Toward An Ultrasonic Sensor for Pressure Vessels

The focus of this paper is an ultrasonic position indication system that is capable of determining one-dimensional target location in a high-temperature steel container with gaseous medium. The combination of the very high acoustical impedance of steel (45.4MRayl) and the very low impedance of a gas, for example, ambient air (0.0004MRayl), causes significant reflections at the interfaces. The strategy of this investigation was to develop an ultrasonic transducer capable of replacing a small portion of pressure vessel wall. In building such a transducer, acoustic matching layers for the steel-gas interface, a mechanically and acoustically competent housing, an efficient piezoelectric element, and appropriate backing materials are developed and tested. The results include a successful housing design, high- temperature acoustic matching layers, and subsequent successful wave forms with good signal-to-noise ratio. Target location through 9.6in.(24.5cm) of ambient air was possible, with a steel pressure boundary 0.456in.(1.160cm) thick, and the use of one matching layer. Our transducer was tested repeatedly to 340°C without apparent degradation. In addition to the experimental results, this investigation includes numerical simulations. Sample wave forms were predicted one dimensionally with the coupled acoustic piezoelectric analysis, a finite element program that predicts wave forms based on Navier’s equation for elastic wave propagation.

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Ultrasonic Sensor for High Temperature Gas Filled Vessels

Volume 5: High Pressure Technology, Nondestructive Evaluation, Pipeline Systems, Student Paper Competition ◽

10.1115/pvp2006-icpvt-11-93009 ◽

2006 ◽

Author(s):

J. S. Sandman ◽

B. R. Tittmann

Keyword(s):

Finite Element ◽

High Temperature ◽

Target Location ◽

Ultrasonic Transducer ◽

Piezoelectric Element ◽

Ambient Air ◽

High Energy ◽

Finite Element Program ◽

Housing Design ◽

Element Program

The focus of this paper is an Ultrasonic Position Indication System (UPIS) that is capable of determining one-dimensional target location in a high temperature steel-container with gaseous medium. The combination of the very high acoustical impedance of steel (45.4MRayl) and the very low impedance of air (0.0004MRayl) causes extremely high-energy losses upon transmission. In addition to the energy loss, propagation through a steel plate produces many internal reflections in the plate. The strategy of this investigation was to develop a self-contained ultrasonic transducer that is capable of replacing a small portion of a high temperature-pressure boundary. In building such a transducer, sufficient acoustic matching layers for the steel-gas interface, a mechanically and acoustically competent housing, a sufficient piezoelectric element, and backing materials are all developed and tested. The results include a successful housing design, high-temperature acoustic matching layers, and subsequent successful waveforms. Target location through 9.6” (24.5cm) of ambient air was successful, with a steel pressure boundary 0.4566” (1.1598cm) thick, and using one matching layer. In addition to the experimental results, this investigation includes numerical simulations. Sample waveforms were predicted one-dimensionally with the Mason model using MatLab, and two-dimensionally with a Coupled Acoustic Piezoelectric Finite Element Method (CAPA) program. The Mason model program predicts waveform changes as the wave travels through various interfaces. CAPA is a finite element program that predicts waveforms based on the equations for ultrasonic wave propagation.

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Mn-doped CaBi4Ti4O15/Pb(Zr,Ti)O3 Ultrasonic Transducers for Continuous Monitoring at Elevated Temperatures

10.20944/preprints201710.0007.v1 ◽

2017 ◽

Author(s):

Makiko Kobayashi ◽

Taiga Kibe ◽

Hajime Nagata

Keyword(s):

High Temperature ◽

Thermal Cycle ◽

Elevated Temperatures ◽

Signal To Noise Ratio ◽

Ultrasonic Transducer ◽

Sol Gel ◽

Ultrasonic Transducers ◽

In Situ Monitoring ◽

Signal To Noise ◽

Noise Ratio

Continuous ultrasonic in-situ monitoring for industrial applications is difficult owing to the high operating temperatures in industrial fields. It is expected that ultrasonic transducers consisting of CaBi4Ti4O15(CBT)/Pb(Zr,Ti)O3(PZT) sol-gel composite could be one solution for ultrasonic nondestructive testing (NDT) above 500 C because no couplant is required and CBT has a high Curie temperature. To verify the high temperature durability, CBT/PZT sol-gel composite films were fabricated on titanium substrates by spray coating, and the CBT/PZT samples were tested in a furnace at various temperatures. Reflected echoes with a high signal-to-noise ratio were observed up to 600 C. A thermal cycle test was conducted from room temperature to 600 C, and no significant deterioration was found after the second thermal cycle. To investigate the long-term high-temperature durability, a CBT/PZT ultrasonic transducer was tested in the furnace at 600 °C for 36 h. Ultrasonic responses were recorded every 3 h, and the sensitivity and signal-to-noise ratio were stable throughout the experiment.

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Dry Coupling of Ultrasonic Transducer Components for High Temperature Applications

Sensors ◽

10.3390/s19245383 ◽

2019 ◽

Vol 19 (24) ◽

pp. 5383 ◽

Cited By ~ 3

Author(s):

Neelesh Bhadwal ◽

Mina Torabi Milani ◽

Thomas Coyle ◽

Anthony Sinclair

Keyword(s):

High Temperature ◽

Room Temperature ◽

High Efficiency ◽

Signal To Noise Ratio ◽

Ultrasonic Transducer ◽

Thin Foil ◽

Filler Material ◽

Dry Coupling ◽

Soft Filler ◽

Component Interface

The viability for dry coupling of piezoelectric ultrasonic transducer components was investigated, using a thin foil of annealed silver as a filler material/coupling agent at each component interface. Criteria used for room temperature evaluation were centered on signal-to-noise ratio (SNR) and echo bandwidth, for a Li-Nb based transducer operating in pulse-echo mode. A normal clamping stress of only 25 MPa, applied repeatedly over three loading cycles on a precisely-aligned transducer stack, was sufficient to yield backwall echoes with a SNR greater than 25 dB, and a 3 dB bandwidth of approximately 65%. This compares to a SNR of 32 dB and a 3 dB bandwidth of 65%, achievable when all transducer interfaces were coupled with ultrasonic gel. The respective roles of a soft filler material, alignment of transducer components, cyclic clamping, component roughness, and component flatness were evaluated in achieving this high efficiency dry coupling, with transducer clamping forces far lower than previously reported. Preliminary high temperature tests indicate that this coupling method is suitable for high temperature and achieves signal quality comparable to that at room temperature with ultrasonic gel.

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ALUCHROM YHf

Alloy Digest ◽

10.31399/asm.ad.ss0899 ◽

2004 ◽

Vol 53 (1) ◽

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

High Temperature ◽

North America ◽

Physical Properties ◽

Tensile Properties ◽

Heat Treating ◽

Pressure Vessels ◽

Temperature Performance ◽

Oxidation Resistant

Abstract Aluchrom YHf is an oxidation resistant ferritic stainless steel alloyed with aluminum. The alloy is approved in North America and Europe for pressure vessels to 899 deg C (1650 deg F). This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-899. Producer or source: ThyssenKrupp VDM GmbH.

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A review of the present state of the art of assessing remanent life of pressure vessels and pressurized systems designed for high temperature service

10.3403/00134767u ◽

2015 ◽

Keyword(s):

High Temperature ◽

Present State ◽

State Of The Art ◽

Pressure Vessels

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Effect of Carbide Content on Temper Embrittlement of 2.25Cr1Mo Steel

Volume 7: Operations, Applications and Components ◽

10.1115/pvp2016-63289 ◽

2016 ◽

Author(s):

Yian Wang ◽

Guoshan Xie ◽

Zheng Zhang ◽

Xiaolong Qian ◽

Yufeng Zhou ◽

...

Keyword(s):

High Temperature ◽

Pressure Vessel ◽

High Stress ◽

Temper Embrittlement ◽

Damage Mechanism ◽

Pressure Vessels ◽

Nondestructive Method ◽

Operating Conditions ◽

Low Alloy Steels ◽

Carbide Content

Temper embrittlement is a common damage mechanism of pressure vessels in the chemical and petrochemical industry serviced in high temperature, which results in the reduction of roughness due to metallurgical change in some low alloy steels. Pressure vessels that are temper embrittled may be susceptible to brittle fracture under certain operating conditions which cause high stress by thermal gradients, e.g., during start-up and shutdown. 2.25Cr1-Mo steel is widely used to make hydrogenation reactor due to its superior combination of high mechanical strength, good weldability, excellent high temperature hydrogen attack (HTHA) and oxidation-resistance. However, 2.25Cr-1Mo steel is particularly susceptible to temper embrittlement. In this paper, the effect of carbide on temper embrittlement of 2.25Cr-1Mo steel was investigated. Mechanical properties and the ductile-brittle transition temperature (DBTT) of 2.25Cr-1Mo steel were measured by tensile test and impact test. The tests were performed at two positions (base metal and weld metal) and three states (original, step cooling treated and in-service for a hundred thousand hours). The content and distribution of carbides were analyzed by scanning electron microscope (SEM). The content of Cr and Mo elements in carbide was measured by energy dispersive X-ray analysis (EDS). The results showed that the embrittlement could increase the strength and reduce the plasticity. Higher carbide contents appear to be responsible for the higher DBTT. The in-service 2.25Cr-1Mo steel showed the highest DBTT and carbide content, followed by step cooling treated 2.25Cr-1Mo steel, while the as-received 2.25Cr-1Mo steel has the minimum DBTT and carbide content. At the same time, the Cr and Mo contents in carbide increased with the increasing of DBTT. It is well known that the specimen analyzed by SEM is very small in size, sampling SEM specimen is convenient and nondestructive to pressure vessel. Therefore, the relationship between DBTT and the content of carbide offers a feasible nondestructive method for quantitative measuring the temper embrittlement of 2.25Cr-1Mo steel pressure vessel.

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CMUT-Based Sensor for Acoustic Emission Application: Experimental and Theoretical Contributions to Sensitivity Optimization

Sensors ◽

10.3390/s21062042 ◽

2021 ◽

Vol 21 (6) ◽

pp. 2042

Author(s):

Redha Boubenia ◽

Patrice Le Moal ◽

Gilles Bourbon ◽

Emmanuel Ramasso ◽

Eric Joseph

Keyword(s):

Signal Processing ◽

Signal To Noise Ratio ◽

Ultrasonic Transducer ◽

Operating Conditions ◽

Geometrical Parameters ◽

Signal To Noise ◽

Coupling Conditions ◽

Sensor Structure ◽

Noise Ratio ◽

Electrical Connections

The paper deals with a capacitive micromachined ultrasonic transducer (CMUT)-based sensor dedicated to the detection of acoustic emissions from damaged structures. This work aims to explore different ways to improve the signal-to-noise ratio and the sensitivity of such sensors focusing on the design and packaging of the sensor, electrical connections, signal processing, coupling conditions, design of the elementary cells and operating conditions. In the first part, the CMUT-R100 sensor prototype is presented and electromechanically characterized. It is mainly composed of a CMUT-chip manufactured using the MUMPS process, including 40 circular 100 µm radius cells and covering a frequency band from 310 kHz to 420 kHz, and work on the packaging, electrical connections and signal processing allowed the signal-to-noise ratio to be increased from 17 dB to 37 dB. In the second part, the sensitivity of the sensor is studied by considering two contributions: the acoustic-mechanical one is dependent on the coupling conditions of the layered sensor structure and the mechanical-electrical one is dependent on the conversion of the mechanical vibration to electrical charges. The acoustic-mechanical sensitivity is experimentally and numerically addressed highlighting the care to be taken in implementation of the silicon chip in the brass housing. Insertion losses of about 50% are experimentally observed on an acoustic test between unpackaged and packaged silicon chip configurations. The mechanical-electrical sensitivity is analytically described leading to a closed-form amplitude of the detected signal under dynamic excitation. Thus, the influence of geometrical parameters, material properties and operating conditions on sensitivity enhancement is clearly established: such as smaller electrostatic air gap, and larger thickness, Young’s modulus and DC bias voltage.

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