Ultrasonic imaging, particle detection, and V(z) measurements in molten zinc using focused clad buffer rods

Abstract

Ultrasonic imaging, particle detection, and V(z) measurements have been performed using focused clad buffer rods in molten zinc at temperature more than 600 °C. The focused ultrasonic waves are generated by a spherical or cylindrical acoustic lens which is fabricated at the end of the clad buffer rod. In order to evaluate its focusing ability, several experiments are carried out at 10 MHz in a pulse-echo mode. The lateral resolution at the focus of the spherical acoustic lens in molten zinc is quantitatively examined and compared with that in water using a thin stainless wire with a diameter of 380 μm. High resolution ultrasonic imaging is carried out by the common C-scan technique. The signal-to-noise ratio of the reflected signals from the flat sample surface at the focus is better than 35 dB. Ultrasonic images are obtained from the amplitude and time delay variations of the reflected signals. An attempt has also been made to detect particles suspended in molten zinc. Backscattered signals from particles are clearly visible at the focal region of the lens. For quantitative materials evaluation, V(z) curve measurements are performed using both spherical and cylindrical surface lenses and the leaky surface acoustic wave velocity of a ceramic (SiC) plate immersed in molten zinc is successfully determined.

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

“…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.…”

“…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.…”

<I>In Situ</I> Observations of Solidification and Melting of Aluminum Alloy Using Ultrasonic Waveguide Sensor

“…In order to overcome such difficulty, recently clad waveguides with superior ultrasonic wave guidance and high SNR have been developed. 14,15) Using such clad waveguides, several ultrasonic pulse-echo measurements have been successfully performed for molten Zn, 16) Al 17,18) and Mg 19,20) at temperature up to 800 C.…”

“…Although a stainless steel was used as waveguide materials in the earlier works, [16][17][18][19][20] it is certain that the steel waveguide is slowly and definitely attacked by chemical reactions with molten Al. We have chosen titanium (Ti) as the waveguide material because the sustainability of Ti in molten Al is higher than that of steel.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The concept of an ultrasonic waveguide is a common technique for molten metal measurements. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] This technique is rather classical, but it is still attractive because of its simplicity, robustness and cost effectiveness. In this technique, measurements are made using a waveguide while the probe end is immersed in molten metals.…”