribution. The nondestructive testing method comprises the following steps: preparing a series of reference test blocks; detecting the density value rho of each reference test block; carrying out alternating magnetic field induction detection on each reference test block based on an electromagnetic induction principle by utilizing an electromagnetic induction detection system to obtain an induction signal X of each reference test block; establishing a calibration curve between the induction signal of each reference test block and the tungsten alloy density by using the obtained data, and establishing a correlation model; detecting different parts of the tungsten alloy part to be detected by using the electromagnetic induction detection system to obtain detection signal values of the different parts; and (5) substituting the detection signal value obtained in the step (5) into the correlation model to obtain the density distribution condition of different parts of the tungsten alloy. The detection method provided by the invention is completely nondestructive, has the characteristics of low detection cost, high efficiency, high precision and the like, is suitable for tungsten alloy parts with alloy elements of nickel, iron, cobalt and the like, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of non-destructive testing of tungsten alloy materials, and specifically relates to a non-destructive testing method for the density and density distribution of tungsten alloys. Background Art

[0002] Tungsten alloys are widely used in the fields of aerospace, nuclear industry, civil industry, etc. due to their good and stable physical and chemical properties. Affected by the preparation process and material characteristics, tungsten alloy parts often have uneven density distribution in different parts, which affects their service performance. To ensure the consistency of the performance of tungsten alloy parts, it is necessary to detect the density distribution of different parts to improve product quality. Traditional detection methods include the Archimedes drainage method and industrial CT method. Among them, the Archimedes drainage method can only detect the overall density of parts, and when detecting the density distribution, it can only destructively dissect the parts, increasing the difficulty of detection. Although industrial CT belongs to a commonly used non-destructive density detection method, it is currently mostly applied to low-density materials such as polymers and composite materials. There are many air gaps in these low-density materials, while tungsten alloy materials belong to high-specific gravity dense sintered materials without air gaps inside, and their density is much higher than that of existing low-density materials. Therefore, it is difficult for the industrial CT method to penetrate high-density tungsten alloy parts, and the density resolution decreases with the increase of its energy, with a long detection cycle and high cost. At the same time, due to the mutual solid solution of metal atoms in tungsten alloys, the magnetic conductivity of ferromagnetic bonding phases decreases, which also requires a high-sensitivity detection system to distinguish density changes.

[0003] Therefore, the current detection methods for the density and density distribution of tungsten alloy materials are destructive to the materials, and have low detection accuracy, low efficiency and low cost.

[0004] In view of this, this patent application is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a non-destructive testing method for the density and density distribution of tungsten alloys, which uses the principle of electromagnetic induction to realize the detection of the density and its distribution of tungsten alloys. It is completely non-destructive, has the characteristics of low detection cost, high efficiency and high precision, and has good application prospects.

[0006] The present invention is realized through the following technical solutions:

[0007] A non-destructive testing method for the density and density distribution of tungsten alloys, comprising:

[0008] (1) Prepare a series of reference blocks, in which the proportion between each alloy element is the same, and is the same as the proportion between each alloy element in the tungsten alloy part to be tested;

[0009] (2) Detect the density value ρ of each reference block;

[0010] (3) Use an electromagnetic induction detection system to perform alternating magnetic field induction detection on each reference block based on the principle of electromagnetic induction, and obtain the induction signal X of each reference block.

[0011] (4) Use the data obtained in steps (2) and (3) to establish a calibration curve between the induction signal of each reference block and the density of the tungsten alloy, and establish a correlation model.

[0012] (5) Use the electromagnetic induction detection system to detect different parts of the tungsten alloy part to be tested, and obtain the detection signal values of different parts.

[0013] (6) Substitute the detection signal values obtained in (5) into the correlation model in (4), and the density distribution of different parts of the tungsten alloy can be obtained.

[0014] Tungsten alloy is a two-phase composite material composed of tungsten phase and bonding phase. The tungsten phase is basically composed of pure tungsten with a large density, and the bonding phase is generally a solid solution of elements such as nickel, iron, and cobalt with a relatively small density. Among them, tungsten is paramagnetic, and the solid solution formed by nickel, iron, etc. is ferromagnetic. Therefore, the distribution of the bonding phase can be detected through the principle of electromagnetic induction, and then the density distribution can be reflected. In the present invention, the principle of electromagnetic induction is used to realize non-destructive detection of the density and its distribution of tungsten alloy, which is applicable to tungsten alloy parts with alloying elements such as nickel, iron, and cobalt. The detection method of the present invention is non-destructive, and based on the principle of electromagnetic induction, the detection result is more accurate, with higher precision, simple operation, and low cost.

[0015] In an optional embodiment, the number of the series of reference blocks is not less than 5, and the ratio of W element to the overall alloying elements is finely adjusted. The W element content of at least one reference block is greater than or less than the W element content of the tungsten alloy part to be tested, so that the W element content of the test block can cover the tungsten alloy material to be tested, and the difference in the W element content between adjacent reference blocks is less than or equal to 0.5Wt%.

[0016] In the present invention, by setting a plurality of series of reference blocks, designing that the W element content of each reference block can cover the tungsten alloy material to be tested, and designing that the difference in the W element content between adjacent reference blocks is less than or equal to 0.5Wt%, the accuracy and precision of the detection result can be significantly improved.

[0017] In an optional embodiment, before detecting the density values of each reference block in step (2), the prepared series of reference blocks are inspected for flaws, and there shall be no defects such as porosity or air holes. Otherwise, the test blocks shall be prepared again.

[0018] In an optional embodiment, the Archimedes drainage method is used to detect the density values of each reference block in step (2).

[0019] In an optional embodiment, the measurement accuracy when measuring the density value of each reference test block is not less than 0.01 g / cm 3 .

[0020] In an optional embodiment, the electromagnetic induction detection system includes at least one excitation coil and one induction coil. The excitation coil is used to generate an alternating electromagnetic field, and the induction coil is used to induce a voltage or current signal in the alternating magnetic field. A closed loop is formed between the excitation coil and the induction coil.

[0021] In an optional embodiment, the induction signal is a voltage signal or a current signal.

[0022] In the present invention, the change in magnetic flux during electromagnetic induction detection is caused by the different proportions of tungsten phase and ferromagnetic bonding phase. And due to the mutual solid solution of metal atoms in the tungsten alloy, the magnetic permeability of the ferromagnetic bonding phase decreases. Therefore, it is required that the detection system has high sensitivity to distinguish density changes. The resolution of current and voltage needs to reach below 50 μA and 50 μV respectively. For the calibration test block, it is required that the test block has no defects such as pores and air gaps after flaw detection before it can be used, and the detection accuracy of the density of the calibration test block should be ≤ 0.01 g / cm 3 . None of the existing detection methods can meet the above multiple requirements at the same time. The present invention utilizes the principle of electromagnetic induction and reasonably designs each reference test block, significantly improving the accuracy and precision of the detection results and meeting the above multiple detection requirements.

[0023] In an optional embodiment, the electromagnetic induction detection system further includes a signal acquisition system, and the signal acquisition system can amplify and acquire the voltage signal or the current signal. By signal amplification, the signal strength can be enhanced and the detection accuracy can be improved.

[0024] In an optional embodiment, the thickness of the series of reference test blocks is the same as the thickness of the tungsten alloy part to be inspected.

[0025] Due to the existence of the skin effect, there is a critical penetration depth of the alternating electromagnetic field in the part, and the critical penetration depth is determined by using test blocks with different thicknesses prepared from the material to be inspected. If the thickness of the object to be inspected is greater than the critical penetration depth, the thickness of the reference test block prepared in step (1) should also be greater than the critical penetration depth; if the thickness of the object to be inspected is less than or equal to the critical penetration depth, the thickness of the reference test block prepared in step (1) should be the same as the thickness of the object to be inspected. And in the present invention, a series of reference test blocks are prepared using the same or similar process as the tungsten alloy material to be inspected.

[0026] In an optional embodiment, the least squares method is used to establish a correlation model between the induction signal of the reference test block and the density of the tungsten alloy. The correlation model equation is:

[0027] ρ = a*X + b

[0028] Where ρ is the density, X is the voltage or current signal value, and a and b are the parameters to be fitted.

[0029] The advantages and beneficial effects of the present invention compared with the prior art are as follows:

[0030] In the present invention, the electromagnetic induction principle is used to detect the density and its distribution of tungsten alloy, which is completely non-destructive, with the characteristics of low detection cost, high efficiency, and high precision. It is applicable to tungsten alloy parts with alloying elements such as nickel, iron, and cobalt, and has good application prospects. Brief Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts. In the drawings:

[0032] Figure 1 is a schematic diagram of a series of reference blocks prepared in Example 1 of the present invention;

[0033] Figure 2 is a schematic diagram of the structure of the electromagnetic induction detection system of the present invention; Figure 3 is a calibration curve diagram of the voltage signal and density detected for a series of reference blocks obtained in the embodiments of the present invention;

[0034] Figure 4 is a schematic diagram when dissecting the tungsten alloy to be detected along the height direction;

[0035] Figure 5 is a schematic diagram of a series of reference blocks prepared in Example 2 of the present invention;

[0036] Figure 6 is a calibration curve diagram of the current signal and density detected for a series of reference blocks obtained in Example 2 of the present invention;

[0037] Figure 7 is a schematic diagram of the state of taking multiple detection points for the tungsten alloy part to be detected in Example 2. Detailed Embodiments

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the embodiments and the drawings. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0039] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: the present invention may be practiced without these specific details. In other instances, well-known structures, circuits, materials, or methods have not been specifically described to avoid obscuring the aspects of the present invention.

[0040] Throughout the specification, references to "one embodiment", "an embodiment", "an example", or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "one embodiment", "an embodiment", "an example", or "an example" throughout the specification are not necessarily all referring to the same embodiment or example. Additionally, the specific features, structures, or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will understand that the diagrams provided herein are for illustrative purposes only and are not necessarily drawn to scale. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0041] In the description of the present invention, the orientation or positional relationship indicated by terms such as "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the scope of protection of the present invention.

[0042] Since only the overall density of the part can be detected by the Archimedes drainage method, if one wants to know its sealing separately, the part needs to be dissected and damaged; although the CT method also belongs to non-destructive testing, it is not applicable to the non-destructive testing of high-density tungsten alloy parts, and the resolution is also low, and the test results are inaccurate.

[0043] To solve the above problems, a new non-destructive testing method for tungsten alloy density and density distribution is proposed in the present invention. Using the principle of electromagnetic induction, according to the different intensities of electromagnetic induction of different parts of the tungsten alloy part due to different compositions, the density distribution of different parts is obtained by using electromagnetic induction signals. The specific method is as follows:

[0044] (1) Prepare a series of reference blocks, in which the proportions between the alloying elements in each reference block are the same and the same as those between the alloying elements in the tungsten alloy part to be tested;

[0045] (2) Detect the density value ρ of each reference block;

[0046] (3) Using an electromagnetic induction detection system, perform alternating magnetic field induction detection on each reference block based on the principle of electromagnetic induction to obtain the induction signal X of each reference block;

[0047] (4) Using the data obtained in steps (2) and (3), establish a calibration curve between the induction signal of each reference block and the density of the tungsten alloy, and establish a correlation model;

[0048] (5) Using the electromagnetic induction detection system to detect different parts of the tungsten alloy part to be inspected, and obtain the detection signal values of different parts;

[0049] (6) Substitute the detection signal values obtained in (5) into the correlation model in (4), and the density distribution of different parts of the tungsten alloy can be obtained.

[0050] Further, the number of the series of reference blocks is not less than 5, and the W element content of at least one reference block is greater than or less than the W element content of the tungsten alloy part to be inspected, and the content difference of the W element in adjacent reference blocks is less than or equal to 0.5 Wt%.

[0051] Further, before detecting the density values of each reference block in step (2), perform flaw detection on the prepared series of reference blocks, and there shall be no defects such as porosity and air holes, otherwise re-prepare the test blocks.

[0052] Further, in step (2), the Archimedes drainage method is used to detect the density values of each reference block.

[0053] Further, the measurement accuracy when measuring the density values of each reference block is not lower than 0.01 g / cm 3 .

[0054] Further, the electromagnetic induction detection system includes at least one excitation coil and one induction coil. The excitation coil is used to generate an alternating electromagnetic field, and the induction coil is used to induce a voltage or current signal in the alternating magnetic field. A closed loop is formed between the excitation coil and the induction coil.

[0055] Further, the induction signal is a voltage signal or a current signal.

[0056] Further, the electromagnetic induction detection system further includes a signal acquisition system, and the signal acquisition system can amplify and acquire the voltage signal or the current signal.

[0057] Further, the thickness of the series of reference blocks is the same as the thickness of the tungsten alloy part to be inspected.

[0058] Further, the least squares method is used to establish the correlation model between the induction signal of the reference block and the density of the tungsten alloy, and the correlation model equation is:

[0059] ρ = a*X + b

[0060] Where ρ is the density, X is the voltage or current signal value, and a and b are fitting parameters to be determined.

[0061] Hereinafter, the non-destructive testing method of this patent will be described in more detail through specific embodiments.

[0062] Embodiment 1:

[0063] 1. In this embodiment, a WNiFe alloy part is taken as the detection object, and for this purpose, 7 tungsten alloy reference blocks are designed.

[0064] 2. The reference blocks are prepared by the same process as the detection object, and the test blocks are as shown in the appendix. Figure 1 as shown.

[0065] 3. Set up an electromagnetic induction detection system. Its detection probe contains an excitation coil and an induction coil, and a closed magnetic circuit is formed between the two. And in the electromagnetic induction detection system, there is also a signal generation module for exciting induction signals, a signal amplifier for amplifying and collecting the detected induction signals, and a filter for filtering the clutter of the detection signals. The collection and processing of the detection signals are realized through the upper computer program. The detection schematic diagram is as shown in the appendix. Figure 2 as shown.

[0066] Use the electromagnetic induction detection system to test the voltage signal values of each reference block. For each reference block, 5 points are measured and the average value is taken. The results are shown in Table 1 in the appendix.

[0067] 4. Measure the density value of each reference block by the Archimedes drainage method, as shown in Table 1 in the appendix.

[0068] Table 1 Measured data of voltage signals and densities of reference blocks

[0069] Specimen Number Average Voltage (mV) <![CDATA[Density (g / cm 3 )]]> 1# 1.7100 18.024 2# 1.6835 18.080 3# 1.6695 18.142 4# 1.6500 18.194 5# 1.6105 18.270 6# 1.6005 18.322 7# 1.5510 18.394

[0070] 5. According to the obtained data, establish a calibration curve for the voltage signal and density of the reference block. Through least squares fitting, the correlation model of voltage-density is obtained as: ρ = 22.13595 - 2.39875 * X, R 2 = 0.9786. The calibration curve is shown in the appendix. Figure 3 .

[0071] 6. Use the electromagnetic induction detection system to perform voltage detection on different parts of the tungsten alloy part to be measured. For each part, 10 points are measured and the average value is taken. 5 points are measured on both the inner and outer surfaces.

[0072] 7. Substitute the voltage values measured in (6) into the correlation model in (5) to calculate the density values, as shown in Table 2 in the appendix.

[0073] Table 2

[0074]

[0075] In order to verify the detection accuracy of the method of the present invention, the tungsten alloy parts were dissected into 5 parts along the height direction (see Appendix Figure 4 ), and then the density values of each dissected part were measured using the Archimedes drainage method, as shown in Appendix Table 2. By comparing the density results of the present method and the drainage method in Table 2, it can be seen that the maximum deviation between the density values measured by the present method and those measured by the Archimedes drainage method is about 0.6%, which proves that the detection accuracy of the present method is relatively high and is better than other non-destructive testing methods.

[0076] Example 2:

[0077] 1. In this example, taking the WNiFeCo alloy parts as the detection object, 5 tungsten alloy reference blocks were designed for this purpose.

[0078] 2. The reference blocks were prepared by the same process as the detection object, and the test blocks are as shown in Appendix Figure 5 .

[0079] 3. An electromagnetic induction detection system was set up. Its detection probe contains an excitation coil and an induction coil, and a closed magnetic circuit is formed between the two. And in the electromagnetic induction detection system, there is also a signal generation module for exciting induction signals, a signal amplifier for amplifying and collecting the detected induction signals, and a filter for filtering the clutter of the detection signals. The collection and processing of the detection signals are realized through the upper computer program. The detection schematic diagram is as shown in Appendix Figure 2 .

[0080] The electromagnetic induction detection system was used to test the current signal values of each reference block. 5 points were measured for each reference block and the average value was taken. The results are shown in Appendix Table 1.

[0081] 4. The density values of each reference block were obtained by using the Archimedes drainage method, as shown in Appendix Table 3.

[0082] Table 3 Measured data of current signals and densities of reference blocks

[0083] Specimen Number Average Current (mA) <![CDATA[Density (g / cm 3 )]]> 1# 0.701 18.090 2# 0.693 18.101 3# 0.681 18.110 4# 0.668 18.130 5# 0.649 18.150

[0084] 5. According to the obtained data, a calibration curve of the current signal and density of the reference block was established. The correlation model of current-density was obtained by least square fitting as: ρ = 18.90545 - 1.16369*X, R 2 = 0.99415. The calibration curve is shown in Appendix Figure 6 .

[0085] 6. The electromagnetic induction detection system was used to measure the tungsten alloy parts to be tested (see Appendix Figure 7The current value was detected. For each part, 20 points were detected and the average value was taken, with 10 points measured on each of the inner and outer surfaces.

[0086] 7. Substitute the current value measured in (6) into the correlation model in (5) to calculate the density value, as shown in Table 4 of the attached table.

[0087] Table 4

[0088]

[0089] In order to verify the detection accuracy of the method of the present invention, the density value of each part was measured using the Archimedes drainage method, as shown in Table 4 of the attached table. By comparing the density results of the method of the present invention and the drainage method in Table 4, it can be seen that the maximum deviation between the density value measured by the method of the present invention and the value measured by the Archimedes drainage method is <0.2%, which proves that the detection accuracy of the method of the present invention is relatively high and is superior to other non-destructive testing methods.

[0090] The above specific embodiments have further detailed the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A non-destructive testing method for the density and density distribution of tungsten alloys, characterized in that, Including: (1) Prepare a series of reference blocks, where the proportion between alloying elements in each reference block is the same and the same as that between alloying elements in the tungsten alloy part to be inspected; (2) Detect the density value ρ of each reference block; (3) Use an electromagnetic induction detection system to perform alternating magnetic field induction detection on each reference block based on the principle of electromagnetic induction, and obtain the induction signal X of each reference block; (4) Use the data obtained in steps (2) and (3) to establish a calibration curve between the induction signal of each reference block and the density of the tungsten alloy, and establish a correlation model; (5) Use the electromagnetic induction detection system to detect different parts of the tungsten alloy part to be inspected and obtain the detection signal values of different parts; (6) Substitute the detection signal values obtained in (5) into the correlation model in (4), and the density distribution of different parts of the tungsten alloy can be obtained.

2. The non-destructive testing method for tungsten alloy density and density distribution according to claim 1, wherein, The number of the series of reference blocks is not less than 5, and the W element content of at least one reference block is greater than or less than the W element content of the tungsten alloy part to be inspected, and the content difference of the W element between adjacent reference blocks is less than or equal to 0.5Wt%.

3. A non-destructive testing method for tungsten alloy density and density distribution according to claim 1, characterized in that, Before detecting the density value of each reference block in step (2), perform flaw detection on the prepared series of reference blocks, and there shall be no defects such as porosity and air holes, otherwise prepare the test block again.

4. A non-destructive testing method for tungsten alloy density and density distribution according to claim 1, characterized in that, In step (2), the Archimedes drainage method is used to detect the density value of each reference block.

5. A non-destructive testing method for tungsten alloy density and density distribution according to claim 4, characterized in that The measurement accuracy when measuring the density value of each reference test block is not less than 0.01 g / cm 3 .

6. A non-destructive testing method for tungsten alloy density and density distribution according to claim 1, characterized in that, The electromagnetic induction detection system includes at least one excitation coil and an induction coil. The excitation coil is used to generate an alternating electromagnetic field, and the induction coil is used to induce a voltage or current signal in the alternating magnetic field. A closed loop is formed between the excitation coil and the induction coil.

7. A non-destructive testing method for the density and density distribution of tungsten alloy according to claim 1, characterized in that, The induction signal is a voltage signal or a current signal.

8. A non-destructive testing method for tungsten alloy density and density distribution according to claim 1, characterized in that The electromagnetic induction detection system further includes a signal acquisition system, and the signal acquisition system can amplify and acquire the voltage signal or the current signal.

9. A non-destructive testing method for the density and density distribution of tungsten alloy according to claim 1, wherein, The thickness of the series of reference blocks is the same as the thickness of the tungsten alloy part to be inspected.

10. A non-destructive testing method for the density and density distribution of tungsten alloy according to claim 1, characterized in that, The least squares method is used to establish the correlation model between the induction signal of the reference block and the density of the tungsten alloy. The correlation model equation is: ρ = a*X + b where ρ is the density, X is the voltage or current signal value, and a and b are parameters to be fitted.

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