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Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 638
Author(s):  
Ofer Tevet ◽  
David Svetlizky ◽  
David Harel ◽  
Zahava Barkay ◽  
Dolev Geva ◽  
...  

Additively manufactured (AM) materials and hot rolled materials are typically orthotropic, and exhibit anisotropic elastic properties. This paper elucidates the anisotropic elastic properties (Young’s modulus, shear modulus, and Poisson’s ratio) of Ti6Al4V alloy in four different conditions: three AM (by selective laser melting, SLM, electron beam melting, EBM, and directed energy deposition, DED, processes) and one wrought alloy (for comparison). A specially designed polygon sample allowed measurement of 12 sound wave velocities (SWVs), employing the dynamic pulse-echo ultrasonic technique. In conjunction with the measured density values, these SWVs enabled deriving of the tensor of elastic constants (Cij) and the three-dimensional (3D) Young’s moduli maps. Electron backscatter diffraction (EBSD) and micro-computed tomography (μCT) were employed to characterize the grain size and orientation as well as porosity and other defects which could explain the difference in the measured elastic constants of the four materials. All three types of AM materials showed only minor anisotropy. The wrought (hot rolled) alloy exhibited the highest density, virtually pore-free μCT images, and the highest ultrasonic anisotropy and polarity behavior. EBSD analysis revealed that a thin β-phase layer that formed along the elongated grain boundaries caused the ultrasonic polarity behavior. The finding that the elastic properties depend on the manufacturing process and on the angle relative to either the rolling direction or the AM build direction should be taken into account in the design of products. The data reported herein is valuable for materials selection and finite element analyses in mechanical design. The pulse-echo measurement procedure employed in this study may be further adapted and used for quality control of AM materials and parts.


2022 ◽  
Vol 12 (2) ◽  
pp. 808
Author(s):  
Upeksha Chathurani Thibbotuwa ◽  
Ainhoa Cortés ◽  
Andoni Irizar

The ultrasound technique is a well-known non-destructive and efficient testing method for on-line corrosion monitoring. Wall thickness loss rate is the major parameter that defines the corrosion process in this approach. This paper presents a smart corrosion monitoring system for offshore wind turbines based on the ultrasound pulse-echo technique. The solution is first developed as an ultrasound testbed with the aim of upgrading it into a low-cost and low-power miniaturized system to be deployed inside offshore wind turbines. This paper discusses different important stages of the presented monitoring system as design methodology, the precision of the measurements, and system performance verification. The obtained results during the testing of a variety of samples show meaningful information about the thickness loss due to corrosion. Furthermore, the developed system allows us to measure the Time-of-Flight (ToF) with high precision on steel samples of different thicknesses and on coated steel samples using the offshore standard coating NORSOK 7A.


Author(s):  
Nikolay P. Aleshin ◽  
Leonid Yu. Mogilner ◽  
Sergey V. Skrynnikov

The urgent task is improvement of the accuracy of diagnosing the linear part of pipelines, structures and equipment of pumping and compressor stations, tank batteries, tank farm complexes. Therewith, it is required not only to identify a defect with a given probability, but also to ensure measurement of its shape and dimensions with accuracy to be sufficient to perform analysis of structures for strength and durability. The article deals with certain possibilities for increasing the detectability of volumetric defects, such as knots, through improvement of the methods for setting parameters of ultrasound pulse-echo testing. The results of research in the field of improvement of the technology for setting advanced ultrasonic systems using phased array antennas are presented. Cylinder-shaped drilled holes of different orientations have been reviewed as artificial defects for setting sensitivity and time base of the flaw-detecting instrument. Following on the earlier published works, the expediency of using vertical cylindrical drilling for setting the equipment is additionally justified: such target is the easiest to manufacture, its parameters are verified much easier than, for example, the parameters of flatbottomed holes. Examples are given of the practical use of drills of various orientations for adjusting sensitivity of monitoring and determination of the indication length of local bulk defects of the base metal and welds. Актуальной является задача повышения точности диагностирования линейной части трубопроводов, сооружений и оборудования перекачивающих и компрессорных станций, резервуарных парков, нефтебаз. При этом требуется не просто выявить дефект с заданной вероятностью, но и обеспечить измерение его формы и размеров с точностью, достаточной для выполнения расчетов конструкций на прочность и долговечность. В статье рассмотрены некоторые возможности повышения выявляемости объемных дефектов типа свищей за счет совершенствования способов настройки параметров ультразвукового контроля эхо-методом. Представлены результаты исследований в области совершенствования технологии настройки современных ультразвуковых систем, использующих фазированные антенные решетки. В качестве искусственных дефектов для настройки чувствительности и временной развертки дефектоскопа рассмотрены цилиндрические сверления разной ориентации. В развитие ранее опубликованных работ обоснована целесообразность применения для настройки оборудования вертикального цилиндрического сверления: такая мишень наиболее проста в изготовлении, ее параметры поверяются значительно проще, чем, например, параметры плоскодонных отверстий. Приведены примеры практического использования сверлений различной ориентации для настройки чувствительности контроля и определения условной протяженности локальных объемных дефектов основного металла и сварных швов.


2021 ◽  
Vol 150 (6) ◽  
pp. 4128-4139
Author(s):  
E. G. Sunethra Dayavansha ◽  
Gary J. Gross ◽  
Matthew C. Ehrman ◽  
Peter D. Grimm ◽  
T. Douglas Mast

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1421
Author(s):  
Jiannan Zhang ◽  
Younho Cho ◽  
Jeongnam Kim ◽  
Azamatjon Kakhramon ugli Malikov ◽  
Young H. Kim ◽  
...  

The coating is applied to prevent corrosion on the surface of ships or marine structures, and the thickness of the coating affects its anti-corrosion effect. As a result, non-destructive testing (NDT) is required to measure coating thickness, and ultrasonic NDT is a convenient and quick way to measure the thickness of underwater coatings. However, the offshore coating’s energy attenuation and absorption rates are high, the ultrasonic pulse echo test is difficult, and the testing environment is harsh. Because of the coating’s high attenuation, the distance of the optimal water delay line designed based on the reflection coefficient of the vertically incident wave is used. To accurately measure the thickness of the coating material, TOF of the reflected echo on the time-domain waveform was evaluated. The experimental results show that, when compared to caliper measurements, the coating thickness measured by the proposed method has a lower error and can be used for accurate measurement. The use of ultrasonic water immersion measurement is almost limitless in terms of size, location, and material of the object to be measured, and it is expected to be used to measure the thickness of the surface coating of ships or marine structures in the water.


Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1607
Author(s):  
Dong-Il Kim ◽  
Ku-Rak Jung ◽  
Yoon-Soo Jung ◽  
Jae-Yeol Kim

Pulse-echo laser ultrasonic propagation imaging is a nondestructive testing technique developed for composite materials and aluminum alloys used in aerospace. Although this method has been in usage for a considerable time, information of the detectable depth and the relationship between ultrasonic frequencies and the acoustic properties of metals is not readily available. Therefore, we investigate the A-scan and C-scan ultrasonic testing data of aluminum alloy, hot rolled steel, stainless steel, and copper alloy, which are used in aircraft bodies, frameworks, and gas pipelines. Experiments are performed with the pulse-width and excitation laser power fixed at 32 ns and approximately 4 W, respectively. The metal specimens include 24 artificial cylindrical defects with a diameter of 5 mm, located at depths of 1–12 mm on the front surface. The A-scan and C-scan data obtained at room temperature indicate the detectable depth for metals via the pulse-echo laser ultrasonic propagation imaging technique.


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