Development of ultrasonic techniques with buffer rod in molten aluminum

Ono, Yuu; Moisan, J.; Jen, C.K.; França, D. R.

doi:10.1109/ultsym.2002.1193520

Cited by 11 publications

(24 citation statements)

References 6 publications

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“…They have been successfully applied to ultrasonic imaging under molten metals (Ihara et al 2000;Rehman et al 2001;Ono et al 2002b;Ono et al 2003Ono et al , 2004Ono et al 2006). The clad buffer rod consists of a mild steel core with a double-tapered shape, a thermal sprayed stainless steel inner cladding, and bronze outer cladding.…”

Section: Focused Clad Rodmentioning

confidence: 99%

“…Tests on the ANL ultrasonic waveguide system were conducted using the LMFBR (liquid metal fast breeder reactor) simulation heat transfer loop (Lynnworth et al 2005) on the ANL campus. The waveguide approach is also used for imaging and inclusion detection in metal smelters where liquid metal temperatures can approach 1000°C (Ihara et al 2000;Rehman et al 2001;Ono et al 2002a). In lightweight metal processing (e.g., aluminum and magnesium) quality is critically associated with inclusions within the molten metal during manufacturing steps.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Under-Sodium Viewing: A Review of Ultrasonic Imaging Technology for Liquid Metal Fast Reactors

Griffin¹,

Posakony²,

Chien³

et al. 2009

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Executive SummaryThis current report is a summary of information obtained in the "Information Capture" task of the U.S. DOE-funded "Under Sodium Viewing (USV) Project." The goal of the multi-year USV project is to design, build, and demonstrate a state-of-the-art prototype ultrasonic viewing system tailored for periodic reactor core in-service monitoring and maintenance inspections. The study seeks to optimize system parameters, improve performance, and re-establish this key technology area which will be required to support any new U.S. liquid-metal cooled fast reactors.The earliest information presented herein dates from the early 1970s when the DOE Hanford Site and Argonne National Laboratory were supporting instrumentation development for sodium-cooled fast reactors (SFRs). The most recent U.S. advanced liquid metal reactor (ALMR) design was the Power Reactor Innovative Small Module (PRISM). The U.S.-sponsored design effort was discontinued in 1995; however, General Electric (GE) continued development up to year 2000. A number of other countries (especially India, Japan, France, and Great Britain) have built and operated fast, metal-cooled reactors and supporting diagnostic instrumentation for in-service inspections. Piezoelectric transducers have been reported in systems used to: (i) acquire in-core images; (ii) perform ultrasonic NDE inspections; and (iii) measure liquid sodium levels, detect structural anomalies, and detect leaks.This study has served to identify important design parameters and options for an ultrasonic USV system. These include:1. The preferred piezoelectric material for liquid sodium temperatures up to 260°C is lead zirconate titanate (PZT). Higher Curie temperature (T c ) materials such as lithium niobate and lead metaniobate have also been used.2. Most demonstrated USV ultrasonic transducers are of the direct sodium immersion type. Only a few designs use an ultrasonic waveguide to isolate the transducer from the molten sodium.3. Poor sodium wetting of the transducer face has been an issue. Degraded wetting results in inefficient mechanical (acoustic) coupling between the transducer and the liquid sodium working fluid. Solutions have required either coating the transducer face (e.g., with evaporated or sputtered gold) or bonding a metal diaphragm to the transducer face (e.g., stainless steel or nickel).4. Thermal shock damage to the piezoelectric transducer is an important issue. Fracture of piezoelectric ceramics due to high thermal gradients/transients or thermal expansion mismatches at the transducer face or backing layer must be considered early in the design process.5. Cable length between the transducer and ultrasonic transceiver has a major impact on received signal amplitude. The minute electrical charges generated by the piezoelectric transducer dictate use of lowcapacitance, radiation-resistant, high-temperature cables, and cable length must be kept as short as possible. Impedance matching and signal conditioning must be considered.6. To date, most ultrasonic USV systems have ...

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Section: Focused Clad Rodmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Under-Sodium Viewing: A Review of Ultrasonic Imaging Technology for Liquid Metal Fast Reactors

Griffin¹,

Posakony²,

Chien³

et al. 2009

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“…This procedure is detrimental for process efficiency, since samples production and characterization are time consuming, and melt conditions can change over the time. On-line monitoring of the melt quality can be a faster procedure, but applications known so far are limited to lab scale chemical composition monitoring using laser induced breakdown spectroscopy (Kai et al, 2002) or chemical sensors based on galvanic cells (Vangrunderbeek et al, 1999;Fray, 1996), inclusion detection by electromagnetic (Makarov et al, 1999;Roderick et al, 2001) or ultrasound techniques (Ono et al, 2002(Ono et al, , 2004 and measurement of hydrogen concentration in molten aluminium alloys either by using highly unstable galvanic cells (Schwandt et al, 2003;Zheng and Zhen, 1993) or very slow carrier gas techniques like AlScan or Telegas (Fergus, 2005).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of ultrasonic aluminium degassing by piezoelectric sensor

Puga¹,

Barbosa²,

Gabriel³

et al. 2011

Journal of Materials Processing Technology

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a b s t r a c tThe purpose of this work was the development of a reliable technique to evaluate the intensity of acoustic cavitation during degassing of aluminium melts and to use it to select the optimum processing time for an envisaged degassing efficiency.A high sensitivity piezoelectric disk type device was used as a sensing feedback in water and liquid AlSi9Cu3 alloy. The signal acquisition and processing was carried out on a dedicated LabVIEW ® based application which allowed real-time monitoring of the piezoelectric sensor's data and ultrasonic parameters. Standard Fast Fourier Transform was applied to obtain the dominant frequencies, as well as the sub and ultra-harmonics. It was found that the amplitude of the FFT sub-harmonic (f/2) was the best indicator to evaluate the process degassing efficiency, and it could be used to select the optimal processing time, independently of other variables.The developed methodology was applied to several AlSi9Cu3 melts, and validated by measuring the final alloy densities and the volume fraction of porosities, revealing that it is an efficient, fast and cost effective technique to evaluate the degassing treatment of aluminium alloys. Experimental curves of AlSi9Cu3 alloy degassing efficiency as a function of f/2 amplitude are presented for different degassing times.

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“…Ultrasonic sensors were developed recently, where clad buffer rods provide superior wave guidance performance of high signal-to-noise ratio at elevated temperatures (5) - (7) . It has been demonstrated that such clad buffer rod can detect silicon carbide particles in molten aluminum in pitch-catch mode (8) . Furthermore, it has been experimentally verified that focused ultrasonic waves can be successfully generated by a spherical acoustic lens fabricated at the probing end of the buffer rod (9) .…”

Section: Introductionmentioning

confidence: 99%

In-Situ Observation of Alumina Particles in Molten Aluminum Using a Focused Ultrasonic Sensor

Ihara

Aso²,

Burhan

2004

JSME Int. J., Ser. A

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Ultrasonic in-situ observation of alumina particles in molten aluminum at temperature up to 800• C is presented. A focused ultrasonic sensor is employed for the high temperature measurement with a high spatial resolution. The sensor mainly consists of a conventional piezoelectric transducer, a taper-shaped clad buffer rod as a waveguide and a cooling system. Martensitic stainless steel is used as a material for the buffer rod and an acoustic lens is fabricated at the probe end of the rod. In order to examine the focusing ability of the acoustic lens, the acoustic field near the focusing zone is numerically evaluated by a finite difference method. Using the developed focused ultrasonic sensor, backscattered echoes from alumina particles of 160 µm suspended in the molten aluminum at 800• C have been observed clearly in pulse echo mode at 10 MHz. The effect of the size and the aggregation condition of the particle on the backscattered echoes has also been examined.

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Development of ultrasonic techniques with buffer rod in molten aluminum

Cited by 11 publications

References 6 publications

Under-Sodium Viewing: A Review of Ultrasonic Imaging Technology for Liquid Metal Fast Reactors

Under-Sodium Viewing: A Review of Ultrasonic Imaging Technology for Liquid Metal Fast Reactors

Evaluation of ultrasonic aluminium degassing by piezoelectric sensor

In-Situ Observation of Alumina Particles in Molten Aluminum Using a Focused Ultrasonic Sensor

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