Railway special flaw detector current calibration device and method

Abstract

The present application relates to the technical field of flaw detector calibration, in particular to a railway special flaw detector current calibration device and method, the current calibration device comprises a walking frame, a hand push rod, a conductive test copper bar, a current sensor, a matching equipment placement trolley and a track mounting plate, two insulating sleeves are sleeved on the conductive test copper bar at intervals, a contact disc is installed at the outer end of the conductive test copper bar, the current sensor is installed on the conductive test copper bar and located between the two insulating sleeves, a multimeter, a power supply and a standard resistance connected with the current sensor circuit are placed on the matching equipment placement trolley, the current calibration method adopts the above-mentioned railway special flaw detector current calibration device, comprising the following steps: step S1, evaluating the standard uncertainty component; step S2, calibrating the current for the wheel set fluorescent magnetic particle flaw detector; step S3, calibrating the current for the axle fluorescent magnetic particle flaw detector; the present application has the characteristics of accurate current measurement and flexible operation.

Description

Technical Field

[0001] This invention relates to the field of flaw detector calibration technology, specifically to a current calibration device and method for a railway-specific flaw detector. Background Technology

[0002] Currently, large-volume fixed fluorescent magnetic particle flaw detectors are commonly used in railway maintenance sites for flaw detection of axles and wheelsets. These devices have a rated magnetizing current of 1kA to 16kA and output short-duration pulsed high current. However, because these flaw detectors are fixed installations, disassembly and assembly are difficult, downtime for maintenance is costly, large-part transport poses high safety risks, and disrupts workshop maintenance schedules, making them difficult to send for testing. Conventional on-site calibration relies solely on A1 test pieces for qualitative judgment, simply assessing the magnetizing capability and defect display effect of the magnetic particle flaw detector. However, the pulse current output of the magnetic particle flaw detector is a crucial parameter for equipment calibration, and the A1 test piece does not provide a quantitative evaluation of this parameter. This makes it impossible to calibrate the current output parameter of railway-specific flaw detectors. Summary of the Invention

[0003] The present invention aims to provide a current calibration device for railway-specific flaw detectors, which solves the problems of current flaw detectors being fixedly installed and unable to be sent for inspection, as well as the lack of equipment for calibrating the current output parameters of railway-specific flaw detectors during maintenance.

[0004] Therefore, the technical solution adopted by this invention is as follows: a current calibration device for a railway-specific flaw detector, the railway-specific flaw detector including a wheelset fluorescent magnetic particle flaw detector and an axle fluorescent magnetic particle flaw detector, including a traveling frame, a push rod, a conductive test copper rod, a current sensor, a supporting equipment mounting trolley and a track mounting plate. The traveling frame is arranged in two symmetrically spaced positions, with traveling wheels installed at the front and rear ends of the bottom of the traveling frame and a lifting platform installed at the top. The traveling frame is provided with a platform for placing an idle track mounting plate, the track mounting plate being used to fix the traveling frame to the working track, and the push rod having its bottom ends centered on the left and right. The conductive test copper rod is mounted on the top of the corresponding side traveling frame, thereby synchronously pushing the traveling frame. Two insulating sleeves are fitted on the left and right sides at intervals, and the insulating sleeves can be placed on the corresponding side lifting platform or the axle support frame of the axle fluorescent magnetic particle flaw detector. A contact disc is installed on the outer end of the conductive test copper rod, thereby increasing the contact area with the clamping device of the flaw detector. The current sensor is installed on the conductive test copper rod and located between the two insulating sleeves. The supporting equipment placement trolley is equipped with a multimeter, power supply and standard resistor connected to the current sensor circuit, thereby forming a sensor circuit to complete the current detection of the railway special flaw detector.

[0005] As a preferred embodiment of the above solution, the track mounting plate includes a flat plate that can be laid along the working track in the factory, track clamps located below the flat plate, and wheel clamps located above the flat plate. The track clamps are side plates spaced left and right with a spacing matching the width of the working track, thereby securing the working track. The wheel clamps are side plates spaced left and right with a spacing matching the width of the wheel, thereby securing the wheel. This design allows for flexible installation, stable installation, and a reasonable structural design.

[0006] Preferably, the lifting platform adopts a single-layer manual scissor lift structure and is equipped with a handwheel for easy manual operation. The lifting platform consists of two sets of symmetrically arranged "X" rods, a lower guide seat, and an upper guide seat. The lower and upper guide seats are provided with guide openings. The upper and lower ends of one side of the "X" rod are respectively hinged to the lower and upper guide seats, and the upper and lower ends of the other side are connected by a horizontal crossbar passing through the guide opening. The handwheel is connected to the horizontal crossbar by a longitudinal screw. The horizontal crossbar on the upper side is threadedly engaged with the longitudinal screw. The outer end of the longitudinal screw passes through the upper guide seat and connects to the upper handwheel. When the handwheel is rotated, the horizontal crossbar moves longitudinally, causing the "X" rod to narrow or expand, thereby raising or lowering the height of the upper guide seat. The structural design is reasonable.

[0007] Further preferably, the standard resistor is 100Ω to 120Ω, which is a reasonable range and suitable for 2KA current detection.

[0008] More preferably, the conductive test copper rod is made of copper, the insulating sleeve is made of rubber, and the contact disc is made of 45# steel. The contact disc is made of the same material as the original axle, which facilitates the simulation of the axle.

[0009] A further preferred embodiment is that the top of the lifting platform is provided with outwardly inclined inclined plates in a mirror-symmetrical manner, which, together with the top of the lifting platform, form a flat-bottomed "V"-shaped tray to support the insulating sleeve, resulting in a reasonable structural design.

[0010] Further preferably, the flat plate has mounting holes at its front and rear ends and is equipped with bolts to be installed on the working track, ensuring a stable installation; the walking frame has limiting posts that can pass through the mounting holes on the platform where the idle track mounting plate is placed, thereby fixing the track mounting plate and making the installation simple and stable.

[0011] This solution also employs a current calibration method for a railway-specific flaw detector, including the following steps:

[0012] Step S1: Using the above-mentioned railway-specific flaw detector current calibration device, and evaluating the standard uncertainty components, calculate the expanded uncertainty U according to the following formula:

[0013] ;

[0014] ;

[0015] in, For standard uncertainty, The standard uncertainty introduced to measure repeatability The standard uncertainty introduced by the sensor indication error, The standard uncertainty introduced by the linearity error of the sensor Standard uncertainty introduced by temperature drift The standard uncertainty introduced by the multi-value representation error, The standard uncertainty introduced for the resolution of a digital multimeter The standard uncertainty introduced by the magnetization current ripple / stability The standard uncertainty introduced by the installation position deviation, where k is the coverage factor;

[0016] Step S2: When calibrating the current for the wheelset fluorescent magnetic particle flaw detector, lay and fix the track mounting plate on the working track that passes through the wheelset fluorescent magnetic particle flaw detector. Place the insulating sleeve on the corresponding side lifting platform. Then, adjust the height of both ends of the conductive test copper rod through the lifting platform until it is aligned with the clamping device of the wheelset fluorescent magnetic particle flaw detector. Then, clamp the conductive test copper rod inward with the clamping device of the wheelset fluorescent magnetic particle flaw detector. Start the power supply to realize the current detection of the wheelset fluorescent magnetic particle flaw detector through the current sensor, multimeter, and standard resistor.

[0017] Step S3: When calibrating the current of the axle fluorescent magnetic particle flaw detector, place the insulating sleeve of the conductive test copper rod directly on the axle support frame of the axle fluorescent magnetic particle flaw detector to replace the original axle. The clamping device of the axle fluorescent magnetic particle flaw detector clamps the conductive test copper rod inward. Start the power supply to realize the current detection of the axle fluorescent magnetic particle flaw detector through the current sensor, multimeter and standard resistor.

[0018] In steps S2 and S3, if the measured current value is outside the specified current value ±10%, the flaw detector is deemed unqualified. If the measured current value is within the specified current value ±10%, but the introduced extended uncertainty value U is outside the specified current value ±10%, the measurement accuracy of the railway-specific flaw detector current calibration device is improved and recalibrated.

[0019] The beneficial effects of this invention are:

[0020] (1) Compared with the current A1 test piece, which does not involve the calibration of the current output parameters of railway-specific flaw detectors, this application designs a device specifically for the calibration of the current output parameters of railway-specific flaw detectors. By replacing the position of the axle or wheel axle with a conductive test copper rod, the clamping device of the railway-specific flaw detector is tightened to clamp the horizontally placed conductive test copper rod. The current is then detected by a current sensor installed on the conductive test copper rod, and the specific value is displayed by a multimeter. The operation is simple, convenient and fast, and there is no need to disassemble the flaw detector for inspection. The current measurement is accurate, and the constructed sensor circuit is suitable for testing currents of thousands of amperes.

[0021] (2) Based on the two different types of wheelset fluorescent magnetic particle flaw detectors and axle fluorescent magnetic particle flaw detectors, the conductive test copper rod is placed separately, which makes it easy to take it out and place it on the axle fluorescent magnetic particle flaw detector to replace the axle. Alternatively, it can be placed on the lifting platform, and then the height of both ends can be adjusted by the lifting platform to keep it horizontal to replace the wheelset for clamping by the wheelset fluorescent magnetic particle flaw detector. It is flexible in operation, has high practical value, and strong adaptability.

[0022] (3) Compared to a simple measurement value, this approach introduces expanded uncertainty, which provides a quantitative description of the possible expected deviation range of the measurement value, thus establishing a clear credibility for the measurement results. In the process of introducing expanded uncertainty, various sources of measurement uncertainty are analyzed, including sensor accuracy, temperature drift, multimeter accuracy, magnetization current ripple / stability, and installation position deviation. This will help users better understand the sources of measurement error and further reduce measurement uncertainty by optimizing the device, such as using a higher-precision sensor and improving the measurement environment.

[0023] In summary, this invention features accurate current measurement, compatibility with current testing of thousands of amperes, flexible operation, high practical value, and compatibility with various flaw detectors. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the current calibration device for a railway-specific flaw detector.

[0025] Figure 2 This is a structural diagram of the lifting platform.

[0026] Figure 3 A schematic diagram of the structure for laying the track mounting plate onto the working track.

[0027] Figure 4 This is a schematic diagram of the current calibration device for a railway-specific flaw detector located on the working track. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments and accompanying drawings:

[0029] like Figures 1-4 As shown, a current calibration device for a railway-specific flaw detector is disclosed. The railway-specific flaw detector mainly consists of a wheelset fluorescent magnetic particle flaw detector and an axle fluorescent magnetic particle flaw detector. The current calibration device consists of a traveling frame 1, a push rod 2, a conductive test copper rod 3, a current sensor 4, a supporting equipment mounting trolley 5, and a track mounting plate 9. The traveling frame 1 preferably has two symmetrically spaced pieces. The traveling wheels 11 are installed at the front and rear ends of the bottom of the traveling frame 1, and a lifting platform 12 is installed at the top. The traveling frame 1 has a platform for placing the idle track mounting plate 9. The track mounting plate 9 is used to fix the traveling frame 1 to the working track. The push rod 2 is installed centered at the left and right ends of the bottom of the corresponding... The top of the side walking frame 1 is used to synchronously push the walking frame 1. The conductive test copper rod 3 is fitted with two insulating sleeves 31 at intervals on the left and right sides. The insulating sleeves 31 can be placed on the corresponding side lifting platform 12 or the axle support frame of the axle fluorescent magnetic particle flaw detector. The outer end of the conductive test copper rod 3 is equipped with a contact disc 32, thereby increasing the contact area with the clamping device of the flaw detector. The current sensor 4 is installed on the conductive test copper rod 3 and located between the two insulating sleeves 31. The supporting equipment placement trolley 5 is equipped with a multimeter 6, a power supply 7 and a standard resistor 8 connected to the current sensor 4 circuit, thereby forming a sensor circuit to complete the current detection of the railway special flaw detector.

[0030] To avoid the equipment located above the wheelset fluorescent magnetic particle flaw detector, the lower ends of the left and right ends of the push rod 2 are vertical, while the upper ends are bent outwards.

[0031] The conductive test copper rod 3 is preferably made of copper, the insulating sleeve 31 is preferably made of rubber insulation material, and the contact disc 32 is made of 45 steel.

[0032] The lifting platform 12 preferably adopts a single-layer manual scissor lift structure and is equipped with a handwheel 121.

[0033] The lifting platform 12 consists of two sets of symmetrically arranged "X" rods 123, a lower guide seat 124, and an upper guide seat 125. The lower guide seat 124 and the upper guide seat 125 are provided with guide openings 126. The upper and lower ends of one side of the "X" rod 123 are respectively hinged to the lower guide seat 124 and the upper guide seat 125, and the upper and lower ends of the other side are connected by a horizontal crossbar passing through the guide opening 126. The handwheel 121 is connected to the horizontal crossbar by a longitudinal screw. The horizontal crossbar located on the upper side is threadedly engaged with the longitudinal screw. The outer end of the longitudinal screw passes through the upper guide seat 125 and is connected to the upper handwheel 121. When the handwheel 121 is rotated, the horizontal crossbar moves longitudinally, causing the "X" rod 123 to narrow or expand, thereby raising or lowering the height of the upper guide seat 125.

[0034] The top of the lifting platform 12 is provided with outwardly inclined plates 122 in a mirror-symmetrical manner, which together with the top of the lifting platform 12 form a flat-bottomed "V" shaped tray to support the insulating sleeve 31.

[0035] Multimeter 6 uses a digital multimeter.

[0036] The standard resistor 8 is preferably 100Ω to 120Ω, and the current sensor 4 is preferably a Hall sensor.

[0037] The track mounting plate 9 consists of two plates that can be laid symmetrically on the working track. The track mounting plate 9 is composed of a flat plate 91 that can be laid along the working track in the factory, a track clamp 92 located below the flat plate 91, and a traveling wheel clamp 93 located above the flat plate 91. The track clamp 92 uses side plates that are spaced to the left and right and whose spacing matches the width of the working track, so as to lock the working track. The traveling wheel clamp 93 uses side plates that are spaced to the left and right and whose spacing matches the width of the traveling wheel 11, so as to lock the traveling wheel 11.

[0038] The front and rear ends of the flat plate 91 are provided with mounting holes and are equipped with bolts to be installed on the working track. The platform of the traveling frame 1 corresponding to the platform where the idle track mounting plate 9 is placed is provided with a limiting post 13 that can pass through the mounting hole, thereby fixing the track mounting plate 9.

[0039] A method for calibrating the current of a railway-specific flaw detector, the specific implementation steps of which are as follows:

[0040] Step S1: Using the above-mentioned railway-specific flaw detector current calibration device, and evaluating the standard uncertainty components, calculate the expanded uncertainty U according to the following formula:

[0041] ;

[0042] ;

[0043] in, For standard uncertainty, The standard uncertainty introduced to measure repeatability The standard uncertainty introduced by the sensor indication error, The standard uncertainty introduced by the linearity error of the sensor Standard uncertainty introduced by temperature drift The standard uncertainty introduced by the multi-value representation error, The standard uncertainty introduced for the resolution of a digital multimeter The standard uncertainty introduced by the magnetization current ripple / stability The standard uncertainty introduced by the installation position deviation, where k is the coverage factor;

[0044] In step S1, the standard uncertainty introduced by measurement repeatability is... .

[0045] The measurement was repeated 10 times at point 2000A, and the experimental standard deviation s≈1.40A. The standard uncertainty introduced by the Hall sensor indication error. Sensor grade 0.5, maximum permissible error ±15A, uniformly distributed, k= , .

[0046] Standard uncertainty introduced by the linearity error of the Hall sensor Linearity error ±0.2% FS, maximum error ±6A, uniform distribution, k= , .

[0047] Standard uncertainty introduced by temperature drift Temperature variation ±2℃, maximum error ±2A, uniform distribution, k= , .

[0048] Standard uncertainty introduced by the error in digital multiplication representation The maximum error after conversion is ±0.75A, following a normal distribution, with k=3. .

[0049] Standard uncertainty introduced based on the resolution of the digital multimeter , ≈0.01A.

[0050] Standard uncertainty introduced by magnetization current ripple / stability Maximum error ±2A, uniformly distributed, k= , .

[0051] Standard uncertainty introduced by installation position deviation Maximum error ±1A, uniformly distributed, k= , .

[0052] When calculating the expanded uncertainty U, k is 2, and the expanded uncertainty U is approximately equal to 19A according to the formula.

[0053] Step S2: When calibrating the current for the wheelset fluorescent magnetic particle flaw detector, the track mounting plate 9 is laid and fixed on the working track passing through the wheelset fluorescent magnetic particle flaw detector. The insulating sleeve 31 is placed on the corresponding side lifting platform 12. Then, the height of both ends of the conductive test copper rod 3 is adjusted by the lifting platform 12 until it is aligned with the clamping device of the wheelset fluorescent magnetic particle flaw detector. Then, the clamping device of the wheelset fluorescent magnetic particle flaw detector clamps the conductive test copper rod 3 inward. The power supply 7 is started to realize the current detection of the wheelset fluorescent magnetic particle flaw detector through the current sensor 4, multimeter 6, and standard resistor 8.

[0054] The track mounting plate 9 is fixed to the working track by bolts at the front and rear ends and track clamps 92. Then, push the push rod 2 to drive the traveling wheel 11 to move along the working track until the traveling wheel 11 is locked on the traveling wheel clamps 93 for fixation. Then, manually adjust the lifting platform 12 to adjust the height of both ends of the conductive test copper rod 3.

[0055] Step S3: When calibrating the current of the axle fluorescent magnetic particle flaw detector, the insulating sleeve 31 of the conductive test copper rod 3 is placed directly on the axle support frame of the axle fluorescent magnetic particle flaw detector to replace the original axle. The clamping device of the axle fluorescent magnetic particle flaw detector clamps the conductive test copper rod 3 inward. The power supply 7 is started to realize the current detection of the axle fluorescent magnetic particle flaw detector through the current sensor 4, multimeter 6, and standard resistor 8.

[0056] The current sensor 4 converts the large current into a standard current signal of 4-20mA, which is then measured by the multimeter 6 and converted into a magnetizing current value.

[0057] Convert using the following formula: Where I is the measured value of the magnetizing current of the flaw detector being calibrated, K is the calibration coefficient of the Hall sensor, K=187.5A / Ma, and Im is the output current measured by the digital multimeter. This is the minimum range of the Hall sensor.

[0058] The Hall sensor output value is 4-20mA, which corresponds to the full range of 0-3000A of the flaw detector we are calibrating. Therefore, when the digital multimeter measures an output current signal of 4mA, it means that the magnetization current measurement value of the flaw detector is zero. When the digital multimeter measures an output current signal of 20mA, it means that the magnetization current measurement value of the flaw detector is 3000A.

[0059] Simultaneously adopt Non-zero values ​​make it easier to diagnose signal loss or disconnection. When a digital multimeter measures an output current signal of 0mA, it indicates that the Hall sensor is not powered or there is a wiring fault.

[0060] In steps S2 and S3, if the measured current value is outside the specified current value ±10%, the flaw detector is deemed unqualified. If the measured current value is within the specified current value ±10%, but the introduced extended uncertainty value U is outside the specified current value ±10%, the measurement accuracy of the railway-specific flaw detector current calibration device is improved for recalibration. For example, the accuracy of current sensor 4 is improved, the accuracy of multimeter 6 is improved, and the installation position of current sensor 4 is adjusted.

Claims

1. A current calibration device for a railway-specific flaw detector, wherein the railway-specific flaw detector includes a wheelset fluorescent magnetic particle flaw detector and an axle fluorescent magnetic particle flaw detector, characterized in that: The system includes a walking frame (1), a push rod (2), a conductive test copper rod (3), a current sensor (4), a supporting equipment mounting trolley (5), and a track mounting plate (9). The walking frame (1) is arranged in two symmetrical intervals. The walking frame (1) has walking wheels (11) installed at the front and rear ends of its bottom and a lifting platform (12) installed at the top. The walking frame (1) has a platform for placing the idle track mounting plate (9). The track mounting plate (9) is used to fix the walking frame (1) onto the working track. The push rod (2) is installed at the top of the corresponding side of the walking frame (1) with its left and right ends centered, so as to push the walking frame (1) synchronously. The conductive test copper rod (3) is installed at the top of the corresponding side of the walking frame (1). The rod (3) is fitted with two insulating sleeves (31) spaced apart on the left and right sides. The insulating sleeves (31) can be placed on the corresponding side lifting platform (12) or on the axle support frame of the axle fluorescent magnetic particle flaw detector. The outer end of the conductive test copper rod (3) is equipped with a contact disc (32) to increase the contact area with the clamping device of the flaw detector. The current sensor (4) is installed on the conductive test copper rod (3) and located between the two insulating sleeves (31). The supporting equipment placement trolley (5) is equipped with a multimeter (6), a power supply (7) and a standard resistor (8) connected to the current sensor (4) circuit, thereby forming a sensor circuit to complete the current detection of the railway special flaw detector.

2. The current calibration device for a railway-specific flaw detector according to claim 1, characterized in that: The track mounting plate (9) includes a flat plate (91) that can be laid along the working track in the factory, a track clamp (92) located below the flat plate (91), and a traveling wheel clamp (93) located above the flat plate (91). The track clamp (92) uses side plates that are spaced to the left and right and whose spacing matches the width of the working track, thereby clamping the working track. The traveling wheel clamp (93) uses side plates that are spaced to the left and right and whose spacing matches the width of the traveling wheel (11), thereby clamping the traveling wheel (11).

3. The current calibration device for a railway-specific flaw detector according to claim 1, characterized in that: The lifting platform (12) adopts a single-layer manual scissor lift structure and is equipped with a handwheel (121). The lifting platform (12) consists of two sets of symmetrically arranged "X" rods (123), a lower guide seat (124), and an upper guide seat (125). The lower guide seat (124) and the upper guide seat (125) are provided with guide openings (126). The upper and lower ends of one side of the "X" rod (123) are respectively hinged to the lower guide seat (124) and the upper guide seat (125). On the other side, the upper and lower ends are connected by a horizontal crossbar passing through the guide opening (126). The handwheel (121) is connected to the horizontal crossbar by a longitudinal screw. The horizontal crossbar on the upper side is threadedly engaged with the longitudinal screw. The outer end of the longitudinal screw passes through the upper guide seat (125) and is connected to the upper handwheel (121). When the handwheel (121) is rotated, the horizontal crossbar moves longitudinally, causing the "X" rod (123) to narrow or expand, thereby raising or lowering the height of the upper guide seat (125).

4. The current calibration device for a railway-specific flaw detector according to claim 1, characterized in that: The standard resistor (8) is 100Ω to 120Ω, and the current sensor (4) is a Hall sensor.

5. The current calibration device for a railway-specific flaw detector according to claim 1, characterized in that: The conductive test copper rod (3) is made of copper, the insulating sleeve (31) is made of rubber insulation, and the contact disc (32) is made of No. 45 steel.

6. The current calibration device for a railway-specific flaw detector according to claim 1, characterized in that: The top of the lifting platform (12) is provided with outwardly inclined plates (122) in a mirror-symmetrical manner, and together with the top of the lifting platform (12), it forms a flat-bottomed "V" shaped tray to support the insulating sleeve (31).

7. The current calibration device for a railway-specific flaw detector according to claim 2, characterized in that: The plate (91) has mounting holes at the front and rear ends and is equipped with bolts to be installed on the working track. The walking frame (1) is provided with a limiting post (13) that can pass through the mounting hole on the platform where the idle track mounting plate (9) is placed, thereby fixing the track mounting plate (9).

8. A method for calibrating the current of a railway-specific flaw detector, characterized in that, Includes the following steps: Step S1: Use the current calibration device for a railway-specific flaw detector as described in any one of claims 1-7, evaluate the standard uncertainty components, and calculate the expanded uncertainty U according to the following formula: ； ； in, For standard uncertainty, The standard uncertainty introduced to measure repeatability The standard uncertainty introduced by the sensor indication error, The standard uncertainty introduced by the linearity error of the sensor Standard uncertainty introduced by temperature drift The standard uncertainty introduced by the multi-value representation error, The standard uncertainty introduced for the resolution of a digital multimeter The standard uncertainty introduced by the magnetization current ripple / stability The standard uncertainty introduced by the installation position deviation, where k is the coverage factor; Step S2: When calibrating the current for the wheelset fluorescent magnetic particle flaw detector, the track mounting plate (9) is laid and fixed on the working track that passes through the wheelset fluorescent magnetic particle flaw detector. The insulating sleeve (31) is placed on the corresponding side lifting platform (12). Then, the height of both ends of the conductive test copper rod (3) is adjusted by the lifting platform (12) to be aligned with the clamping device of the wheelset fluorescent magnetic particle flaw detector. Then, the clamping device of the wheelset fluorescent magnetic particle flaw detector clamps the conductive test copper rod (3) inward. The power supply (7) is started and the current of the wheelset fluorescent magnetic particle flaw detector is detected by the current sensor (4), multimeter (6), and standard resistor (8). Step S3: When calibrating the current for the axle fluorescent magnetic particle flaw detector, place the insulating sleeve (31) of the conductive test copper rod (3) directly on the axle support frame of the axle fluorescent magnetic particle flaw detector to replace the original axle. The clamping device of the axle fluorescent magnetic particle flaw detector clamps the conductive test copper rod (3) inward. Start the power supply (7) to realize the current detection of the axle fluorescent magnetic particle flaw detector through the current sensor (4), multimeter (6), and standard resistor (8). In steps S2 and S3, if the measured current value is outside the specified current value ±10%, the flaw detector is deemed unqualified. If the measured current value is within the specified current value ±10%, but after introducing the extended uncertainty value U, it is outside the specified current value ±10%, the measurement accuracy of the railway-specific flaw detector current calibration device is improved and recalibrated.

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