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Non-destructive tests do not damage the material or product being tested.
Frequently they are built into production processes, as is the case
with pipe tested using eddy current equipment.
Hydrostatic, Pneumatic
Testing
This
is used to test the manufactured item under pressure equivalent to or
greater than pressure to be encountered in service. The majority of
products manufactured endure vigorous testing. Our Hydrostatic facilities
can pressure test up to 910 BarG (13,200 psig) and our Pneumatic facilities
can test to a pressure of 413 BarG (6,000 psig) nitrogen. Vee Bee can
also offer actual flow proof tests on their in-house liquid flow test
rig (air proof testing also available).
Radiography (X-Ray)
Testing
The main benefits of radiography are that it provides a non-destructive
method of detecting hidden flaws in materials and fabrications and provides
a permanent quality record. It is particularly good at detecting volumetric
flaws such as voids, gas pores and solid inclusions. It is also good
at determining the nature and dimensions (length and width) of flaws.
It cannot, however, be used to measure the dimensions of flaws in the
through-thickness direction.
Liquid (Dye) Penetrant
Testing
Liquid penetrant testing offers a fast and relatively simple means of
surface inspection, making it attractive to a number of industries.
Dye penetrant testing is used as a quick and simple method for checking
that welds and other susceptible areas are free from surface-breaking
flaws.
Magnetic Particle Testing
MPI is often used to look for cracking at welded joints and in areas
identified as being susceptible to environmental cracking (e.g. stress
corrosion cracking or hydrogen induced cracking), fatigue cracking or
creep cracking. Wet fluorescent MPI finds widespread use in looking
for environmental damage on the inside of vessels.
Ultrasonic Testing
Planar flaws that break the surface and lie at 90° to the scanned
surface e.g. fatigue cracks in weld toes and stress corrosion cracking.
Visual inspection
A visual examination can be used to check for obvious problem areas,
such as leaks, excess vibration or misalignment. On exposed metal surfaces
it can also be used to check for corrosion. There are various aids to
visual inspection. As well as magnifying glasses, there are devices
for measuring pit depths, weld leg length and surface profiles.
Strain-Gauge Testing
Strain gauges, are small, bondable sensors which are applied to a component,
having no mass or significant effect and do not degrade the component
performance. Static and / or dynamic loads are applied to the component
to determine material stress. This allows loads to be applied to a component
to simulate field applications. The data is collected and analyzed and
is the basis for fatigue evaluations and failure analysis.
Brittle (coating) Lacquer
Testing
Brittle (Coating) Lacquer testing allows critical stress areas on a
component structure to be visualized as the stress directions and stress
distribution. This provides location and orientation for stain gauges.
Cryogenic Testing
Testing in liquid nitrogen to required sub-zero temperatures.
Tensile Tests
This is probably the most revealing of the mechanical tests that
can be performed upon a specimen of pipe or tubular product material.
By recording the gradually increasing load applied and the extension
during loading a Stress-Strain Graph can be plotted. From this Graph
the following values can be computed. |
• Tensile Strength
• Yield Strength or Proof Stress
• Elongation
• Elastic Limit or Yield Point
• Modulus of Elasticity
• Reduction of Area |
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Hardness Tests
These tests determine the resistance of a material to indentation. |
• Brinell Hardness
Test
• Vickers Diamond Hardness Test
• Rockwell Hardness Test |
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Impact Test
In this type of test, a sample is subjected to sudden force to measure
its toughness or resistance to shock. |
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Manipulating Tests
These tests prove the ductility of certain tubular products and
confirm the soundness of welds. |
• Bend Tests
• Flange Test
• Flattening Test
• Flare or Drift Test |
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Corrosion Tests
Various corrosion tests are available using different corrosive
environments to indicate the performance of material under heavy
duty applications. |
• Weld Decay
Test
• Strauss Test
• Huey Test
• Potentiostat Test |
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