Abstract

One effective way to inspect or monitor large components such as pipes or plates is to use guided wave testing (GWT) systems. A number of commercially available GWT systems suitable for inspection of various components at ambient and elevated temperatures have been developed by different groups. Development of GWT systems for monitoring at high temperatures is very challenging, because the sensor is exposed to a harsh environment for long periods. Some experimental work and findings related to SHM of pipes operating at temperatures up to 200°C have been reported. In the nuclear and petrochemical industries, however, there is a need for monitoring of components operating at temperatures up to 650°C. Magnetostriction is promising transduction mechanism for high temperature applications because generation of elastic waves in materials does not require soldered joints, which a limiting factor in other transducer designs. The work presented here demonstrates significant progress in the generation of guided waves at elevated temperatures utilizing a ferromagnetic strip with a high magnetostriction coefficient, attached to the component under test. The strip material evaluated during this effort was a special alloy of Iron Cobalt (FeCo). The transduction efficiency as a function of temperature and strip magnetization were studied. It was shown that the necessary transduction can be supported at a satisfactory level in a temperature range up to 800°C, with variations in signal amplitude in the order of 6 dB. The most suitable temperature range was found to be below the recrystallization temperature of 700°C for this material. The results of the test can be used to improve magnetostrictive sensor designs for SHM of pipes operating at 500 °C.

How to Cite:

Vinogradov, S. ., Cobb, A. . & Fisher, J. ., (2019) “Evaluation of FeCo magnetostrictive sensors for SHM of components operating in harsh environmental conditions”, Review of Progress in Quantitative Nondestructive Evaluation .