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Development of High Temperature Ultrasonic Sensors for Molten Metals Monitoring

用于熔融金属监测的高温超声波传感器的开发

基本信息

批准号：
14350397
负责人：
IHARA Ikuo
金额：
$ 4.86万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

High temperature ultrasonic sensors with acoustic wave-guides and their applications to molten metals monitoring have been studied. The main results obtained are the following:(1) A focused ultrasonic sensor with a tapered clad buffer rod is designed and its focusing ability for particles detection in molten metals such as aluminum and magnesium have evaluated by a numerical simulation method. It is found that the focused ultrasonic wave could be useful to detect a small particle with a diameter almost equal to one wavelength. The amplitude of the scattered wave from the particle strongly depends on the clustering condition of the several particles.(2) Laboratory validation of the use of focused ultrasonic sensors for alumina particles detection in molten aluminum at 800℃ has been demonstrated. Back-scattered signals from the particles of 160 μm in average diameter are clearly observed in the focal region of the acoustic lens at 10 MHz.(3) A new high temperature ultrasonic sensor with a titanium buffer rod has been applied to the in situ monitoring of the solid-liquid interface of an aluminum alloy (Al-12.6%Si) during unidirectional solidification at 700℃. A clear reflected echo from a stable solid-liquid interface of the aluminum alloy has been successfully monitored. In addition, the reflected echo from the growing interface during unidirectional solidification has also been monitored. The growth rate of the interface was determined to be 0.12 mm/s from the monitored echo.It is therefore considered that the developed ultrasonic technique is a promising candidate for on-line monitoring during molten metal processing.

本文研究了高温声波导传感器及其在金属熔体监测中的应用。主要研究结果如下：（1）设计了一种锥形包层缓冲棒聚焦超声传感器，并通过数值模拟的方法评价了该传感器对铝、镁等金属熔体中颗粒的聚焦能力。发现聚焦的超声波可以用于检测直径几乎等于一个波长的小颗粒。粒子的散射波的振幅强烈地依赖于几个粒子的聚集条件。(2)实验室验证了使用聚焦超声传感器在800℃熔融铝中检测氧化铝颗粒的方法。在10 MHz频率下，在声透镜的聚焦区可以清楚地观察到平均直径为160 μm的粒子的后向散射信号。(3)采用一种新型钛缓冲棒高温超声传感器，对Al-12.6%Si铝合金在700℃定向凝固过程中的固液界面进行了原位监测。在稳定的铝合金固液界面上成功地监测到了清晰的反射回波。此外，还对定向凝固过程中生长界面的反射回波进行了监测。由监测的回波确定界面的生长速率为0.12 mm/s，因此认为所开发的超声技术是一种有前途的候选人，用于在线监测在熔融金属加工过程中。