Non-Destructive Testing Services

Eddy - how does it work?

Eddy Current Testing is commonly used to detect surface and near-surface flaws, metal and coating thickness measurement and sorting metals by grade and hardness.

Eddy Current Testing equipment is extremely portable, which allows our technicians to inspect equipment or components that are difficult to access as well as being sensitive to very small cracks.

DPI - how does it work?

The Dye Penetrant Testing process is based on the ability of a liquid to be drawn into a surface-breaking flaw by capillary action.

The first step is to clean the component that is being tested before applying the penetrant. Then a visible or fluorescent dye that is either water or solvent-based is then applied to the surface of the component by a variety of applications including spraying, brushing, dipping or full immersion of the component into the penetrant dye.

During the penetration time, or dwell time, the coloured dye penetrates any surface breaking flaws that might exist in the component through capillary action. The length of the penetration time depends on the dye or penetrant that is being used.

Any excess penetrant is then removed from the surface of the tested component before it is dried. A developing agent is then applied. The developing agent draws the penetrant out of any surface breaking flaws and onto the surface in a reverse process of capillary action. This forms a visible indication that reveals any flaws in the component ready for a visual inspection and reporting.

Our inspectors then perform a visual inspection using either white light or ultraviolet light depending on the type of penetrant that was used.

UT – how does it work?

The technique of ultrasonic testing makes use of a pulser/receiver unit to power an ultrasonic transducer. This transducer is placed in contact with the material or component that is being tested and generates pulsed sound waves into the object.

The reflected sound waves or echos are received back by the transducer and any internal discontinuities will cause the signals to be displayed on the display unit. Our skilled investigators will then interpret these signals to determine if there are any flaws or defects present in the material.

Ultrasonic testing provides a high degree of accuracy when determining the size and shape of any flaws or defects. This testing method also has the ability to locate subsurface defects and provides far better depth penetration than other non-destructive testing methods.

MPI – how does it work?

During the process of Magnetic Particle Inspection, the specimen is magnetised either locally or overall depending on the size of the specimen and a magnetic field is induced in the component. The testing process analyses the magnetic flux around the tested component.

If the tested material is sound, then the magnetic flux will predominantly remain inside the material. However, if there is a surface-breaking flaw during the Magnetic Particle Inspection then the magnetic field will be distorted, causing local magnetic flux leakage around the flaw on the surface.

This leakage can be detected by dusting the surface of the specimen with fine magnetic particles such as ferrous iron filings. The particles will then be attracted to the area of the flux leakage, creating a visible indication of the defect.

The indication is then noted and evaluated by the operator to determine what might have caused the flaw and suggest action to take.

There are two methods of Magnetic Particle Inspection. The first is white colour contrast, which is ideal for daylight and site work. The other makes use of UltraViolet light. Here at Apex NDT, we provide both an ultraviolet method as well as the black and white contrast method.