CN105301096A - Array type flexible eddy current probe for hollow axle inner wall flaw detection - Google Patents

Abstract

The invention discloses an array type flexible eddy current probe used for flaw detection on the inner wall of a hollow axle, belonging to the technical field of eddy current nondestructive testing. Including array receiving printed lines, excitation printed lines, flexible substrate. The flexible substrate has a multi-layer structure to enable complex routing of the receive and excitation tracks. Each element of the array receiving printed line adopts a spiral routing form, and a one-dimensional receiving array uses an excitation printed line for excitation, and the routing of the excitation printed line forms a surrounding layout for each receiving element in the group . The array flexible eddy current probe adopts the form of separation of excitation and reception, can be applied to the detection of omni-directional defects on the inner wall of hollow axles or other tubular components, and can realize absolute and differential detection methods. The array type flexible eddy current probe can complete the flaw detection work without mechanical rotation, improves the detection efficiency, and can adopt multiple sets of arrays to improve the reliability of flaw detection.

Description

Array flexible eddy current probes for flaw detection on the inner wall of hollow axles

technical field

The invention relates to a non-destructive testing probe, in particular to an array type flexible eddy current probe used for flaw detection on the inner wall of a hollow axle.

Background technique

In the late 1980s, eddy current array technology was proposed and gradually developed into a hot research field. Compared with the traditional eddy current single probe, the eddy current array sensor can achieve high-speed scanning of the surface of the measured workpiece without mechanically moving the probe or reducing the degrees of freedom required for mechanical scanning under the premise of ensuring the same detection sensitivity and spatial resolution. In this way, the accuracy requirements for mechanical scanning equipment and the corresponding cost expenditure are reduced, and the detection time is saved, which facilitates the in-situ detection of key components, and shows outstanding advantages in the detection or measurement of large-area workpieces. The eddy current array sensor has potential improvement space in the aspects of probe structure design, detection implementation strategy and signal imaging processing, which can eliminate the blindness problem of defects and long cracks in a certain direction, and improve the reliability and quality of its detection. With the advancement of processing technology, the realization of array flexible eddy current probes provides a feasible solution for the detection and measurement of complex workpiece surfaces, and further improves the adaptability of eddy current detection technology.

Eddy current array testing technology is widely used in non-destructive testing and online monitoring of cracks or corrosion defects, such as the detection of widespread micro-cracks in steam generator heat transfer pipes in nuclear power plants, online monitoring of fatigue cracks in aircraft metal bolt structures or riveting structures, and high-pressure turbine Crack detection of blades, corrosion detection of the outer surface of oil and gas pipelines, etc. The technique is also used for laser welding seam quality assessment, including the detection and characterization of transverse and longitudinal surface cracks, lack of fusion, weld porosity, and other surface discontinuities in the weld.

For the flaw detection of inner wall cracks of hollow axles, the traditional method is to use ultrasonic testing. Due to the influence of natural waves, ultrasonic testing has a certain blind area on the surface of the workpiece to be tested, which affects the reliability and accuracy of flaw detection of hollow axle inner wall cracks. In addition, the hollow axle ultrasonic flaw detector currently operating in actual production uses a probe frame composed of multiple ultrasonic probes. When detecting cracks on the inner wall of the hollow axle, the probe needs to rotate the probe in addition to the axial feed movement, so the efficiency is high. needs improvement. In recent years, ultrasonic phased array probes have also been developed to detect defects on the inner wall of hollow axles, but in order to detect omnidirectional cracks, the shape and arrangement of the piezoelectric wafers of the probes are complicated. The above-mentioned array flexible eddy current probe is based on the principle of electromagnetic induction, and has certain advantages for the detection of surface defects of conductive material components, so it is suitable for the detection of inner wall defects of hollow axles. In the patent with publication number CN101413922A, a self-generating and self-retracting array type flexible eddy current probe high-sensitivity non-destructive testing method and its probe device are proposed. By increasing the individual inductance of the coil unit, the probe sensitivity is improved. Compared with the form of self-sending and self-receiving, the use of separate wiring for excitation and reception can make the probe design more flexible, and can achieve better adaptability to the detection of different workpieces through complex wiring.

Contents of the invention

The technical problem solved by the present invention is to provide an array type flexible eddy current probe for flaw detection on the inner wall of hollow axles, which can detect all-directional defects on the inner wall of hollow axles (or other tubular components) in absolute or differential detection methods. detection.

Technical scheme of the present invention is as follows:

An array flexible eddy current probe for flaw detection on the inner wall of a hollow axle, including a flexible substrate, excitation printed lines and receiving printed lines, the flexible substrate has a multi-layer structure, and the excitation printed lines and receiving printed lines are arranged in a multi-layer structure The layer and between layers; the receiving printed line is in an array layout, and the array layout is composed of several one-dimensional receiving arrays. Each receiving array element of the receiving printed line adopts a spiral routing form, and each receiving array element The size, line width, thickness and number of turns are consistent, and the spacing between adjacent receiving elements in the one-dimensional receiving array is consistent but the winding direction is opposite; each one-dimensional receiving array is excited by an excitation printed line, and the excitation printed The traces of the printed wires form a surrounding layout for each receiving element in the one-dimensional receiving array, and the current flows in opposite directions in adjacent surrounding circles formed by exciting the printed wires.

Preferably, the exciting printed lines and the receiving printed lines are located on different layers, and the shape of the spiral trace of each receiving array element in the receiving printed lines and the shape of the enclosing circle of the excited printed lines are both rectangular.

Preferably, the shielding area is formed by pouring copper on the same layer area outside the receiving printed line.

Preferably, the exciting printed lines and the receiving printed line arrays of adjacent one-dimensional receiving arrays have the characteristics of mirror symmetry; the receiving elements of different one-dimensional receiving arrays are electrically connected.

Preferably, the excitation printed lines and the receiving printed line arrays of adjacent one-dimensional receiving arrays are misaligned; the receiving elements of different one-dimensional receiving arrays are electrically connected.

Compared with the prior art, the present invention has the following advantages and prominent technical effects: the array type flexible eddy current probe disclosed in the present invention for flaw detection on the inner wall of the hollow axle adopts the form of separation of excitation and reception to realize detection of defects in the inner wall of the hollow axle in all directions Detection, and can use absolute and differential detection methods, the separation of excitation and reception makes the design of the probe more flexible and more adaptable. The array type flexible eddy current probe can complete flaw detection work without mechanical rotation, improves detection efficiency, and can adopt multiple sets of arrays to improve flaw detection reliability and flaw detection sensitivity.

Description of drawings

Fig. 1 is a structural schematic diagram of an array type flexible eddy current probe used for flaw detection on the inner wall of a hollow axle according to the present invention.

Fig. 2 is a schematic diagram of the first array distribution mode of the present invention.

Fig. 3 is a schematic diagram of the second array distribution mode of the present invention.

Fig. 4 is a schematic diagram of the third array distribution mode of the present invention.

Fig. 5 is a schematic diagram of the shielding area of the array type flexible eddy current probe of the present invention.

Fig. 6 is a schematic diagram of the excitation eddy current field distribution of the array type flexible eddy current probe of the present invention.

In the figure: 1-flexible substrate; 2-excitation printed line; 3-receiving printed line; 4-receiving array element; 5-shielding area; 6-hollow axle; 7-one-dimensional receiving array.

detailed description

The present invention will be described in further detail below with reference to the accompanying drawings, but the array type flexible eddy current probe for flaw detection of the inner wall of the hollow axle of the present invention is not limited to the embodiment.

As shown in Figure 1, the array type flexible eddy current probe used for flaw detection on the inner wall of the hollow axle according to the present invention includes a flexible substrate 1, an excitation printed line 2 and a receiving printed line 3, and the flexible substrate 1 has a multi-layer structure , the excitation printed line 2 and the receiving printed line 3 are arranged at the level of the multilayer structure and between layers; the receiving printed line 3 is in an array layout, and the array layout is composed of several one-dimensional receiving arrays 7, and the receiving Each receiving element 4 of the printed line 3 adopts a spiral routing form, and the size, line width, thickness and number of turns of each receiving element 4 are consistent, and the distance between adjacent receiving elements 4 in the one-dimensional receiving array 7 is kept Consistent but in the opposite direction; each one-dimensional receiving array 7 uses an excitation printed line 2 for excitation, and the routing of the excitation printed line 2 forms a surrounding layout for each receiving array element 4 in the one-dimensional receiving array 7, and The current flows in opposite directions in the adjacent encircled circles formed by the excitation printed line 2 .

The excitation printed line 2 and the receiving printed line 3 are located on different layers, and the spiral routing shape of each receiving element 4 in the receiving printed line 3 and the shape of the surrounding circle of the exciting printed line 2 are both rectangular, as shown in FIG. 2 , It can also be circular or other shapes, as shown in Figure 3.

The array-type flexible eddy current probe used for flaw detection on the inner wall of the hollow axle can be composed of two sets of arrays, and the two arrays form a mirror image paired layout, as shown in Figure 2 and Figure 3, two upper and lower receiving array elements 4 opposite to each other form Differential pairs, so that the differential detection of eddy current probes can be realized. In addition, two adjacent receiving array elements 4 in the one-dimensional receiving array 7 may also form a differential pair. Such a differential layout can not only suppress interference signals, but also realize omni-directional crack detection. Apply an alternating current with the same amplitude and frequency in the same direction as shown in Figure 2 to the two excitation printed lines 2, then the inner wall surface of the hollow axle near any excitation printed line will form the same shape as the excitation printed line A similar reverse vortex is shown in Figure 6. For cracks in any direction, when the probe moves toward the feed motion, it will always hinder the direction of the excitation eddy current of a certain element, thus affecting the current signal in the receiving element. For the longitudinal cracks and transverse cracks that are exactly at the positions of two adjacent array elements, there may be missed detection if only two arrays are used. To avoid this situation, four arrays can be used for dislocation arrangement.

The array-type flexible eddy current probe used for flaw detection on the inner wall of the hollow axle can also be composed of two one-dimensional receiving arrays 7 that are misaligned with each other, and adopt absolute detection, as shown in Figure 4. Such a layout can effectively avoid missed detection. .

In addition, in order to avoid the interference of the test result by exciting the printed line in the non-array element area, the array type flexible eddy current probe used for the inner wall flaw detection of the hollow axle can be shielded by pouring copper on the same layer area other than the receiving printed line 3 area.

The above-mentioned embodiments are only used to further illustrate the array type flexible eddy current probe used for the inner wall flaw detection of the hollow axle of the present invention, but the present invention is not limited to the embodiments, and any simple modification made to the above-mentioned embodiments according to the technical essence of the present invention , equivalent changes and modifications all fall within the protection scope of the technical solution of the present invention.

Claims (5)

1. An array type flexible eddy current probe for flaw detection on the inner wall of a hollow axle, characterized in that: it contains a flexible substrate (1), an excitation printed line (2) and a receiving printed line (3), and the flexible substrate (1) has The multi-layer structure, the excitation printed line (2) and the receiving printed line (3) are arranged at the level of the multi-layer structure and between layers; the receiving printed line (3) is in an array layout, and the array layout consists of several A one-dimensional receiving array (7) is formed, and each receiving element (4) of the receiving printed line (3) adopts a spiral routing form, and the size, line width, thickness and number of turns of each receiving element (4) are the same. consistent, the spacing between adjacent receiving elements (4) in the one-dimensional receiving array (7) is consistent but the winding direction is opposite; each one-dimensional receiving array (7) uses an excitation printed line (2) for excitation, and the excitation The traces of the printed lines (2) form a surrounding layout for each receiving array element (4) in the one-dimensional receiving array (7), and the current flows in opposite directions in adjacent surrounding circles formed by exciting the printed lines (2). 2. The array type flexible eddy current probe for flaw detection on the inner wall of a hollow axle according to claim 1, characterized in that: the excitation printed lines (2) and the receiving printed lines (3) are located in different layers, and the receiving printed lines (3) are located in different layers. The shape of the helical routing of each receiving array element (4) in the line (3) and the shape of the enclosing circle of the exciting printed line (2) are both rectangular. 3. The array type flexible eddy current probe for flaw detection on the inner wall of the hollow axle according to claim 1 or 2, characterized in that: the shielding area (5 ). 4. The array type flexible eddy current probe for flaw detection on the inner wall of a hollow axle according to claim 1 or 2, characterized in that: the exciting printed line (2) and the receiving printed line of the adjacent one-dimensional receiving array (7) (3) The array has the feature of mirror symmetry; the receiving array elements (4) between different one-dimensional receiving arrays (7) are electrically connected. 5. The array-type flexible eddy current probe for flaw detection on the inner wall of a hollow axle according to claim 1 or 2, characterized in that: the exciting printed line (2) and the receiving printed line of the adjacent one-dimensional receiving array (7) (3) The arrays are misplaced; the receiving array elements (4) between different one-dimensional receiving arrays (7) are electrically connected.