CN116242912A - In-situ ultrasonic detection system and method for flaw detection of cross countersunk head bolt - Google Patents

Abstract

The invention relates to a flaw detection in-situ ultrasonic detection system and a flaw detection method for a cross countersunk head bolt, wherein the system comprises a high-frequency ultrasonic signal host, an intelligent control terminal and a probe; the high-frequency ultrasonic signal host computer is in data connection with the intelligent control terminal through a network; the probe is in communication connection with the high-frequency ultrasonic signal host through a data line; the probe comprises a main body, wherein one end of the main body is provided with an interface for communication connection; the other end of the main body is a detection end; the detection end is provided with an annular wafer prepared based on the Fresnel equal-area ring belt principle and a guide end positioned in the center of the annular wafer and used for being matched with a cross groove on the cross countersunk head bolt; the main body is internally provided with a signal transmitting line and a signal receiving line which are used for connecting the annular wafer and the interface. The invention has good coupling effect, and can effectively avoid the problem that clutter and defect waves are covered caused by scattering or attenuation due to sound energy dispersion caused by the cross grooves; the detection effect of the cross countersunk head bolt is greatly improved.

Description

In-situ ultrasonic detection system and method for flaw detection of cross countersunk head bolt

Technical Field

The invention relates to the field of bolt flaw detection, in particular to a cross countersunk head bolt flaw detection in-situ ultrasonic detection system and a flaw detection method.

Background

The bolt connection is used as one of more common connecting pieces in the engineering field, is widely used in different parts of various aircrafts, and can tightly connect various mechanical parts together. Among various mechanical connections, the connection of bolts is widely regarded as one of the most common, simplest and most effective connection tools and modes, but due to the fact that the bolts have complex working environments in the actual use process, the bolts are easy to fail and fall off, the service strength of the machine is affected, the service life of the machine is obviously reduced, the strength and the rigidity are affected, and very serious consequences can be caused in the equipment use process.

However, in industry, due to the large number of types of bolts, the detection difficulty is high, and targeted measures are required for different types of bolts. The nondestructive detection method is researched for the cross countersunk head bolt under the condition that the cross countersunk head bolt fails, breaks and falls off to inhale an airflow channel to damage a rotating moving part.

The test block adopted by the patent is specially customized to be in accordance with the size of a practically used bolt, different types of defects are designed by selecting bolts with different parameters, various test blocks are manufactured, the defects are detected and analyzed by utilizing an ultrasonic nondestructive testing method, an ultrasonic probe conforming to the characteristics of the cross countersunk head bolt is designed, the thought of designing and manufacturing the test block is verified, defect detection parameters are summarized, the rule is summarized, the optimal detection parameters are obtained, and the method has a certain reference significance for practical maintenance and guarantee work.

Most mechanical components are subjected to stress fatigue, fracture, etc., wherein the mechanical components are also greatly affected by the damaging factors. With the development of technology, the modern manufacturing industry is also moving toward high speed, high temperature and high pressure. Since the mechanical component is in a high-strength environment for a long time, the damage factor caused by the mechanical component is increased, and particularly the damage of the damage factor is increased at the welding seam part, the inspection of the material of the component is also very critical, so as to prevent the damage or defect of the material from further increasing the severity of the damage to the mechanical component. In the process of detecting the workpiece, the internal structure of the material, such as air holes, cracks and other defects, can be detected by a nondestructive testing technology under the condition of not damaging the detected integral component.

The ultrasonic detection mainly comprises the steps of irradiating an object by utilizing the principle of ultrasonic reflection, transmission and scattering on the surface layer and the internal structure of a material by utilizing ultrasonic waves, enabling information in the object to be contained in ultrasonic echoes through the interaction between the ultrasonic waves and a medium where the ultrasonic waves are located, receiving the modified ultrasonic signal echoes by adopting a proper mode, then processing and extracting the received ultrasonic waves, and converting the information in the object which is not easy to directly observe and obtain into the information which can be obtained. The ultrasonic detection produces strong waveform change on the micro cracks and structural defects on the surface of the building, and has the characteristics of high detection speed, low cost, good sensitivity and automatic detection. Therefore, in terms of nondestructive testing, ultrasonic testing occupies a critical position in nondestructive testing by its own superiority.

Ultrasonic testing has been studied for a long time abroad. The ultrasonic inspection has a very wide coverage range, and is widely applied to the fields of machinery manufacturing industry, steel industry and the like. Rapid progress has also been made in foreign digital ultrasound system research due to the great popularity of electronic computers and the increasing development of digital technology. The development process can be divided into three stages, namely a virtual reality flaw detection system, a digital flaw detection system and a virtual reality flaw detection system based on computer software. Currently, ultrasound systems developed abroad have been able to achieve a considerable degree of automation. For example, the reciprocal conversion of A, B, C type scanning can be accomplished, and the multiple scanning channels are all identical. In domestic aspects, china starts to develop acoustic detection technology as early as the 60 th century of 20 th century. By the 70 s of the 20 th century, acoustic testing has achieved corresponding research results and has enabled the fabrication of analog ultrasonic meters using transistors or integrated circuits. Such devices typically include display and nixie tube display devices and automatic cursor readout acoustic parameter devices. The early invention has a great pushing effect on the development of Chinese ultrasonic measuring equipment. In the later 80 s of the 20 th century, china is stepping into the development process of digital ultrasonic equipment. The corresponding field measurement work can be completed by using the networking of the microcomputer and the equipment. After a certain device is used, the automatic detection function can be realized. And due to the further development of computer technology and the continuous expansion of detection markets, the development of ultrasonic detection in China has also been greatly progressed. Many domestic devices are not lower in accuracy and other technical indicators than foreign countries. In China, the devices are used as a main control unit through a computer, have high-speed data collection and data processing capacity, can finish automatic analysis, input and storage of parameters in the acoustic field, and have good later analysis and processing functions.

Ultrasonic inspection of bolts is one of the most common non-destructive inspection means currently in use. It determines the geometry and location of the defect by reflecting the region and frequency of the echo on the ultrasound instrument display. The working mechanism of ultrasonic flaw detection is that according to the basic characteristics of ultrasonic waves, the sound waves are reflected when the sound waves hit an obstacle. However, because the geometric dimensions of the defect vary greatly from wavelength to wavelength, sound cannot be continuously transmitted forward and totally reflected. When the geometric dimensions of the defect are small compared to the length, sound is continuously transmitted around the notch. When the root of the bolt is cracked, the original root of the tooth has increased resistance to sound. Sounds that can bypass the root are largely blocked and the crack propagates inward, reflecting the sound that is not blocked. At the same time, the acoustic energy reflected back into the probe rises, causing the defect wave to be much higher than the normal tooth wave height on the phosphor screen. In this way, a crack can be detected. The ultrasonic high-frequency probes used in China at present are mainly divided into longitudinal wave probes and transverse wave probes. When the surfaces of the two ends of the bolt are flat, a longitudinal wave small angle probe can be used, the angle is determined according to the length of the detected threaded area and the diameter of the end face, and the angle is at the other side of the end face of one end; scanning is performed using a shear wave probe when the shear wave probe has not been mounted to the tip.

Ultrasonic probes, also known as transducers or transducers, are a type of mechanical element that transmits and receives ultrasonic waves, and are one of the most critical components that make up an ultrasonic measurement system. Because the cross countersunk head bolt is different from a common flat head bolt, the cross groove on the cross countersunk head bolt has poor coupling effect with the common ultrasonic straight probe, and the scattered ultrasonic waves are easily scattered to cause scattering or attenuation, and the scattered ultrasonic waves are transmitted back to the straight probe along a complex line, so that clutter appears on an oscillography screen, and defect waves with lower wave height can be covered, and the defect waves cannot be detected well. Therefore, special probes are required to be designed for ultrasonic detection of the cross countersunk head bolts to meet the flaw detection requirements.

Disclosure of Invention

The first object of the invention is to provide a cross countersunk head bolt flaw detection in-situ ultrasonic detection system, which has good coupling effect, and can effectively avoid the problems of clutter and defect wave masking caused by scattering or attenuation due to acoustic energy dispersion caused by a cross groove; the detection effect of the cross countersunk head bolt is greatly improved.

The technical scheme for realizing the first purpose of the invention is as follows: the invention relates to a cross countersunk head bolt flaw detection system, which comprises a high-frequency ultrasonic signal host, an intelligent control terminal and a probe; the high-frequency ultrasonic signal host computer is in data connection with the intelligent control terminal through a network; the probe is in communication connection with the high-frequency ultrasonic signal host through a data line;

the high-frequency ultrasonic signal host is used for exciting the high-frequency ultrasonic signals according to the control instruction, supplying the excitation of the high-frequency ultrasonic signals to the probe, processing the received echo signals into echo waveforms and calculation results, and transmitting the echo waveforms and calculation results to the intelligent control terminal;

the intelligent control terminal is used for setting detected technological parameters, sending control instructions to the high-frequency ultrasonic signal host, receiving echo waveforms and calculation results from the high-frequency ultrasonic signal host and displaying detection results;

the probe is used for sending out ultrasonic waves to the cross countersunk head bolt according to the excitation of the high-frequency ultrasonic signals provided by the high-frequency ultrasonic signal host machine and transmitting the received echo signals to the high-frequency ultrasonic signal host machine;

the probe comprises a main body, wherein one end of the main body is provided with an interface for communication connection; the other end of the main body is a detection end; the detection end is provided with an annular wafer and a guide end head which is positioned in the center of the annular wafer and is used for being matched with the cross groove on the cross countersunk head bolt; the main body is internally provided with a signal transmitting line and a signal receiving line which are used for connecting the annular wafer and the interface.

Meanwhile, the device also comprises a step-shaped test block and a cross countersunk head bolt sample piece for carrying out process parameter calibration; a blind hole corresponding to a type of cross countersunk head bolt is formed in each step plane of the step-shaped test block; the blind hole can be matched with the guide end socket; the height of each step is the distance from the detection surface of the cross countersunk head bolt of the corresponding model to the first thread; the cross countersunk head bolt sample pieces are cross countersunk head bolts of various types, and groove type artificial defects are processed at the first thread of the cross countersunk head bolts; the intelligent control terminal is used for calibrating the process parameters and storing the calibrated process parameters into a detection mode.

Further, the high-frequency ultrasonic signal host comprises an ultrasonic transmitting and receiving circuit, a signal acquisition circuit, an ultrasonic control circuit and a data processing circuit; an ultrasonic control algorithm module is arranged in the ultrasonic control circuit; a signal processing algorithm module is arranged in the data processing circuit;

the ultrasonic control circuit is used for receiving the control instruction and sending echo waveforms and calculation results to the intelligent control terminal;

the ultrasonic control algorithm module is used for analyzing the control instruction and setting the technological parameters of the ultrasonic transmitting and receiving circuit according to the control instruction;

the ultrasonic transmitting and receiving circuit is used for exciting high-frequency ultrasonic signals and receiving echo signals according to technological parameters and transmitting the echo signals to the signal acquisition circuit;

the signal acquisition circuit is used for converting echo signals into digital signal sequences and sending the digital signal sequences to the data processing circuit;

the signal processing algorithm module in the data processing circuit is used for reading the digital signal sequence and processing the digital signal sequence into echo waveforms and calculation results.

Further, the annular wafer is located on the outer side end face of the main body of the probe and is further provided with an acoustic matching layer, and the acoustic matching layer and the annular wafer are coaxially arranged with the guide end head. By arranging the acoustic matching layer, on one hand, the best matching and the best penetration of the acoustic performance of the annular piezoelectric wafer can be achieved, so that the annular piezoelectric wafer has the best sensitivity and spectral characteristics under the central frequency, and meanwhile, the annular wafer can be protected, the annular forbidden wafer and the electrode layer are protected, and the annular wafer is prevented from being damaged in the flaw detection process.

The second object of the present invention is to provide a flaw detection method using the above-mentioned cross countersunk head bolt flaw detection system, which can realize accurate flaw detection of the cross countersunk head bolt.

The technical scheme for realizing the second purpose of the invention is as follows: the flaw detection method by using the cross countersunk head bolt flaw detection in-situ ultrasonic detection system comprises the following steps:

s1, preparing: the probe is in communication connection with a high-frequency ultrasonic signal host, and then the high-frequency ultrasonic signal host and the intelligent control terminal are opened; then reading a currently stored process parameter setting file; then entering a working state of in-situ ultrasonic detection of the cross countersunk head bolt; the currently stored process parameter setting file is the recorded detection process parameter of the cross countersunk head bolt of a certain model;

s2, selecting a corresponding process parameter setting file on the intelligent control terminal according to the type of the cross countersunk head bolt to be detected, and then entering a detection state;

s3, coating a proper amount of coupling agent on the end face of a screw cap of the inspected cross countersunk head bolt, and clamping the guide end head of the probe into the center of a cross groove of the inspected cross countersunk head bolt; slowly rotating the probe to observe the change condition of echo reflection signals in a waveform display area on the intelligent control terminal; if the amplitude of the echo signal wave is found to be changed in the process of rotating the probe, the probe is fixed at the highest position of the echo signal wave;

s4, the high-frequency ultrasonic signal host machine processes the echo signals from the probe into echo waveforms and calculation results, and transmits the echo waveforms and calculation results to the intelligent control terminal;

s5, the intelligent control terminal processes the received echo waveform and the calculation result, displays the processed echo waveform and the calculation result on a display interface of the intelligent control terminal, and outputs a detection result.

Before step S2, process parameter calibration can be performed as required; the process parameter calibration steps are as follows:

A. preparing a stepped test block and a cross countersunk head bolt sample; a blind hole corresponding to a type of cross countersunk head bolt is formed in each step plane of the step-shaped test block; the blind hole can be matched with the guide end socket; the height of each step is the distance from the detection surface of the cross countersunk head bolt of the corresponding model to the first thread; the cross countersunk head bolt sample pieces are cross countersunk head bolts of various types, and groove type artificial defects are processed at the first thread of the cross countersunk head bolts;

B. inputting the specification, model and number of the probe at the intelligent control terminal, and inputting the length of the cross countersunk head bolt to be calibrated;

C. placing the probe on a blind hole of a step with the height corresponding to the length of the checked cross countersunk head bolt on the step-shaped test block, and finding out first reflected waves of the bottom surface of the step-shaped test block;

D. on the intelligent control terminal, the control line of the detection range is moved to the crest of the primary reflected wave on the bottom surface of the stepped test block;

E. clicking a detection range setting button to finish setting range parameters of the detection wave gate;

F. transferring the probe to the end face of a nut of a cross countersunk head bolt of a corresponding model on a cross countersunk head bolt sample piece, rotating the probe, and searching for the highest wave of the artificial grooving reflection signal of the cross countersunk head bolt sample piece;

G. moving a wave gate start line to the left side of the artificial grooving reflection signal and a wave gate end line to the right side of the artificial grooving reflection signal on the intelligent control terminal; in the process, the reflection signal of the manual cutting groove is kept unchanged;

H. clicking a detection wave gate setting button to finish setting of detection wave gate parameters and detection sensitivity;

I. observing whether the highest wave of the reflected signal of the artificial grooving appears in the range of the detection wave gate; if the deviation exists, the process parameter adjustment is carried out, or the process parameter calibration operation is carried out again until the conditions are met.

The invention has the positive effects that: (1) The invention has good coupling effect, and can effectively avoid the problem that clutter and defect waves are covered due to scattering or attenuation caused by sound energy dispersion caused by cross grooves; the detection effect of the cross countersunk head bolt is greatly improved.

(2) The invention can detect the artificial defects of 1mm deep, 1mm long and 0.13mm wide at the thread root of the cross countersunk head bolt, and has obvious defect reflection wave and clear waveform. And simultaneously, fatigue cracks of the cross groove type countersunk head bolts can be detected.

(3) Through experiments, the common longitudinal wave probe, the small-angle longitudinal wave probe, the double-wafer probe, the small-wafer probe and the cross wedge probe can not detect the artificial defects of the cross groove type countersunk head bolts, but the probe can detect the artificial defects of the cross groove type countersunk head bolts with the length ranging from 22mm to 90 mm.

Drawings

In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which

FIG. 1 is a schematic diagram of electrical connection of a cross countersunk head bolt flaw detection in-situ ultrasonic detection system;

FIG. 2 is a schematic diagram of the structure of the probe in the present invention;

FIG. 3 is a schematic diagram of a step-like test block according to the present invention;

FIG. 4 is a graph showing an example of a 1mm kerf simulated crack reflected wave for detecting a 36mm long, 6mm diameter bolt real sample in accordance with the present invention;

FIG. 5 is a graph showing an example of a 2mm kerf simulated crack reflected wave for detecting a full pattern of a 46mm long, 6mm diameter bolt according to the present invention;

FIG. 6 is a graph of an exemplary reflected wave of a 2mm kerf simulated crack for detecting a 82mm long, 6mm diameter bolt real sample in accordance with the present invention;

FIG. 7 is an ultrasonic signal generation module circuit in the present invention;

FIG. 8 is an ultrasonic signal receiving and amplifying module circuit in the present invention;

FIG. 9 is a circuit of a second-stage amplification module of an ultrasonic signal according to the present invention;

FIG. 10 is a signal acquisition circuit of the present invention;

fig. 11 is an ultrasonic control circuit in the present invention.

Detailed Description

Referring to fig. 1 to 3, the in-situ ultrasonic detection system for flaw detection of the cross countersunk head bolt comprises a high-frequency ultrasonic signal host machine 1, an intelligent control terminal 2 and a probe 3; the high-frequency ultrasonic signal host 1 is in data connection with the intelligent control terminal 2 through a network; the probe 3 is in communication connection with the high-frequency ultrasonic signal host 1 through a data line; the network connection may be a wired network connection or a wireless network connection.

The high-frequency ultrasonic signal host 1 is used for exciting a high-frequency ultrasonic signal according to a control instruction, supplying the excitation of the high-frequency ultrasonic signal to the probe 3, processing a received echo signal into an echo waveform and a calculation result, and transmitting the echo waveform and the calculation result to the intelligent control terminal 2;

the intelligent control terminal 2 is used for setting detected technological parameters, sending control instructions to the high-frequency ultrasonic signal host 1, receiving echo waveforms and calculation results from the high-frequency ultrasonic signal host 1 and displaying detection results;

the probe 3 is used for sending out ultrasonic waves to the cross countersunk head bolt according to the excitation of the high-frequency ultrasonic signals provided by the high-frequency ultrasonic signal host machine 1 and transmitting the received echo signals to the high-frequency ultrasonic signal host machine 1; of course, when detecting different types of cross countersunk head bolts, because the bolt length is different, in order to guarantee detection accuracy, different types of probes need to be prepared.

The probe 3 comprises a main body 31, and one end of the main body 31 is provided with an interface 32 for communication connection; the other end of the main body 31 is a detection end; the detection end is provided with an annular wafer 33 and a guide end 34 which is positioned in the center of the annular wafer 33 and is used for being matched with a cross groove on the cross countersunk head bolt; a signal transmitting line 35 and a signal receiving line 36 for connecting the ring-shaped wafer 33 and the interface 32 are provided in the main body 31; as shown in fig. 2, the damping 37 is further disposed in the main body, and the damping 37 can support the annular wafer 33 and absorb ultrasonic waves emitted from the back of the annular wafer, so that inconvenience caused by detecting and detecting the cross groove bolts in the prior art is effectively solved, efficient and accurate detection can be stably and effectively performed on the bolts, and the ultrasonic inspection device is ingenious in structure and efficient and practical. An electrical impedance 38 is also provided between the signal transmission line 35 and the signal receiving line 37, and both ends of the electrical impedance 38 are connected to the signal transmission line and the signal receiving line.

The annular wafer 33 is further provided with an acoustic matching layer 39 on the outer end face of the body 31 of the probe 3, and the acoustic matching layer 39 and the annular wafer 33 are both coaxially arranged with the guide tip 34. By providing the acoustic matching layer 39, on the one hand, the best matching and the best penetration of the acoustic performance of the ring-shaped piezoelectric wafer 33 can be achieved, so that the ring-shaped piezoelectric wafer 33 has the best sensitivity and spectral characteristics at the center frequency, and meanwhile, the ring-shaped wafer 33 can be protected, the ring-shaped wafer 33 and the electrode layer are protected, and damage of the ring-shaped wafer 33 in the flaw detection process is avoided.

The dimensions of the annular wafer 33 are two kinds of phi 8 phi 4 inner holes and phi 6 phi 3 inner holes, and the two kinds of probes 3 are adopted for two kinds of bolts phi 8 and phi 6 respectively. The bottom of each probe 3 is provided with an acoustic matching layer 39, the thickness of the acoustic matching layer 39 is determined according to the frequency of the annular wafer 33, the optimal penetration performance is designed to be one quarter wavelength to realize the optimal bandwidth, resolution, signal to noise ratio and sensitivity of the probe 3, and simultaneously, in order to improve the service life of the probe 3, each probe 3 is provided with an electrical matching, and the electrical impedance 38 is determined according to the frequency and the size of the annular wafer 33. The advantage is to optimize the overall performance of the probe 3, with the emphasis on being acceptable for use in a long-term high voltage environment.

At the same time comprise the steps for carrying out the processA step-shaped test block 4 for parameter calibration and a cross countersunk head bolt sample piece; a blind hole 41 corresponding to a type of cross countersunk head bolt is formed in each step plane of the step-shaped test block 4; the blind hole 41 can be matched with the guide end head 34; the blind hole 41 has a size of

The height of each step is the distance from the detection surface (namely the end surface of the nut) of the cross countersunk head bolt of the corresponding model to the first thread; the cross countersunk head bolt sample pieces are cross countersunk head bolts of various types, and groove type artificial defects are processed at the first thread of the cross countersunk head bolts; the intelligent control terminal 2 is used for calibrating process parameters and storing the calibrated process parameters into a detection mode.

The high-frequency ultrasonic signal host 1 comprises an ultrasonic transmitting and receiving circuit 11, a signal acquisition circuit 12, an ultrasonic control circuit 13 and a data processing circuit 14; an ultrasonic control algorithm module 131 is arranged in the ultrasonic control circuit 13; a signal processing algorithm module 141 is arranged in the data processing circuit 14;

the ultrasonic control circuit 13 is used for receiving a control instruction and sending an echo waveform and a calculation result to the intelligent control terminal 2;

the ultrasonic control algorithm module 131 is used for analyzing the control instruction and setting the technological parameters of the ultrasonic transmitting and receiving circuit according to the control instruction;

the ultrasonic transmitting and receiving circuit 11 is used for exciting high-frequency ultrasonic signals and receiving echo signals according to technological parameters and transmitting the echo signals to the signal acquisition circuit 12;

the signal acquisition circuit 12 is configured to convert the echo signal into a digital signal sequence and send the digital signal sequence to the data processing circuit 14;

the signal processing algorithm module 141 in the data processing circuit 14 is configured to read the digital signal sequence and process the digital signal sequence into an echo waveform and a calculation result.

Wherein the ultrasonic transmitting-receiving circuit 11 includes an ultrasonic signal generating module circuit, an ultrasonic signal receiving-amplifying module circuit, and an ultrasonic signal secondary amplifying module circuit, see fig. 7 to 9. The echo signals can be further amplified through the ultrasonic signal secondary amplification module circuit, and the signals can be conveniently sampled and identified in the later period.

The signal acquisition circuit 12 and the ultrasound control circuit 13 can be seen in fig. 10 and 11, respectively.

The flaw detection method by using the cross countersunk head bolt flaw detection in-situ ultrasonic detection system comprises the following steps:

s1, preparing: the probe 3 is in communication connection with the high-frequency ultrasonic signal host 1, and then the high-frequency ultrasonic signal host 1 and the intelligent control terminal 2 are opened; then reading a currently stored process parameter setting file; then entering a working state of in-situ ultrasonic detection of the cross countersunk head bolt; the currently stored process parameter setting file is the recorded detection process parameter of the cross countersunk head bolt of a certain model;

s2, selecting a corresponding process parameter setting file on the intelligent control terminal 2 according to the type of the cross countersunk head bolt to be detected, and then entering a detection state;

s3, coating a proper amount of coupling agent on the end face of a screw cap of the inspected cross countersunk head bolt, and clamping a guide end 34 of the probe 3 into the center of a cross groove of the inspected cross countersunk head bolt; slowly rotating the probe 3, and observing the change condition of echo reflection signals in a waveform display area on the intelligent control terminal 2; if the amplitude of the echo signal wave is found to be changed in the process of rotating the probe 3, the probe 3 is fixed at the highest position of the echo signal wave;

s4, the high-frequency ultrasonic signal host 1 processes the echo signal from the probe 3 into an echo waveform and a calculation result and transmits the echo waveform and the calculation result to the intelligent control terminal 2;

s5, the intelligent control terminal 2 processes the received echo waveform and the calculation result, displays the processed echo waveform and the calculation result on a display interface of the intelligent control terminal, and outputs a detection result.

Before step S2, process parameter calibration can be performed as required; the process parameter calibration steps are as follows:

A. preparing a stepped test block 4 and a cross countersunk head bolt sample; a blind hole 41 corresponding to a type of cross countersunk head bolt is formed in each step plane of the step-shaped test block 4; the blind hole 41 can be matched with the guide end head 34; the depth of the blind hole 41 corresponds to the height of each step; the height of each step is the distance from the top of the cross countersunk head bolt of the corresponding model to the first thread; the cross countersunk head bolt sample pieces are cross countersunk head bolts of various types, and the first thread of each cross countersunk head bolt is provided with a manual cutting groove;

B. inputting the specification, model and number of the probe 3 into the intelligent control terminal 2, and inputting the length of the cross countersunk head bolt to be calibrated;

C. placing the probe 3 on a stepped blind hole 41 with the height corresponding to the length of the checked cross countersunk head bolt on the stepped test block 4, and finding out first reflected waves of the bottom surface of the stepped test block 4;

D. on the intelligent control terminal 2, the control line of the detection range is moved to the crest of the primary reflected wave on the bottom surface of the stepped test block;

E. clicking a detection range setting button to finish setting range parameters of the detection wave gate;

F. transferring the probe 3 to the end face of a nut of a cross countersunk head bolt of a corresponding model on a cross countersunk head bolt sample piece, rotating the probe 3, and searching for the highest wave of the artificial grooving reflection signal of the cross countersunk head bolt sample piece;

G. moving a wave gate start line to the left side of the artificial grooving reflection signal and a wave gate end line to the right side of the artificial grooving reflection signal on the intelligent control terminal 2; in the process, the reflection signal of the manual cutting groove is kept unchanged;

H. clicking a detection wave gate setting button to finish setting of detection wave gate parameters and detection sensitivity;

I. observing whether the highest wave of the reflected signal of the artificial grooving appears in the range of the detection wave gate; if the deviation exists, the process parameter adjustment is carried out, or the process parameter calibration operation is carried out again until the conditions are met.

By using the cross countersunk head bolt flaw detection system and the flaw detection method, the echo waveform and the calculation result when the cross countersunk head bolt is detected respectively can be referred to fig. 4 to 6, wherein the circled part in the figure is displayed as an abnormal result.

FIG. 4 is a graph showing an example of a 1mm kerf simulated crack reflected wave for detecting a 36mm long, 6mm diameter bolt real sample in accordance with the present invention;

FIG. 5 is a graph showing an example of a 2mm kerf simulated crack reflected wave for detecting a full pattern of a 46mm long, 6mm diameter bolt according to the present invention;

FIG. 6 is a graph showing an example of the detection of a 2mm cut simulated crack reflection wave for a 82mm long, 6mm diameter bolt real sample according to the present invention.

While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be had by the present invention, it should be understood that the foregoing description is merely illustrative of the present invention and that no limitations are intended to the scope of the invention, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the invention.

Claims (6)

1. The ultrasonic detection system for detecting the flaw of the cross countersunk head bolt in situ is characterized in that: the device comprises a high-frequency ultrasonic signal host, an intelligent control terminal and a probe; the high-frequency ultrasonic signal host computer is in data connection with the intelligent control terminal through a network; the probe is in communication connection with the high-frequency ultrasonic signal host through a data line;

the high-frequency ultrasonic signal host is used for exciting the high-frequency ultrasonic signals according to the control instruction, supplying the excitation of the high-frequency ultrasonic signals to the probe, processing the received echo signals into echo waveforms and calculation results, and transmitting the echo waveforms and calculation results to the intelligent control terminal;

the intelligent control terminal is used for setting detected technological parameters, sending control instructions to the high-frequency ultrasonic signal host, receiving echo waveforms and calculation results from the high-frequency ultrasonic signal host and displaying detection results;

the probe is used for sending out ultrasonic waves to the cross countersunk head bolt according to the excitation of the high-frequency ultrasonic signals provided by the high-frequency ultrasonic signal host machine and transmitting the received echo signals to the high-frequency ultrasonic signal host machine;

the probe comprises a main body, wherein one end of the main body is provided with an interface for communication connection; the other end of the main body is a detection end; the detection end is provided with an annular wafer and a guide end head which is positioned in the center of the annular wafer and is used for being matched with the cross groove on the cross countersunk head bolt; the main body is internally provided with a signal transmitting line and a signal receiving line which are used for connecting the annular wafer and the interface.

2. The ultrasonic in-situ inspection system for cross countersunk head bolts in a test machine of claim 1, wherein: the device also comprises a stepped test block and a cross countersunk head bolt sample piece for carrying out process parameter calibration; a blind hole corresponding to a type of cross countersunk head bolt is formed in each step plane of the step-shaped test block; the blind hole can be matched with the guide end socket; the height of each step is the distance from the detection surface of the cross countersunk head bolt of the corresponding model to the first thread; the cross countersunk head bolt sample pieces are cross countersunk head bolts of various types, and groove type artificial defects are processed at the first thread of the cross countersunk head bolts; the intelligent control terminal is used for calibrating the process parameters and storing the calibrated process parameters into a detection mode.

3. The ultrasonic in-situ inspection system for cross countersunk head bolts according to claim 1 or 2, wherein: the high-frequency ultrasonic signal host comprises an ultrasonic transmitting and receiving circuit, a signal acquisition circuit, an ultrasonic control circuit and a data processing circuit; an ultrasonic control algorithm module is arranged in the ultrasonic control circuit; a signal processing algorithm module is arranged in the data processing circuit;

the ultrasonic control circuit is used for receiving the control instruction and sending echo waveforms and calculation results to the intelligent control terminal;

the ultrasonic control algorithm module is used for analyzing the control instruction and setting the technological parameters of the ultrasonic transmitting and receiving circuit according to the control instruction;

the ultrasonic transmitting and receiving circuit is used for exciting high-frequency ultrasonic signals and receiving echo signals according to set technological parameters and transmitting the echo signals to the signal acquisition circuit;

the signal acquisition circuit is used for converting echo signals into digital signal sequences and sending the digital signal sequences to the data processing circuit;

the signal processing algorithm module in the data processing circuit is used for reading the digital signal sequence and processing the digital signal sequence into echo waveforms and calculation results.

4. The ultrasonic in-situ inspection system for cross countersunk head bolts in a test machine of claim 1, wherein: the annular wafer is located on the outer side end face of the main body of the probe and is further provided with an acoustic matching layer, and the acoustic matching layer and the annular wafer are coaxially arranged with the guide end head.

5. A flaw detection method using the cross countersunk head bolt flaw detection in-situ ultrasonic detection system as claimed in claim 1, characterized by comprising the steps of:

s1, preparing: the probe is in communication connection with a high-frequency ultrasonic signal host, and then the high-frequency ultrasonic signal host and the intelligent control terminal are opened; then reading a currently stored process parameter setting file; then entering a working state of in-situ ultrasonic detection of the cross countersunk head bolt; the currently stored process parameter setting file is the recorded detection process parameter of the cross countersunk head bolt of a certain model;

s2, selecting a corresponding process parameter setting file on the intelligent control terminal according to the type of the cross countersunk head bolt to be detected, and then entering a detection state;

s3, coating a proper amount of coupling agent on the end face of a screw cap of the inspected cross countersunk head bolt, and clamping the guide end head of the probe into the center of a cross groove of the inspected cross countersunk head bolt; slowly rotating the probe to observe the change condition of echo reflection signals in a waveform display area on the intelligent control terminal; if the amplitude of the echo signal wave is found to be changed in the process of rotating the probe, the probe is fixed at the highest position of the echo signal wave;

s4, the high-frequency ultrasonic signal host machine processes the echo signals from the probe into echo waveforms and calculation results, and transmits the echo waveforms and calculation results to the intelligent control terminal;

s5, the intelligent control terminal processes the received echo waveform and the calculation result, displays the processed echo waveform and the calculation result on a display interface of the intelligent control terminal, and outputs a detection result.

6. The flaw detection method according to claim 5, wherein: before step S2, process parameter calibration can be performed as required; the process parameter calibration steps are as follows:

A. preparing a stepped test block and a cross countersunk head bolt sample; a blind hole corresponding to a type of cross countersunk head bolt is formed in each step plane of the step-shaped test block; the blind hole can be matched with the guide end socket; the height of each step is the distance from the detection surface of the cross countersunk head bolt of the corresponding model to the first thread; the cross countersunk head bolt sample pieces are cross countersunk head bolts of various types, and groove type artificial defects are processed at the first thread of the cross countersunk head bolts;

B. inputting the specification, model and number of the probe at the intelligent control terminal, and inputting the length of the cross countersunk head bolt to be calibrated;

C. placing the probe on a blind hole of a step with the height corresponding to the length of the checked cross countersunk head bolt on the step-shaped test block, and finding out first reflected waves of the bottom surface of the step-shaped test block;

D. on the intelligent control terminal, the control line of the detection range is moved to the crest of the primary reflected wave on the bottom surface of the stepped test block;

E. clicking a detection range setting button to finish setting range parameters of the detection wave gate;

F. transferring the probe to the end face of a nut of a cross countersunk head bolt of a corresponding model on a cross countersunk head bolt sample piece, rotating the probe, and searching for the highest wave of the artificial grooving reflection signal of the cross countersunk head bolt sample piece;

G. moving a wave gate start line to the left side of the artificial grooving reflection signal and a wave gate end line to the right side of the artificial grooving reflection signal on the intelligent control terminal; in the process, the reflection signal of the manual cutting groove is kept unchanged;

H. clicking a detection wave gate setting button to finish setting of detection wave gate parameters and detection sensitivity;

I. observing whether the highest wave of the reflected signal of the artificial grooving appears in the range of the detection wave gate; if the deviation exists, the process parameter adjustment is carried out, or the process parameter calibration operation is carried out again until the conditions are met.

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