What are the four stages of weld inspection?

Weld inspection is a service that has been provided at NDT Group for years. Our team has a huge amount of experience in this area and has tested welds in a vast number of environments and conditions. 

But what are the steps that our technicians go through to ensure that your components are safe and secure? Here is the process we go through, every time we come to assess one of your site’s welds. 

1. Visual Weld Inspection

The first stage involves visually inspecting the weld in question. It requires an experienced eye and can help identify immediate areas of concern. 

Things we look for include:

  • Visible cracks/flaws
  • Excessive waste slag
  • Visible leaks
  • Visible corrosion

We also look at the quality of the weld itself, using weld gauges to assess whether the weld has the correct shape. The flatness, convexity and concavity of the weld itself are checked to ensure that it has the correct integrity. 

2. Determine the best NDT solution

There are various non-destructive testing methods that can be used to inspect welds. They include magnetic particle inspection, radiography, dye penetrant inspection and eddy current inspection. 

All of these methods have their own advantages. But depending on the weld, they may not be suitable for every situation. Eddy current testing, for example, is excellent if you have a surface that is covered in layers of paint as no preparation is required. However, the technique cannot detect flaws that are deep under the surface of the very large weld. Often, a variety of techniques are applied so that the welds can be thoroughly inspected. 

However, one of the best solutions is phased array ultrasonic testing. The probe’s head holds multiple transducers, which means the sound waves can be multidirectional, ensuring all flaws are detected. The sound waves can reach significant depths, and the surface of the component does not require rigorous and thorough preparation, as is the case with other NDT tests. 

pipe being tested
Phased Array being applied to a weld on a pipe.

3. Apply the test

If phased array is chosen as the best method, the weld in question is treated with a couplant gel and the apparatus is positioned over the weld by the technicians.  

The equipment is swept along the length of the weld, and sound waves are sent out from transducers. The waves bounce off the back of the component being scanned and are read by a receiver and the data is sent to a computer. 

If the sound waves hit a flaw within the component, the signal bounces back faster, meaning the computer can build an image of the interior’s integrity. This image can be stored and assessed later if required. 

4. Analyse

Once the phased array test has been completed, the computer image can be inspected and any flaws that have been identified can be fixed by your welding team. 

After the welding team has repaired the weld, phased array can be applied again to ensure that the flaw has been dealt with. 

Thorough welding testing

Our process ensures that your site’s welds are assessed according to the highest standards. From a visual inspection of the weld, right through to reassessing repairs, we can deliver assurance that your assets are safe. 

Responsive testing that delivers assurance that your equipment is safe.

Contact us for a quality testing service with a fast report turnaround. We can respond to any challenge.


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