Eddy Current testing Services in Bangalore. NABL accredited lab in India. Experts in Crack detection, Sorting. Heat Exchanger, Boiler Tube Inspection.

Yes, eddy current testing is highly effective at detecting hidden welds, even when they’ve been ground smooth or concealed beneath surface coatings. The technique works by inducing electromagnetic fields into the metal and monitoring how these fields interact with the material. Welded areas have different electrical conductivity and magnetic properties compared to the base metal, which creates distinct signals that our equipment picks up.

At Trinity NDT, we’ve successfully identified longitudinal welds in square tubes that were invisible to the naked eye and misrepresented as seamless by suppliers. This makes eddy current testing an invaluable tool for quality control and supplier verification when material integrity is critical.

We verify seamless tubes through advanced eddy current testing combined with careful material analysis. Our certified technicians use specialized probes that scan the entire tube surface, looking for the characteristic electromagnetic signatures that indicate welding or seams. Seamless tubes show uniform electrical properties throughout, while welded tubes exhibit disruptions in the electromagnetic field at the weld location. 

We calibrate our equipment specifically for the tube material and geometry you’re testing, then systematically scan to map any anomalies. The process is non-destructive, relatively quick, and provides definitive documentation that proves whether tubes are truly seamless or contain hidden welds. This verification is essential for industries like oil and gas, aerospace, and power generation where seamless specifications exist for safety and performance reasons.

Seamless tubes are manufactured from a solid billet of metal that’s pierced and drawn into shape without any joints, while welded tubes are formed by rolling flat metal and joining the edges through welding. The difference matters significantly for high-pressure, high-temperature, or critical structural applications. Seamless tubes typically offer superior strength, uniform wall thickness, and better resistance to failure because they lack a weld seam—the weakest point in welded tubes. 

In applications like pressure vessels, heat exchangers, or hydraulic systems, using welded tubes when seamless are specified can lead to catastrophic failures, leaks, or shortened service life. Unfortunately, some suppliers misrepresent welded tubes as seamless to command higher prices or meet specifications they can’t actually fulfill. That’s where Trinity NDT’s verification testing protects your investment and safety.

The testing time depends on the number of tubes, their length, and diameter, but eddy current testing is generally one of the faster NDT methods available. For a typical square tube inspection to detect welds or seams, we can often complete the examination in minutes per tube once equipment is calibrated. A batch of tubes can usually be tested within a few hours to a day in our laboratory. 

The speed advantage comes from eddy current testing being a surface and near-surface technique that doesn’t require extensive preparation like some other methods. You’ll receive a comprehensive report documenting our findings, including the location of any welds detected, which gives you the evidence needed for supplier discussions or quality assurance documentation.

Absolutely. Eddy current testing is a proven, industry-standard non-destructive testing method that’s widely accepted for material verification and quality control. At Trinity NDT, our technicians are ASNT-certified and follow established testing protocols that ensure accuracy and repeatability. The electromagnetic principles behind eddy current testing are well-understood and scientifically sound—the technique reliably detects material property changes that indicate welding. 

We provide detailed reports with clear documentation of our findings, including equipment calibration records and testing parameters. This level of documentation has been successfully used by our clients in supplier negotiations, warranty claims, and quality audits. When material specifications matter, eddy current testing provides the objective evidence you need to verify you’re getting what you paid for.

Trinity NDT offers both laboratory and field testing services for tube verification. Our portable eddy current equipment allows us to conduct on-site inspections at your facility, supplier location, or project site when needed. However, laboratory testing often provides more controlled conditions, better access to the full range of our equipment, and the ability to handle larger inspection volumes efficiently. 

For the square tube seam detection case study we completed, testing was performed in our laboratory where we could optimize probe configuration and calibration. We’re happy to discuss your specific situation and recommend whether lab or field testing makes more sense based on factors like tube quantity, location, timeline, and project requirements. Contact us to discuss the best approach for your tube verification needs.