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Weld Testing is Vital to Keep Your System Running Smoothly

by Mar 19, 2019Weld Testing

Estimated Reading Time: 4 minutes

Weld testing by our team of experts safeguards your components and systems. A weld flaw could kick off a catastrophic series of events that may cause damage to – or complete failure of – the system you have in place.

Axenics has been providing premier welding services to original equipment manufacturers for 35 years, and we believe our technicians’ testing skills are just as vital as their skills in performing the actual welds. We employ several non-destructive weld testing methods to make certain your welded components are free from any leaks or damage points.

Weld testing to detect potential leaks is a vital step to keep costs under control, as man hours are saved when damage-free components are in place, and the cost of materials can be controlled by not having to re-purchase them once a leak has caused damage to the system.

Visual Weld Testing

Visual weld inspection remains an important tactic in inspecting for potential leaks, as well as an opportunity to audit your products for consistency. Our visual inspections are often combined with different forms of non-destructive weld testing, such as hydrostatic testing or helium leak testing. Whether it’s for a small run of components or many repeated pieces, we’re looking for consistency and high-quality.

Dependent on the type of metal being inspected, our team is looking for a range of characteristics during a visual inspection. While the standards can vary for each project, we’re often looking for potential problem areas, such as:

  • Consistency in the materials
  • Corrosion of materials
  • Fissures in the welds
  • Flaws on the surface of materials
  • Banding distortion

Hydrostatic Testing

Hydrostatic testing is one non-destructive method that we use to ensure welds are free of leaks. This type of test utilizes water pressure to identify potential leak points. Hydrostatic testing is executed by:

  • Completely filling a component with water (or a liquid with dye in it)
  • Putting the component into a tank
  • Adding air pressure to the component in excess of the normal operating pressure the component is designed for (This factor of safety is typically 166.66%, 143% or 150% of the designed working pressure)
  • Holding the air pressure for a predetermined time frame
  • Leaks in the welds (or potentially the structure of the component) are found if the pressure changes

Hydrostatic testing is a determining factor in whether a welded component can safely hold a pressure rating. If you have components that have been rebuilt or repaired, hydrostatic testing is a good solution for finding potential problem areas. Axenics performs the test for our customers on 4B cylinders that require stamping per regulation of the Department of Transportation (DOT).

Axenics also performs hydrostatic testing to check the strength of welds for low-pressure stainless steel canisters. The testing method is also used for storage tanks, fire extinguishers and chemical pipelines.

Helium Leak Testing

Helium is the ideal element used to detect cracks in welds, as it is a safe, inert gas. Helium atoms are tiny and also have low viscosity, so the little atoms can travel quickly.

Pressure testing and vacuum testing are two forms of helium leak testing we use to ensure your components are free of weld defects. We perform helium leak tests on any weld where a component will be used to transport liquids or gases.

Vacuum helium leak tests that Axenics performs are executed by:

  • Pulling a vacuum onto a weldment
  • Spraying helium in very small amounts around potential leak points
  • Using a helium leak detector a.k.a Mass Spectrometer Leak Detector (MSLD) to “pull” the helium into the weld and into the MSLD, which sounds an audible alarm if a leak is detected

Pressure helium leak testing is performed by:

  • Pressurizing the weldment with helium and using a sniffer probe connected to the MSLD around potential leak areas
  • Pulling helium through the leak and into the MSLD, which sounds the audible alarm if  a leak is present

To pass a helium leak test at Axenics, the maximum leak rate that we use is 5 x 10-9 mbar l/s.

Any rate larger than this would be considered a leaking part and would be rejected.

We perform hydrostatic testing and helium leak testing as a regular element of our quality control process, but we can also perform the testing as a stand-alone service. Our team of experts can help identify which weld testing methods would work the best for your end products.

Two Additional Noteworthy Elements of Weld Testing

All of the instruments we use for weld testing are regularly inspected by our in-house technicians to make certain the machines are performing at top-level, ensuring 100% accurate test results for your components.

After non-destructive weld testing, such as helium leak testing or hydrostatic testing, is performed, the weld may be put through a destructive test, because the pieces of the weld and components should break down in a certain way.

All of the weld testing performed at Axenics end with successful results before the components make their way to you.

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