JP2014126375A - Hardening quality inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hardening quality inspection device capable of highly accurately inspecting a hardening quality of an inspection object by nondestructive inspection.SOLUTION: This hardening quality inspection device includes: a power source 2 for applying a current via probes 3, 3 for current application; a pair of probes 4, 4 for voltage measurement for making the pair of probes 4, 4 for voltage application contact two points different from the probes 3, 3 for voltage application in the surface of an inspection object 1 applied with the current by the power source 2 and for measuring the voltage between these two points; and quality measurement means 12 for measuring the hardening quality of the inspection object 1 from the voltage measured by the probes 4, 4 for voltage measurement. The inspection object 1 is provided with current application position changing means for changing a position to be applied with the current by the probes 3, 3 for current application.

Description

  The present invention relates to a quenching quality inspection apparatus for inspecting quenching quality such as surface hardness and quenching depth in rolling device parts such as bearings and bearing parts.

  A rolling part such as a bearing is subjected to a quenching process and a tempering process. Among these processes, in the surface hardening process such as induction hardening process, carburizing process, carbonitriding process, etc., the surface hardened layer is inspected for quality assurance. In this inspection, an actual product is cut and the depth of the cured layer is measured by measuring the hardness in the depth direction from the product surface on the cut surface. If the product cannot be cut, the test piece is heat-treated in the same furnace as the product, the test piece is cut, and the cured layer depth is measured in the same manner as described above. The guarantee is made.

In the destructive inspection for cutting a product, the product is discarded by this inspection, and there is a problem that the material cost is increased. In addition, there is a problem that it takes time to cut the product and to measure the hardness in the depth direction using a hardness meter, which increases the number of steps.
Since the product that cannot be cut is not an actual product inspection, there are problems such as poor guarantee accuracy.

  For this reason, the method of inspecting a hardening hardening layer nondestructively is proposed (patent documents 1 and 2). Among them, there is a potential difference method in which a plurality of probes are pressed against a measurement object, a current is supplied from an energization probe, and a voltage between other probes is measured. This method utilizes the fact that the magnetic permeability and conductivity of the material change due to quenching.

JP 2009-047664 A JP 2010-243173 A

  However, the conductivity and permeability vary depending on the measurement location of the measurement object. For this reason, there is a problem that the measurement voltage varies depending on the place where the probe is pressed, and the quenching quality measurement accuracy is deteriorated.

  An object of the present invention is to provide a quenching quality inspection apparatus capable of accurately inspecting the quenching quality of an inspection object by nondestructive inspection.

A quenching quality inspection apparatus according to the present invention includes a power source 2 for applying a current via current application probes 3 and 3 brought into contact with the surface of an inspection object 1;
A pair of voltage measurements in which the surface of the inspection object 1 to which a current is applied by the power source 2 is brought into contact with two points different from the current application probes 3 and 3 and the voltage between the two points is measured. Probes 4 and 4,
Quality measuring means 12 for measuring the quenching quality of the inspection object 1 from the voltages measured by the voltage measuring probes 4 and 4;
In quenching quality inspection equipment with
Current application position changing means 10 and 10A for changing the position to which current is applied by the current application probes 3 and 3 for the inspection object 1 are provided.

According to this configuration, the current application probes 3 and 3 are brought into contact with the surface of the inspection object 1, and a current is supplied from the power source 2 through the current application probes 3 and 3. In this state, the voltage, that is, the potential difference between the two points is measured by the pair of voltage measuring probes 4 and 4 brought into contact with the surface of the inspection object 1. The quality measuring means 12 measures the quenching quality of the inspection object 1 from the measured voltage.
When a constant current is applied to the inspection object 1, the voltage between the voltage measuring probes 4 and 4 changes depending on the conductivity and magnetic permeability at the position to be measured.
The permeability and conductivity of the steel material change due to quenching. Generally, the higher the hardness of a steel material by quenching, the smaller the permeability and conductivity. For this reason, the voltage between the two points varies depending on the quenching quality such as quenching hardness. Therefore, information on the quenching quality can be obtained by measuring the voltage between the two points. In this case, the current application position changing means 10, 10 </ b> A changes the position where the current application probe 3, 3 applies the current to the inspection object 1. The quality measuring unit 12 obtains information on the quenching quality based on the voltages respectively measured at the changed positions, thereby reducing the influence of variation in conductivity and magnetic permeability depending on the measurement location.

  The quality measuring means 12 may have a function of averaging voltages at positions measured by the current application position changing means 10 and 10A. By taking the average of the voltages at a plurality of measured positions in this way, the influence of variation in conductivity and magnetic permeability depending on the measurement location can be reduced, and the inspection accuracy of nondestructive inspection can be easily improved.

  The current application position changing means 10 may have means for changing the position at which the voltage is measured by the voltage measuring probes 4, 4 with respect to the inspection object 1. In this case, the voltage at each measurement location can be measured easily and reliably without the need to manually change the voltage measurement probes 4 and 4 with respect to the inspection object 1.

The current application position changing means 10 may be configured such that the current application probes 3 and 3 and the voltage measurement probes 4 and 4 are integrally rotatable. In this case, it is sufficient for the current application probes 3 and 3 to have at least a pair of current application probes 3 and 3, which can reduce the number of parts and reduce the manufacturing cost.
The current application position changing means 10 may be configured to rotate a head 8 in which the current application probes 3 and 3 and the voltage measurement probes 4 and 4 are integrated. In this case, it is not necessary to handle the current application probes 3 and 3 and the voltage measurement probes 4 and 4 separately, and the measurement workability can be improved.

A plurality of pairs of the current application probes 3 and 3 may be provided, and the current application position changing means 10A may switch a current application probe pair to which a current is applied. In this case, among the plurality of pairs of current application probes 3, 3, voltage is applied to the object 1 to be inspected by sequentially applying current separately between the predetermined current application probes 3, 3. The position for measuring the voltage by the probes 4 and 4 can be changed.
A plurality of pairs of the voltage measuring probes 4 and 4 are provided, and the current application position changing means 10A switches the current applying probe pair for applying a current and switches the voltage measuring probe pair for measuring a voltage. It may be. In this case, when changing the voltage measurement position, it is not necessary to separate the current application probe pair and the voltage measurement probe pair from the surface of the inspection object 1 each time, and it is simpler than the example in which the head 8 is rotated. The voltage at each measurement location can be measured.

  The current application probe pair for applying the current and the voltage measurement probe pair for measuring the voltage are arranged in a straight line when viewed from the longitudinal direction of the probes, and the two outer probes are arranged in the current direction. An application probe pair, and the two inner probes may be voltage measurement probe pairs.

As the quenching quality, at least one of the surface hardness and the quenching depth of the inspection object 1 may be inspected.
The quality measuring unit 12 may include a determination unit 6a that determines that quenching is abnormal when at least one of the surface hardness and the quenching depth of the inspection object 1 falls below a predetermined value. Thus, by providing the determination part 6a, quality abnormality determination can be performed easily and objectively.

The quenching quality inspection apparatus according to the present invention includes a power source that applies a current via a current application probe brought into contact with the surface of the inspection object, and the surface of the inspection object to which a current is applied by the power source. A pair of voltage measurement probes for measuring the voltage between the two points in contact with two points different from the current application probe, and the voltage measured by these voltage measurement probes, In a quenching quality inspection apparatus equipped with a quality measuring means for measuring quenching quality,
Current application position changing means for changing a position to apply a current to the inspection object by the current application probe is provided. For this reason, the quenching quality of the inspection object can be accurately inspected by nondestructive inspection.

It is a block diagram which shows the basic structure of the hardening quality inspection apparatus which concerns on 1st Embodiment of this invention. It is an enlarged view of the principal part of the quenching quality inspection apparatus. It is a top view of the principal part of the quenching quality inspection apparatus. It is a figure which shows the positional relationship of the head and inspection target object of the quenching quality inspection apparatus. It is a top view of the principal part of the quenching quality inspection apparatus which concerns on other embodiment of this invention. It is a block diagram which shows the conceptual structure of the quenching quality inspection apparatus. It is a figure which shows the positional relationship of the head and inspection target object of the quenching quality inspection apparatus. It is a figure which shows one usage example of the said quenching quality inspection apparatus.

A quenching quality inspection apparatus according to a first embodiment of the present invention will be described with reference to FIGS. The following description also includes a description of the quenching quality inspection method. First, the basic structure of the quenching quality inspection apparatus according to this embodiment will be described.
As shown in FIG. 1, this quenching quality inspection method applies current to the surface of the inspection object 1 by a direct current potential method or an alternating current potential method, which will be described later, and two arbitrary points on the surface of the inspection object 1. The quenching quality is inspected by measuring the voltage or potential difference between them. The inspection object 1 is a steel product such as a bearing or a bearing component that has been subjected to a quenching process. However, it is not limited to these steel products.

  The current applied to the inspection object 1 is an alternating current or a direct current described later. A current is applied to the inspection object 1 from the power source 2 through the pair of current application probes 3 and 3. A pair of voltage measurement probes 4 and 4 are brought into contact with two points different from the current application probe 3 on the surface of the inspection object 1 to which the current is applied, and a voltage between the two points is obtained. Measurement is performed by the voltage measuring unit 5. The measured voltage is processed by the signal processing unit 6, the quenching quality of the inspection object 1 is evaluated, and the evaluation result is displayed on the display device 7.

When a constant current is applied to the inspection object 1, the voltage between the voltage measuring probes 4, 4 changes depending on the conductivity and permeability of the measurement object 1 at the measurement location. Here, the depth δ through which the current flows is expressed by the following equation (1).
δ = √ (1 / πfσμ) (1)
Where f is the frequency of the alternating current, σ is the conductivity, and μ is the magnetic permeability.

  The permeability and conductivity of steel products change due to quenching of steel products. Generally, the higher the hardness of a steel material by quenching, the smaller the permeability and conductivity. For this reason, the voltage between the two points varies depending on the quenching quality such as quenching hardness. Therefore, information on the quenching quality can be obtained by measuring the voltage between the two points.

On the other hand, from equation (1), the penetration depth δ of the alternating current flowing through the inspection object 1 varies depending on the frequency f of the alternating current. The penetration depth δ of the alternating current can be changed by changing the frequency f. Therefore, by measuring the voltage between two points while changing the penetration depth δ of the alternating current, the quenching hardness distribution in the quenching depth direction can be inspected. That is, for example, when a high-frequency alternating current is applied to the inspection object 1, the current can flow only near the surface of the inspection object 1 due to the skin effect, and thus the surface such as the surface hardness due to quenching of the inspection object 1. Information can be obtained.
When a direct current or a low-frequency alternating current is applied to the inspection object 1, the current flows to the inside of the inspection object 1, and internal information such as a quenching depth by quenching the inspection object 1 can be obtained. it can.

The DC potential difference method is a method in which a DC current is applied to the inspection object 1, and the magnitude of the voltage between the voltage measuring probes 4 and 4 is measured.
The AC potential difference method is a method in which an AC current is applied to the inspection object 1, and the phase difference between the voltage amplitude and the current between the voltage measuring probes 4 and 4 is measured.
In the AC potential difference method, amplitude and phase can be measured, and further, phase detection makes it less susceptible to noise, so measurement with higher accuracy than the DC potential difference method is possible.
In actual measurement, a calibration curve is prepared in advance by measuring a sample with different quenching depth and surface hardness, and the quenching of the inspection object 1 is performed by comparing the measurement result of the inspection object 1 with the calibration curve. Estimate depth and surface hardness.

  As shown in FIG. 1, this quenching quality inspection apparatus has a head 8, a measuring device 9, a display device 7, and a current application position changing means 10 (FIG. 2). The head 8 is formed by integrating a pair of current application deep needles 3 and 3 and a pair of voltage measurement deep needles 4 and 4 through a housing 11. Among these, the current application deep needles 3 and 3 are brought into contact with the surface of the inspection object 1 and apply a current to the inspection object 1 from the power source 2 of the measuring device 9. The voltage measuring deep needles 4 and 4 are brought into contact with two points different from the current applying deep needles 3 and 3 on the surface of the inspection object 1 to which a current is applied, and the voltage between the two points is measured. It is supposed to be.

  As shown in FIG. 2, the current application deep needle pairs 3 and 3 and the voltage measurement deep needle pairs 4 and 4 are arranged in parallel at a predetermined distance, and as shown in FIG. , 4 are arranged in a straight line when viewed from the longitudinal direction, and the outer two deep needles are the current application deep needle pairs 3 and 3, and the inner two deep hands are the voltage measurement deep needle pairs 4 and 4. Are arranged as follows. As shown in FIG. 2, each current application deep needle 3 and each voltage measurement deep needle 4 are each formed in a bar shape, and one end of each deep needle 3, 4 protrudes from the end face of the housing 11 to be inspected 1. Contact the surface of the.

As shown in FIG. 1, the other end of each current application deep needle 3 is connected to the power source 2 of the measuring device 9, and the other end of each voltage measuring deep needle 4 is connected to a voltage described later in the measuring device 9. It is connected to the measurement unit 5.
The measuring device 9 has a power source 2 and quality measuring means 12.
For example, an AC power source is used as the power source 2. The power source 2 includes, for example, a variable frequency oscillation circuit and an amplification circuit that amplifies an alternating current output from the oscillation circuit and applies a current to the inspection object 1. The oscillation circuit is connected to the signal processing unit 6 of the quality measuring unit 12 and changes the frequency and amplitude in accordance with an instruction from the signal processing unit 6. It is also possible to apply a direct current to the inspection object 1 using the alternating current power source.

The quality measuring unit 12 measures the potential difference between the pair of voltage measuring deep needles 4, 4, that is, the voltage measuring unit 5 that measures the voltage, and the quenching quality of the inspection object 1 from the voltage measured by the voltage measuring unit 5. And a signal processing unit 6.
The signal processing unit 6 determines at least one of the surface hardness and the quenching depth of the inspection object 1 as the quenching quality in light of the relationship between the voltage value for each quality item and the set quality value for each quality item. To estimate. The signal processing unit 6 includes a determination unit 6a, a frequency change command unit 6b, and a current application position change command unit 6c described later.

  The determination unit 6a determines that quenching is abnormal when at least one of the measured surface hardness and quenching depth of the inspection object 1 is lower than a predetermined value (set quality value). The determination unit 6a includes, for example, an electronic circuit that calculates surface hardness and the like proportional to the voltage measured by the voltage measurement unit 5. This determination unit 6a has a relationship setting means (not shown) in which the relationship between the signal based on the voltage, the surface hardness, and the quenching depth is set by an arithmetic expression or a table, and the signal based on the measured voltage The surface hardness or quenching depth of the inspection object 1 is calculated in light of the setting means. The set quality value is a threshold value appropriately set by various tests or the like, and is stored in a rewritable storage medium or the like.

The frequency change command unit 6 b gives a command to variably set the frequency and amplitude of the AC signal to the oscillation circuit of the power supply 2. The determination unit 6a obtains surface information such as surface hardness due to quenching of the inspection object 1 by giving a command to the power source 2 so that the AC signal has a high frequency of, for example, 1 kHz to 20 kHz by the frequency change command unit 6b. Is possible. The determination unit 6a obtains internal information such as the quenching depth of the inspection object 1 by giving a command to the power supply 2 so that the AC signal has a low frequency of, for example, 1 Hz to 100 Hz by the frequency change command unit 6b. Is possible.
The frequency change command unit 6b sets, for example, a plurality of types of rules such as a change width, a frequency, a change repetition period, and the like for changing the frequency according to the type of intended quenching quality, the type of the inspection object 1, and the like. In addition, any rule may be selected by appropriate input.

  The display device 7 is connected to the measuring device 9 via a drive circuit (not shown). The display device 7 is realized by, for example, a liquid crystal display, an organic EL display, a CRT display, a printer, or the like. The display device 7 displays the quenching quality measured by the quality measuring means 12.

  As shown in FIG. 2, the current application position changing means 10 changes the position applied by the current application probes 3, 3 with respect to the inspection object 1. The current application position changing means 10 includes a head rotating unit 13 that rotates the head 8 about its rotation axis, and a terminal 14 such as a slip ring or a rotor connector. The head rotating unit 13 is made of, for example, a motor, and the head 8 is fixed to the tip of the head rotating unit 13 via a terminal 14. Therefore, the current application position changing means 10 allows the current application probes 3 and 3 and the voltage measurement probes 4 and 4 to rotate integrally.

  A current application position change command unit 6c (FIG. 1) in the signal processing unit 6 is connected to the head rotation unit 13, and the current application position change command unit 6c rotates the head 8 at an angle determined about its rotation axis. A rotation command to be driven is given to the head 8. As shown in FIG. 4, based on the rotation command from the current application position change command unit 6 c, the head 8 is rotated relative to the inspection object 1 to measure voltages at a plurality of positions on the surface of the inspection object 1. obtain.

  As shown in FIGS. 1 and 2, the determination unit 6 a in the signal processing unit 6 has a function of averaging voltages at positions measured by the current application position changing means 10. For example, after measuring the voltage with the pair of voltage measuring probes 4 and 4 at an arbitrary position where the head 8 is opposed to the inspection object 1, the position of the head 8 with respect to the inspection object 1 is not changed. Then, the head 8 is moved away from the surface of the inspection object 1 and the head 8 is rotated by a predetermined angle by the head rotating unit 13. Thereafter, the head 8 is brought into contact with the surface of the inspection object 1 again, and the voltage is measured by the pair of voltage measuring probes 4 and 4. In this way, while rotating the head 8 around its axis, the voltage flowing between the voltage measuring probes 4 and 4 is measured at each rotation angle, and the average value of these measured values is calculated by the determination unit 6a. It is like that.

The effect will be described.
The current application probes 3 and 3 are brought into contact with the surface of the inspection object 1, and a current is supplied from the power source 2 through the current application probes 3 and 3. In this state, the voltage between two points, that is, the potential difference is measured by the pair of voltage measuring probes 4 and 4 brought into contact with the surface of the inspection object 1. The quality measuring means 12 measures the quenching quality of the inspection object 1 from the measured voltage.
When a constant current is applied to the inspection object 1, the voltage between the voltage measuring probes 4 and 4 changes depending on the conductivity and magnetic permeability at the position to be measured.

  The permeability and conductivity of the steel material change due to quenching. Generally, the higher the hardness of a steel material by quenching, the smaller the permeability and conductivity. For this reason, the voltage between the two points varies depending on the quenching quality such as quenching hardness. Therefore, information on the quenching quality can be obtained by measuring the voltage between the two points. In this case, the current application position changing means 10 changes the position to which the current is applied to the inspection object 1 by the current application probes 3 and 3. The quality measuring unit 12 obtains information on the quenching quality based on the voltages respectively measured at the changed positions, thereby reducing the influence of variation in conductivity and magnetic permeability depending on the measurement location.

The quality measuring means 12 averages the voltages at the positions measured by the current application position changing means 10. By taking the average of the voltages at a plurality of measured positions in this way, the influence of variation in conductivity and magnetic permeability depending on the measurement location can be reduced, and the inspection accuracy of nondestructive inspection can be easily improved.
The current application position changing means 10 has a function of changing the position at which the voltage is measured by the voltage measuring probes 4 and 4 with respect to the inspection object 1. In this case, the voltage measuring probes 4 and 4 can be driven with respect to the inspection object 1 by the head rotating unit 13 made of a motor without the need to manually change the voltage, so that the voltage at each measurement location can be easily set. And it can be measured reliably.

In the current application position changing means 10, the current application probes 3, 3 and the voltage measurement probes 4, 4 are integrally rotatable, so that at least a pair of current application probes is used as the current application probe. 3 and 3 are sufficient, the number of parts can be reduced, and the manufacturing cost can be reduced.
Since the current application position changing means 10 rotates the head 8 in which the current application probe 3 and the voltage measurement probe 4 are integrated, the current application probe 3 and the voltage measurement probe 4 It is not necessary to handle each separately, and the workability of measurement can be improved.

Another embodiment will be described.
In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  FIG. 5 is a plan view of the main part of a quenching quality inspection apparatus according to another embodiment of the present invention. FIG. 6 is a block diagram showing a conceptual configuration of the quenching quality inspection apparatus. FIG. 7 is a diagram showing a positional relationship between the head 8 and the inspection object 1 of the quenching quality inspection apparatus. As shown in FIG. 5, a plurality of pairs of current application probes 3 are provided and a plurality of pairs of voltage measurement probes 4 are provided. As shown in FIG. 6, the current application position changing means 10A applies a current application for applying a current. The probe pairs 3 and 3 may be switched, and the voltage measurement probe pairs 4 and 4 for measuring the voltage may be switched. In this example, the above-described head rotating unit is not provided.

  As shown in FIG. 5, the head 8 is provided with a plurality of pairs (four pairs in this example) of current application deep needles 3 and voltage measurement deep needles 4 on the circumference. The center between each pair of current application deep needles 3 and 3 and the center of each pair of voltage measurement deep needles 4 and 4 are arranged to coincide with the center of the head 8. Current application deep needles 3 are arranged on the outer peripheral side of the end face of the head 8 at regular intervals in the circumferential direction (in this example, 45 degrees), and these current application deep needles are arranged on the inner peripheral side of the end face of the head 8. 3, voltage measuring deep needles 4 are arranged at regular intervals in the circumferential direction.

  The current application position changing means 10A causes a current to flow through the diagonal current application deep needles 3 and 3, and the diagonal voltage measurement deep needles 4 in phase with the current application deep needles 3 and 3. The probe pairs are sequentially switched so that the voltage between the four can be measured. The current application position changing means 10A includes current application deep needles 3 and 3 for passing current, and switches 15 and 16 for switching voltage measurement deep hands 4 and 4 for measuring voltage, respectively. The current application position change command unit 6c (FIG. 1) gives a switch command to the switch 15 so that the current flows through the pair of current application deep needles 3 and 3 through which the current should flow. At the same time, the current application position change command unit 6c (FIG. 1) gives a switch command to the switch 16 so that the pair of voltage measuring deep hands 4 and 4 whose voltages are to be measured can be measured.

  According to this configuration, a voltage is applied to the inspection object 1 by sequentially applying current between the predetermined current application probes 3 and 3 among the plurality of pairs of current application probes 3 and 3. The position where the voltage is measured by the measurement probes 4 and 4 can be changed. The quality measuring means 12 averages the voltages at the positions measured by the current application position changing means 10A. By taking the average of the voltages at a plurality of measured positions in this way, the influence of variation in conductivity and magnetic permeability depending on the measurement location can be reduced, and the inspection accuracy of nondestructive inspection can be easily improved. In this example, when the voltage measurement position is changed, the head 8 does not need to be separated from the surface of the inspection object 1 each time, and the voltage at each measurement location can be measured more easily than in the first embodiment.

  FIG. 8 shows an example of a nondestructive inspection performed using the quenching quality inspection apparatus. Here, the quenching quality of the rolling surface 21a of the inner ring 21 of the bearing is inspected. An inner ring 21 is fitted to a small diameter portion of the rotating shaft 22, and the rotating shaft 22 is configured to be rotatable around the axis L <b> 1 by a driving source (not shown). A fixing member 22 for fixing the head 8 is provided at the tip of the head advance / retreat driving source 23, and the head 8 fixed to the fixing member 22 is configured to be movable in the direction of the axis L1 by driving the head advance / retreat drive source 23. Is done. As the head advance / retreat drive source 23, a fluid pressure cylinder, a motor and a ball screw mechanism, or the like can be applied.

  The fixing member 22 presses the head 8 against the rolling surface 21a with an appropriate pressing force. By rotating the rotating shaft L1 and moving the head 8, the head 8 can be slid on the entire peripheral surface of the rolling surface 21a of the inner ring 21, and the quenching quality can be inspected at all or several places on the circumference. In this case, since all the quenching quality can be inspected online by the display device 7 (FIGS. 1 and 6), the quality assurance capability can be enhanced. Note that the head 8 may be moved manually, for example, without providing the head advance / retreat drive source 23, the fixing member 22 or the like, and the quenching quality of the rolling surface 21a or the like may be inspected.

DESCRIPTION OF SYMBOLS 1 ... Inspection object 2 ... Power supply 3 ... Current application deep needle 4 ... Voltage measurement deep needle 8 ... Head 10, 10A ... Current application position changing means 12 ... Quality measurement means 13 ... Head rotating part

Claims (10)

A power supply for applying a current via a current application probe brought into contact with the surface of the inspection object;
A pair of voltage measuring probes for contacting the two points different from the current applying probe on the surface of the inspection object to which a current is applied by the power source and measuring a voltage between the two points;
Quality measuring means for measuring the quenching quality of the inspection object from the voltage measured by these voltage measuring probes,
In quenching quality inspection equipment with
A quenching quality inspection apparatus, comprising: a current application position changing means for changing a position to which a current is applied to the inspection object by the current application probe.   2. The quenching quality inspection apparatus according to claim 1, wherein the quality measuring means has a function of averaging voltages at positions measured by the current application position changing means.   The quenching quality inspection apparatus according to claim 1 or 2, wherein the current application position changing means includes means for changing a position at which a voltage is measured by the voltage measuring probe with respect to the inspection object. Quality inspection device.   The quenching quality inspection device according to any one of claims 1 to 3, wherein the current application position changing means integrally rotates the current application probe and the voltage measurement probe. Quenching quality inspection equipment.   5. The quenching quality inspection apparatus according to claim 4, wherein the current application position changing means includes a head rotating unit that rotates a head in which the current application probe and the voltage measurement probe are integrated. apparatus.   4. The quenching quality inspection apparatus according to claim 1, wherein a plurality of pairs of the current application probes are provided, and the current application position changing unit is configured to apply a current application probe pair. Quenching quality inspection device that switches between   7. The quenching quality inspection apparatus according to claim 6, wherein a plurality of pairs of the voltage measuring probes are provided, and the current application position changing means switches the current application probe pairs to which the current is applied and also measures the voltage. Quenching quality inspection device that switches the probe pair for measurement.   The quenching quality inspection apparatus according to any one of claims 1 to 7, wherein the current application probe pair for applying the current and the voltage measurement probe pair for measuring the voltage are the probe. The quenching quality inspection apparatus in which the two outer probes are current application probe pairs and the inner two probes are voltage measurement probe pairs, which are arranged in a straight line when viewed from the longitudinal direction.   The quenching quality inspection apparatus according to any one of claims 1 to 8, wherein the quenching quality inspection apparatus inspects at least one of a surface hardness and a quenching depth of the inspection object as the quenching quality.   The quenching quality inspection apparatus according to claim 9, wherein the quality measuring means includes a determination unit that determines that quenching is abnormal when at least one of the surface hardness and the quenching depth of the inspection object is lower than a predetermined value. Having quenching quality inspection equipment.

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