RU2698485C1 - Hybrid ultrasonic-emission diagnostics method of structural materials quality - Google Patents

Abstract

FIELD: diagnostic method.

SUBSTANCE: use: for hybrid ultraduicing-emission diagnostics of structural materials quality. Summary of invention consists in the fact that exposure of the test sample to a pressurized liquid jet 350…380 MPa at speed 800…850 m/s, wherein one or more acoustic emission sensors are mounted on the test sample and acoustic emission parameters are recorded during the time of the liquid jet action, method includes evaluating the quality of its structural material, wherein evaluation of the quality of the structural material of the sample is carried out by comparing the period of activation of cracks, which is determined from the current feed rate S, which varies according to the law of equitelong motion, and the presence of a frequency spectrum of the Hartmann-type resonator of the acoustic emission signal from the area of action of the jet on the target, with corresponding characteristics of the reference sample or with available values of previously diagnosed samples.

EFFECT: possibility of levelling local source of hydro erosion destruction of surface layer at the point of water ultrastructure and higher quality of procedure of ultrasonic diagnostics by minimization of hydroerosion destruction of survey object surface.

1 cl, 2 dwg

Description

The invention relates to the field of monitoring and diagnostics of the erosive properties of materials and parts used in mechanical engineering, shipbuilding and other industries, as well as being under hydrodynamic loading, in particular, components of shipbuilding equipment, hydroelectric power plants, etc. associated primarily with erosion resistance of the surface. It can be used at the preliminary stages of the technological process of manufacturing products with the aim of rapid express selection of materials from those offered on the market and produced by various manufacturers.

Hybrid ultra-jet emission diagnostics can be subjected to samples from structural materials with different selective physical and mechanical properties formed using various manufacturing processes, using different starting components in composition to obtain one or another type of composite material.

There is a method of rapid diagnostics of the surface layer of materials, including exposure to the surface of the material of a liquid jet in combination with chemically active gases under a pressure of at least 50 MPa at a speed of 100-850 m / s., Exposure time in the range of 10-60 s. (RF patent No. 2518359 dated 04/11/2014)

The disadvantage of this method is the presence of a local focus of hydroerosive destruction of the surface layer at the site of exposure to the ultra-jet of water.

The closest method of the same purpose to the claimed invention according to the totality of features is a method for diagnosing the quality of structural materials, in which a test sample is exposed to a liquid stream under a pressure of 350 ... 380 MPa at a speed of 800 ... 850 m / s. Install one or more acoustic emission sensors on the sample. The acoustic emission parameters are recorded during the time of exposure to a liquid stream. Assess the quality of the structural material of the sample by comparing the relative values of the mass ablation of the material and the parameters of acoustic emission with the corresponding characteristics of the reference sample, or with the available values of previously diagnosed samples (RF patent No. 2518590 of 06/10/2014). This method is adopted as a prototype.

Signs of the prototype, which coincides with the essential features of the proposed method, is the impact on the test sample with a liquid jet under a pressure of 350 ... 380 MPa at a speed of 800 ... 850 m / s; at the same time, one or more acoustic emission sensors are installed on the test sample and the acoustic emission parameters are recorded during the time of exposure to the liquid jet; assess the quality of the structural material of the sample.

The disadvantage of this method, adopted as a prototype, is the presence of a local focus of hydroerosive destruction of the surface layer at the site of exposure to the ultra-jet of water, which, to some extent, limits the possible field of application of the method in practice.

The objective of the invention is the leveling of the local focus of hydroerosive destruction of the surface layer at the site of exposure to the ultra-jet of water and improving the quality of the procedure of ultra-jet diagnostics (USD) by minimizing the hydroerosive destruction of the surface of the object of study. The solution to this problem is relevant and will expand the application capabilities of the DCM method in the field of diagnostics of the current state of parts in operation.

The problem was solved due to the fact that in the known method of hybrid ultra-jet emission diagnostics of the quality of structural materials, including exposure to the test sample with a liquid jet under a pressure of 350 ... 380 MPa at a speed of 800 ... 850 m / s, while one is installed on the test sample or several acoustic emission sensors and record the parameters of acoustic emission during the time of exposure to a liquid stream, assess the quality of the structural material of the sample, according to the invention, assess The quality of the structural material of the sample is carried out by comparing the crack activation period, which is judged by the current feed rate S, which varies according to the law of equal slow motion and the presence of a frequency spectrum of a Hartmann-type resonator of the acoustic emission signal from the zone of the jet impact on the target, with the corresponding characteristics of the reference sample, or with existing values of previously diagnosed samples.

The onset of the formation of a cavern is determined by the presence of a frequency spectrum of acoustic emission caused by a nascent Hartmann-type resonator.

The features of the proposed technical solution, distinctive from the prototype — the quality of the structural material of the sample is assessed by comparing the crack activation period, which is judged by the current feed rate S, which varies according to the law of equidistant motion and the presence of a frequency spectrum of a Hartmann-type resonator of the acoustic emission signal from the jet exposure zone on the target, with the corresponding characteristics of the reference sample, or with the available values of previously diagnosed samples; the beginning of the formation of a cavern is determined by the presence of the frequency spectrum of acoustic emission caused by a nascent Hartmann-type resonator.

During the experiments, the authors for the first time established an unambiguous relationship between the activation period (duration of the incubation period) and material damage. The basic idea of minimal hydroerosive destruction is based on the unambiguous relationship between the activation period and material damage.

Evaluation of the quality of the structural material of the sample by comparing the crack activation period, which is judged by the current feed rate S, which varies according to the law of equidistant motion and the presence of the frequency spectrum of a Hartmann-type resonator of the acoustic emission signal from the zone of influence of the jet on the target, with the corresponding characteristics of the reference sample, or with the available values of previously diagnosed samples, it will minimize the hydroerosive destruction of the surface of the object of study. As a result, the leveling of the local focus of hydroerosive destruction of the surface layer at the site of exposure to the ultra-jet of water is ensured and the quality of the ultra-jet diagnostic procedure (DDM) is improved.

The presence of acoustic emission sensors installed on the sample and registration of acoustic emission parameters during the time of exposure to a liquid stream will allow to obtain comparative characteristics with respect to the standard or the compared sample.

Similarly, the acoustic emission parameters are compared - the amplitude-frequency characteristics with the acoustic emission parameters of the standards or previously diagnosed samples. The difference in the results of this effect judges the physicomechanical state of the surface layer of the sample and its erosion resistance during hydro-jet treatment.

The inventive method is illustrated by the drawings shown in FIG. 1-2.

In FIG. 1 shows a diagram of a method.

The diagram shows: 1 - inkjet head; 2 - high-energy liquid jet; 3 - test sample; 4 - test substrate; 5 - base; 6 - acoustic emission sensor; 7 - speaker system; 8 - computer; 9 - clip; S is the feed rate of the cutting head; F _CR - the force of the clamp.

In FIG. 2 shows a signal from an acoustic emission sensor.

During the experiment, the amplitude of the acoustic emission signal from the zone of the jet impact on the target was recorded.

A method for diagnosing the quality of structural materials is as follows.

Set the sample 1 on the base 5, using the clamp 9, the acoustic emission sensor 6, connected through the speaker system 7 to the computer 8 for the corresponding processing of the acoustic signal. From the jet nozzle of a hydraulic nozzle 1, a high-speed (800 ... 850 m / s) liquid jet 2 is supplied under pressure of 350 ... 380 MPa, which, hitting the diagnosed surface of sample 3, causes hydroerosion of its surface in the direction of supply S. High-energy jet of liquid (water) 2 causes an intense process of wave formation recorded by the acoustic emission sensor 6.

With the beginning of the action of the jet of liquid 2 on the sample 3, the parameters of acoustic emission are recorded (recording the signal of acoustic emission), which is completed at the end of the action of the jet 2.

Supply S is subject to the law of equidistant motion, which leads to a uniform increase in the time of local exposure to the sample undergoing diagnostics. When the time of local exposure to the sample becomes no less than the period of activation of the cracks, hydraulic fracture begins, which leads to the appearance of a low-frequency resonator of the Hartmann type, the spectrum of which is recorded by acoustic-emission equipment, after which the equipment gives a signal to turn off the high-speed jet and the effect on the material ceases, i.e. . its further hydrocracking does not occur.

Acoustic emission parameters are compared — the amplitude-frequency characteristics — with the acoustic emission parameters of a reference sample, or with the available values (database) of previously diagnosed samples.

An example of a specific implementation.

Three samples of structural corundum ceramics of various manufacturers were diagnosed.

The hybrid ultrasound emission diagnostic process consisted of the following main steps:

- installation and fastening of ceramic samples in technological equipment on the coordinate table of waterjet cutting FlowSystem manufactured in the USA;

- installation of an acoustic emission sensor on the surface of the experimental sample and its connection to the instrument of the four-channel oscilloscope AKIP-4110/1 manufactured by Pico Technology with broadband acoustic sensors operating in the frequency range from 1 to 500 KHz;

- ultra-jet impact on the surface of the corundum ceramic plate under specified technological conditions (jet speeds of 800 ... 850 m / s and the distance from the nozzle exit of the hydro-jet installation to the surface of the diagnosed sample 2 mm) and varying according to the law of uniformly slow feed motion S of the cutting head from a speed of 1000 mm / min to a speed of 2 mm / min for three samples;

- recording the acoustic emission signal (AE) and its values on a personal computer;

- entry of experimental data in a table for further analysis of the results.

During the experiments, the following results were obtained: a typical graph of the signal change from the sensor is shown in FIG. 2:

I - the beginning of the movement of the jet head, the amplitude of the AE signal is relatively stable;

II - plot of active growth, the amplitude of the AE signal caused by a nascent Hartmann-type resonator (a cavern is formed);

III - site of active hydroerosion, the existence of a stationary resonator;

IV - section off the working fluid pressure;

V is the stroke of the inkjet head without fluid supply (noise level of the equipment);

VI - section of pressure relief and shutdown of the installation.

Analyzing the resulting graph in FIG. 2, it is possible to judge the diagnostic mode, and most importantly, determine the speed of movement of the jet head corresponding to the end / beginning of hydroerosive destruction, which, in turn, is uniquely associated with such an important material parameter as the crack activation period. Knowing the crack activation period, one can quite easily find the material damage or residual product life by comparing it with reference (model) samples.

Thus, the inventive method for diagnosing the quality of structural material is acceptable for the selection of optimal materials. The advantage of the method is that it allows you to level the local focus of hydroerosive destruction of the surface layer at the site of exposure to the ultra-jet of water and to improve the quality of the procedure of ultra-jet diagnostics by minimizing the hydroerosive destruction of the surface of the object of study. In addition, it allows to reduce the complexity of testing, to expand the possibilities of exposure to a high-energy jet for the diagnostic procedure of materials by changing the parameters of the jet while maintaining the reliability of the diagnostic information about the properties of the materials.

Claims (2)

1. The method of hybrid ultra-jet emission diagnostics of the quality of structural materials, including exposure to the test sample with a liquid jet under a pressure of 350 ... 380 MPa at a speed of 800 ... 850 m / s, while one or more acoustic emission sensors are installed on the test sample and acoustic parameters are recorded emission during the time of exposure to a liquid jet, assess the quality of its structural material, characterized in that the quality of the structural material of the sample is evaluated by we compare the crack activation period, which is judged by the current feed rate S, which varies according to the law of equal slow motion, and the presence of the frequency spectrum of a Hartmann-type resonator of the acoustic emission signal from the zone of the jet's impact on the target, with the corresponding characteristics of the reference sample or with the previously diagnosed values samples. 2. The method according to p. 1, characterized in that the beginning of the formation of a cavern is determined by the presence of a frequency spectrum of acoustic emission caused by a nascent Hartmann-type resonator.

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