Method and system for non-destructive material inspection

Abstract

A method for determining one or more material states of a hysteretic ferromagnetic material and / or a non-hysteretic material may include interrogating the hysteretic ferromagnetic material and / or the non-hysteretic material with an input time-varying magnetic field and detecting a magnetic response and / or an acoustic response over time from the hysteretic ferromagnetic material and / or the non-hysteretic material. The method may also include determining a time-dependent non-linear characteristic of the received magnetic response and / or acoustic response, and associating the time-dependent non-linear characteristic of the received magnetic response or acoustic response with one or more material states of the material.

Description

[0001] This application is a divisional application of an application with an application date of October 19, 2018, PCT international application number of PCT / US2018 / 056637, Chinese national phase application number of 201880073614.9, and invention name of “Method and system for non-destructive material inspection”. Technical Field

[0002] The present disclosure relates to materials inspection and, more particularly, to non-destructive materials inspection. Background Art

[0003] Systems and methods for evaluating hard spots and / or other suitable material conditions and inhomogeneities (e.g., in pipeline steel or other suitable materials) for nondestructive inspection of pipelines, pipes, steel plates, welded structures, and different types of welds that may include, but are not limited to, girth welds, fillet welds, lap welds, and butt welds are valuable in determining material integrity (e.g., pipeline integrity). For example, such systems and methods can nondestructively obtain information about welds and pipeline materials of such materials.

[0004] Currently, pipeline inspection gauges (PIGS) are used as tools to perform non-destructive pipeline inspections to detect anomalies and defects in pipelines, such as cracks and hard spots. The most commonly used technologies include magnetic flux leakage (MFL), ultrasonic crack detection tools (UT), and electromagnetic acoustic transducers (EMAT) that couple electromagnetic energy with mechanical waves. Similarly, non-destructive inspections of welds are also performed using technologies including magnetic particle detection, ultrasonic detection, and eddy current detection. These inspection technologies are based on the principle that anomalies and defects have certain material properties that are detectably different from those of the bulk material, such as leaked magnetic flux due to differences in magnetic permeability or reflected ultrasonic waves due to differences in mechanical vibration behavior.

[0005] There is a useful but overlooked material property that can be used to detect anomalies and defects in pipelines, pipes, steel plates, welded structures, and different types of welds that may include but are not limited to girth welds, fillet welds, lap welds, and butt welds. This is the nonlinear nature of the magnetic response in ferromagnetic materials. The nonlinear magnetic response provides information and accuracy that cannot be obtained using current methods of detecting magnetic flux leakage or linear response functions. Due to the importance of material integrity and material and weld quality, there is a continuing need to further improve the state of the art in nondestructive material inspection technology by improving inspection systems and methods. The present disclosure provides a solution for this need. Summary of the invention

[0006] According to at least one aspect of the present disclosure, a method for determining one or more material states of a sample composed of at least one hysteresis ferromagnetic material and / or at least one non-hysteresis material. The method may include interrogating the sample with an input time-varying magnetic field, and detecting a magnetic response or an acoustic response over time from the hysteresis ferromagnetic material and / or at least one non-hysteresis material. The method may also include determining a time-dependent nonlinear characteristic of the received magnetic field or acoustic response, and correlating the time-dependent nonlinear characteristic of the received magnetic response or acoustic response with one or more material states of the material.

[0007] Determining the time-dependent nonlinear characteristics may include performing a frequency domain analysis, such as a power spectral density analysis of the received magnetic field or acoustic response to create power spectral density data. In some embodiments, determining the time-dependent nonlinear characteristics may include determining one or more harmonic peaks in the power spectral density (PSD) data.

[0008] Determining one or more harmonic peaks may include determining one or more harmonic coefficients of the spectral density data.For example, determining one or more harmonic coefficients and / or peaks may include determining odd harmonic coefficients and / or peaks of the spectral density data.

[0009] In certain embodiments, determining odd harmonic coefficients and / or peaks may include determining the 3rd and / or 5th harmonics of the spectral density data. Correlating the time-dependent nonlinear characteristics may include comparing and correlating the 3rd and / or 5th harmonics with one or more material states of the interrogated sample.

[0010] The sample being interrogated (including at least one hysteresis ferromagnetic material and / or at least one non-hysteresis material) may include, but is not limited to, a test material consisting of at least one material phase having one or more material states. One or more material states may include, but are not limited to, the presence of at least one material phase in a hysteresis ferromagnetic material and / or a non-hysteresis material. In certain embodiments, the hysteresis ferromagnetic material may include, but is not limited to, steel, nickel, cobalt, and alloys thereof, such as various carbon steels. In certain embodiments, the non-hysteresis material may include, but is not limited to, air, aluminum, austenitic stainless steel, duplex stainless steel, and high manganese steel. The material phase may include, but is not limited to, at least one of austenite, martensite, ferrite, pearlite, bainite, lath bainite, acicular ferrite, and quasi-polygonal ferrite having different chemical compositions and / or crystal orientations. The inhomogeneity of the sample may include, but is not limited to, a test material consisting of more than one material phase. A non-limiting example of inhomogeneity is, for example, a hard spot (spot) and / or a crack / defect in a steel pipe.

[0011] According to at least one aspect of the present disclosure, a non-transitory computer-readable medium may include instructions for executing any suitable method described herein and / or any suitable portion thereof. For example, the method may include: generating a time-varying magnetic field and detecting a magnetic response or acoustic response signal over time from a magnetic sensor or an acoustic sensor, determining a time-dependent nonlinear characteristic of the received magnetic field or acoustic response, and associating the time-dependent nonlinear characteristic of the received magnetic response or acoustic response with one or more material states of the material. Any other suitable portion of any embodiment of the method described herein may be included in addition or alternatively.

[0012] According to at least one aspect of the present disclosure, a device for detecting one or more material states of an interrogated sample composed of at least one hysteresis ferromagnetic material and / or at least one non-hysteresis material may include: a magnetic transmitter configured to output an interrogation magnetic field; a magnetic sensor or an acoustic sensor configured to receive a magnetic response or an acoustic response, respectively, and convert the magnetic response or the acoustic response into a magnetic signal or an acoustic response signal; and a processor configured to perform any suitable method described herein and / or any suitable part thereof. In some embodiments, the device may include an indicator configured to indicate one or more states of the material to a user. In some embodiments, the output device may include an indicator, which means to notify one or more nearby users of appropriate immediate real-time actions, and the user can directly observe the indicator. In some other embodiments, the output device 207 may also include a device for communicating with a user, which also means to notify the user of appropriate immediate real-time actions, but the user may be located in a remote location, and the communication may be routed by wire or wirelessly. In some other embodiments, the output device 207 may also include a data collection and storage device for subsequent retrieval and post-processing, rather than for immediate real-time actions.

[0013] These and other features of the subject disclosed systems and methods will become more readily apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order that those skilled in the art to which the subject disclosure pertains will readily understand how to make and use the devices and methods of the present disclosure without undue experimentation, embodiments thereof will be described in detail below with reference to certain drawings, wherein:

[0015] Figure 1 is a flow chart of an embodiment of a method according to the present disclosure.

[0016] Figure 2A is a schematic diagram of an embodiment of a device according to the present invention, the device being shown with the transmitting coil and the pick-up coil being located on the same side of the material.

[0017] Figure 2B-2D They are used on air, martensite and ferrite respectively. Figure 2A Power spectral density plot of an embodiment.

[0018] Figure 3A is a schematic diagram of an embodiment of an apparatus according to the present disclosure, the apparatus being shown with a transmitting coil and a pickup coil located on opposite sides of a material.

[0019] Figure 3B-3D They are used on air, martensite and ferrite respectively. Figure 3A Power spectral density plot of an embodiment.

[0020] Figure 4A and 4B shows the same side configuration (e.g., Figure 2A Simulation results of nonlinear magnetic detection of model materials for the configuration of ).

[0021] Figure 5A and 5B A schematic embodiment of a setup for testing the nonlinear magnetic response of a model material under a strong external magnetic field is shown.

[0022] Figures 6A-6C The 2nd harmonic PSD test results at different frequencies are shown.

[0023] Figures 7A-7C An axially symmetric simulation of a horseshoe magnet on a steel tube is shown.

[0024] Fig. 8A An embodiment of a setup for nonlinear magnetoacoustic detection is shown.

[0025] Figure 8B PSD results for nonlinear magnetoacoustic detection are shown.

[0026] Fig. 9 is an example arrangement that includes four copies of the magnetic sensor and / or acoustic sensor located at different locations around and / or paired with each magnetic transmitter.

[0027] Fig.10 is an example arrangement that includes 8 copies of magnetic sensors and / or acoustic sensors at different locations around and / or paired with each magnetic transmitter.

[0028] Figures 11A-11F The results for a real pipe with a hard phase in the weld are shown. Fig.11A , 11B , 11D and 11E) and a pipe portion having no hard phase in the weld ( Fig. 11C and 11F) is the data of nonlinear magnetic detection performed.

[0029] Figures 12A-12C Embodiments of detecting and distinguishing between inhomogeneities of ferromagnetic materials with hysteresis and non-hysteresis materials are shown.

[0030] Figures 13A-13E The application of the disclosed apparatus in detecting anomalies in real pipeline steel is shown. Fig.13A and 13B are plots of the data generated from the two configurations of the device relative to the sample. Fig. 13C Is from Fig.13A and 13B A data graph of the combined data set of both and at any particular location. Fig. 13C Use only Fig.13A and 13B The lower value of the normalized 3rd harmonic between . Fig.13E is an overlay of the Vickers hardness (VHN) measurement on a sample photograph. Fig.13D Is from Fig.13E Extract of data.

[0031] Figures 14A-14C are the power spectral density plots used on air, martensite, and ferrite respectively.

[0032] Figures 15A-15B The application of the device of the present disclosure in detecting anomalies in a carbon steel plate is shown.

[0033] Figures 16A-16B The application of the device of the present disclosure in detecting anomalies in a carbon steel plate is shown. DETAILED DESCRIPTION

[0034] All numerical values ​​in the detailed description and claims herein are modified by the value indicated by "about" or "approximately" and take into account experimental errors and variations that would be expected by one of ordinary skill in the art. The present invention relates to methods and apparatus for detecting the nonlinear magnetic response of a sample composed of at least one hysteretic ferromagnetic material. The linear response function of the magnetic material is given by the following equation

[0035] B(x)=μ0(H(x)+M(x))=F(H(x))

[0036] Where H(x) is the applied field strength (in amperes per meter) which may vary with position (x) in space, M(x) is the magnetization (in amperes per meter) which depends on position (x) as well as the initial magnetization state of the material, μ0 is the permeability constant (in henries per meter), B(x) is the magnetic flux density (in teslas) which may vary with position (x) in space, and F(H(x)) is a function that depends on H(x). Hereinafter, B(x), H(x), M(x), and F(H(x)) will be referred to as B, H, M, and F(H), respectively, and / or (if the corresponding parameters vary with time) B(t), H(t), M(t), and F(H(t)). This linear dependence is the type of response seen in static magnetic fields. Current inspection tools, such as magnetic flux leakage (MFL) and electromagnetic acoustic transducer (EMAT) tools, are configured to respond to a function that is primarily linearly dependent on H. It should be noted that for ferromagnetic materials, this dependence can be complex. When the applied magnetic field is time-varying, linear operators no longer describe the relationship between the applied magnetic field and the magnetization. The magnetic flux density B(t) in a ferromagnetic material with an applied time-varying magnetic field H(t) can be approximated by a linear operator and the time integral of a series of nonlinear functions:

[0037]

[0038] Function F2 causes a second-order nonlinear response, function F3 causes a third-order nonlinear response, and function F n This causes an nth-order nonlinear response. Time integration It means that the magnetic flux density B(t) depends on the function F n (H n (t)) history.

[0039] The present invention utilizes these nonlinear responses to provide a better method for characterizing material states and inhomogeneities in ferromagnetic materials. If the applied magnetic field H(t) is sinusoidal and varies sinusoidally with frequency ω, the second-order response varies with 2ω, the third-order response varies with 3ω, and the n-order response varies with nω. If the applied field has an arbitrary time dependence, the nonlinear response can be extracted from the analysis of the time dependence of the signal, which can be caused by the magnetization and magnetic flux density (B(t) in Equation 1). In some cases, this can be accomplished by Fourier analysis of the time dependence of the signal caused by the magnetization and magnetic flux density (B(t) in Equation 1). In some instances, the nonlinear response can be characterized directly from the time dependence of the signal caused by the magnetization and magnetic flux density (B(t) in Equation 1).

[0040] Reference will now be made to the accompanying drawings, in which like reference numerals identify like structural features or aspects of the present disclosure. For purposes of explanation and illustration, and not limitation, a schematic diagram of an embodiment of a method according to the present disclosure is shown in FIG. Figure 1 The method is shown in FIG. 1 and is generally indicated by reference numeral 100. Other embodiments and / or aspects of the present disclosure are described in Figure 2A-16B The systems and methods described herein can be used to determine the material state of a material (eg, material phase and / or imperfections in a metal pipeline).

[0041] A general understanding of the nonlinear magnetic response in hysteretic ferromagnetic materials is provided below. The following embodiments provide a fast, simple and versatile method to detect the material state and inhomogeneities of the sample under study. Non-limiting examples of inhomogeneities are hard spots and / or cracks / defects in, for example, steel pipes. Certain embodiments described herein do not require a built-in ferromagnetic core and can therefore be calibrated in an air environment to provide an accurate background signal. The method also allows calibration in environments other than air (e.g., immersing the sample in oil).

[0042] The nonlinear response of the magnetic flux density (B(t) in Equation 1) in an applied time-varying magnetic field causes a number of detectable responses. These responses track the time dependence of the magnetic flux density created by the applied time-varying magnetic field, and the nonlinear response is caused by the magnetization and the magnetic flux density (B(t) in Equation 1). It has been shown both theoretically and experimentally that symmetric hysteresis responses result in odd harmonics, while asymmetric hysteresis responses result in even harmonics. Symmetric hysteresis responses are typically connected to, but not limited to, ferromagnetic materials, and asymmetric hysteresis responses are typically connected to, but not limited to, residual magnetization states in hysteresis materials, and embodiments may also be applied to detecting the magnetization state of hysteresis materials. One embodiment of the present invention includes interrogating a sample with a time-varying magnetic field from a magnetic transmitter, and detecting the magnetic flux density (B(t) in Equation 1) with a magnetic sensor close to the sample. A variation of this embodiment includes incorporating a DC magnetic field for bias magnetization. Another variation includes measurement of a sample with residual magnetization. Yet another variation includes measurement of a demagnetized sample. A different embodiment includes interrogating the sample with a time-varying magnetic field from a magnetic transmitter and detecting the magnetic flux density (B(t) in Eq. 1) and the nonlinear magnetoacoustic response (e.g., similar to EMAT, but looking at the nonlinear spectrum of the acoustic signal). A variation of this embodiment includes incorporating a DC magnetic field that biases the magnetization. Another variation includes measurements on samples with residual magnetization. Yet another variation includes measurements on demagnetized samples.

[0043] The general principle of nonlinear magnetic response relies on applying a time-varying magnetic field H(t) to a sample and detecting the response. AC magnetic modulation with angular frequency ω=2πf This AC modulation can be achieved by time-varying current (Consider Ampere's law And in our frequency range Inside, the second can be ignored). DC magnetizing field can also be applied by a DC current or a permanent magnet and results in a total magnetic field generated by the source: For ferromagnetic materials such as carbon steel and other ferrite phases in steel, the relative permeability μ connecting the magnetic fields B and H is r is a hysteresis and nonlinear operator. Therefore, the main magnetic field Inside the ferromagnetic material it will be nonlinear and can be described as a Taylor series

[0044]

[0045] According to Faraday's law Induced electric field in steel and the eddy currents generated are all nonlinear, since the conductivity σ in steel is generally a scalar and a linear operator. Eddy currents are only distributed around the surface of the conductive material and according to Ampere's law Generating a secondary magnetizing field As a result, the secondary magnetization field Will include home Similar nonlinear information.

[0046] Different ferromagnetic materials have different hysteresis curves and magnetic responses, and will lead to different nonlinear harmonic coefficients under the same magnetic modulation. The difference in harmonic coefficients can be measured in two ways:

[0047] 1. Non-linear magnetic detection: The total magnetization field is non-linear and can be measured by a magnetic sensor at point A in the air:

[0048] 2. Nonlinear magnetoacoustic detection. In a large constant DC magnetic field In the case of And emit time-varying mechanical waves. This magnetoacoustic response is also nonlinear.

[0049] The last consideration is the sinusoidal modulation Different nonlinear harmonics are generated under the condition that all nonlinear effects originate from When the local hysteresis BH loop is symmetrical inside the hysteresis material, after half a period Reverse its direction This usually occurs near zero magnetization. Using the Taylor expansion from equation (1), symmetry constraints show that and Therefore, for even n, the harmonic coefficients In other words, a symmetrical BH curve prohibits the generation of even harmonics and only allows odd harmonics. In contrast, if the BH loop is asymmetrical, there may be All Taylor coefficients in the expansion In other words, an asymmetric BH curve allows for both odd and even harmonics.

[0050] Reference now Figure 1 , a method 100 for determining one or more material states of a sample composed of at least one hysteretic ferromagnetic material may include interrogating (e.g., at box 101) a hysteretic ferromagnetic material by applying a time-varying magnetic field. Optionally, in box 101, an additional DC magnetic field may be applied. Optionally, a demagnetizing magnetic field may be applied in box 101. Optionally, the sample in box 101 may have a remanent magnetization. The DC magnetic field is a magnetic field that does not vary with time, and the demagnetizing magnetic field is a time-varying magnetic field used to eliminate the remanent magnetization of the material. A time-varying magnetic response or acoustic response is detected in box 103. The method 100 may also include determining (e.g., at box 105) a time-dependent nonlinear characteristic of the received magnetic field or acoustic response, and correlating the time-dependent nonlinear characteristic of the received magnetic response or acoustic response with one or more material states of the material (e.g., at box 107).

[0051] Interrogating a hysteretic ferromagnetic material with an input time-varying magnetic field may include, but is not limited to, utilizing at least one magnetic transmitter that generates a time-varying magnetic field and placing the magnetic transmitter in a proximity position to the sample being interrogated. For example, an example proximity (or proximity position) of the magnetic transmitter is 1 cm from the surface of the sample being interrogated; a more preferred proximity position of the magnetic transmitter is 0.2 cm or less from the surface of the sample being interrogated; and a more preferred proximity position of the magnetic transmitter is in direct contact with the surface of the sample being interrogated.

[0052] The time-varying magnetic field may include, but is not limited to, a combination of a sine wave, a square wave, a triangle wave, and symmetrical and asymmetrical pulses. In certain embodiments, a preferred time-varying magnetic field may include a sine wave with a peak amplitude ranging from 0.01 millitesla to 1 Tesla and a frequency ranging from 1 Hz to 1 MHz. A more preferred time-varying magnetic field may include a sine wave with a peak amplitude ranging from 0.1 millitesla to 10 millitesla and a frequency ranging from 100 Hz to 100 kHz. For inspecting 4140 carbon steel material and other carbon steel materials such as X60 and / or X65 carbon steel made by thermomechanical controlled processing (TMCP), a preferred time-varying magnetic field may include a sine wave with a peak amplitude ranging from 0.01 millitesla to 1 Tesla and a frequency ranging from 1 Hz to 1 MHz; a more preferred time-varying magnetic field may include a sine wave with a peak amplitude ranging from 0.1 millitesla to 10 millitesla and a frequency ranging from 100 Hz to 100 kHz; an even more preferred time-varying magnetic field may include a sine wave with a peak amplitude ranging from 0.1 millitesla to 10 millitesla and a frequency ranging from 8 kHz to 100 kHz; an even more preferred time-varying magnetic field may include a sine wave with a peak amplitude ranging from 0.5 millitesla to 5 millitesla and a frequency ranging from 8 kHz to 100 kHz.

[0053] Similar to common practice in other nondestructive inspection tools, those familiar with the technology can optimize the time-varying magnetic field by calibrating the nonlinear magnetic response and / or the magnitude of the 3rd harmonic relative to the frequency range, amplitude range, and material phase.

[0054] The magnetic transmitter may include, but is not limited to, a device that generates a time-varying magnetic field, such as a transmitting coil, a translational / rotational magnet (e.g., a neodymium magnet, a ceramic magnet, an electromagnet, or a superconducting magnet). In certain embodiments, a preferred magnetic transmitter may include a transmitting coil having an outer diameter between 2 mm and 10 cm, a number of turns between 1 and 100,000, and an inductance between 0.001 mH and 1000 mH. In certain embodiments, a more preferred magnetic transmitter may include a transmitting coil having an outer diameter between 5 mm and 5 cm, a number of turns between 10 and 1000, and an inductance between 0.01 mH and 100 mH. In certain embodiments, a more preferred magnetic transmitter may include a transmitting coil having an outer diameter of 1 inch (25.4 mm), 100 turns, and an inductance of L to 0.25 mH. In certain embodiments, a smaller diameter magnetic transmitter may be used to generate inspection results with higher lateral spatial resolution. In certain embodiments, an even more preferred magnetic transmitter may include one or more coils having a diameter less than 1 inch to improve the lateral spatial resolution of the inspection results.

[0055] Detecting the magnetic response or the acoustic response may include, but is not limited to, utilizing at least one magnetic sensor or an acoustic sensor configured to receive the magnetic response or the acoustic response, respectively, and convert the magnetic response or the acoustic response into a magnetic response signal or an acoustic response signal. Preferably, the magnetic sensor is located in an area near the magnetic transmitter. In one embodiment, the distance between the magnetic sensor and the magnetic transmitter is less than 50 meters, preferably less than 10 meters, preferably less than 1 meter, preferably less than 10 centimeters, preferably less than 1 centimeter, preferably less than 1 millimeter, and even more preferably in direct contact with each other.

[0056] The magnetic response may include, but is not limited to, the spatially varying magnetic field generated by the interrogated material due to the input time-varying magnetic field and any additional magnetic fields. The magnetic sensor may include, but is not limited to, a device that receives the magnetic response from at least one point or averaged position on the sensing area and converts the magnetic response into a digital or analog signal that can be interpreted by a computer or observer, such as a pick-up coil, a Hall sensor, a fluxgate magnetometer, a cesium atomic magnetometer, or a superconducting SQUID magnetometer. In certain embodiments, a preferred magnetic sensor may include a sensing coil having an outer diameter between 2 mm and 10 cm, a number of turns between 1 and 100,000, and an inductance between 0.001 mH and 1000 mH. In certain embodiments, a more preferred magnetic transmitter may include a transmitting coil having an outer diameter between 5 mm and 5 cm, a number of turns between 10 and 1000, and an inductance between 0.01 mH and 100 mH. In certain embodiments, an even more preferred magnetic sensor may include a sensing coil having an outer diameter of 1 inch, 100 turns, and an inductance of L ~ 0.25mH. In certain embodiments, a smaller diameter magnetic sensor may be used to generate inspection results with higher lateral spatial resolution. In certain embodiments, a more preferred magnetic sensor may include one or more coils having a diameter less than 1 inch to improve the lateral spatial resolution of the inspection results. In one embodiment, the magnetic sensor is selected so that it can respond quickly enough to record signals caused by at least second-order nonlinear effects, in a more preferred embodiment, the magnetic sensor is selected so that it can respond quickly enough to record signals caused by at least third-order nonlinear effects, and in an even more preferred embodiment, the magnetic sensor is selected so that it can respond quickly enough to record signals caused by at least fifth-order nonlinear effects.

[0057] The acoustic response may include, but is not limited to, mechanical movement of the interrogated material due to the input time-varying magnetic field and any additional magnetic fields. The acoustic sensor may include, but is not limited to, a device that receives the acoustic response from at least one point or averaged position on the sensing area and converts the acoustic response into a digital or analog signal that can be interpreted by a computer or observer, such as a piezoelectric acoustic transducer, a microphone, a seismograph, or a seismometer. In certain embodiments, a preferred acoustic sensor may include a ceramic piezoelectric acoustic transducer having a diameter of 1.2 cm and a resonant frequency of 500 kHz. In one embodiment, the acoustic sensor is selected so that it can respond quickly enough to record signals caused by at least second-order nonlinear effects, in a more preferred embodiment, the acoustic sensor is selected so that it can respond quickly enough to record signals caused by at least third-order nonlinear effects, and in an even more preferred embodiment, the sensor is selected so that it can respond quickly enough to record signals caused by at least fifth-order nonlinear effects.

[0058] Determining the time-dependent nonlinear characteristic may include performing a frequency domain analysis, such as a power spectral density analysis of the received magnetic response or acoustic response to create power spectral density data. In some embodiments, determining the time-dependent nonlinear characteristic may include determining one or more harmonic peaks in the power spectral density data.

[0059] Determining one or more harmonic peaks may include determining one or more harmonic coefficients in the spectral density data.For example, determining one or more harmonic coefficients and / or peaks may include determining odd-order harmonic coefficients and / or peaks in the spectral density data.

[0060] In some embodiments, determining odd harmonic coefficients and / or peaks may include determining the 3rd and / or 5th harmonics of the spectral density data. Correlating the time-dependent nonlinear characteristics may include comparing and correlating the 3rd and / or 5th harmonics to one or more material states of the interrogated sample. In some embodiments, the normalized spectral density data is in the range of 10 -6 The third harmonic and above are associated with material conditions including, but not limited to, the presence of ferrite or pearlite carbon steel phases in the interrogated sample; the normalized spectral density data range from 10 -8 to 10 -6 The small 3rd harmonic of is associated with material states including, but not limited to, the presence of hard steel phases such as martensite or lath bainite carbon steel phases or non-hysteretic materials such as air gaps in the sample being interrogated.

[0061] The sample being interrogated may include, but is not limited to, a test material consisting of at least one material phase having one or more material states. One or more material states may include, but is not limited to, at least one material phase in a hysteresis ferromagnetic material or a non-hysteresis material. In certain embodiments, the hysteresis ferromagnetic material may include, but is not limited to, steel, nickel, cobalt, and alloys thereof, such as various carbon steels. In certain embodiments, the non-hysteresis material may include, but is not limited to, air, aluminum, austenitic stainless steel, duplex stainless steel, and high manganese steel. The material phase may include, but is not limited to, at least one of austenite, martensite, ferrite, pearlite, bainite, lath bainite, acicular ferrite, and quasi-polygonal ferrite having different chemical compositions and / or crystal orientations. The inhomogeneity of the sample may include, but is not limited to, a test material consisting of more than one material phase. A non-limiting example of inhomogeneity is, for example, hard spots and / or cracks / defects in a steel pipe.

[0062] According to at least one aspect of the present disclosure, a non-transitory computer-readable medium may include instructions for performing any suitable method described herein and / or any suitable portion thereof. For example, the method may include generating a time-varying magnetic field and detecting a magnetic response or acoustic response signal over time from a pickup coil, determining a time-dependent nonlinear characteristic of the received magnetic field or acoustic response, and correlating the time-dependent nonlinear characteristic of the received magnetic response or acoustic response with one or more material states of the material. Any other suitable portion of any embodiment of the method described herein may be included in addition or alternatively.

[0063] Additional references Figure 2A According to at least one aspect of the present disclosure, a device 200 for detecting one or more material states of a hysteretic ferromagnetic material (e.g., a sample 221 including a hysteretic ferromagnetic material) may include a transmitting coil 201 configured to output an interrogation magnetic field, a pickup coil 203 or an acoustic transducer (e.g., as described in more detail below) configured to receive a magnetic response or an acoustic response, respectively, and convert the magnetic response or the acoustic response into a magnetic signal or an acoustic response signal. The device 200 may include a processor 205 configured to perform any suitable method, for example, as described above and / or any suitable portion thereof.

[0064] In certain embodiments, the device 200 may include an output device 207 configured to indicate one or more states of the material to a user. The system 200 may include any other suitable signal processing components as understood by those of ordinary skill in the art (e.g., one or more digitizers, galvanometers, signal generators, one or more bandpass filters, one or more preamplifiers or amplifiers, etc.). The output device 207 may include, but is not limited to, an indicator, which means that appropriate immediate real-time actions are notified to one or more nearby users, and the user can directly observe the indicator. The output device 207 may also include, but is not limited to, a device for communicating with a user, which also means notifying the user of appropriate immediate real-time operations, but the user may be in a remote location and the communication may be routed by wire or wirelessly. The output device 207 may also include data collection and storage devices for subsequent retrieval and post-processing and analysis.

[0065] Carbon steel is a key material in the pipeline and oil & gas industries. In general, all carbon steels are composed of multiple material phases. Ferrite, the soft phase of carbon steel, is a key material phase in carbon steel. Hard phases such as martensite or lath bainite are formed in the steel when it is rapidly quenched from high temperatures (e.g., from 900°C) to room temperature, which may occur during steel mill plate manufacturing or resistance seam welding processes. The presence of hard steel phases such as martensite or lath bainite phases may be particularly destabilizing because they are more susceptible to failure and cracking than the soft ferrite phase. As a result, carbon steel samples composed of ferrite and martensite were tested herein because an application in a pipeline is a good example of where such a device may be used. Any other suitable materials and applications are contemplated herein.

[0066] In the illustrated embodiment, a voltage or current signal (e.g., a sine wave with a frequency of f) can be generated by a signal generator 209. With current flowing through it, the transmitting coil 201 acts as a magnetic transmitter to generate a modulated magnetic field. The transmitting coil 201 used to generate the data below includes an outer diameter of approximately 1 inch, 100 turns, and an inductance of L ~ 0.25mH. The electrical impedance of the transmitting coil is Z coil =R internal +iωL. Typically, the internal resistance of the coil is R internal is relatively small (<1Ω for the coils we tested), while the imaginary inductive term increases proportionally with frequency. Any other suitable coil having any suitable characteristics may be used.

[0067] To minimize the impedance effect of the inductor and maximize the output current, capacitor C211 is used to change the total impedance to When or The imaginary terms can be eliminated when 1kHz to 100kHz frequencies are used to generate the following data, and different capacitors can be used at different frequencies to ensure that the same transmitting coil 201 The current flowing through the transmitting coil 201 may be measured by an ammeter 213 and recorded by a first digitizer 215 .

[0068] To detect the magnetic response from nearby materials, a magnetic sensor such as the pickup coil 203 can be used to measure the time-varying magnetic signal. The voltage generated by the pickup coil 203 is It is related to the number of turns N of the pickup coil 203 and the time derivative of the local magnetic field. and is related to the cross-sectional area of ​​loop A. This voltage can be measured, for example, by a second digitizer 217. An optional preamplifier and / or a bandpass filter 219 can be used between the pickup coil 203 and the second digitizer 217, for example, to enhance weak signals or detect specific frequency components in the measured signal when necessary. After receiving the waveforms of the transmit current and the pickup voltage from the two digitizers, a PSD analysis can be performed in real time by the processor 205 to extract the nonlinear coefficients and / or peaks of the test material.

[0069] The transmitting coil 201, the pickup coil 203 and the material being interrogated may be arranged in any suitable configuration. Two specific examples are shown in 2A and 3A. Figure 2A In the embodiment, the transmitting coil 201 and the pickup coil 203 are placed on the same side of the interrogated material (e.g., a ferromagnetic plate), and this configuration can be easily applied to conventional PIG for non-destructive pipeline inspection. Figure 3A , an alternative configuration is shown in which the transmitter coil 201 and the pick-up coil 203 are placed on opposite sides of the material being interrogated.

[0070] Therefore, if Figure 2A As shown, the system 200 can be configured for use on a single side of the material being interrogated. As described above, in some embodiments, the one or more states of the material to be determined may include, for example, the material phase. Figure 2B-2D Example results for determining the material phases of air (as a baseline), martensite (as a first phase), and ferrite (as a second phase) at locations in sample 221 are shown in FIG.

[0071] As a control experiment, the device 200 was tested at 10kHz in air without any conductive / magnetic material within half a meter. The power spectral density (PSD) of the transmitted current and the pickup voltage is shown as the solid and dashed curves. The peak values ​​of the higher harmonics (2nd, 3rd, 4th, 5th, etc.) are at least seven orders of magnitude lower than the main frequency 10kHz. These small harmonic values ​​are due to electronic processing and system noise and should be calibrated as a benchmark for material testing.

[0072] Table 1

[0073]

[0074] Reference Figure 3A In some embodiments, the system 200 may be configured for use on the opposite side of the material being interrogated. Figure 3B-3D Example results for determining material phases for air (as a baseline), martensite (as a first phase), and ferrite (as a second phase) are shown in FIG.

[0075] Table 2

[0076]

[0077] As can be seen in both examples, the odd harmonics show orders of magnitude differences between the different material types, allowing, for example, identification of the different materials. Once a coupon of martensite or ferrite (Sample 221) (e.g., 38.1mm (L) x 25.4mm (W) x 4.7mm (H)) is placed at the end of the coil, the nonlinear response changes dramatically. The even harmonics do not change significantly, while the peaks of the odd harmonics increase dramatically, with the most significant increases coming from the 3rd and 5th harmonics at 30kHz and 50kHz (e.g., Figure 2C and 2D ). In particular, at the peak of the third harmonic, the martensitic sample ( Figure 2C ) increases by one order of magnitude, while in the ferrite sample ( Figure 2D ). In the data shown, the main harmonic peak is used as the standard calibration and all higher order harmonic coefficients are normalized relative to the main peak.

[0078] In addition, the most notable features are the 3rd and 5th harmonics. The structure on the same side (for example, Figure 2A ) or the configuration of the opposite side (e.g. Figure 3A ) were observed. In both configurations, the cross-air (~1x10 -8 ), martensite (~1x10 -7 Up to 5x10 -7 ) and ferrite (~1x10 -5 Up to 5x1-5 ) provides a unique nonlinear magnetic signature that can, for example, be used directly to detect hard phases, such as martensite phases, constituting hard spots in pipeline steels.

[0079] In principle, the self-inductance of the transmitting coil varies with the nearby ferromagnetic material, and due to the hysteresis response, this variation should naturally be nonlinear. We have observed the emission current ( Figure 2B-3D ). Although ferromagnetic materials can be distinguished by analyzing only the voltage and current from a single transmit coil, the signatures of different materials are less distinguishable than when measured from the pickup coil. In this regard, in some embodiments, the transmit coil and the pickup coil may be the same coil.

[0080] Referring to Table 3, in some embodiments, the system 200 can be configured for use on a single side of the interrogated material, and the transmitting coil and the pickup coil can be placed in a preferred nearby position, which is a limited distance from the surface of the interrogated sample. The distance and / or spacing between the interrogated sample and the two coils is called the lift-off distance. Figure 2C-2D The unique nonlinear magnetic characteristics are shown when the two coils are in direct contact with the surface of the sample being interrogated. Table 3 here shows that similar unique nonlinear magnetic characteristics are observed even when there is a lift-off distance of 0.8 mm or 2.0 mm. For ferrite or martensite, the normalized third harmonic decreases slightly with the increase of the amount of lift-off distance, but the total peak value of the third harmonic in the case of ferrite is about two orders of magnitude larger than that of martensite, regardless of the lift-off distance of 0, 0.8 mm or 2.0 mm. Martensite (~1x10 -7 Up to 5x10 -7 ) and ferrite (~1x10 -5 Up to 5x10 -5 ) provides a unique nonlinear magnetic signature that can be used to detect specific material phases, such as the martensite phase, even in the presence of a constant or time-varying lift-off distance during application.

[0081] Table 3

[0082]

[0083] Reference Figure 4A and 4B, computer simulations were performed to incorporate the hysteresis response and understand the experimentally observed 3rd harmonics for the ferrite and martensite phases. The hysteresis model used here was originally developed by Jiles and Atherton and is known as the JA model. There are five parameters in the JA model to describe the hysteresis response of a particular material, and in the simulations, these five parameters were obtained by best matching the JA hysteresis curves with experimental measurements from the literature. Two different sets of parameters were obtained for the ferrite and martensite phases, and the complete hysteresis curves are shown in Figure 4A Then, the COMSOL multiphysics computer software package was used to calculate the ferrite phase and the martensite phase. Figure 2A-3D The magnetic response was simulated under the same experimental conditions and parameters.

[0084] The simulation combines the five JA parameters with a full Maxwell equations solver to account for the nonlinear hysteresis permeability. As the simulation starts with zero remanent magnetization, the results ( Figure 4B ) shows that odd harmonics exist only in the case of ferrite and martensite, which is consistent with the theoretical description of the symmetrical BH curve. In addition, in the simulation results, the 3rd and 5th harmonics of ferrite are about 1.5 orders of magnitude (~40 times) larger than those of martensite, which is also consistent with the experimental results mentioned above. Using reliable simulation tools, the quantitative connection between the generation of harmonics and the hysteresis curve has been clarified. In addition, the specific amplitude and frequency of AC magnetic modulation can be designed to optimize the detection of hard phases in specific applications.

[0085] Figure 4A The complete hysteresis curves for ferrite (solid curve) and martensite (dashed curve) are shown. By matching the hysteresis curves with experimental measurements from the literature, five JA parameters can be obtained. Figure 4B Shown is the Figure 2A Simulated power spectral density (PSD) results of nonlinear magnetic detection for martensite (dashed curve) and ferrite (solid curve) in the configuration of . It can be seen that only odd harmonics appear due to the symmetrical magnetization. For the 3rd and 5th harmonics, the difference of about 1.5 orders of magnitude between ferrite and martensite is consistent with the experimental observations mentioned above.

[0086] In the next example, additional experimental tests are performed to better understand the nonlinear characteristics being measured. Since the hysteresis loops of ferromagnetic materials are highly nonlinear and history-dependent, we expect the nonlinear magnetic response of these materials to be dependent on their magnetization state. Therefore, the measurement of the nonlinear magnetic response can in principle be an indicator of the magnetization state of the test material and can provide additional information when detecting magnetic anomalies.

[0087] Based on the theoretical description, a locally symmetric hysteresis loop will only lead to odd harmonics, and this will happen in two cases: 1) the material has a small remanent magnetization compared to the saturation magnetization, which is applicable to Figure 2A-3D , or 2) the material is externally magnetized in a direction perpendicular to the small AC magnetic modulation.

[0088] exist Figure 5A The latter case was tested in . An identical specimen 221 (ferrite or martensite, 38.1 mm (L) x 25.4 mm (W) x 4.7 mm (H)) was magnetized across the long edge of the specimen 221 using two neodymium permanent magnets 223a, 223b placed at the ends of the specimen 221. The north pole of one of the magnets 223a was facing upward, while the other magnet 223b was in the opposite orientation. A large carbon steel plate 225 was attached to the bottom to complete the magnetic flux loop. The cross-sectional dimensions of the bundle of transmitting and pickup coils 201, 203 were 1 inch by 2 inches, and the shorter side (1 inch) of the coil bundle was aligned with the longer side (1.5 inches) of the specimen 221 to avoid interference with the fringe field near the end, as shown in FIG. Figure 5A As shown. In this case, the magnetization at the center of the sample 221 is in the horizontal direction, while the small AC magnetic modulation from the coil is in the vertical direction. The experimental results are shown in Table 4, and for both the ferrite and martensite cases, all harmonic peaks experience little change before and after this perpendicular magnetization. In addition, the even harmonics are very small and similar to the noise level in the baseline air case (first row in the table), which is consistent with our theoretical description.

[0089] This symmetry in the hysteresis loop may be broken if the magnetization direction is not perpendicular to the direction of the AC modulation. Figure 5B As shown, by rotating the coil bundle horizontally by 90 degrees and aligning its longer side (~2 inches) with the longer side of the steel sample, the AC magnetic modulation generated by the transmitting coil 201 will strongly interfere with the fringe field at the end of the steel sample, thereby breaking the symmetry of the hysteresis loop and allowing even harmonics. Compared with the unmagnetized steel sample in the same configuration, in Tables 4-5, we indeed experimentally observe an increase in the 2nd harmonic, which is consistent with our theory. In addition, the peak value of the odd harmonics is reduced by at least an order of magnitude.

[0090] Figure 5A and 5B An embodiment of a setup for testing the nonlinear magnetic response of a model material under a strong external magnetic field is shown. Figure 5A In the embodiment of , when the shorter side of the coil bundle is aligned with the longer side of the steel specimen, the magnetic modulation is mostly perpendicular to the external magnetization in the steel specimen. Therefore, the external magnetization does not change the nonlinear response. The experimental results are summarized in Table 4 below.

[0091] Table 4

[0092]

[0093] exist Figure 5B In the embodiment of , when the longer side of the coil bundle is aligned with the longer side of the steel specimen, the magnetic modulation strongly interferes with the fringe fields in the steel and they are almost not perpendicular to each other. The symmetry breaking leads to an increase in the 2nd harmonic and an unexpected decrease in the odd harmonics, as summarized in Table 5 below.

[0094] Table 5

[0095]

[0096]

[0097] To see a more pronounced symmetry breaking effect, the ferromagnetic material can be strongly magnetized and the external magnetization can subsequently be removed. Tests were performed using a mild steel sample with a remanent magnetization or residual magnetization of more than half the saturation magnetization value, which is a model material. Figures 6A-6C In this study, a series of tests were performed on the carbon steel sample before and after magnetization. Figure 6B As shown, a significant increase in odd harmonics is detected, similar to the previous data in Tables 1 and 2. The large carbon steel plate is then locally magnetized around a specific point "B" with a 1.27 cm cube 0.8 Tesla neodymium permanent magnet. After removing the permanent magnet from the plate, the residual magnetization around point "B" on the carbon steel plate should exceed 0.4 Tesla. Compared with the carbon steel PSD before magnetization ( Figure 6B ) compared to the nonlinear magnetic detection near the magnetized region “B”. Figure 6C It is now clear that, in addition to the steel phase detection via odd-numbered harmonics, the detection of even-numbered harmonics can also provide other material information, such as the magnetization state of the material, which includes the pre-existing remanent magnetization of the material.

[0098] Figures 6A-6C As shown in Figure 2A The measured values ​​for air ( Fig. 6A )、Low Carbon Steel Plate( Figure 6B ) and the low carbon steel sheet after magnetization ( Figure 6C ) are the power spectral density (PSD) results of nonlinear magnetic detection of the . The dashed and solid curves are the PSD of the pickup voltage and emission current, respectively. Table 6 summarizes the normalized harmonic coefficients for the pickup voltage across all samples here.

[0099] Table 6

[0100]

[0101] exist Figures 6A-6C In , the pick-up circuit was slightly modified to enhance the signal-to-noise ratio near the 3rd harmonic (using an RLC bandpass filter with a resonance frequency of 30kHz), so that the reference calibration in an air environment experiences stronger harmonics from electronic noise, while the ratio of higher harmonics between samples is unchanged.

[0102] In addition to manipulating the magnetization of the steel, samples were tested at different frequencies from 1 kHz to 100 kHz. Some examples of mild steel with 1 kHz and 10 kHz are shown in Table 7 and later in Figure 8B An example with 100 kHz is shown in Table 7. Table 7 shows the normalized harmonic coefficients for nonlinear magnetic detection of air and carbon steel at 1 kHz and 10 kHz.

[0103] Table 7

[0104]

[0105] Frequency-dependent skin depth in conductive materials "In the case of magnetic fields and the complex dynamics of domain walls, it is difficult to predict the frequency dependence of the nonlinear magnetic response. However, our experiments show that it is possible to measure significant nonlinear magnetic responses in ferromagnetic materials across a frequency band from 1kHz to 100kHz, and that this frequency-dependent response can be used to provide material information at different depths."

[0106] In accordance with at least one aspect of the present disclosure, embodiments include, but are not limited to, using an external magnetic field to modulate nonlinear magnetoacoustic detection. Computer simulations were performed to demonstrate the functionality of these embodiments. Although symmetry breaking effects can lead to the generation of even harmonics, which may be useful for detecting residual magnetization of steel, the effects on odd harmonics may be relatively complex. It has been observed that Figure 6B and 6C The enhancement of the third harmonic in Figure 5B The attenuation of the third harmonic in. Figures 7A-7C , which describes, but is not limited to, an embodiment of a method for adjusting magnetization in a steel pipe to achieve consistency in measurement and avoid this potential complexity. The embodiment of the method involves an external magnetic field applied by a horseshoe magnet having a magnetic field of 10 5 A / m magnetization and Fig. 7A For example, the COMSOL multiphysics computer package can be used to simulate the magnetic field strength when a horseshoe magnet moves vertically along the pipe wall at a speed of 0.5 m / s. Figure 7B and 7C The spatially varying induced magnetic field is shown.

[0107] Fig. 7AAn embodiment of a horseshoe magnet 700 moving on a steel pipe 701 is shown. Regions 703 and 705 are squares with a width of 3 cm. The vertical length of region 707 is 4 cm. Region 709 has an inner diameter of 2 cm and an outer diameter of 5 cm. The pipe is axially symmetrical with a radius of 15 cm and a thickness of 8 mm. The pipe consists of a ferrite phase, except for a circular region 711 with a radius of 3 mm. The magnet moves vertically upward at a speed of 0.5 m / s. Figure 7B The vertical z-component of the magnetic flux density in the horseshoe magnet and the pipe wall is shown. Figure 7C An example of a horseshoe magnet and the horizontal r-component of the magnetic flux density in the pipe wall is shown.

[0108] The magnetic field in the steel tube between the legs of the horse hoof is almost in the vertical z direction (|B z |~-0.2 to 0.4T), where |B in the horizontal direction is due to small hard phase defects and the hysteresis characteristics of the material. r |~Up to 0.8*10 -2 As a result, this external magnetic adjustment can effectively modify and align the steel pipe along Fig. 7A The magnetization of the vertical axis near the middle circular area 711 and the small vertical AC magnetic modulation based on this configuration will be one of the preferred implementations for pipeline applications because it results in a unique and understandable 3rd harmonic feature, such as Figure 5A shown.

[0109] Reference now Fig. 8A and 8B , together with nonlinear magnetic detection, embodiments herein include nonlinear magnetoacoustic detection based on the same principle. Fig. 8A An embodiment of an apparatus 800 for nonlinear magnetoacoustic sensing is shown. For example, a large carbon steel plate 801 (6 inches by 2 inches by 0.5 inches) can be magnetized with two neodymium permanent magnets 803a, 803b. A carbon steel rod 805 (or any other suitable material rod) can be attached to the opposite sides of the permanent magnets 803a, 803b to complete the magnetic flux loop. An acoustic transducer 807 can be attached (e.g., glued) to the front center of the 6×2 inch surface of the carbon steel plate 801, and a current transmitting coil (not shown) can be attached to the rear center of the opposite surface of the carbon steel plate 801.

[0110] When used as Fig. 8A When two attached neodymium permanent magnets magnetize a large carbon steel plate, a strong DC magnetic field exists inside the carbon steel plate. Once a small AC magnetic modulation is applied to the transmitting coil, the time-varying magnetic field generates oscillating eddy currents It interacts with a strong DC magnetic field, which generates an oscillating Lorentz body force This coupled response is often called the magnetoacoustic response, and the mechanical motion is measured by an acoustic sensor such as a piezoelectric acoustic transducer.

[0111] Figure 8B The experimental PSD results for nonlinear magnetoacoustic detection are shown. The dashed and solid curves are the PSD of the received acoustic signal and the transmitted current, respectively. Since the transducer used for the simulation has a resonant frequency of 500kHz, the mechanical motion is almost unmeasurable for a 10kHz magnetic modulation. Instead, a 100kHz magnetic modulation is used, and the PSD of the acoustic signal is observed ( Figure 8B As mentioned above, due to the change of self-inductance, a weaker third harmonic is also generated in the PSD of the emission current ( Figure 8B appears in the solid curve in .

[0112] Implementations or designs of the nondestructive material inspection systems described herein may include, but are not limited to, multiple copies of magnetic transmitters, magnetic sensors, acoustic sensors, and horseshoe magnets located at preferred locations near the material being interrogated. In certain embodiments, such implementations include, but are not limited to, one or more copies of magnetic sensors and / or acoustic sensors paired with one magnetic transmitter. In certain embodiments, a preferred arrangement includes four copies of magnetic sensors and / or acoustic sensors 900 located at different locations around and / or paired with each magnetic transmitter 901 (e.g., Fig. 9 A more preferred arrangement may include eight copies of the magnetic sensor and / or acoustic sensor 1000 (in Fig.10 ). Even more preferred arrangements may include maximum copies of magnetic sensors and / or acoustic sensors of different sizes located at different locations around and / or paired with each magnetic transmitter. In certain embodiments, such embodiments include, but are not limited to, at least one horseshoe magnet with two legs contacting the surface of the interrogated material. In certain embodiments, such embodiments include, but are not limited to, at least one magnetic transmitter and at least one of the magnetic sensor or acoustic sensor located at the center of the horseshoe magnet. In certain embodiments, such embodiments include, but are not limited to, optional magnets or electromagnets to adjust the magnetization in the interrogated material. In certain embodiments, such embodiments include, but are not limited to, optional magnets or electromagnets to provide a DC magnetic field.

[0113] According to at least one aspect of the present disclosure, the embodiments can be used without limitation to detect real pipes having a hard phase in a weld. Figures 11A-11F, for example, the embodiments can be applied to detect anomalies in real pipeline steel. A cylindrical pipe section of about 10 cm in length, 21 cm in radius and 0.5 cm in thickness, which was taken from an old pipeline before the 1970s, was tested. Most of the pipe has a ferrite / pearlite phase, while the seam welds in the pipe are joined by resistance welding without heat treatment and therefore contain bainite or martensite hard steel phases. During the measurement, the long side of the coil bundle was aligned with the circumferential direction. Under 10 kHz magnetic modulation, the nonlinear magnetic response at different angular positions was measured from the inside and outside of the pipe section, and the normalized 3rd harmonic coefficients are shown in Fig.11A and 11B middle.

[0114] Fig.11A Data of normalized 3rd harmonic coefficients around a cylindrical pipe section with 10 kHz magnetic modulation are shown. The dashed curve represents measurements from outside the pipe and the solid curve represents measurements from inside the pipe. Fig. 11B The graph shows the relationship between the distance from the weld and the Fig.11A The same data in . Fig. 11C Data for normalized 3rd harmonic coefficients with 10 kHz magnetic modulation are shown, measured in a separate experiment across an arc segment of pipeline material without a hard steel phase in the seam weld. The dashed curve represents measurements from outside the pipeline, the solid curve represents measurements from inside the pipeline.

[0115] exist Fig.11A In the example, the measurement from the outside of the pipe (dashed curve) shows a 3rd harmonic that fluctuates around 1x10-5 in the ferrite / ferrite pearlite region, and drops sharply to almost 1x10-5 near the joint containing bainite or martensite hard steel phases. -7 The angular position of the hard point is identified as the minimum point in the dashed curve at 294.5 degrees, which is within 1 degree of the actual hard microstructure point.

[0116] In embodiments where the coil is placed inside the pipe, the flux lines inside the cylinder can be quite different and can be highly compressed, which can change the nonlinear measurement. Experimental measurements from inside the pipe do show a different pattern of 3rd harmonic response ( Fig.11A The solid curve in the figure shows a double-minimal near the weld. From symmetry considerations, the midpoint of the double-minimal (293.2 degrees) best describes the location of the measured anomaly, which is also within 1 degree of the actual hard martensite point. The quartet pattern in the solid curve may come from the remanent magnetization of the material, while the double-minimal feature and the significantly lower harmonic response may come from a specific EM resonance mode inside the intact cylindrical pipe.

[0117] In contrast, Fig. 11CIn , we tested an arcuate section of pipeline material that had no hard phases such as martensite or bainite phases in the seam weld. Fig. 11C In the , the measurements from the outside and inside of the pipe section are shown as dashed and solid curves, respectively. Since the cut section is an arc rather than a complete cylinder, the results for the inside and outside are similar. Although both data show some reduction in the 3rd harmonic around the actual weld flash (between 49 mm and 63 mm), these anomalies (coefficient ~1x10 -6 ) is still not significant enough to indicate the presence of a hard phase such as martensite or bainite, which has a mass close to 1x10 -7 Instead, small cracks with a depth of about 1 mm were observed on the outer surface of the weld nodule. Fig. 11C Changes in the third harmonic in can be used to indicate the presence of air gaps, cracks or different stress states around the weld.

[0118] These same pipe sections were also tested with 100kHz AC magnetic modulation, and the data for the cylindrical pipe sections are shown at Figures 11D-11E , while the data for the arc-shaped pipe segment is shown in Fig.11F middle. Figures 11D-11F Shown with Figures 11A-11C Similar measurements were made, but using 100 kHz magnetic modulation and only from the outside of the pipe material. For the cylindrical pipe section, measurements from the outside of the weld showed clear features around the weld containing hard phases such as martensite or bainite phases ( Fig.11D and 11E ). In contrast, for the curved pipe section, the measured curve of the nonlinear magnetic response is quite flat because the weld contains only ferrite or ferrite-pearlite phase with small cracks.

[0119] Figures 12A-12C An embodiment of the detection and differentiation between non-hysteresis material and non-hysteresis material with inhomogeneities of ferromagnetic hysteresis material is shown. Figures 12A-12C In the test, the system 200 can be configured to Fig. 12B As described above, in some embodiments, the one or more states of the material to be determined may include, for example, one or more specific material phases. Example results for determining the material phase between a non-hysteretic material and a non-hysteretic material having an inhomogeneity of a hysteretic ferromagnetic material are shown in FIG. Figures 12A-12C middle.

[0120] As Fig. 12A In the control experiment, the device 200 was tested at a frequency of 10kHz in air without any conductive / magnetic material within half a meter. The current used here is lower than that in Figure 2B -D and Figure 3B -D to lower the electronic noise floor. The power spectral density (PSD) of the pickup voltage is shown. The peak values ​​of the higher harmonics (2nd, 3rd, 4th, etc.) are at least 9 orders of magnitude below the main frequency of 10kHz. These small harmonic values ​​are due to electronic processing and system noise and should be calibrated to the baseline for the specific material tested.

[0121] As in from Figures 12A-12C As can be seen in these examples, both the even and odd harmonics show a non-hysteretic material ( Fig. 12B ) and ferromagnetic materials with hysteresis ( Fig. 12C ) between non-hysteresis materials, for example, thereby allowing identification of different materials. Non-limiting examples of non-hysteresis materials include austenitic stainless steel, duplex stainless steel, and high manganese steel. Non-limiting examples of non-hysteresis materials with inhomogeneities of hysteresis ferromagnetic materials include high manganese steel with ε martensite inclusions. Figures 12A-12B It is shown that when the ends of the coil are placed on a plate of non-hysteresis material (e.g., 200 mm (L) × 200 mm (W) × 20 mm (H)), the non-linear magnetic response does not change dramatically. This is consistent with the fact that non-hysteresis material is a linear magnetic material with a constant magnetic permeability and therefore it does not show any non-linear magnetic response. Fig. 12A and 12C It is shown that when the end of the coil is placed on a non-hysteresis material plate with inhomogeneities of hysteresis ferromagnetic material (e.g., 200 mm (L) × 200 mm (W) × 20 mm (H) and inhomogeneities of more than 5% in the material weight fraction), the nonlinear response changes dramatically. The peaks of both odd and even harmonics increase dramatically. In particular, with Fig. 12B In the case of a non-hysteretic material with inhomogeneity of ferromagnetic material having hysteresis, Fig. 12C The peak value of the third harmonic in the ferromagnetic material increases by two orders of magnitude, providing a unique nonlinear magnetic signature of non-hysteretic materials that can be directly used to detect inhomogeneities in ferromagnetic materials with hysteresis.

[0122] Similar to common practice in other non-destructive inspection tools, one skilled in the art can calibrate the peak of the nonlinear magnetic response and / or the 3rd harmonic relative to different fractions of inhomogeneities with hysteretic ferromagnetic material in a non-hysteretic ferromagnetic material. Thus, with appropriate calibration, the disclosed methods and systems can be used to measure material phase fractions of a sample having two or more material phases, such as a non-hysteretic material with an inhomogeneity with hysteretic ferromagnetic material.

[0123] According to at least one aspect of the present disclosure, embodiments may be used without limitation to detect undesirable phases on the surface and / or in the bulk of real TMCP steel plates and / or pipes. Figures 13A-13E , embodiments can be applied, for example, to detect anomalies in real pipeline steel. A curved pipe section was cut from a TMCP pipe (28" inside diameter (ID) and approximately 3 / 4" thick), and an approximately 4" by 4" area of ​​the pipe section was tested. The majority of the pipe had a ferrite / pearlite and / or softer granular bainite phase, while a portion of the ID surface contained lath bainite or martensite hard steel phases that were naturally formed during TMCP manufacturing at the steel mill.

[0124] When the longer side of the coil bundle including the magnetic sensor / acoustic sensor 1300 and the magnetic transmitter 1301 is aligned with the Fig.13A When the horizontal direction (i.e., the circumferential direction of the pipeline) is aligned, the normalized third harmonic data graph is shown in Fig.13A When the long side of the same coil bundle is Fig. 13B When aligned in the vertical direction (i.e. the longitudinal direction of the pipeline) as shown, the normalized 3rd harmonic data is shown in Fig. 13B middle. Fig. 13C Is from Fig.13A and 13B The data graph of the combined data set, and at any particular location, Fig. 13C Use only Fig.13A and 13B The lower value of the normalized 3rd harmonic between .

[0125] On the same pipeline section, two different abnormal areas appear with two different transmitter-sensor orientations. Fig.13A The white to light gray area around the upper left and Fig. 13B The white to light grey area is around the lower right. To verify that the two areas from different emitter-sensor orientations are consistent with the actual material hardness characteristics, the TMCP pipe section was cut and ten cross-sectional material samples were made from different parts of the pipe section. Then, those samples were metallographically polished and Vickers hardness (VHN) measurements were performed on the cross-sections at 100 μm below the surface with a 100 g load by indentation. For example, Fig.13E cut out one of the cross-sectional samples at the location of box 13D, and Fig.13D The corresponding Vickers hardness (VHN) measurement for a particular sample is shown in the one-dimensional measurement bar and simple data plot. Fig.13E A collection of ten VHN results is shown. The hardness measuring strips were placed where the cross-section samples were cut.

[0126] Consistent with the Vickers hardness measurement, in a specific normalized 3rd harmonic data plot ( Figures 13A-13C) can capture the upper left and lower right hard regions, such as Fig.13E Specifically, Fig.13A and Fig. 13B The data with emitter-sensor orientation can be captured separately Fig.13E The upper left and lower right hard areas in the figure. The data anisotropy comes from the inherent texture anisotropy of carbon steel generated by the manufacturing process (such as hot rolling process), and in order to obtain better and more complete inspection results, the preferred transmitter-sensor arrangement may include many copies of the sensor located at different locations around each magnetic transmitter and / or each magnetic transmitter pair.

[0127] In the illustrated embodiment, the transmitter coil 201 and the pickup coil 203 used to generate the following data comprise coils having a maximum outer diameter of approximately 3 / 4 inches and an inductance of L ~ 7 mH. FIG. 14A to FIG. 14C In the data shown, the transmitter coil 201 and the pickup coil 203 are placed on the same side of the interrogated material (eg, a ferromagnetic plate).

[0128] The smaller diameter coil is similar to the previously disclosed Figure 2B -D and Figure 3B -D. As a control experiment, the device 200 was tested at 10 kHz in air without any conductive / magnetic material within half a meter. The power spectral density (PSD) of the pickup voltage is shown in Figures 14A-14C In the case of air ( Fig.14A ), the peak values ​​of the higher harmonics (2nd, 3rd, 4th, 5th, etc.) are at least 8 orders of magnitude lower than the main frequency of 10kHz. These small harmonic values ​​are due to electronic processing and system noise and should be calibrated as a baseline for material testing.

[0129] From Figure 2B -D to Figure 3B -D, the odd harmonics show order of magnitude differences between different material types, for example, allowing identification of different materials. Once a martensitic or ferritic sample (e.g., 38.1 mm (L) x 25.4 mm (W) x 4.7 mm (H)) is placed at the end of the smaller coil, the nonlinear response changes dramatically. The even harmonics do not experience significant changes, while the peaks of the odd harmonics increase dramatically, with the most significant increases coming from the 3rd and 5th harmonics at 30 kHz and 50 kHz (e.g., Fig. 14B and 14C ). In particular, in the martensitic specimen ( Fig. 14B ), the peak value of the third harmonic increases by more than three orders of magnitude; in the ferrite sample ( Fig. 14C), the peak value of the 3rd harmonic increases by more than five orders of magnitude, for example, thereby providing a unique nonlinear magnetic signature that can be directly used to detect hard phases such as martensite phases that constitute hard spots in pipeline steel.

[0130] According to at least one aspect of the present disclosure, smaller diameter magnetic transmitters and sensors can be used to generate inspection results with higher lateral spatial resolution. In the illustrated embodiment, the transmitting coil 201 and the pickup coil 203 used to generate the following data include: Figures 15A-15B The 3 / 4 inch diameter coil used in the 2D scanner. Both the transmitting coil and the pickup coil are mounted on the carriage of the 2D scanner. The 2D scanner is capable of moving the carriage in a flat horizontal plane with a minimum step size of less than 0.1 mm in any dimension, and the 2D spatial motion and position of the carriage and / or coil are controlled and monitored by computer program code.

[0131] In accordance with at least one aspect of the present disclosure, embodiments may be used without limitation to inspect real pipes and plates having spatially varying hard phases on the surface and / or in the bulk. Figures 15A-15B For example, the embodiments can be applied to detect anomalies in carbon steel plates. Fig.15A As shown in the figure to the right, a flat 4140 carbon steel plate (e.g., 12" (L) x 6" (W) x 11 / 4 (H)) was tested. The majority of the plate has a ferrite / pearlite phase, while there are seven hard phase regions or horizontal stripes of hard zones. These simulated hard zones are made by localized surface heating using an electron beam in a vacuum environment, followed by rapid self-quenching using the steel body as a heat sink. The heating parameters used in HZ1 to HZ7 are different, so the seven hard zones have different local hardness and width, and they contain different volume fractions of lath bainite or martensite hard steel phases.

[0132] During the measurements using the 2D autoscanner, the transmitting and pickup coils were placed within 0.1 cm of the interrogated sample surface, and the longer side of the coil bundle was aligned with the longer direction (12") of the plate. The nonlinear magnetic response at different 2D locations across the entire steel plate was measured at 10 kHz magnetic modulation, and from these measurements, the data plots of the normalized 3rd harmonic coefficients are shown in Figure 2. Fig.15A As shown in the left figure. Fig.15A As shown in the figure on the left, darker grey indicates higher values ​​of the normalized 3rd harmonic (softer material properties), while white indicates lower values ​​of the normalized 3rd harmonic (harder material properties). All seven hard phase regions (HZ1 to HZ7) are detected by nonlinear magnetic response measurements, with different 3rd harmonic levels between them.

[0133] To verify that the nonlinear magnetic response measurements and the resulting data plots are consistent with the material hardness characteristics, Fig.15A The dashed line 15B in the right figure cuts through a 4140 carbon steel plate. Along dashed line 15B, seven cross-sections of the material were made and metallographically polished, and Vickers hardness (VHN) measurements were performed on the cross-sections by stamping at 100 μm below the surface with a 100 gram load. The hardness measurements across HZ1 to HZ5 along dashed line 15B are shown in Fig. 15B In the right figure. For HZ6 and HZ7, the hardness measurement did not capture any elevated hardness when measured 100 μm below the surface, indicating that HZ6 and HZ7 do not have elevated hard zones at 100 μm or deeper. The nonlinear magnetic response in a specific normalized 3rd harmonic is plotted along the same dot-dash line 15B based on the Vickers hardness measurement and the results are shown in Fig. 15B In the right figure, the normalized 3rd harmonic data is able to capture all of HZ1 to HZ7 with consistent correlation to the height and width of the results. Specifically, for both the 3rd harmonic response and the hardness measurement, the FWHM (full width at half maximum) width is marked for all measured hard areas. The width measured from the 3rd harmonic response differs by between 1mm and 2mm from the width measured from the hardness measurement, which is generally considered to be the ground truth. In the embodiment shown, the nonlinear magnetic response is able to detect surface hard areas with a lateral spatial resolution of 2mm or more.

[0134] Reference FIG. 16A to FIG. 16B For example, the embodiments can be applied to detect anomalies in carbon steel plates. Fig.16A In the left figure, a flat TMCP carbon steel plate (e.g., 9" (L) × 5" (W) × 1" (H)) was tested. The majority of the plate has a ferrite / pearlite phase and / or a soft grained bainite phase, while there are regions with hard phases or hard zones with four vertical stripes, the centers of which are marked by cross marks on the plate. These simulated hard zones are made by localized surface heating using an electron beam in a vacuum environment, followed by rapid self-quenching with the steel body as a heat sink. The heating parameters used here are the same as those used for HZ2 to HZ5 in the previous plate (Figure A14), so these four hard zones have different local hardness and width, and they contain different volume fractions of lath bainite or martensite hard steel phases. Under the same heating parameters, the hardness in HZ2 to HZ5 between 4140 carbon steel and TMCP carbon steel is also different due to the different chemical properties of the base steel plates.

[0135] Using the same 2D automatic scanner, based on nonlinear magnetic response measurements, Fig.16A The right figure shows the data graph of the normalized third harmonic coefficients. Fig.16AAs shown in the figure on the right, black to dark gray indicates higher values ​​of the normalized 3rd harmonic (softer material properties), and white to light gray indicates lower values ​​of the normalized 3rd harmonic (harder material properties). All four hard phase regions (HZ2 to HZ5) are detected by nonlinear magnetic response measurements, with different 3rd harmonic levels between them.

[0136] In order to verify and test the sensitivity of the nonlinear magnetic response measurement consistent with the material hardness characteristics, the following Fig.16A The TMCP carbon steel plate is cut along the dashed line 16B shown in the left figure. Along the dashed line 16B, a cross-section of the material sample is made and metallographically polished, and the Vickers hardness of the cross section is measured by indentation at 100 μm below the surface with a load of 100 g. As an example, Fig. 16B The cross-sectional hardness diagram across HZ3 is shown in the top figure of FIG. In the cross section, the elevated hard zone has a semi-elliptical shape with a width of approximately 8.0 mm and a depth of 1.1 mm, wherein the Vickers hardness within the hard zone increases by an average of 40 (VHN greater than 250). As shown in the scanning electron microscope image ( Fig. 16B As shown in the lower left, the material microstructure in the bulk region (VHN less than 250) is a mixture of granular bainite and acicular ferrite, while Fig. 16B The material microstructure in the elevated hard zone (VHN greater than 250) is a mixture of granular and lath bainite, shown at the bottom right. From the Vickers hardness measurements, the FWHM width for HZ3 from the 3rd harmonic response was determined to be approximately 10.0 mm across the same dashed line 16B, which is consistent with the hardness measurements with a 2 mm spatial resolution.

[0137] Similar to common practice in other non-destructive inspection tools, one familiar with the art can calibrate the nonlinear magnetic response and / or the peak value of the 3rd harmonic relative to different levels of Vickers hardness (VHN), surface area size, and depth of the hard metallurgical phase in the sample. Thus, with appropriate calibration, the methods and systems of the present disclosure can be used to measure Vickers hardness values ​​and material phase fractions of samples having two or more material phases, such as hysteresis materials having inhomogeneities of hard metallurgical phases.

[0138] The foregoing method can be extended to the inspection of other steel components including but not limited to bolts, forgings, castings, etc.

[0139] According to at least one aspect of the present disclosure, embodiments may be used without limitation to detect hysteresis magnetic material phases in non-hysteresis materials. Non-hysteresis materials may include, but are not limited to, aluminum, austenitic stainless steel, duplex stainless steel, and high manganese steel. Examples of hysteresis magnetic material phases include, but are not limited to, at least one of martensite, ε martensite, ferrite, pearlite, bainite, lath bainite, acicular ferrite, and quasi-polygonal ferrite. A first example application of detecting hysteresis magnetic material phases in non-hysteresis materials includes determining the amount of magnetic ferrite content in duplex stainless steel (DSS), which can be used to grade the DSS or as a quality control measure. More specifically, the amount of delta ferrite in a ferrite-austenite DSS can be determined and used to grade the ferrite-austenite DSS or as a quality control to determine whether the amount of delta ferrite falls within a desired range.

[0140] In yet another example, when austenitic stainless steel (e.g., grade 304, 308, 316, etc.) weldments and austenitic stainless steel welds are exposed to high temperatures, for example, when refinery operations such as pipes, containers, reactors, and weld overlays are exposed to hydroprocessing conditions or hydroprocessing conditions, the detection of hysteresis magnetic material phases in non-hysteresis materials can be used for quality control. Under such conditions, a (e.g., ferrite) σ phase (hysteresis magnetic material phase) can be formed, which can make the material brittle. The methods and devices described herein can be used to measure the amount of brittle σ phases in all or part of a refinery operation or to detect their presence or absence. In hydroprocessing, typically, the refinery operation and its welds contain austenitic stainless steel. In hydroprocessing, typically, the refinery operation downstream of the reactor contains austenitic stainless steel, while the welds in the refinery operation upstream, in, and downstream of the reactor contain austenitic stainless steel. Reactors in hydroprocessing are typically composed of Cr-Mo materials with austenitic steel weld overlays. In some embodiments, the methods and apparatus described herein can also be used to measure the amount of ferrite content or detect the presence or absence of ferrite in the girth weld and seam weld of austenitic stainless steel pipes, vessels and cladding layers used to manufacture heavy wall Cr-Mo reactors in hydroprocessing reactors in D / S. In order to prevent weld solidification cracks in stainless steel weldments, the ferrite content needs to meet the desired amount.

[0141] In each of the above examples of detecting a hysteretic magnetic material phase in a non-hysteretic material, a calibration sample can be prepared using different amounts of the hysteretic magnetic material phase in the non-hysteretic material to correlate the nonlinear magnetic response signal with the amount or content of the hysteretic magnetic material phase.

[0142] According to at least one aspect of the present disclosure, the embodiments can be used without limitation to characterize the hardness of the weld. Fig.13A-E disclosure, VHN or Brinell hardness values ​​(BHN) of different weld materials can be correlated with the nonlinear magnetic response signal described herein. In a first example of application to characterize weld hardness, a handheld device can be used to measure a nonlinear magnetic response signal about a weld (new, old or repaired) or a portion thereof, which can then be correlated with VHN and / or BHN.

[0143] Another example of the application of characterizing the hardness of a weld is to identify the type of electric resistance weld (ERW) (e.g., low frequency heat treated ERW, low frequency non-heat treated ERW, high frequency heat treated ERW, and high frequency non-heat treated ERW). In this example, the nonlinear magnetic response signal base pipeline can be associated with the type of ERW compared to the nonlinear magnetic response signal of the ERW. This correlation can be determined by standard calibration measurements. The implementation of such a method can use an online pipeline inspection instrument, an automatic or manually pulled pipeline inspection tool, a steel mill inspection tool, a ditch inspection tool, a handheld inspection device, etc. In another example of the application of characterizing the hardness of a weld, the hardness and pipeline grade of the base pipeline are identified using an in-ditch inspection. In this example, the nonlinear magnetic response signal can be calibrated and correlated with the hardness, tensile and / or yield strength of the material of the base pipeline. This correlation can be used to determine the pipeline grade using an in-ditch inspection.

[0144] In another example of applying characterization of weld hardness, the hardness of the repaired weld (e.g., seam weld and / or girth weld). In one example, the repaired weld may be associated with a pressure vessel (e.g., composed of Cr-Mo1 / 2Cr steel) used in a hydroprocessing and hydroprocessing reactor. The repair process may include removing the weld and the metal portion around the weld and replacing / repairing the area. The newly formed weld may be optionally heat treated. The inspection process may include determining whether the repaired weld (with or without post-weld heat treatment) meets industry standards and / or company regulations for weld hardness and / or determining hard spots in the weld.

[0145] Another similar example includes measuring the hardness of welds associated with 21 / 4Cr-V steel containers. The inspection process may include determining whether the fabricated welds and / or repaired welds (with or without post weld heat treatment) meet industry standards and / or company specifications for weld hardness and / or identifying hard spots in the welds.

[0146] Another similar example includes the management of weld hardness over time. That is, containers, pipes, etc. can be inspected over time to monitor the hardness and / or location and size of hard spots. The inspection can be performed using any suitable device (which can include handheld devices and automated crawlers). The inspection process can be performed on manufacturing welds and / or repair welds (with or without post weld heat treatment).

[0147] In another embodiment using a nonlinear magnetic response signal associated with weld hardness and / or hard spots in a weld, specifically, weld roots and / or weld caps may be inspected and analyzed. In a preferred example, the application may be applied to field welding of risers and sour service pipelines. Optionally, inspection of root welds by the nonlinear magnetic response signal method / device described herein may be performed in conjunction with laser root profiling. Increased hardness in a root weld (e.g., girth weld root) may result from high cooling rates in an improper welding procedure (e.g., using a Cu cooling shoe close to the weld root) and / or dissolved copper contamination in the weld metal from a device such as a Cu cooling shoe.

[0148] In yet another example of using a nonlinear magnetic response signal associated with weld hardness and / or hard spots in a weld, the quality of a back weld can be evaluated. A back weld is an internal repair to a manually performed ring weld. Determining the location and size of the hardness and / or hard spots in a back weld can verify whether the back weld meets industry standards and / or company specifications for hardness, or can determine whether further repair is required. Such methods can be implemented using an online pipeline inspection instrument, an automated or manually pulled pipeline inspection tool, a handheld inspection device, and the like.

[0149] In another example of using a nonlinear magnetic response signal associated with weld hardness and / or hard spots in a weld, the methods and apparatus described herein can be used in conjunction with a weld defect for producing a ring weld and / or ultrasonic testing defects for inspecting a ring weld. The defect is an automated machine that can move around a pipe to produce a ring weld and / or inspect a ring weld. The apparatus described herein can be combined with the defect to measure a nonlinear magnetic response signal of a ring weld after the ring weld is formed (i.e., using a weld defect), or can also measure the ultrasonic response of a ring weld (i.e., using an ultrasonic testing defect).

[0150] In accordance with at least one aspect of the present disclosure, embodiments may be used without limitation to characterize the hardness, tensile strength, and / or yield strength of materials used to produce or inner pipes or similar structures. Fig.13A -E disclosure, the hardness (e.g., VHN or BHN), tensile strength and / or yield strength of different materials used in the production or internal pipelines or similar structures can be related to the nonlinear magnetic response signals described herein. Once the hardness, tensile strength and / or yield strength are determined, the pipeline grade can be derived. The implementation of such a method can use an online pipeline inspection instrument, an automatic or manually pulled pipeline inspection tool, a steel mill inspection tool, a trench inspection tool, a handheld inspection device, etc.

[0151] According to at least one aspect of the present disclosure, embodiments may be used without limitation to detect and locate hard areas (e.g., cold worked areas or dents) that may cause stress corrosion cracking, which reduces the integrity of pipelines and similar structures. Stress corrosion cracking is the formation or growth of cracks in a corrosive environment. In austenitic stainless steel and aluminum alloys, chlorides (e.g., NaCl, KCl, and MgCl2) may be sources of stress corrosion cracking. Stress corrosion cracking typically begins with small flaws on the surface that propagate under conditions where fracture mechanics predicts that failure should not occur. The ability to detect stress corrosion cracking and / or areas of localized hard working areas (hard areas) that may cause stress corrosion cracking using non-destructive material inspection methods or tools can mitigate failures of pipelines or other structures. Such methods may be implemented using online pipeline inspection instruments, automatic or manually pulled pipeline inspection tools, handheld inspection devices, and the like.

[0152] As will be appreciated by those skilled in the art, aspects of the present disclosure may be embodied as systems, methods, or computer program products. Thus, aspects of the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects that may all be generally referred to herein as "circuits," "modules," or "systems." In addition, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer-readable media having computer-readable program code embodied thereon.

[0153] Any combination of one or more computer readable media may be utilized. A computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared or semiconductor system, device or device, or any suitable combination of the foregoing. More specific examples (non-exhaustive list) of computer readable storage media would include the following: an electrical connection with one or more wires, a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In this article, a computer readable storage medium may be any tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device or device.

[0154] A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electromagnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and may communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0155] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0156] Computer program code for performing the operations of various aspects of the present disclosure may be written in any combination of one or more programming languages ​​including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as the "C" programming language or similar programming languages, and visual programming languages ​​such as LabView, Igor, or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, such as in current pipeline inspection instrument (PIG) ​​technology, the onboard computer and processor on the PIG are sent via pipelines, during which the computer uses preloaded instructions and program code to control the onboard transmitters and sensors, perform initial analysis, and store measurement results. At the pipeline exit, the user retrieves the PIG and downloads the stored data, which can be further analyzed and post-processed on another computer with a different program code.

[0157] Aspects of the present disclosure are described above with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to embodiments of the present invention. It will be understood that each block diagram and / or block diagram of the flowchart and the combination of the block diagram and / or block diagram in the flowchart can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a device for implementing the functions / actions specified in one or more boxes of the flowchart and / or block diagram.

[0158] These computer program instructions may also be stored in a computer-readable medium, which may instruct a computer, other programmable data processing device, or other device to operate in a specific manner, so that the instructions stored in the computer-readable medium produce a manufactured product, including instructions for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0159] The computer program instructions may also be loaded onto a computer, other programmable data processing device, or other device, so that a series of operational steps are performed on the computer, other programmable device, or other device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide a process for implementing the functions / actions specified herein.

[0160] Through laboratory experiments and computer simulations, nonlinear magnetic and magnetoacoustic systems and methods have been disclosed for detecting and distinguishing ferromagnetic materials with different hysteresis curves (e.g., distinguishing hard martensitic spots from soft ferrite phases). Examples of hysteresis materials include ferromagnetic materials (e.g., steel, nickel, cobalt, etc.) and certain alloys thereof, such as various carbon steels. It has also been observed that the nonlinear magnetic response depends on the initial / residual magnetization of the material, and to avoid this complexity, embodiments include effective methods for adjusting the internal magnetization of the material. In the above example, Fig. 7A , 7B An example of this effective approach is provided without limitation in the discussion of and 7C where the material is externally magnetized in a direction perpendicular to a small AC magnetic modulation.

[0161] Furthermore, based on basic electromagnetics, the natural derivative of the nonlinear magnetic response is nonlinear eddy current generation. Once coupled with a large permanent magnetic field, the eddy currents generate nonlinear mechanical waves, thereby generating a magnetoacoustic response with the evaluated hysteresis material. To improve the detection of magnetic anomalies (e.g., in pipeline inspection), nonlinear magnetic embodiments can be incorporated into MFL settings within conventional PIG systems, and nonlinear magnetoacoustic detection embodiments can be applied to existing EMAT sensors, as understood by those skilled in the art.

[0162] Embodiments provide unprecedented nonlinear magnetic and magnetoacoustic detection to, for example, identify defects and hard spots / regions in pipelines. Embodiments provide highly distinguishable features to distinguish various hysteresis materials (e.g., soft ferritic steels / regions and hard martensitic steels / regions) through a deep understanding of the nonlinear magnetic response. In particular, even and odd subharmonic responses have been studied and their relationship to the magnetic properties and state of the material has been discovered. In addition, embodiments are highly advantageous for field applications because the method can be used over a wide frequency band (e.g., 100 Hz to 1 MHz), which may be very advantageous for high-speed inspections and deep scanning, and embodiments operate at low currents and low magnetic fields without a metal core, and are therefore relatively energy efficient.

[0163] Improvements in non-destructive pipeline inspection significantly reduce the risk of pipeline failure and leakage. The embodiments provide a new tool in the arsenal of methods for pipeline inspection.

[0164] As described above and as shown in the accompanying drawings, the method and system of the present disclosure provide nondestructive material inspection with excellent performance. In one application, the method and system can be used as a nondestructive evaluation tool for in-line inspection to identify material phases and evaluate the area with higher hardness, metal loss or cracks from the inside of the pipeline. In another application, the method and system can be used as a nondestructive evaluation tool to screen metal plates by identifying material phases and evaluating the area with higher hardness, metal loss or cracks from the surface of the metal plate. In another application, the method and system can be used as a handheld device to screen metal pipes, plates, surfaces, welds and joints by identifying material phases and evaluating the area with higher hardness, metal loss or cracks from the surface of the metal object. In another application, the method and system can be used as a nondestructive evaluation tool to identify the steel phase, welding type and / or heat treatment state of the pipeline weld under the condition of electric resistance welding (ERW). Additionally, in another application, the method and system may be used as a nondestructive evaluation tool to inspect girth weld roots by identifying material phases and evaluating areas of higher hardness, metal loss, or cracks on risers and sour service pipelines.

[0165] In the above applications, the material phase may include, but is not limited to, at least one of austenite, martensite, ferrite, pearlite, bainite, lath bainite, acicular ferrite, and quasi-polygonal ferrite. In certain embodiments, the system may be incorporated into a non-destructive evaluation tool to interrogate the material using an input time-varying magnetic field and to correlate the time-dependent nonlinear characteristics of the received magnetic response or acoustic response with one or more material states of the material. Non-limiting examples of non-destructive evaluation tools include in-line pipeline inspection instruments, automated or manually pulled pipeline inspection tools, steel mill inspection tools, and handheld inspection devices.

[0166] In certain embodiments, the present application may include, but is not limited to, multiple copies of magnetic transmitters, magnetic sensors, acoustic sensors, and horseshoe magnets located at preferred locations near the interrogated material. In certain embodiments, the present application may include, but is not limited to, one or more copies of magnetic sensors and / or acoustic sensors paired with one magnetic transmitter. In certain embodiments, the preferred arrangement includes four copies of magnetic sensors and / or acoustic sensors located at different locations around each magnetic transmitter and / or paired with each magnetic transmitter (e.g., Fig. 9 A more preferred arrangement may include eight copies of the magnetic sensor and / or acoustic sensor located at different locations around and / or paired with each magnetic transmitter (e.g. Fig.10 As shown). An even more preferred arrangement may include maximum copies of magnetic sensors and / or acoustic sensors of different sizes and located at different locations around and / or paired with each magnetic transmitter. In certain embodiments, the application includes but is not limited to at least one horseshoe magnet with two legs contacting the surface of the interrogated material. In certain embodiments, the application includes but is not limited to at least one magnetic transmitter and at least one of the magnetic sensor or acoustic sensor located at the center of the horseshoe magnet. In certain embodiments, the application includes but is not limited to optional magnets or electromagnets to adjust the magnetization in the interrogated material. In certain embodiments, the application includes but is not limited to optional magnets or electromagnets that provide a DC magnetic field for magnetoacoustic response.

[0167] In certain embodiments, the application may include, but is not limited to, a computer-controlled automatic moving platform to move magnetic transmitters, magnetic sensors, and acoustic sensors to detect magnetic responses or acoustic responses at different spatial locations. In certain embodiments, the application may include, but is not limited to, a manually controlled translation and rotation platform to move magnetic transmitters, magnetic sensors, and acoustic sensors to detect magnetic responses or acoustic responses at different spatial locations. In certain embodiments, the application may include, but is not limited to, a handheld device comprising at least one magnetic transmitter and one magnetic sensor. In certain embodiments, the interrogation samples in the present application may include, but are not limited to, low-frequency heat-treated ERW pipes, low-frequency non-heat-treated ERW pipes, high-frequency heat-treated ERW pipes, and high-frequency non-heat-treated ERW pipes.

[0168] Example Embodiments

[0169] A first embodiment of the present invention is a method for determining the material state of at least one hysteresis ferromagnetic material and / or at least one non-hysteresis material, wherein the method comprises: interrogating the hysteresis ferromagnetic material and / or the non-hysteresis material with an input time-varying magnetic field; detecting a magnetic response and / or an acoustic response over time from the hysteresis ferromagnetic material and / or the non-hysteresis material; determining a time-dependent nonlinear characteristic of the received magnetic response and / or acoustic response; and associating the time-dependent nonlinear characteristic of the received magnetic response and / or acoustic response with one or more material states of the material. Optionally, the example embodiment may include one or more of the following items: Element 1: wherein the interrogation magnetic field includes an additional magnetic field; Element 2: Element 1 and wherein the additional magnetic field includes a constant DC magnetic field; Element 3: wherein the interrogation magnetic field includes a demagnetizing magnetic field; Element 4: wherein one or more material states of the material are material phases, and wherein the material includes a hysteretic ferromagnetic material; Element 5: wherein one or more material states of the material are material phases, and wherein the material includes at least one non-hysteretic material; Element 6: wherein one or more material states of the material are the presence of a non-hysteretic material, and wherein the material includes at least one hysteretic material; Element 7: wherein determining the time-dependent nonlinear characteristic includes performing a frequency domain analysis to create power spectral density data, the frequency domain analysis including a power spectral density analysis of the received magnetic response and / or acoustic response; Element 8: Element 7 and wherein determining the time-dependent nonlinear characteristic includes determining one or more harmonic peaks in the power spectral density data; and Element 9: Element 8 and wherein determining the one or more harmonic peaks includes Determining one or more harmonic coefficients in the spectral density data; Element 10: Element 9 and wherein determining one or more harmonic coefficients and / or peaks includes determining odd harmonic coefficients and / or peaks in the spectral density data; Element 11: Element 10 and wherein determining odd harmonic coefficients and / or peaks includes determining 3rd and / or 5th harmonics in the spectral density data; Element 12: Element 11 and wherein associating the time-dependent nonlinear characteristics includes comparing and correlating the 3rd and / or 5th harmonics with one or more material states; Element 13: Element 9 and wherein determining one or more harmonic coefficients and / or peaks includes determining even harmonic coefficients and / or peaks in the spectral density data; Element 14: Element 13 and wherein determining even harmonic coefficients and / or peaks includes determining 2nd harmonics in the spectral density data; Element 15: Element 14 and wherein the step of associating the time-dependent nonlinear characteristics includes comparing and correlating the 2nd harmonic with additional material information, the additional material information including the magnetization state of the material and the pre-existing remanent magnetization of the material.Element 16: wherein the one or more material states include the presence of at least one material phase of a hysteretic ferromagnetic material and / or a non-hysteretic material; Element 17: wherein the hysteretic ferromagnetic material includes steel, and wherein the material phase includes at least one of austenite, martensite, ferrite, pearlite, bainite, lath bainite, acicular ferrite, quasi-polygonal ferrite; Element 18: the method further comprises: wherein the one or more material states of the material are one or more first material states of the material; repeating the steps of interrogating, detecting, determining, and associating using an input time-varying magnetic field in different configurations to produce one or more second material states of the material; and combining the material state of the material with one or more first material states of the material. One or more first material states and one or more material second states to produce a combined data set representing the one or more material states; examples of combinations include but are not limited to combining elements 1 and 3 and optionally further combining with element 2; combining two or more of elements 4-6; elements 7, 8, 10 (optionally combined with one or both of elements 11 and 12), element 13 (optionally combined with one or both of elements 14-15); element 16 combined with one or more of elements 4-6 and optionally further combined with element 17; elements 16 and 17 combined; element 18 combined with one or more of elements 1-17; and any combination thereof.

[0170] Another embodiment of the present invention includes a non-transitory computer-readable medium including instructions for performing the method of the first embodiment, optionally with one or more of elements 1-18.

[0171] Yet another embodiment of the present invention includes an apparatus for detecting a material state of at least one hysteretic ferromagnetic material and / or at least one non-hysteretic material, wherein the apparatus comprises: at least one magnetic transmitter configured to output an interrogating time-varying magnetic field; at least one magnetic sensor and / or acoustic sensor configured to receive a magnetic response and / or an acoustic response and convert the magnetic response and / or the acoustic response into a magnetic response signal and / or an acoustic response signal; and a processor configured to perform a method comprising: detecting a magnetic signal and / or an acoustic response signal over time from at least one magnetic sensor and / or acoustic sensor; determining a time-dependent nonlinear characteristic of the magnetic signal and / or the acoustic signal; and correlating the time-dependent nonlinear characteristic of the magnetic signal and / or the acoustic signal with one or more material states of the material. Optionally, the embodiment may include one or more of the following: Element 1; Element 2; Element 3; Element 4; Element 5; Element 6; Element 7; Element 8; Element 9; Element 10; Element 11; Element 12; Element 13; Element 14; Element 15; Element 16; Element 17; Element 18; Element 19: wherein the device includes an output device that is configured to indicate one or more states of the material to a user; Element 20: Element 19 and wherein the device includes an indicator that notifies one or more nearby users of appropriate immediate real-time actions and the users can directly observe the indicator; Element 21: Element 19 and wherein the device includes a device for communicating with the user, which also indicates that the user is notified of appropriate immediate real-time actions, but the user may be located at a remote location and the communication may be conducted via wired or wireless routing; Element 22: Element 19 and wherein the device includes data collection and storage storage device for later retrieval and post-processing rather than for immediate real-time action; Element 23: wherein the process includes determining and correlating time-dependent nonlinear characteristics of the magnetic and / or acoustic signals in real time using an onboard computer; Element 24: wherein the magnetic and / or acoustic signals are stored to a computer-readable storage medium for a post-processing step that includes determining and correlating time-dependent nonlinear characteristics of the magnetic and / or acoustic signals; Element 25: wherein the at least one magnetic sensor and / or acoustic sensor is 4 copies of the magnetic sensor and / or acoustic sensor located at different locations around each of the at least one magnetic transmitter and / or paired with each of the at least one magnetic transmitter; Element 26: wherein the at least one magnetic sensor and / or acoustic sensor is 8 copies of the magnetic sensor and / or acoustic sensor located at different locations around each of the at least one magnetic transmitter and / or paired with each of the at least one magnetic transmitter.Examples of combinations include, but are not limited to: elements 1 and 3 combined, and optionally further combined with element 2; two or more of elements 4-6 combined; element 7, element 8, element 10 (optionally with one or both of elements 11 and 12), element 13 (optionally with one or both of elements 14-15) combined; element 16 combined with one or more of elements 4-6, and optionally further combined with element 17; elements 16 and 17 combined; element 18 combined with one or more of elements 1-17; one or more of elements 1-18 combined with one or more of elements 19-26; element 19 combined with two or more of elements 20-22 and optionally one or two of elements 23-24; elements 25 and 26 combined (e.g., two or more configurations of a device implemented together in a tool); element 25 and / or element 26 combined with one or more of elements 1-24; and any combination thereof.

[0172] While the apparatus and methods of the subject disclosure have been shown and described with reference to embodiments, those skilled in the art will readily appreciate that modifications and / or variations may be made thereto without departing from the spirit and scope of the subject disclosure.

Claims

1. A method for inspecting a steel material comprising at least one hysteretic ferromagnetic material and / or at least one non-hysteretic material using a non-destructive evaluation method to identify one or more material states and / or one or more inhomogeneities in the steel material, the method comprising the following steps: interrogating the hysteretic ferromagnetic material and / or the non-hysteretic material with an input time-varying magnetic field; scanning the steel material and detecting a magnetic response and / or an acoustic response over time from the hysteretic ferromagnetic material and / or the non-hysteretic material; determining a time-dependent nonlinear characteristic of the received magnetic response and / or acoustic response; as well as correlating said time-dependent nonlinear characteristics of the received magnetic response and / or acoustic response to said one or more material states and / or one or more inhomogeneities in the steel material, wherein the one or more material states and / or one or more inhomogeneities in the steel material include one selected from the group consisting of: a weld structure, a girth weld, a fillet weld, a lap weld, a butt weld, and any combination thereof, wherein interrogating the hysteretic ferromagnetic material and / or the non-hysteretic material is performed using a transmitter coil and a pickup coil configured for use on the same side of the material, wherein the transmitter coil and the pickup coil are arranged at 0.8 mm to 2.0 mm from the material, wherein determining the time-dependent nonlinear characteristic comprises performing a frequency domain analysis, the frequency domain analysis comprising a power spectral density analysis of the received magnetic response and / or acoustic response to create power spectral density data, wherein determining the time-dependent nonlinear characteristic comprises determining one or more harmonic peaks in the power spectral density data, wherein determining the one or more harmonic peaks comprises determining one or more harmonic coefficients in the spectral density data, wherein determining the one or more harmonic coefficients and / or peaks comprises determining odd harmonic coefficients and / or peaks in the spectral density data, wherein determining the odd harmonic coefficients and / or peaks comprises determining third harmonics and / or fifth harmonics in the spectral density data, wherein correlating the time-dependent nonlinear characteristic comprises comparing and correlating the third harmonic and / or the fifth harmonic with the one or more material states, and Among them, the third harmonic and the fifth harmonic of the ferrite phase are at least 1.5 orders of magnitude larger than the third harmonic and the fifth harmonic of the martensite phase.

2. The method according to claim 1, wherein: The interrogation magnetic field includes an additional magnetic field.

3. The method according to claim 2, wherein: The additional magnetic field comprises a constant DC magnetic field.

4. The method according to claim 1, wherein: The interrogation magnetic field includes a degaussing magnetic field.

5. The method according to claim 1, wherein: The one or more material states of the material include the presence of a non-hysteretic material, and wherein the material includes at least one hysteretic ferromagnetic material.

6. The method according to claim 1, further comprising: in, The one or more material states of the material are one or more first material states of the material; repeating the interrogating, detecting, determining, and associating steps using an input time-varying magnetic field in different configurations to produce one or more material second states of the material; as well as The one or more first material states and one or more second material states of the material are combined to produce a combined data set representing the one or more material states.

7. A non-transitory computer readable medium comprising instructions for executing a method of inspecting a steel material comprising at least one hysteretic ferromagnetic material and / or at least one non-hysteretic material using a non-destructive evaluation method to identify one or more material conditions and / or one or more inhomogeneities in the steel material, the method comprising: interrogating the hysteretic ferromagnetic material and / or the non-hysteretic material with an input time-varying magnetic field; scanning the steel material and detecting a magnetic response and / or an acoustic response over time from a magnetic sensor and / or an acoustic sensor; determining a time-dependent nonlinear characteristic of the received magnetic response and / or acoustic response; as well as associating the time-dependent nonlinear characteristics of the received magnetic response and / or acoustic response with the one or more material conditions and / or one or more inhomogeneities in the steel material, wherein the one or more material conditions and / or one or more inhomogeneities in the steel material comprise one selected from the group consisting of: a weld structure, a girth weld, a fillet weld, a lap weld, a butt weld, and any combination thereof, wherein interrogating the hysteretic ferromagnetic material and / or the non-hysteretic material is performed using a transmitter coil and a pickup coil configured for use on the same side of the material, wherein the transmitter coil and the pickup coil are arranged at 0.8 mm to 2.0 mm from the material, wherein determining the time-dependent nonlinear characteristic comprises performing a frequency domain analysis, the frequency domain analysis comprising a power spectral density analysis of the received magnetic response and / or acoustic response to create power spectral density data, wherein determining the time-dependent nonlinear characteristic comprises determining one or more harmonic peaks in the power spectral density data, wherein determining the one or more harmonic peaks comprises determining one or more harmonic coefficients in the spectral density data, wherein determining the one or more harmonic coefficients and / or peaks comprises determining odd harmonic coefficients and / or peaks in the spectral density data, wherein determining the odd harmonic coefficients and / or peaks comprises determining third harmonics and / or fifth harmonics in the spectral density data, wherein correlating the time-dependent nonlinear characteristic comprises comparing and correlating the third harmonic and / or the fifth harmonic with the one or more material states, and Among them, the third harmonic and the fifth harmonic of the ferrite phase are at least 1.5 orders of magnitude larger than the third harmonic and the fifth harmonic of the martensite phase.

8. A device for detecting the material state of at least one hysteretic ferromagnetic material and / or at least one non-hysteretic material, comprising: at least one magnetic transmitter configured to output an interrogation time-varying magnetic field; at least one magnetic sensor and / or acoustic sensor configured to receive a magnetic response and / or an acoustic response and convert the magnetic response and / or the acoustic response into a magnetic response signal and / or an acoustic response signal; as well as a processor configured to perform a method of inspecting a steel material comprising the at least one hysteretic ferromagnetic material and / or the at least one non-hysteretic material using a non-destructive evaluation method to identify one or more material states and / or one or more inhomogeneities in the steel material, the method comprising scanning the steel material and detecting the magnetic signal and / or acoustic response signal over time from at least one magnetic sensor and / or acoustic sensor; determining a time-dependent nonlinear characteristic of the magnetic signal and / or the acoustic signal; as well as associating the time-dependent nonlinear characteristics of the magnetic signal and / or the acoustic signal with the one or more material states and / or one or more inhomogeneities in the steel material, wherein the one or more material states and / or one or more inhomogeneities in the steel material comprise one selected from the group consisting of: a weld structure, a girth weld, a fillet weld, a lap weld, a butt weld, and any combination thereof, wherein interrogating the hysteretic ferromagnetic material and / or the non-hysteretic material is performed using a transmitter coil and a pickup coil configured for use on the same side of the material, wherein the transmitter coil and the pickup coil are arranged at 0.8 mm to 2.0 mm from the material, wherein determining the time-dependent nonlinear characteristic comprises performing a frequency domain analysis, the frequency domain analysis comprising a power spectral density analysis of the received magnetic response and / or acoustic response to create power spectral density data, wherein determining the time-dependent nonlinear characteristic comprises determining one or more harmonic peaks in the power spectral density data, wherein determining the one or more harmonic peaks comprises determining one or more harmonic coefficients in the spectral density data, wherein determining the one or more harmonic coefficients and / or peaks comprises determining odd harmonic coefficients and / or peaks in the spectral density data, wherein determining the odd harmonic coefficients and / or peaks comprises determining third harmonics and / or fifth harmonics in the spectral density data, wherein correlating the time-dependent nonlinear characteristic comprises comparing and correlating the third harmonic and / or the fifth harmonic with the one or more material states, and Among them, the third harmonic and the fifth harmonic of the ferrite phase are at least 1.5 orders of magnitude larger than the third harmonic and the fifth harmonic of the martensite phase.

9. The device according to claim 8, wherein: The interrogation magnetic field includes an additional magnetic field.

10. The device according to claim 9, wherein: The additional magnetic field comprises a constant DC magnetic field.

11. The device according to claim 8, wherein: The device comprises an output device configured to indicate the one or more states of the material to a user.

12. The device according to claim 8, wherein: The at least one magnetic sensor and / or acoustic sensor is 4 copies of the magnetic sensor and / or acoustic sensor located at different positions around each of the at least one magnetic transmitter and / or paired with each of the at least one magnetic transmitter.

13. The device according to claim 8, wherein: The at least one magnetic sensor and / or acoustic sensor is 8 copies of the magnetic sensor and / or acoustic sensor located at different positions around each of the at least one magnetic transmitter and / or paired with each of the at least one magnetic transmitter.

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