JPS58501196A - Method and apparatus for magnetically testing the mechanical properties of a moving elongated ferromagnetic sample - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Moving extended ferromagnetic sample machine Method and apparatus for magnetically testing magnetic properties Technical field The present invention relates to methods for non-destructive testing of materials and articles, and more particularly to methods for non-destructive testing of materials and articles. Magnetic testing for determining the mechanical properties of elongated ferromagnetic materials in motion; It relates to a device that performs.

Background technology The magnetic and mechanical properties of ferromagnetic materials depend on, for example, the chemical composition obtained during manufacture and Known based on structure. Therefore, the desired mechanical properties of steel, such as hardness, The formation of strength, ultimate strength, yield strength and malleability is a function of chemical composition constants and manufacturing processes. This can be ensured by maintaining stability. Chemical composition and used Certain changes (within tolerance) in the manufacturing process that These changes allow the determination of mechanical properties by measuring magnetic properties. A dependent correlation exists between mechanical and magnetic properties. The best magnetism for the above purposes The properties are coercive force and residual induction (magnetism).

In the conventional method named ``Method of measuring residual magnetism'' (see, Accepted Patent Specification Letter No. 53-j9109, International Classification GOIN 27/68 ), the sample piece (plate) passes between two electromagnets, but the two electromagnets arranged in opposing relationship on both sides of the plate, one at the top and the other at the bottom. It is placed. These electromagnets cause magnetic footprints to form within the test material, causing the magnetic The mark extends in the direction of movement of the test material. Along the path that traverses the magnetic tracks The transducer mounted for movement is at the same distance from the electromagnet. It is located in The signal from the transducer measures the amount of residual magnetism in the sample plate. used to make decisions. The test results obtained with this method have no effect on measurement accuracy. affected by the displacement of the test material due to the vibrations exerted on it.

Additionally, the presence of moving parts makes this method even more difficult to perform and reduces its reliability. Let it go down.

Title: "Method and apparatus for detecting the presence of magnetic anomalies in ferromagnetic and non-ferromagnetic materials" In other previously known methods (see British Patent No. 1.498,2 No. 18, International Classification GOIN 27/86), the test material penetrates inside the annular magnet, The test material is magnetized by the magnetic field of a ring magnet. Test material A? The parameter is of the signal formed in the detection coil under the action of the magnetic dipole set in the test material. Determined by size. amplitude that gives rise to a signal that is therefore representative of the properties of the test material. is proportional to the magnitude of the magnetic dipole and velocity of the test material.

The dependence of the output signal on the speed of the test material mentioned above affects the accuracy of the method. figure.

Furthermore, it is suitable for generating magnetization/gurus with repeating pulses of variable frequency. Magnetically inspecting the circular section of a moving ferromagnetic object equipped with a tagus generator The method is known (see USSR Inventor's Certificate No. 696369, May 1, 1979) 1 day). Solenoid in which the magnetic means are provided in anti-parallel relationship with the pulse generator circuit It is formed in the form of a do. Inside one of the solenoids, that solenoid The reading devices are mounted symmetrically about the axis. If the readout device you are using is inside the circuit A conventional ferroprobe-gr inclinometer is placed at adimeter), so the sum of those output signals is taken. Ru.

The field coil of the ferro globe is connected to the excitation circuit through a power amplifier and measured. A coil is connected to the input of a selective amplifier tuned to the second harmonic.

The mechanical properties of the materials are magnetically tested using the method described above as follows.

A sample piece passes inside a magnetizing solenoid and between a plurality of ferroglobe inclinometers.

As a pulsed current forms a magnetic symbol through the coil of a magnetizing solenoid be swept away. The parameters of the above pulses form a maximum slope for the remanence region. selected so that The reciprocating frequency of magnetization/Grus is the speed of the moving sample piece. The magnetic symbol is selected depending on the degree of There is no residual magnetic field within the lenoid. Ferroglobe inclinometers respond to inclination, The slope is the same as the direction in which the residual magnetic field component is moving (normal), Represents the mechanical properties of the specimen. The sample piece moving between the ferroglobes If uniformly separated from them, their signals are equal and combined The added signal is equal to the sum of all signals. The specimen is displaced from the center line of its path of motion. If the signal strength from the ferroglobe placed on one side increases, while the other The strength of the signal from the ferroglobe placed on the side of the test specimen decreases, but If there is no change in the physical characteristics, the sum of these signals is (where the amplitude of vibration is small) , you can get it for a certain amount.

The above-described method and apparatus allow test results to be obtained over a sufficiently wide range and with the desired accuracy. The reason for not eliminating the influence of vibration on accuracy is due to the This is because the dependence of the gradient of remanent magnetism on distance is nonlinear.

On the other hand, the applicability of the method and device described above is limited to samples having a circular cross section.

Disclosure of invention The present invention eliminates the possibility of sample vibration caused by vibration and sample speed changes without affecting the test results. Determine the mechanical properties of a sample of any cross section with high precision by eliminating the effects of displacement. A method and apparatus for magnetically testing a moving elongated ferromagnetic material to ensure that It is about providing.

The object of the present invention is to move a part of a sample in opposite directions to a saturation point using a pulsed magnetic field. magnetizing the sample to form a magnetized residual induction region in a spot; the step of determining the magnitude of the residual induction used to determine the mechanical properties of the A method for magnetically measuring the mechanical properties of a moving elongated ferromagnetic sample In accordance with the present invention, the gradient of residual induction is electrically transmitted along the magnetized portion. one polarity of this signal indicating the change in residual induction between the regions. The residual induction is obtained by selecting the mother root of and integrating the selected root. magnetically determine the mechanical properties of a moving elongated ferromagnetic sample whose size is determined. This is achieved by a method of measuring.

Another object of the present invention is to provide a magnetizing 9-lux generator, which surrounds the sample and is placed along the sample. and is connected in an antiparallel relationship to the output of the magnetization/glucose generator. a coil surrounding the sample and suitable for converting the residual induction gradient into an electrical signal. a transducer connected to a measuring circuit connected to an indicator. The present invention provides an apparatus for magnetically testing a moving elongated ferromagnetic sample. Originally, the measuring circuit comprises a key, an integrator connected in series with the key, and the truncator. A comparator circuit suitable for selecting the point in time when the output signal of the sensor duplexer is considered to be zero. , the comparator circuit having an input connected to the transducer and an output thereof. a moving elongated ferromagnetic whose force is electrically connected to the control input of said key This is achieved by means of a device for magnetically testing samples.

The comparison circuit electrical connection with the control input of the key is preferably through a control unit. is carried out, and the output of the integrator selects a point in time when the output signal of the integrator is the calyx. connected to the other input of said control unit through another comparator circuit suitable to , the integrator circuit through a current generator, the other output of the control unit being controlled. is preferably connected to the other input of the . Such a proposed device Variant configurations can improve the reproducibility of test results at large ambient temperature differences. , improve the noise immunity of the device.

The proposed method and device are suitable for testing due to sample velocity and vibration, which are related to the accuracy of test results. Eliminates the effects of material displacement and makes it possible to expand the range of magnetic testing products. Ru. The test results obtained by the present invention and apparatus are: residual induction, l? Nodo no no 9ra The present invention is determined only by a meter and therefore represents the mechanical properties of the sample with high precision. will be described in more detail below in connection with the embodiments shown in the accompanying drawings, Figure 1 (,) shows the distribution of residual induction gradient along the sample in the magnetic domain according to the present invention. Figure 1(b) shows the residual induction gradient in the magnetic domain based on the present invention. Illustrating the slope distribution, Figure 2 is a block diagram of the proposed device; Figure 3 shows the transducer output at various speeds of the sample according to the invention. It represents the signal in the FIG. 4 is a time chart illustrating the operation of the device shown in FIG. FIG. 5 shows another variant of the proposed device, FIG. 6 explains the operation of the apparatus shown in FIG. 5, and the essence of the invention can be understood from the following description. be made clear. The sample is exposed to a noggle-shaped magnetic field to generate a spot of residual induction. magnetized. Figure 1(a) shows that the sample is magnetized until it is saturated in the opposite direction. The structure of this spot is illustrated with regions located close to each other along the Ru. The function B=B←) representing the structure of this induced spot is sufficient to understand the essence of the present invention. will be used later for the purpose of When the sample is moving, the function F←)-dB←)/d The slope of the residual induction, expressed as Here, ε(1) is the transformer that converts the above slope into an electrical signal. This is the induced electromotive force of the spacer. Such transducers include e.g. It can be a measuring induction coil integrated into the proposed device described below.

Based on Faraday's law of induction and induction, the induced electromotive force ε(1) of the induction coil is The accuracy of the given function φ(1) expressed as the time variation of the amount of magnetic flux coupled with It is a differential.

Therefore, the integral of the function ε(1) in a given time interval (T1 #T2) is simply instantaneous. It is determined by the function φ(1) at the time interval T1 and T2. Two, - Tong Lai From Buninotsu's equation, it is as follows.

According to the proposed method, the instantaneous time TI is independent of the sample velocity. - a magnetic field in the direction through the sensor (section The instantaneous time T2 corresponds to the passage of the part of the sample that has been ), the sample section magnetized until it is saturated passes through the transducer. The reason is that at these instants, there is no relation to the velocity of the sample. Since the signal from the transducer is equal to zero (its polarity is reversed) It is. Therefore, if a pulse of one pole is selected from the transducer signal, , is integrated and we get the following equation where φ(X2)2φ(TI)=φ(begins the integration) The instantaneous time Tls, that is, the time when the residual magnetic flux crosses the section X2 of the test object, is the magnetic flux passing through the irradiance dazer, φ(Xx)=φ(T2)−−φ is the instantaneous time T2 (at which the integration ends), i.e., the residual Magnetic flux passing through the transdazer at the time when the residual magnetic flux crosses section X1 of the sample Adashi, Br is the distribution function of the residual induction for the section and K is the transducer no e is a constant coefficient determined by a parameter and an integrator.

Therefore, the obtained relationship is The reason is that the axial displacement of T1 and T2 is not included. If the total magnetic flux coupled to the coil (as divisions X2 and Xl) is actually This is because it is concentrated within. The above relationship moves through the transducer. independent of sample velocity. The output signal is the amount of residual induction in the sample and the shape of its division. (in other words, the amount of residual magnetic flux in the test specimen).

The proposed method can be implemented by the apparatus illustrated in FIG. This device is a magnetizing pulse The output of the magnetizing coil 2 is connected in parallel to the magnetizing coil 2. . The coil 2 is arranged along the sample 3 and surrounds the sample. Distance between magnetic coils The distance is selected depending on the actual situation in which the proposed method is implemented. The equipment is further includes a transducer that converts the residual induced slope into an electrical signal. This The transducer is preferably designed in the form of a measuring coil 4. This The signal surrounds the sample 3 and is connected to the measurement circuit including the key 5, the integrator 6 and the comparator circuit 7. It is connected. A key 5 and an integrator 6 are connected to the coil 4 in series. comparison Circuit 7 selects the instantaneous time when the signal from coil 4 passes through the zero level. It has an input connected to the coil 4. Output of comparison circuit 7 is electrically connected to the control electrode of the key 5. The measurement circuit is connected to the output of the integrator can be connected to any suitable recording device.

The device operates as follows. The magnetization pulse generator 1 applies the voltage to the magnetization coil 2. In response to the pulse, the magnetizing coil generates a residual induced spot on the sample. A cut is formed (Fig. 1(a)). Such spots are periodically It is self-evident that it can be formed either from time to time or from time to time.

When the sample 3 passes through the measuring coil 4, the residual induced spot generates a signal ε(1) The measuring coil is applied so as to cause the saturation in the direction formed at instant T1 The magnetized part passes through the measuring coil 4 until the sum is reached, and the comparison circuit 7 opens the key 5. It works like this.

The integrator 6 starts integrating the signal applied from the measuring coil 4. moment At T2, the comparator circuit 7 operates again to close the key 5. As a result , the output voltage of the integrator 6 is within the time interval ('r, t T2) may be proportional to the integral value of the signal from 4. This voltage is recorded and then applied to any The integrator is then cleared and the measurement is The normal circuit becomes ready to start processing the next virus. of integrator 6 A time chart of the voltage at the output is illustrated in FIG. The signal recorded by The size of the specimen is used to determine the mechanical properties of the specimen.

Reproduction of test results under conditions of large atmospheric temperature differences and equipment subject to large noises. The accuracy is preferably ensured by using the proposed device in the variant disclosed below. be converted into

Referring to FIG. 5, apart from the device shown in FIG. includes a control unit 8, through which the comparator circuit 7 is connected to the key 5. electrically connected to the control input of the The output of the integrator 6 passes through another comparison circuit 9. is connected to the other input of the control unit 8, and the other comparison circuit 9 is connected to the other input of the control unit 8. 6 is adapted to select that instantaneous time when the output signal is zero. control uni The other output of cut 8 is connected to the integrator through a controlled current generator 10. , and also connect the output of the control unit to any suitable device for recording for a time interval. during which the controlled current generator 10 is energized by the control unit 8. Ru.

T1 and T2 are instantaneous times (Figure 3), and in opposite directions at that time The residual induction spot area in the maximally magnetized test material passes through the measuring coil 4. pass

The device of the above variant operates as follows. The moving test material is transferred to coil 2. more magnetized. The shape of the residual induced spot is illustrated in FIG. 1(,). Test material When the non-magnetized portion of the material 3 passes through the measuring coil 4, the output signal of the coil is zero.

Key 5 is closed. Controlled current generator 10 is turned off. Output of integrator 6 The force signal is zero. The residual induction spot when passing through the measurement coil 4 is the coil The above-mentioned induced electromotive force is generated (Fig. 3). The comparator circuit 7 (Fig. 5) detects the instant T1. It operates in The control unit 8 opens the key 5 and receives the signal from the measuring coil 4. signal is applied to the integrator 6. The output voltage of the above integrator is determined by the comparator circuit 9, which is the noise immunity of the device. operating above the threshold that determines the At moment T2 (Fig. 3), the control unit 8 in response to closing the key 5 and turning on the controlled current generator 10. In response, the comparator circuit 7 is activated again, which causes the capacitor (not shown) of the integrator 6 to is discharged by the current of the current generator 10 controlled above. Output voltage of integrator 6 If is zero, the comparator 9 operates and the control unit 8 starts the controlled current generator 10. Turn it on. The device is now ready for the next pulse process.

In this case, the mechanical properties of the test material are determined by the operating time of the controlled current generator 10. determined. This time can be converted to a digital signal and applied to an indicator . If the controlled current generator 10 is a controlled direct current generator, during its operation is the output voltage of the integrator 6 at instantaneous time T2 (Fig. 6), which is 2 That is, the time chart of the output voltage of the integrator 6 is proportional to 1ε(t)at. (Illustrated in the figure). As is clear from the above description, this integral value is The displacement of the test material over the entire area of the measuring coil 4 is is also determined only by the parameters of the residual induced spot.

The method and apparatus described above are useful in reading out data representing the dimensions of the residual induced spot. axial displacements of the test material and transducers for these displacements. allows the reduction of errors caused by nonlinear dependence of the signal.

Furthermore, the proposed method and apparatus address the dependence of the signal for reading out the velocity of the test material and its Collaborative listing and eliminating errors.

Measurement accuracy obtained by using the method and device proposed by the invention allows testing of rolled products of arbitrary cross-section, for example, because the test This is because the test material does not require a symmetrical cross section. Therefore, the present invention is directed to the manufacturing process. Suitable for testing the mechanical properties of rolled steel products and pipes. Can be done.

FI5.1 international search report

Claims (1)

[Claims] 1. A pulsed magnetic field is applied to a part of the sample in the opposite direction, and the residual magnetization reaches the saturation point. magnetizing the sample so as to form a spot in the retention induction region; mechanical properties of the sample; movement comprising the step of determining and constant the magnitude of the residual induction used to determine the This method is used to magnetically measure the mechanical properties of elongated ferromagnetic samples. select one polarity of the signal indicating a change in residual induction between the regions; and the magnitude of the residual induction is determined by integrating the selected pulses. Magnetic measurement of mechanical properties of a moving elongated ferromagnetic sample characterized by How to determine. 2. A magnetizing pulse generator, which surrounds the sample and is arranged along the sample; The magnetizing coil is connected in an antiparallel relationship to the output of the pulse generator, and the Connected to an indicator suitable for surrounding the sample and converting the residual induction slope into an electrical signal. A moving elongate beam comprising a transducer connected to a measuring circuit In an apparatus for magnetically testing magnetic samples, The measuring circuit comprises a key (5), an integrator (6) connected in series with the key and the trigger. suitable for selecting the point in time when the output signal of the transducer (4) is zero. a comparator circuit (7), the comparator circuit (7) being connected to the transducer (4); has a connected input, and its output is electrically connected to the control input of the yJ key (5). magnetically testing a moving elongated ferromagnetic sample characterized by A useless device. 3. Electrical connection of the comparison circuit (7) with the control input of the key (5) is made on the control unit. through the integrator (8), and the output of the integrator (6) is said through another comparator circuit (9) suitable for selecting the point in time at which the force signal is zero. connected to the other input of the control unit, and the other output of said control unit (8) connected to the other input of said integrating circuit (6) through a controlled current generator (10); 3. The device according to claim 2, characterized in that: