Thickness and Corrosion Testing.
Metals, plastics, ceramics, glass or virtually any other material which conducts ultrasound can be accurately gauged over a wide range of thicknesses. One of the uses for ultrasound is to assess material thinning due to corrosion or erosion, including many types of pitting action.
A range of items susceptible to corrosive thinning include: Boilers and pressure vessels. Heat exchanger tubing, flanges and pipe work. Ship hulls, decking and bulkheads. Storage tanks and associated pipe work.
By comparing original build specifications with present day thickness readings, an idea of the rate of corrosion can be established.
Through Coating Testing.
Many items requiring testing will have surface coatings of one form or another, the most common being paint. If the correct technique is not used a reading that includes the coating thickness will be produced.
If the coating varies in thickness across the test piece, a false indication of material thickness or corrosion can be obtained. The use of multi bounce echo testing can ignore the coating and give a true indication of the material thickness.
Copyright Worcester NDT. 2016