CN102645484A - Electromagnetic acoustic emission nondestructive testing device for metal materials - Google Patents

Abstract

The invention relates to an electromagnetic acoustic emission nondestructive testing device for metal materials, which is used for testing crack defects of the metal materials by means of the acoustic wave emission technology. The testing method includes the steps that pulse heavy current generated by a pulse heavy current generator is loaded on the metal materials to be tested, acoustic emission signals are excited if the metal materials to be tested have cracks, the acoustic emission signals are tested by four piezoelectric transducers and input into a head amplifier by signal wires, then the acoustic emission signals are amplified by the head amplifier and input into a personal computer (PC), the PC performs two-dimensional time difference location according to the collected acoustic emission signals, and the crack defects existing in the metal materials to be tested are tested by means of the location. The electromagnetic acoustic emission nondestructive testing device comprises the pulse heavy current generator, the four piezoelectric transducers, the head amplifier and the PC. According to the electromagnetic acoustic emission nondestructive testing device, the defect of the secondary damage on the metal materials to be tested during the metal material testing process in prior art is overcome, the application range of the acoustic emission technology is broadened, the identification efficiency of the acoustic emission technology is improved, and the electromagnetic acoustic emission nondestructive testing device is suitable for industrial applications.

Description

Electromagnetic sound emission the cannot-harm-detection device of a kind of metal material

Technical field

Technical scheme of the present invention relates to the crack-type defect that utilizes in the sound wave emissions technical testing metal material, the cannot-harm-detection device of a kind of electromagnetic sound of metal material emission specifically.

Background technology

Along with developing rapidly of modern equipment manufacture, constantly improve the bearing stress level of hardware and equipment, the fracture failure accident of hardware and equipment then often takes place.For essential industry fields such as space flight, electric power, chemical industry, navigation and nuclear energy, the fracture failure accident of hardware and equipment tends to bring immeasurable serious consequence.The traditional device maintaining method need be done regular stop production to overhaul to hardware and equipment, has blindness, brings a lot of inconvenience to production.Generation for the fracture failure accident of preventing hardware and equipment; Require to find as early as possible the dangerous crackle in hardware and the equipment, acoustic emission becomes the important detection method of the dangerous crackle in hardware and the equipment with its high sensitivity and dynamic monitoring characteristic.

Though tradition acoustic emission detection method can realize the dynamic damage of metal material is detected; But its shortcoming mainly contains two: at first, testing conditions is harsh, must apply whole mechanical load to tested metal; Just can inspire acoustic emission phenomenon when defective is in active state, and then realize detecting; Secondly, under the effect that adds mechanical load, extra additional injury appears in metal material easily, makes testing process to being caused secondary damage by geodesic structure.These method and apparatus have greatly limited the range of application of acoustic emission testing technology, are inappropriate for actual commercial Application.

Under the prerequisite that keeps acoustic emission detection method advantage, how to enlarge its range of application and improve its recognition efficiency, to be suitable for actual commercial Application, become important development direction of acoustic emission.

Summary of the invention

Technical matters to be solved by this invention is: electromagnetic sound emission the cannot-harm-detection device that a kind of metal material is provided; Be based on the mode that pulse high current directly loads; Realize the nondestructive examination of metal material crack-type defect; Overcome prior art and in the metal material testing process, understood the shortcoming that cause secondary damage to metal structure to be measured, enlarged the acoustic emission range of application and improved its recognition efficiency, and be suitable for actual commercial Application.

The present invention solves this technical problem the technical scheme that is adopted: electromagnetic sound emission the cannot-harm-detection device of a kind of metal material; The steps include: to draw two leads are fixed in metal material to be measured respectively with the plastics clamper two ends, again with four piezoelectric transducer S from the electrode of the high-voltage capacitance of pulse high current generator ₁, S ₂, S ₃And S ₄Four vertex positions by rhombus are placed on this metal material to be measured, and each piezoelectric transducer is connected to prime amplifier through signal wire respectively, and prime amplifier is wired to PC again; The pulse high current generator is connected the alternating current of 220v and produced pulse high current, and this pulse high current is loaded on the metal material to be measured, if there is crackle in metal material to be measured, can be inspired acoustic emission signal, and this acoustic emission signal is by four piezoelectric sensor S ₁, S ₂, S ₃And S ₄Detection is also passed through signal wire input prime amplifier; Amplify acoustic emission signal and import PC by this prime amplifier; This PC carries out two dimension time difference location according to the acoustic emission signal that is collected, thereby detection and localization goes out the crack defect that this metal material to be measured exists.

Electromagnetic sound emission the cannot-harm-detection device of above-mentioned a kind of metal material, said PC carries out two dimension time difference location according to the acoustic emission signal that is collected, and its calculation procedure is: at first confirm the velocity of wave V of respective metal material, and calculate piezoelectric transducer S ₁Probe and piezoelectric transducer S ₃Probe spacing be a, piezoelectric transducer S ₂Probe and piezoelectric transducer S ₄The spacing of probe be b, according to the acoustic emission signal sequencing that PC collects, confirm piezoelectric transducer S ₁With piezoelectric transducer S ₃Between the time difference Δ t of acquired signal ₁, and piezoelectric transducer S ₂With piezoelectric transducer S ₄Between the time difference Δ t of acquired signal ₂, obtain acoustic emission source according to computing formula, i.e. the coordinate of crack tip position:

$\left\{\begin{array}{c}x=\frac{{\mathrm{\Δt}}_{1}V}{2a}[{\mathrm{\Δt}}_{1}V+2\sqrt{{(x-a/2)}^2+y^2}]---\left(1\right)\\ y=\frac{{\mathrm{\Δt}}_{2}V}{2b}[{\mathrm{\Δt}}_{2}V+2\sqrt{{(y-b/2)}^2+x^2}]---\left(2\right).\end{array}\right.$

The invention has the beneficial effects as follows: the substantive distinguishing features of electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention is; Pulse high current is loaded on the metal material to be measured; Receive the influence of the crackle on the metal material to be measured; Electric current forms tangible concentration effect at the crack tip place, causes splitting near the current density of point and sharply increases.Under the effect in magnetic field, the crack tip place produces Lorentz force, and the direction of Lorentz force makes the outwards expansion respectively of crackle both sides, and then inspires acoustic emission phenomenon.Utilize piezoelectric sensor to detect acoustic emission signal and carry out signal Processing and can obtain crack information on the metal material, thereby realize Non-Destructive Testing the metal material crack-type defect with PC.The marked improvement of the electromagnetic sound of metal material of the present invention emission lossless detection method and device thereof is, 1. the static state at metal material to be measured does not detect with having under the effect that adds mechanical load, and the structure of metal material to be measured is not caused secondary damage; 2. enlarge the range of application of acoustic emission detection method, do not received the restriction of the type and the shape of metal material to be measured; 3. the electromagnetic sound of metal material of the present invention emission lossless detection method is simple to operate, and the building block of its device is simple in structure and cheap.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is further specified.

Fig. 1 is the schematic process flow diagram of electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention.

Fig. 2 is the formation synoptic diagram of electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention.

Fig. 3 is the location synoptic diagram of the two-dimentional time difference in electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention.

Fig. 4 is the two-dimentional time difference finder process flow diagram in electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention.

Embodiment

Embodiment illustrated in fig. 1 showing; The flow process of electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention is: pulse high current is loaded on the metal material to be detected, if there is crackle in metal material to be detected, can be inspired acoustic emission signal; Detect this acoustic emission signal; Transmit acoustic emission signal, detected acoustic emission signal is amplified, carry out data acquisition and processing and obtain a result.

Embodiment illustrated in fig. 2 showing, electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention is made up of pulse high current generator, four piezoelectric transducers, prime amplifier and PCs.

Embodiment illustrated in fig. 3 showing, four sensor S are adopted in the two-dimentional time difference location in electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention ₁, S ₂, S ₃And S ₄Constitute the rhombus array and carry out the two dimensional surface location, by piezoelectric transducer S ₁With piezoelectric transducer S ₃The time difference Δ t of acquired signal ₁Obtain hyperbolic curve 1, by piezoelectric transducer S ₂With piezoelectric transducer S ₄The time difference Δ t of acquired signal ₂Obtain hyperbolic curve 2, piezoelectric transducer S ₁Probe and piezoelectric transducer S ₃Probe spacing be a, piezoelectric transducer S ₂Probe and piezoelectric transducer S ₄The spacing of probe be b, velocity of wave is V, so, acoustic emission source, promptly the crack tip position be located in two hyp intersection point Q (x, y) on, its Coordinate Calculation formula is seen formula (1) (2).

Embodiment illustrated in fig. 4 showing, the two-dimentional time difference finder flow process in electromagnetic sound emission the cannot-harm-detection device of a kind of metal material of the present invention is: velocity of wave V and four piezoelectric transducer S of importing the respective metal material respectively ₁, S ₂, S ₃And S ₄Coordinate.According to the coordinate of four piezoelectric transducers, calculate piezoelectric transducer S ₁Probe and piezoelectric transducer S ₃Probe between apart from a, calculate piezoelectric transducer S ₂Probe and piezoelectric transducer S ₄Probe between distance b.→ according to the acoustic emission signal sequencing that PC collects, calculate piezoelectric transducer S ₁With piezoelectric transducer S ₃Between the time difference Δ t of acquired signal ₁, and piezoelectric transducer S ₂With piezoelectric transducer S ₄Between the time difference Δ t of acquired signal ₂→ calculate the acoustic emission source coordinate based on time difference ranging formula, realize location to defective.

Embodiment 1

The pulse high current generator is connected the alternating current of 220v and produced pulse high current, and the peak point current of pulse high current is at 800 amperes, and pulse width is 220 microseconds.This pulse high current is loaded on the aluminum metallic material to be measured that is of a size of 500mm * 115mm * 15mm; This aluminum metallic material to be measured is inspired acoustic emission signal; This signal is 2/4/6 prime amplifier by the detection of the piezoelectric sensor of four R15a models and through signal wire input U.S. PAC company model; Amplify acoustic emission signal and import PC by this prime amplifier; This PC carries out two dimension time difference location according to the acoustic emission signal that is collected, and its calculation procedure is: at first confirm the velocity of wave V of this aluminum metallic material to be measured, and calculate piezoelectric transducer S ₁Probe and piezoelectric transducer S ₃Probe spacing be a, piezoelectric transducer S ₂Probe and piezoelectric transducer S ₄The spacing of probe be b, according to the acoustic emission signal sequencing that PC collects, confirm piezoelectric transducer S ₁With piezoelectric transducer S ₃The time difference Δ t of acquired signal ₁, and piezoelectric transducer S ₂With piezoelectric transducer S ₄Between the time difference Δ t of acquired signal ₂, obtain acoustic emission source according to computing formula, i.e. the coordinate of crack tip position:

$\left\{\begin{array}{c}x=\frac{{\mathrm{\Δt}}_{1}V}{2a}[{\mathrm{\Δt}}_{1}V+2\sqrt{{(x-a/2)}^2+y^2}]---\left(1\right)\\ y=\frac{{\mathrm{\Δt}}_{2}V}{2b}[{\mathrm{\Δt}}_{2}V+2\sqrt{{(y-b/2)}^2+x^2}]---\left(2\right)\end{array}\right.$

Above-mentioned two dimension time difference finder flow process is: velocity of wave V and four piezoelectric transducer S of importing the respective metal material respectively ₁, S ₂, S ₃And S ₄Coordinate.→ according to the coordinate of four piezoelectric transducers, calculate piezoelectric transducer S ₁Probe and piezoelectric transducer S ₃Probe between apart from a, calculate piezoelectric transducer S ₂Probe and piezoelectric transducer S ₄Probe between distance b.→ according to the acoustic emission signal sequencing that PC collects, calculate piezoelectric transducer S ₁With piezoelectric transducer S ₃Between time difference of acquired signal, and piezoelectric transducer S ₂With piezoelectric transducer S ₄Between the time difference Δ t of acquired signal ₂→ calculate the acoustic emission source coordinate based on time difference ranging formula, realize location to defective.

Final detection and localization goes out the crack defect position that this aluminum metallic material to be measured exists, and positioning error is 2mm.

Embodiment 2

The pulse high current generator is connected the alternating current of 220v and produced pulse high current, and the peak point current of pulse high current is at 1860 amperes, and pulse width is 250 microseconds.This pulse high current is loaded on the alloy steel metal material to be measured that is of a size of 500mm * 115mm * 15mm; This alloy steel metal material to be measured is inspired acoustic emission signal; This signal is 2/4/6 prime amplifier by the detection of the piezoelectric sensor of four R15a models and through signal wire input U.S. PAC company model; Amplified acoustic emission signal and imported PC by this prime amplifier, this PC carries out two dimension time difference location according to the acoustic emission signal that is collected, and following step is with embodiment 1.

Final detection and localization goes out the crack defect position that this alloy steel metal material to be measured exists, and positioning error is 1mm.

Embodiment 3

The pulse high current generator is connected the alternating current of 220v and produced pulse high current, and the peak point current of pulse high current is at 3000 amperes, and pulse width is 300 microseconds.This pulse high current is loaded on the aluminum metallic material to be measured that is of a size of 500mm * 115mm * 15mm; This aluminum metal to be measured is inspired acoustic emission signal; This signal is 2/4/6 prime amplifier by the detection of the piezoelectric sensor of four R15a models and through signal wire input U.S. PAC company model; Amplified acoustic emission signal and imported PC by this prime amplifier, this PC carries out two dimension time difference location according to the acoustic emission signal that is collected, and following step is with embodiment 1.

Final detection and localization goes out the crack defect position that this alloy steel metal material to be measured exists, and positioning error is 1mm.

Claims (3)

1. the electromagnetic sound of a metal material is launched the cannot-harm-detection device; It is characterized in that step is: the electromagnetic sound emission lossless detection method of metal material; The steps include: to draw two leads are fixed in metal material to be measured respectively with the plastics clamper two ends, again with four piezoelectric transducer S from the electrode of pulse high current generator ₁, S ₂, S ₃And S ₄Four vertex positions by rhombus are placed on this metal material to be measured, and each piezoelectric transducer is connected to prime amplifier through signal wire respectively, and prime amplifier is wired to PC again; The pulse high current generator is connected the alternating current of 220v and produced pulse high current, and this pulse high current is loaded on the metal material to be measured, if there is crackle in metal material to be measured, can be inspired acoustic emission signal, and this acoustic emission signal is by four piezoelectric sensor S ₁, S ₂, S ₃And S ₄Detection is also passed through signal wire input prime amplifier; Amplify acoustic emission signal and import PC by this prime amplifier; This PC carries out two dimension time difference location according to the acoustic emission signal that is collected, thereby detection and localization goes out the crack defect that this metal material to be measured exists.

2. according to electromagnetic sound emission the cannot-harm-detection device of the said a kind of metal material of claim 1, it is characterized in that: the peak point current of used pulse high current is at 800～3000 amperes, and pulse width is 150～300 microseconds.

3. launch the cannot-harm-detection device according to the electromagnetic sound of the said a kind of metal material of claim 1; It is characterized in that: said PC carries out two dimension time difference location according to the acoustic emission signal that is collected; Its calculation procedure is: at first confirm the velocity of wave V of respective metal material, and calculate piezoelectric transducer S ₁Probe and piezoelectric transducer S ₃Probe spacing be a, piezoelectric transducer S ₂Probe and piezoelectric transducer S ₄The spacing of probe be b, according to the acoustic emission signal sequencing that PC collects, confirm piezoelectric transducer S ₁With piezoelectric transducer S ₃The time difference Δ t of acquired signal ₁, and piezoelectric transducer S ₂With piezoelectric transducer S ₄Between the time difference Δ t of acquired signal ₂, obtain acoustic emission source according to computing formula, i.e. the coordinate of crack tip position:

$\left\{\begin{array}{c}x=\frac{{\mathrm{\Δt}}_{1}V}{2a}[{\mathrm{\Δt}}_{1}V+2\sqrt{{(x-a/2)}^2+y^2}]---\left(1\right)\\ y=\frac{{\mathrm{\Δt}}_{2}V}{2b}[{\mathrm{\Δt}}_{2}V+2\sqrt{{(y-b/2)}^2+x^2}]---\left(2\right).\end{array}\right.$

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