Penetrant Testing Materials
The penetrant materials used today are much more sophisticated than the kerosene and whiting first used by railroad inspectors near the turn of the 20th century. Today's penetrants are carefully…
Where Is Non-Destructive Testing Used?
Depending on how broadly you define NDT you could say that it’s used in almost every industry in the world, since visual inspections (whether formalized or casual) take place in…
What Is NDT—A Closer Look
We’ve already covered what NDT stands for and how the phrase is used in the field. Now let’s dive in and look more closely at some of the details that…
The Benefits of Laser-Based Inspection
Lasers have been used in the welding industry for over 30 years for seam-tracking while welding, for inspection of weld surface quality, and for corrosion detection on existing structures. Today’s…
Laser-based inspection
Laser shearographyLaser shearography uses an interferometer to detect the out-of-plane derivative of deformation of the subject due to the non-homogeneous strain field caused by subsurface flaws. Creating an out-of-plane stress…
Erosion corrosion
Erosion corrosion is the corrosion of a metal which is caused or accelerated by the relative motion of the environment and the metal surface. It is characterised by surface features…
Basic Principles of Liquid Penetrant Inspection
Liquid penetrant inspection (LPI), also known as dye penetrant inspection (DPI) or penetrant testing (PT), was first developed in the early 1940s to detect flaws on the surface of materials.…
Coating thickness measurement methods
Various methods of NDT are used for the measurement of coating thickness – paint thickness, plating thickness, anodising etc. These methods may be X-ray, electron backscatter, magnetic, etc and the…
Acoustic methods
Acoustic methods (also known as sonic testing, vibration testing, mechanical impedance testing) depend on exciting vibrations in a specimen by a local impact and then measuring some properties of the…
ACFM technique
The Alternating Current Field Measurement (ACFM) technique is a non-contact electromagnetic technique capable of both detecting and sizing (length and depth) defects in metals. The basis of the technique is…
