Destructive and Nondestructive Testing of Welds | How NDT Ensures Quality

The criticality of welding in many types of industrial applications demands effective inspection for quality assurance. The common practices for ensuring quality are destructive and non-destructive testing (NDT) of welds. Typically, destructive testing is used for qualifying the welders, and the welding procedures. With non-destructive testing, it can be easier to maintain productivity and quality control through the early identification of potential flaws in the weld.

While each inspection procedure has its own checklist of benefits, the use of NDT has been growing among industries. Here’s why.

Destructive and Non-Destructive Testing of Welds

In destructive testing, the weld is tested to the failure point through different tests, including tensile, compression, fatigue, and other types of tests. The welding procedure and welders are considered certified as long as the weld can exceed the specified requirement limit. This certified weld procedure is used as a standard and recreated as close as possible for the subsequent welds and inspected through visual inspection. The drawback of this method is that the tested structure is damaged and the sample used for testing and standardization cannot be representative of the different load conditions. For safety purposes, every component should be tested in regular intervals for varying load conditions. This can be economically taxing for industries.

With non-destructive testing, major and minor weld flaws can be easily identified in each component being tested. Without any assumptions required from visual inspection, the component can be used safely without any compromise to industrial operation or human lives.

Read more about NDT solutions for weld inspection.

Non-Destructive Testing: The Ideal Inspection Practice

Ensuring quality in welds requires a testing method to detect major and minor flaws that pose a threat to structural integrity. For efficient testing and accurate results, different types of NDT methods can be utilized. This includes liquid penetrant, magnetic particle (MPT), radiography (RT), eddy current (ECT), and ultrasonic testing (UT).

Read more about the different NDT methods for weld inspection.

To ensure the welds are up to quality and safety standards, guidelines have been set forth by different organizations including the American Society of Nondestructive Testing (ASNT), the International Standard for Organizations (ISO), and the American Petroleum Institute (API). In certain industries and countries, the understanding of these guidelines is vital for analysts to ensure safety standards and maintain effective welding operations.

Read more about the NDT standards in welding.

In aerospace, automotive, power generation, nuclear industries, and more, weld flaws can have severe hazardous outcomes. To ensure quality, the weld is inspected for inclusion, cracks, pores, and other types of flaws. With ECT, the variation in the flow of current can be monitored to identify the potential flaws. The ability to identify minor flaws makes it a reliable method for quality assurance.

Read more about eddy current for weld inspection.

Leveraging NDT in Different Industries and Applications

Butt welds, in pipes or tubes, are prone to cracking and corrosion, which can severely damage the integrity of the system. NDT technologies such as EC, UT, and RT scanners and probes provide stability in inspection and accuracy in flaw detection. The advanced inspection ability facilitates inspection along rough weld surfaces and along complex geometries to deliver accurate inspection results, and thus, productivity and cost-efficiency.

Read more about NDT for butt weld inspection.

In the aerospace industry, weld testing is required for identifying porosity, strength, lack of fusion, or inclusions. The welding standard in the aerospace industry can be met with the help of NDT methods that may include ECT, UT, MPT, or RT. Phased array ultrasonic testing (PAUT), however, has been the trusted inspection method in the aerospace industry for its ability to provide a volumetric inspection to identify all kinds of flaws along complex geometrical structures.

Aluminum has been used widely in industries from aerospace to automotive for its excellent structural properties. However, the welds in aluminum are not exempt from flaws and require careful inspection for potential signs of cracking, porosity, and other types of flaws. ECT and UT are the desired inspection methods that allow the detection of surface, near-surface and volumetric flaws with absolute precision.

Read more about NDT for aluminum welding.

Quality welds in pipelines provide assurance on safety improvement and risk minimization. For in-depth flaw detection in the pipeline, UT inspection has been trusted. The UT solution can provide faster and complete coverage, helping to minimize downtime and improve cost-efficiency while reducing the chances for spills and risks to human lives.

Downtime and lack of resources can be among the challenges in the inspection of boiler tube welds. Effective NDT technologies can support the mitigation of such challenges with their ability to provide volumetric inspection of a wide range of tube diameters and offer a precise characterization of the flaw. Fast and accurate inspection ensures efficiency and allows industries the opportunity to optimize their welding system.

Read more about boiler tube weld inspection.

Leveraging NDT to Ensure Structural Integrity

The ability to identify all major and minor flaws without causing any destruction to the system makes NDT the ideal choice when choosing between destructive and nondestructive testing of welds. The advanced NDT solutions have further made it easier for industries to optimize their process and ensure safety through high-speed scanning, high-resolution imaging, and probe flexibility—without compromising the quality of the welded structure.

With NDT, each weld structure can be ideally inspected without having to risk the reliance on visual inspection. Industries can trust the reliability of NDT for accurate and precise weld quality analysis.

Zetec has been a leading provider of NDT instruments, probes, and scanners for decades. To learn more about our UT weld inspection solutions, contact us today.