Ultrasonic Testing (UT)

Ultrasonic Testing (UT)
In ultrasonic testing, high-frequency sound waves are transmitted into a material to detect imperfections or to locate changes in material properties. The most commonly used ultrasonic testing technique is pulse echo, whereby sound is introduced into a test object and reflections (echoes) from internal imperfections or the part's geometrical surfaces are returned to a receiver. Below is an example of shear wave weld inspection. Notice the indication extending to the upper limits of the screen. This indication is produced by sound reflected from a defect within the weld.

Magnetic Particle Testing (MT)

Magnetic Particle Testing (MT)
This NDT method is accomplished by inducing a magnetic field in a ferromagnetic material and then dusting the surface with iron particles (either dry or suspended in liquid). Surface and near-surface flaws disrupt the flow of the magnetic field within the part and force some of the field to leak out at the surface. Iron particles are attracted and concentrated at sites of the magnetic flux leakages. This produces a visible indication of defect on the surface of the material. The images above demonstrate a component before and after inspection using dry magnetic particles.

Radiography (RT)

Radiography (RT)
RT involves using penetrating gamma- or X-radiation on materials and products to look for defects or examine internal or hidden features. An X-ray generator or radioactive isotope is used as the source of radiation. Radiation is directed through a part and onto film or other detector. The resulting shadowgraph shows the internal features and soundness of the part. Material thickness and density changes are indicated as lighter or darker areas on the film or detector. The darker areas in the radiograph below represent internal voids in the component.

Visual and Optical Testing (VT)

Visual and Optical Testing (VT)
The most basic NDT method is visual examination. Visual examiners follow procedures that range from simply looking at a part to see if surface imperfections are visible, to using computer controlled camera systems to automatically recognize and measure features of a component.

liquid Penetrant Testing

Liquid Penetrant Testing

Dye penetrant inspection (DPI), also known as liquid penetrant examination (LPE), is a type of non-destructive testing used generally in the detection of surface flaws in non-ferrous alloys. The dye penetrant inspection (DPI) method employs a penetrating liquid, applied to the surface of the component and enters the flaw, crack or seam. After the excess penetrant has been cleared from the surface, the penetrant is drawn back out and the crack is observed using a white light or UV light. Dye penetrant inspection (DPI) can also be used for the inspection of ferrous materials where magnetic particle inspection is difficult to apply. In some cases Dye penetrant inspection (DPI) can be used on non-metallic materials. Variations include the use of fluorescent dyes, where a black (UV) light is used to illuminate the residual penetrant. This Dye penetrant inspection (DPI) technique has even higher sensitivity than normal LPE but can only be used in the absence of other light sources.

Dye penetrant inpection can be applied to any non-porous clean material, metallic or non-metallic material, but is unsuitable for dirty or rough surfaces.

Shear wave ultrasonic testing

Shear Wave, sometimes referred to as Angle Beam Ultrasonic testing, can be used to inspect pipe, critical welds in pressure vessels and plate weldments, and can be used to inspect cracks for depth, size, length and orientation.