Non-destructive inspection of metals

Non-destructive testing aims to determine the integrity of components either during their manufacture or in service. Solid metals, mainly alloys based on iron, aluminum, titanium, copper, etc., are widely used for such components. Their physical properties, particularly in the areas of acoustic propagation, thermal conductivity, electrical conductivity, and their potential magnetic behavior, allow for a wide range of inspection techniques to be considered. We will discuss inspection techniques using ultrasound, infrared thermography, magnetostatic techniques (magnetoscopy), and electromagnetic techniques (including eddy currents).

This article omits other techniques (visual inspections, dye penetrant testing, camera or X-ray imaging, etc.) which are covered in specific articles in the collection.

Non-destructive testing can provide essential information about:

• the presence of internal defects, in particular using ultrasonic testing;

• the presence of subcutaneous defects that can be detected by ultrasound or infrared thermography;

• the presence of surface defects, which can be detected by magnetic particle inspection, eddy current testing, infrared thermography, or ultrasonic testing.

This article first details the issues involved, then briefly presents the various techniques, specifying how to take into account the physical properties of metals. Finally, several applications of defect detection are described, including the technological advances now available.