Showing papers on "Time-of-flight diffraction ultrasonics published in 2015"
TL;DR: These TOFD ultrasonic transducers based on PMNT/epoxy 1–3 composite exhibit considerably improved performance over the commercial PZT/ep oxygen 1-3 composite TOFD Ultrasonic transducer.
Abstract: 5–6 MHz PMNT/epoxy 1–3 composites were prepared by a modified dice-and-fill method. They exhibit excellent properties for ultrasonic transducer applications, such as ultrahigh thickness electromechanical coupling coefficient kt (85.7%), large piezoelectric coefficient d33 (1209 pC/N), and relatively low acoustic impedance Z (1.82 × 107 kg/(m2·s)). Besides, two types of Time-of-Flight Diffraction (TOFD) ultrasonic transducers have been designed, fabricated, and characterized, which have different matching layer schemes with the acoustic impedance of 4.8 and 5.7 × 106 kg/(m2·s), respectively. In the detection on a backwall of 12.7 mm polystyrene, the former exhibits higher detectivity, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −21.93 dB and 102.7%, respectively, while the later exhibits broader bandwidth, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −24.08 dB and 117.3%, respectively. These TOFD ultrasonic transducers based on PMNT/epoxy 1–3 composite exhibit considerably improved performance over the commercial PZT/epoxy 1–3 composite TOFD ultrasonic transducer.
23 citations
TL;DR: An analytical approach for simulation of ultrasonic diffracted wave signals from cracks in two-dimensional geometries based on a novel Huygens-Fresnel Diffraction Model (HFDM), able to evaluate back-wall signal amplitude and lateral wave signal amplitude, quantitatively is presented.
10 citations
Patent•
22 Jul 2015
TL;DR: In this article, an ultrasonic detecting and positioning method and device based on TOFD (time of flight diffraction) and a phased array is presented. But the method is not suitable for the detection of weld joints.
Abstract: The invention relates to an ultrasonic detecting and positioning method and device based on TOFD (time of flight diffraction) and a phased array. The device comprises a TOFD detection unit and a phased array detection unit, wherein the TOFD detection unit is used for scanning weld joints with a TOFD-based ultrasonic detection method to determine positions of defects; the phased array detection unit is used for scanning weld joints nearby the determined defect positions with a phased-array-based ultrasonic detection method, identifying defects with sizes exceeding a preset size threshold and positioning the identified defects. Position information of the defects in horizontal and depth directions can be determined accurately through phased-array-based ultrasonic detection, during positioning in cooperation with TOFD detection, the defects of the weld joints are accurately positioned with TOFD scanning serving as a main method and phased array scanning serving as an auxiliary method, and problems that the positioning accuracy of TOFD scanning is poor and transverse defects cannot be detected during non-parallel scanning are solved.
9 citations
Patent•
30 Dec 2015
TL;DR: In this article, a water spray type automatic scanning device for ultrasonic TOFD nondestructive testing is proposed, where the probe clamping portion is used for carrying testing probes and enabling the probes to be in close contact with a tested workpiece through certain coupling pressure.
Abstract: The invention relates to a water spray type automatic scanning device for ultrasonic TOFD nondestructive testing. The water spray type automatic scanning device for ultrasonic TOFD nondestructive testing consists of a probe clamping portion, a coupling water circulating portion, a probe spacing PCS adjustment portion and a three-dimensional movement portion, wherein the probe clamping portion is used for carrying testing probes and enabling the probes to be in close contact with a tested workpiece through certain coupling pressure; the probe clamping portion is connected with the PCS adjustment portion through an L-shaped connecting piece to realize accurate adjustment of probe spacing PCS; the PCS adjustment portion is connected with the three-dimensional portion through an L-shaped connecting piece to realize probe height adjustment, ultrasonic TOFD-B scanning and D scanning; the coupling water circulating portion is responsible for filling water in water spray probes to form a coupling water layer on a contact surface between the workpiece and the probes, and can realize cyclic utilization of coupling water. The water spray type automatic scanning device for ultrasonic TOFD nondestructive testing has the advantages that the ultrasonic intensity and signal stability can be kept during automatic scanning, the influence of human factors on testing results is reduced, the testing efficiency is improved and the wear of the probes due to direct contact between the probes and the workpiece is avoided.
7 citations
02 Apr 2015
TL;DR: In this paper, an overview of the models integrated in the CIVA software platform and devoted to ultrasonic TOFD simulation is presented, and experimental validations have been performed both on planar blocks containing calibration holes and various notches and also on a specimen with an irregular entry surface.
Abstract: The ultrasonic TOFD (Time of Flight Diffraction) Technique is commonly used to detect and characterize disoriented cracks using their edge diffraction echoes. An overview of the models integrated in the CIVA software platform and devoted to TOFD simulation is presented. CIVA allows to predict diffraction echoes from complex 3D flaws using a PTD (Physical Theory of Diffraction) based model. Other dedicated developments have been added to simulate lateral waves in 3D on planar entry surfaces and in 2D on irregular surfaces by a ray approach. Calibration echoes from Side Drilled Holes (SDHs), specimen echoes and shadowing effects from flaws can also been modelled. Some examples of theoretical validation of the models are presented. In addition, experimental validations have been performed both on planar blocks containing calibration holes and various notches and also on a specimen with an irregular entry surface and allow to draw conclusions on the validity of all the developed models.
6 citations
Patent•
10 Jun 2015
TL;DR: In this paper, a method and a device for TOFD (Time of Flight Diffraction) detection of a pressure pipeline on the basis of an ultrasonic phased array is presented.
Abstract: The invention relates to a method and a device for TOFD (Time of Flight Diffraction) detection of a pressure pipeline on the basis of an ultrasonic phased array, and aims to ensure that the provided detection method and a system can be used for performing defect detection on the interior of the pressure pipeline and have the technical characteristics of strong interference resistance, high detection speed, accurate result and convenience in use The technical scheme is as follows: the device for the TOFD detection of the pressure pipeline on the basis of the ultrasonic phased array comprises an ultrasonic detector host, a robot control module, two conic phased array probe devices, an instrument device, a probe clamping device, a pipeline climbing robot, a coaxial cable, a coder, a centering device, a large-angle center fixing device and a metal flexible tube The method using the device for the TOFD detection of the pressure pipeline on the basis of the ultrasonic phased array comprises the following steps: (1) adjusting detection positions; (2) emitting ultrasonic waves; and (3) receiving reflected waves
6 citations
TL;DR: In this paper, a linear frequency modulated (LFM) pulse with a large time-bandwidth product can be used as the exciting signal in the ultrasonic inspection of the austenitic stainless steel welds, which can both enhance the average transmitted power and increase the signal to noise ratio (SNR) and time resolution by pulse compression process.
Abstract: The main problems for ultrasonic inspection of austenitic stainless steel welds are low signal to noise ratio (SNR) and detection accuracy, caused by anisotropic and heterogeneous material structure with bulky columnar crystal. In order to overcome the problems mentioned above, a linear frequency modulated (LFM) pulse with a large time-bandwidth product can be used as the exciting signal in the ultrasonic inspection of the austenitic stainless steel welds, which can both enhance the average transmitted power and increase the SNR and time resolution by pulse compression process. Therefore, the ultrasonic time-of-flight diffraction (TOFD) technique with the LFM excitation was carried out to realize an accurate sizing and locating detection in austenitic stainless steel welds. Compared with the conventional TOFD testing, the SNR can be increased 12–15 dB, and the measured accuracy is also enhanced obviously. Accordingly the measured depth error is less than 0.81 % and the length error is less than 2.5 %. The proposed method can both enhance the capabilities of the ultrasonic inspection of austenitic welds and the measurement accuracy of ultrasonic TOFD testing.
6 citations
Patent•
22 Jul 2015
TL;DR: In this paper, a pressure pipeline TOFD detection device based on an ultrasonic phased array was proposed, which has the characteristics of high interference resistance, high detection speed, accurate result and convenience in use.
Abstract: The utility model relates to a pressure pipeline TOFD detection device based on an ultrasonic phased array, and aims to provide a detection device for detecting defects in a pressure pipeline. The pressure pipeline TOFD detection device has the characteristics of high interference resistance, high detection speed, accurate result and convenience in use. According to the technical scheme, the pressure pipeline TOFD detection device based on the ultrasonic phased array comprises an ultrasonic detector host unit, a robot control module, two conical phased array probe devices, an instrument device, a probe clamping device, a pipeline climbing robot, a coaxial cable wire, an coder, a straightener, a large-angle centering machine and a metal flexible pipe.
5 citations
TL;DR: The efficiency of the algorithms was analyzed by comparing and validating the size of defect with that of standard radiographic results in the form of error percentage, indicating that the Region- Based Level Set algorithm is the best as compared to Discontinuity Based Segmentation algorithm for defect segmentation and characterization in TOFD images.
Abstract: Background/Objectives: Grain structure of Austenitic Stainless Steel (ASS) weld causes difficulty in defect detection while inspecting using Time of Flight Diffraction (TOFD) method. This study aims at comparing segmentation methods to overcome this difficulty based on defect characterization. Methods/Statistical Analysis: This study makes use of TOFD and Radiographic images of ASS weld pads fabricated with defined linear and volumetric defects. The Region-Based Level Set algorithm and Discontinuity Based Segmentation algorithm were explored for achieving flaw segmentation and quantitative characterization and validation of the result with that of standard radiographic results. Findings: The efficiency of the algorithms was analyzed by comparing and validating the size of defect with that of standard radiographic results in the form of error percentage. The consistency of error percentage in defect sizing (up to 11%) achieved by Region- Based Level Set algorithm for all the test images given in the database indicate that, this algorithm is the best as compared to Discontinuity Based Segmentation algorithm(error percentage up to 47%) for defect segmentation and characterization in TOFD images. Application/Improvements: The segmentation algorithm enables automation of measurement process and enhanced detection and characterization of defects at the initial stage. Further, it reduces human fatigue caused by operator while defect detection as the volume of data increases. The future direction is to fully automate the system in order to save time for interpretation and to modify the algorithm to segment images with multiple defects.
5 citations
Patent•
09 Sep 2015
TL;DR: In this article, a method for improving longitudinal resolution of TOFD (time of flight diffraction) detection with a Burg algorithm based autoregressive spectrum extrapolation technology is presented.
Abstract: The invention discloses a method for improving longitudinal resolution of TOFD (time of flight diffraction) detection with a Burg algorithm based autoregressive spectrum extrapolation technology, and belongs to the technical field of ultrasonic non-destructive detection. The method adopts an ultrasonic detection system comprising a TOFD ultrasonic detection instrument, TOFD probes, a scanning device, software integrating TOFD conventional analysis functions and a computer. According to the method, TOFD scanning is performed on defects, collected time-domain aliasing signals containing upper-end and lower-end diffraction waves of the defects are subjected to autoregressive spectrum extrapolation processing; the -6dB frequency bandwidth is taken as the benchmark, defect signals in the frequency band range are selected, defect signals outside the frequency band range are estimated with the Burg algorithm, so that the frequency bandwidth is broadened, the longitudinal resolution of defect detection is improved, and the defect height quantification is realized. Compared with other methods for improving the longitudinal resolution of TOFD detection, the method does not have additional requirements for a hardware system, is not limited by exciting pulse time width of the detecting probes, and has higher engineering application value.
4 citations
TL;DR: In this article, the authors used time-of-flight-diffraction (ToFD) for non-destructive testing by ultrasound for detecting faults and discontinuities in different components.
Patent•
25 Mar 2015
TL;DR: In this article, a method for testing and identifying P92 steel weld metal microcracks was proposed, which comprises the steps of generating the P92 steels welded metal micro-cracks through simulation; testing a test block with the TOFD method and recording small recognizable defects in an image; testing the small defects obtained through the TOFLD method with the phase array method, and recording smaller defects, with length-width ratios larger than 3, in image; dissecting the interfaces of small defects to obtain a metallographic specimen, conducting dimensional measurement, and comparing
Abstract: The invention discloses a method for testing and identifying P92 steel weld metal microcracks. The method comprises the steps of generating the P92 steel weld metal microcracks through simulation; testing a test block with the TOFD method and recording small recognizable defects in an image; testing the small defects obtained through the TOFD method with the phase array method, and recording small defects, with length-width ratios larger than 3, in an image; dissecting the interfaces of the small defects to obtain a metallographic specimen, conducting dimensional measurement, and comparing a measurement result with the TOFD test image and the phase array test image; determining the morphology criteria for testing the P92 steel weld metal microcracks which are: a, small defects with dot characteristics and lengths smaller than 4 mm in the TOFD test image and b, small defects with length-width ratios larger than 3 in the phase array scan image; conducting field testing on P92 steel weld metal by means of the morphology criteria. By the adoption of the method, the rate of detection of microcracks in the P92 steel weld metal is increased, and potential safety hazards threatening safe operation of a unit are eliminated.
01 Jan 2015
TL;DR: In this paper, the authors used TOFD (Time of Flight Diffraction) method which employs low frequency probe and concentrate on the inspection area that longitudinal waves turn into transverse waves has been used.
Abstract: Polyethylene material has some specification that makes very difficult any kind of inspection based on ultrasonic. The acoustic impedance and sound velocity in this kind of material are near to the materials commonly used in ultrasonic wedges. Also this kind of materials are highly attenuative materials for ultrasound. To inspection of polyethylene circumferential but welds and overcome to all the problems mentioned, the especial technique of TOFD (Time of Flight Diffraction) method which employs low frequency probe and concentrate on the inspection area that longitudinal waves turn into transverse waves has been used. The purpose of inspection is determining the exact location of surface and internal welding defects. For this purpose, two separate polyethylene pipes with 10 inch in diameter, 15 mm thickness and also 25 inch diameter, 28 mm thickness, were selected. In total 40 artificial defects which involve 28 side drill holes in deferent depths and 12 surface and sub-surface notches were created. All artificially created defects were detected with very good accuracy. Unlike the conventional TOFD method which have 2 to 3 mm dead zone, by using the above method even surface notch with 0.5 mm has been detected.
Patent•
18 Feb 2015
TL;DR: In this paper, a manual multichannel TOFD scanning frame is presented, which consists of a total coder, a roller, a pushing handle and a plurality of pairs of probe assemblies.
Abstract: The invention provides a manual multichannel TOFD (time of flight diffraction) scanning frame and belongs to the technical field of machines. The manual multichannel TOFD scanning frame can be used for solving the problems that the existing TOFD scanning frame is inconvenient in operation and scanned data is not accurate enough. The multichannel TOFD scanning frame comprises a total coder, a roller, a pushing handle and a plurality of pairs of probe assemblies as well as a vertical beam and a plurality of cross beams, wherein the probe assemblies are electrically connected with the total coder, the roller and the probe assemblies are arranged on the cross beam, the pushing handle and the total coder are connected above the vertical beam, an alarm and a steering angle instrument are also arranged on the scanning frame, the steering angle instrument is arranged on the vertical beam and is electrically connected with the total coder, and the alarm is electrically connected with the total coder. The multichannel TOFD scanning frame has the advantages that whether the direction of travel of the scanning frame shifts from a desired track or not is detected by virtue of the steering angle instrument, and an alarm is given to inform a scanning worker of adjusting a scanning direction, so that accuracy of defect data obtained by scanning is guaranteed.
TL;DR: In this article, the TOFD ultrasonic inspection method was used for thin duplex steel weld joint inspection, where the authors proposed an extended research on the inspection of duplex steels, especially in welded joints.
Abstract: The use of non-destructive inspection techniques in conventional stainless steels is well established. However the non-destructive inspection of duplex and superduplex steels is a big challenge as those steels, being composed of ferrite and austenite, have some particularities. When using ultrasound, for instance, its waves propagate well in ferrite, but suffer strong attenuation, scattering and refraction in austenite. An extended research is proposed on the inspection of duplex steels, especially in welded joints, which presents the worst problems in those steels (incorrect ferrite/austenite balance and precipitation of deleterious phases). The aim of this work was to use the TOFD ultrasonic inspection method for the thin duplex steel weld joint inspection.
01 Jan 2015
Journal Article•
TL;DR: An image enhancement method based on synthetic aperture focusing technique (SAFT) that was able to accurately judge for crack defect and can be improved by 6.4% compared to that of traditional detection method.
Abstract: when testing the defect by ultrasonic time of flight diffraction (TOFD), the image signal detected is often re- shaped and resulted in inaccuracy of defect measurements because the probe beam has a limited range. This paper pro- posed an image enhancement method based on synthetic aperture focusing technique (SAFT). A mathematical model of testing image was first established based on the generation process of the image. A method was then designed for detect- ing defects in near surface blind area based on filtering of through waves. Finally, a synthetic aperture focusing algorithm based on peak capture pretreatment was used to enhance the resolution of the image. By applying the above method to test a crack defect of 15mm, the method was able to accurately judge for crack defect. Also, the measuring accuracy can be improved by 6.4% compared to that of traditional detection method.
Posted Content•
TL;DR: A blind deconvolution scheme based on statistical wavelet estimation, where the wavelet is statistically estimated from the signal itself by a kurtosis-based metric, which increases the time resolution of diffraction techniques.
Abstract: In this paper we present a blind deconvolution scheme based on statistical wavelet estimation. We assume no prior knowledge of the wavelet, and do not select a reflector from the signal. Instead, the wavelet (ultrasound pulse) is statistically estimated from the signal itself by a kurtosis-based metric. This wavelet is then used to deconvolve the RF (radiofrequency) signal through Wiener filtering, and the resultant zero phase trace is subjected to spectral broadening by Autoregressive Spectral Extrapolation (ASE). These steps increase the time resolution of diffraction techniques. Results on synthetic and real cases show the robustness of the proposed method.
Patent•
13 May 2015
TL;DR: In this article, a TOFD ultrasonic non-destructive-detection self-positioning clamp for a welding rotor is presented. And the welding rotor can be accurately aligned to a welding seam.
Abstract: The utility model belongs to the field of detecting robots and particularly relates to a TOFD ultrasonic nondestructive-detection self-positioning clamp for a welding rotor. The TOFD ultrasonic nondestructive-detection self-positioning clamp comprises an absorbing type mobile platform, a positioning system, a clamp sliding rail and a self-adaptive clamp. The TOFD ultrasonic nondestructive-detection self-positioning clamp is used for clamping a TOFD ultrasonic nondestructive-detection wedging block and a probe and enabling the wedging block to automatically adapt to the surface angle of the welding rotor according to the two rotary freedom degree of the tail end of the clamp and the elasticity of a spring and to be closely attached with the surface of the welding rotor; and the axial positioning with the welding rotor can be realized under the action of the positioning system, so that the wedging block can be accurately aligned to a welding seam.
Patent•
06 May 2015
TL;DR: In this article, the TOFD ultrasonic non-destructive testing self-positioning fixture of a welded rotor is used for clamping a TOFD testing wedge block and a probe, the wedge block automatically adapts to surface angle of the welded rod through two rotational degrees of freedom of the tail end of the fixture and spring force and is tightly pasted with the rod.
Abstract: The invention belongs to the field of testing robots and in particular relates to a TOFD ultrasonic non-destructive testing self-positioning fixture of a welded rotor. The fixture comprises an adsorption type mobile platform, a positioning system, a fixture slideway and a self-adaption fixture. The TOFD ultrasonic non-destructive testing self-positioning fixture of the welded rotor is used for clamping a TOFD ultrasonic non-destructive testing wedge block and a probe, the wedge block automatically adapts to surface angle of the welded rotor through two rotational degrees of freedom of the tail end of the fixture and spring force and is tightly pasted with the welded rotor, and axial positioning between the fixture and the welded rotor can be realized under action of the positioning system so that the welded block can accurately aim at a welded joint.
Patent•
23 Dec 2015
TL;DR: In this article, the utility model relates to a visual ultrasonic wave TOFD welding seam detecting system that can singlely use, sweep including ultrasonic testing and look into frame and screen data display device, the ultrasonic detection who is responsible for the welding seam respectively shows with the detection data are accurate.
Abstract: The utility model relates to a visual ultrasonic wave TOFD welding seam detecting system that can singlely use, sweep including ultrasonic testing and look into frame and screen data display device, the ultrasonic detection who is responsible for the welding seam respectively shows with the detection data are accurate, screen data display device loads to sweep to look into in ultrasonic testing and puts up, ultrasonic testing sweep look into detect the welding seam in, data are in the special TOFD instrument indication of distal end, to detect the complete demonstration of data again on ultrasonic testing sweeps the screen data display device on looking into the frame through the data line, realize single independent the detection, system convenient to use, it is extravagant to reduce the manpower, detection efficiency is high and the testing result is stable.
Patent•
04 Sep 2015
TL;DR: In this article, a fixing device for a nondructive test and a nondestructive testing device using the same and, more specifically, to a fixing devices for a non-destructive test which ensures to derive a highly reliable testing result by collinearly placing a center of a pair of probes when applying a TOFD method, and to increase work convenience of a tester.
Abstract: The present invention relates to a fixing device for a nondestructive test and a nondestructive testing device using the same and, more specifically, to a fixing device for a nondestructive test which ensures to derive a highly reliable testing result by collinearly placing a center of a pair of probes when applying a TOFD method, and to increase work convenience of a tester, by which a pair of pressurizing members, which fixate a probe used for the nondestructive test of various test materials, has the same displacement to one another, and pressurizes the probe; and also by applying the probe having various sizes and conformations with a single fixing device for nondestructive test.
Patent•
07 Jan 2015
TL;DR: In this paper, an acoustic beam spread angle testing device of an ultrasonic detection probe by time-of-flight diffraction is presented. But the authors do not specify the type of magnetic clip that is attached to the basic test block.
Abstract: The utility model discloses an acoustic beam spread angle testing device of an ultrasonic detection probe by time of flight diffraction. The acoustic beam spread angle testing device comprises a basic test block, a wedge block and a magnetic clip, wherein the basic test block is made from carbon steel, and comprises a sector test block and a rectangular test block which is integrally connected with the sector test block, wherein the central angle of the sector test block is 90 degrees; 0-90-degree scale lines are engraved on the circular arc lateral surface of the sector test block; the wedge block is put above the basic test block; the magnetic clip is tightly attracted on the basic test block, and comprises a strip-shaped iron sheet with an end part which can be buckled. By the acoustic beam spread angle testing device, the angle of the main acoustic beam spread angle, the angle of an upper semi-spread angle and the angle of the lower semi-spread angle of the probe can be obtained directly, so that the calculation process is prevented, the measurement errors can be reduced effectively, the detection technology precision and the practical data detection precision are improved, and moreover, the stability of the probe in the testing process can be ensured.
01 Jan 2015
TL;DR: In this article, a tethered 10" tool was developed for inspection of circumferential cracks at anode pads welded on the pipes, which can be used with a modified sensor carrier providing similar detection and sizing performance as for axial cracking.
Abstract: Typically inline inspection is carried out for the detection and sizing of geometry defects, corrosion / wall thickness loss and cracking defects. Regarding cracking, most of the time axial cracking (SCC, seam weld cracks....) is observed due to the typical loading condition in pressurized pipes. Since 1994 ultrasonic crack inspection tools are available for the reliable detection of such cracks using conventional ultrasonic shear wave technique. This technique is well suited for detection but has limited depth sizing capabilities as the reflection amplitudes are affected by several other factors apart from depth. Under special conditions (bending forces, poor welding) cracking can also appear in circumferential direction. For this type of cracks, basically the same type of tool can be used with a modified sensor carrier providing similar detection and sizing performance as for axial cracking. In offshore applications, however, accurate sizing in particular of crack depth is an important requirement as offshore verification and repair work is usually very cost-intensive. In order to provide a high POD together with good sizing performance a tethered 10" tool was developed for inspection of circumferential cracks at anode pads welded on the pipes. It contains a pulse - echo (PE) unit for reliable detection and a TOFD (time-of-flight-diffraction) unit for accurate sizing of circumferential cracks. The PE technique is used for fast screening during the forward inspection. The TOFD measurement which is basically stationary is performed on the backward inspection by stopping at every location where a crack indication was detected by the PE inspection. Extensive testing of the new tool was performed at a 10" test pipeline with circumferential cracking at original anode pads. Blind testing took place with 64 artificial weld defects and an unknown number of fatigue cracks at the anode pads which were generated by full scale fatigue testing of the corresponding pipes. After testing the sizes of the fatigue cracks (length, depth) were determined by destructive examination. The comparison of the results from ILI inspection and destructive testing showed that the ILI tethered tool fully met the specification with regard to detection and sizing. After the successful validation the tool was used for a tethered inspection of a 10" offshore pipeline (length 8 km). In the paper the inspection concept and the setup of the new tool will be described. Results from the qualification tests as well as from the first inspection run performed with the new tool will be presented.
Patent•
06 May 2015
TL;DR: In this article, a TOFD ultrasonic nondestructive testing robot system applicable to a steam turbine welding rotor is presented. But the robot is not equipped with a high-resolution camera.
Abstract: The invention discloses a TOFD ultrasonic nondestructive testing robot system applicable to a steam turbine welding rotor. The system is mainly composed of six parts including a movable platform, a positioning rod, probes, a clamp, a control platform and ultrasonic testing equipment. By virtue of the system, the difficulty in TOFD ultrasonic testing manual work of the steam turbine welding rotor is overcome and the disadvantages of an existing testing equipment scheme are overcome; the system has the advantages that a working range is expanded, the position of a welding line is accurately positioned, and testing operation can be carried out in a narrow space; and the clamp is provided with a plurality of groups of the probes so that the detection of the plurality of groups of the probes can be finished once and the detection efficiency is improved.
Patent•
01 Apr 2015
TL;DR: In this article, a TOFD check process for inner wall defects of nuclear power thick-wall austenite steel pipes is described, where a relatively large probe diameter is adopted to improve the measurement precision and resolution of the defects at the inner wall.
Abstract: The invention discloses a TOFD check process for inner wall defects of nuclear power thick-wall austenite steel pipes. According to the TOFD check process, 10-degree probes are used; the control process comprises the following steps: 1) adjusting the distance between the probes to ensure that TOFD acoustic beams are focused at the inner wall of a pipeline; 2) adopting a relatively large probe diameter; 3) selecting a relatively low probe frequency; 4) respectively carrying out off-center parallel scanning on two sides of the weld joint; 5) processing the formed image according to a synthetic aperture focusing technology. According to the TOFD check process, 10-degree probes are used so that the signal attenuation is relatively small; a relatively large probe diameter is adopted so that benefit is brought to improve the measurement precision and resolution of the defects at the inner wall; a relatively low probe frequency is used so that the acoustic wave can achieve the inner wall without too large attenuation; off-center scanning is respectively carried out on two sides of the weld joint, so that the dead zones at the weld joint of the inner wall can be eliminated; the formed image is processed by a synthetic aperture focusing technology, so that the error can be reduced.
Patent•
04 Nov 2015
TL;DR: In this article, a visual ultrasonic TOFD weld joint detection system capable of achieving single use is presented. But the system is not suitable for the detection of weld joints and data are displayed on a far-end TOFD instrument.
Abstract: The invention relates to a visual ultrasonic TOFD weld joint detecting system capable of achieving single use. The system comprises an ultrasonic detecting scanning frame and a screen data display device which are responsible for ultrasonic detecting of a weld joint and accurate display of detected data respectively; the screen data display device is installed on the ultrasonic detecting scanning frame, data are displayed on a far-end special TOFD instrument while the ultrasonic detecting scanning frame detects the weld joint, and then the detected data are completely displayed on the screen data display device installed on the ultrasonic detecting scanning frame through a data line to achieve single independent detecting. The system is convenient to use, manpower waste is reduced, the detecting efficiency is high, and the detecting result is stable.
TL;DR: In this paper, a numerical simulation of immersion TOFD (I-TOFD) detection for low thicknesses pipe ring weld was performed by Ultrasonic simulation software Wave 3000, where the authors get the sound field characteristics of diffraction wave through setting eight receivers in receiving area.
Abstract: The numerical simulation of immersion TOFD (I-TOFD) detection for low thicknesses pipe ring weld was performed by Ultrasonic simulation software Wave 3000. The author get the sound field characteristics of diffraction wave through setting eight receivers in receiving area, thus determine the strongest diffraction wave energy range between 50°~60°.In the simulation, the author found that the longitudinal wave inspired by source after refraction in water-steel interface, continue to spread along under the surface of water-steel interface, and then the wave go back to the water again. We call the wave as the lateral wave of I-TOFD. So the defects can be determined according to the lateral wave and the bottom echo wave. The result of numerical simulation verified the feasibility of using I-TOFD method in detecting low thicknesses pipe ring weld in theory.
01 Jan 2015
TL;DR: In pipeline steels, which are generally made of low carbon and low alloy high strength steels to meet the requirements, girth welds are used to join the pipes Submerged arc welding (SAW), semi-automatic or fully automatic welding system, is used to obtain better welding quality as mentioned in this paper.
Abstract: In pipeline steels, which are generally made of low-carbon and low alloy high strength steels to meet the requirements, girth welds are used to join the pipes Submerged arc welding (SAW), semi-automatic or fully automatic welding system, is used to obtain better welding quality The parameters and used equipment changes with regards to the desired properties, ie pipe diameter and wall thickness Ultrasonic phased array and combined inspection systems, ie TOFD, have many significant advantages over conventional methods for pipeline inspection The ad-vantages can be better interpretation, higher detection rates, no chemical wastes, no safety hazards and no requirement the specific area for inspection Trend in the inspection system is decreasing the inspection time and increasing the detection sensitivity Automatic systems, ie PipeWizard, become popular with increasing demands