High Resolution Measurement of Coatings Inside Thick, Hot, Steel Pipes

Coatings are used across many industries to protect the inside walls of metal pipe work against corrosion. Standard transducers for ultrasonic wall thickness measurements, however, are typically not capable of monitoring these coatings, and so it is difficult to detect when these coating require re-application prior to the metal pipe itself degrading. This work demonstrates the detection and thickness measurement of 10 to 40 μm thick silicone resin coatings from the far side of a 6 mm thick mild steel wall, utilizing a high temperature thin film sensor capable of conforming to curved surfaces.