RU2637376C1 - Approximation method for definition of geometric sizes of discontinuities in ferromagnetic products and device for its implementation - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: group of inventions is implemented as a device containing a magnetizing unit, Hall sensors, amplifiers, ADCs and processing unit where they register and determine the maximum values of axial and azimuthal components of defect scattering field, the width and the length of the defect. Using the algorithm and the database of signals from defects, they determine the parameters of the defect, the signals of which are closest to the measured ones, and these parameters are considered to be the parameters of the measured defect.

EFFECT: improving the accuracy of determining the parameters of defects.

2 cl, 3 dwg

Description

The invention relates to the field of magnetic non-destructive methods for monitoring ferromagnetic products. The invention can be used to determine the geometric dimensions of continuity defects in a ferromagnetic product, as well as to develop software algorithms for magnetic flaw detectors.

There are many instruments for assessing [1, 2, 3] the geometric parameters of continuity defects similar in structure, characteristics, and application. All these devices (for example, [3] - a prototype) contain a magnetization block of the control object, primary transducers for recording defect scattering fields generated at the same time, a signal processing block, an indicator, and a scanning system.

.A common drawback of all these devices is that they only detect the presence of defects and only some measure their depth and width (while having insufficient accuracy and complexity of implementation) and do not measure other necessary (as shown in Fig. 1) parameters of defects, such as depth h, width m, tilt angle α, length

.

The objectives of the proposed technical solution are: the ability to determine the depth (with the necessary accuracy), width, angle and extent of defects, the development of the device and the algorithm of its program for determining defect parameters.

The problem is solved in that in the known approximation method for determining the geometric dimensions of continuity defects in a ferromagnetic product, which consists in magnetizing the test object and using transducers such as Hall sensors, according to the signals they judge the presence and size of defects, according to the invention, two rows of transducers located along and transversely to the scanning direction, which is measured in the axial and orthogonal ₀ field components in _a scattering defect fixed Maximal values of the two components - the B _{0 max} - axial, B _{a max} - orthogonal to the axial component of fixed duration Δt time interval when the transmitter is above the defect and the defect length is calculated indicative l ₀ = V _ck ⋅Δt, where V _SC - speed scans, record the number n of orthogonal component meters in which the signal is not equal to zero, and calculate the approximate defect width m _a = n⋅Δ, where Δ is the width of the transducer control zone, using four measured parameters (B _{0 max} , B _{a max} , Δt , n) using the signal database when modeling defects, a defect is determined whose signals are closest to the measured ones, and the parameters of this defect are taken as the parameters of the unknown defect (m, h, α, l) taking into account the approximate values of l ₀ and m _a .

In terms of the device, the task is solved in that a known device for implementing an approximation method for determining the parameters of continuity defects of ferromagnetic products, comprising a magnetizing device, a unit of converters for measuring the magnetic field of the dispersion of defects, an amplifier of signal converters, an analog-to-digital converter, a signal processing unit, a recording device the presence and size determination of defects, the scanning device according to the invention is equipped with two rows of eobrazovateley along and transverse to the direction of scanning and measuring axial B ₀ and orthogonal in _a magnetic field components, in the processing unit are provided blocks to measure the maximum values of the axial B _{0 max} and orthogonal B _{a max} leakage field components, blocks for measuring signal time interval duration ₀ The axial component of the magnetic field above the defect blocks to determine the number of transducers, fixing the orthogonal component of the magnetic field in which the signal is not zero, Regis riruyuschee device also comprises memory elements, where the results of simulation of defects of different sizes are stored.

In FIG. Figure 1 shows defects such as crack and risk, and the parameters of defects are indicated. In FIG. 2 shows a block diagram of a device for magnetic flaw detection. In FIG. 3 shows an algorithm for determining the geometric dimensions of defects.

The block diagram of the proposed device for determining the geometric dimensions of continuity defects in ferromagnetic products, contains serially connected magnetization unit 1, a control object 2, transducers for measuring the axial component B _{0 of the} magnetic field of dispersion of defect 3, amplifier 4, ADC in channel B ₀ 5, converters for measuring in _a orthogonal component 6, an amplifier 7, ADC channel B _and 8, 9, scan, maximum system measuring unit 10 _max B _0, the measurement unit signal duration Δt B ₀ 11 unit is measured Nia maximum value _{max and} the signal B 12, the measuring channel number n in _a transducer, where the signal is not zero.

The proposed device (. Figure 2) comprises transducers for measuring two orthogonal components of the magnetic field defect scattering (in the case of a cylindrical OK - axial and azimuthal B _{0 and} B components). If the scanning speed in the direction of the axis is V ₀ , and the pulse duration B ₀ is fixed in the processing unit Δt, then the length (Fig. 1) of the defect is l ₀ = V ₀ × Δt.

Fixation of B _{a is} carried out by a series of converters located in the direction of the component B _a , the length of the sensitivity zone in this direction is Δ. Thus, if n transmitters of the series is fixed in _a signal, the width (FIG. 1) defect m _a = n × Δ. In addition, the maximum values B _{0 max} and B _{a max} are recorded in the processing unit.

To determine the depth of the defect h and the angle of inclination α (Fig. 1), the dependence of the combinations of signal parameters on the combinations of defect parameters (m, h, α, l) for objects whose electrophysical parameters correspond to the parameters of the controlled objects was carried out in the ANSYS software environment. Based on the results, an extensive database was compiled for all practically possible combinations of defect parameters, an algorithm was developed, and a program was developed (Fig. 3) for determining all defect parameters that best matches the resulting combination of signal parameters. The parameters of the model correspond to the conditions of the magnetic control procedure for real objects. The block diagram of the proposed device is shown in FIG. 2. The operation of the algorithm is clear from FIG. 3. A sequential exclusion of options is made for which at least one of the signal parameters does not correspond to the measured ones.

The method is the basis for the operation of the flaw detector according to the structural diagram in FIG. 2. The device operates as follows.

The magnetization unit 1 brings the control object 2 (or its portion) to a state close to technical saturation. Magnetosensitive transducers 3, 6, for example, Hall sensors, the signals of which are amplified by amplifiers 4, 7 and through ADCs 5.8, enter processing units 10-13, where, according to the proposed method described above, the maximum axial and ₀ azimuthal components B _max and B _{max a} leakage field of the defect, the duration Δt of the signal V _0, the number of n transmitters and using an algorithm (FIG. 3) and the base data signals from defects (stored in memory) is determined parameters defect, whose signals are closest to the measured, and these parameters (defect) are considered the parameters of the measured defect. This data is fed to a recording device 14, in which, from the stored in the memory variants of the defect signals, the algorithm is selected according to FIG. 3, the closest option, the defect parameters of this option (l, m, h, α) are taken as the parameters of the measured defect. The number of transducers is chosen so as to avoid defects during the passage control.

Information sources

1. R.V. Zagidulin and others. RF patent No. 1777067 "A method for determining the parameters of a surface defect such as a crack on a ferromagnetic object." BI No. 43, 1992.

2. O.A. Bulychev et al. RF patent No. 1810809 "Method for determining the width of a crack in a ferromagnetic product." BI No. 15, 1993.

3. Non-destructive testing. In 5 kn. Prince 3. Electromagnetic control: a practical guide. V.G. Gerasimov, A.D. Pokrovsky, V.V. Sukhorukov / Under. ed. V.V. Sukhorukov. - M.: Higher School, 1992. - 128 p.

Claims (2)

1. An approximation method for determining the geometric dimensions of continuity defects in a ferromagnetic product, which consists in magnetizing the control object and using transducers (Hall sensors), by the signals of which they judge the presence and size of defects, characterized in that they use two rows of transducers located along and across the scan which measure the axial B ₀ and orthogonal B _a components of the defect scattering field; fix the maximum values of both components B _{0 max} (axial), B _{a max} (orthogonal), for the axial component, record the duration Δt of the time interval when the transducer is above the defect, and calculate the length l _{0 of the} defect l ₀ = V _ck * Δt, where V _ck is the scanning speed; record the number n of azimuthal component meters in which the signal is not equal to zero, and calculate the defect width m _a = n × Δ, where Δ is the width of the transducer control zone; four measured parameters (B _{0 max} , B _{a max} , l ₀ , m _a ), using the database of similar signals for modeling defects, determine the defect, the signals of which are closest to the measured, and the parameters of a certain defect are taken as the parameters of an unknown defect (m , h, α, l), where m is the width, h is the depth, α is the angle of inclination, l is the length. 2. A device for implementing an approximation method for determining the parameters of continuity defects of ferromagnetic products, comprising a magnetizing device, a transducer block for measuring the defect magnetic field, an amplifier of the signal transducers, an analog-to-digital converter, a signal processing unit, a recording device for the presence and size determination of defects, a scanning device characterized in that it is equipped with two rows of transducers located along and across the scan direction measuring and measuring the axial B ₀ and orthogonal B _a components of the magnetic field (where B ₀ is the component of the defect magnetic field in the scanning direction, B _a is the component of the magnetic field in the direction perpendicular to scanning), the processing unit provides blocks for measuring the maximum axial values ( At _{0 max)} and orthogonal (B _{and max)} constituents scattering field, units for measuring the length of the axial component of the time interval signal B ₀ magnetic field above the defect, determining the number of transducers, fixing the boiling the orthogonal component of the magnetic field in which the signal is not zero, the recording device also comprises memory elements, where the results of simulation of defects of different sizes are stored.

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