June 8, 2018
NDT inspections are an important service. As such, portable equipment is continually in use in all kinds of industrial locales, including petrochemical complexes and chemical processing facilities. Of interest to the on-site workers, there's a desire to know more about the Non-Destructive Testing procedures. Where does it begin? What steps and what tests come into play as the service proceeds? First off, a pair of seasoned eyes is just enough.
The inspector pauses to scoop up some instruments. Carrying a powerful flashlight when visibility is low, this expert individual is alert and diligent. A handheld magnifier slips out of its pouch when a particular weld seam draws near. Advanced instruments come out of the toolkit when a closer look is desired. Flexible endoscopes, cameras, pocket-sized thermometers, these early tests seek out surface flaws with a keen eye and tools that aid this visually keyed step.
Hairline fractures reveal their outlines when a pressure vessel bulges. As the heat fades, the metal contracts and the crack is hidden. Liquid penetrants aren't fooled by hidden fractures. When non-destructive tests require more than a visual check, these dyes are tugged from the toolkit. Sprayed or brushed onto the pressure equipment, the liquid seeps into a surface discontinuity to highlight a defect. Capillary action is essential here, so minutes or hours of dwell time are needed to properly pull off this test.
Two of the most essential NDT techniques have received an early mention. However, before either of these surface tests can be conducted, the test area needs prepping. Patches of light rust and dirt, paint and water block visual inspections. Take note of the rust, then take up a wire brush and clean these contaminants away. A conscientious NDT investigator carries wire brushes and puff bulbs, plus de-greasing agents and light detergents. Consider prep work an important visual test promoter. For dye penetrants, though, a clean and dry surface is essential.
The fungal growths are removed, the stains and dirt are gone, and the paint has been washed away. Despite that clean surface, there's pitting and bleed marks on the metal. Elsewhere a measurable pressure drop is being recorded on an instrument panel. When these conditions appear, it's time to intensify the pressure equipment tests and call in the advanced NDT kit. From here, portable radiographic tests, ultrasonic devices, and eddy current detectors move into action. They seek out subsurface discontinuities, measure wall thicknesses, and generally detect what cannot be seen with a pair of sharp eyes.
Fusion - Weld Engineering Pty Ltd
ABN 98 068 987619
1865 Frankston Flinders Road,
Hastings, VIC 3915
Ph: (03) 5909 8218
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