TUBE INSPECTION
CORE SERVICE OFFERINGS
Tube Inspection
We undertake eddy current, Remote Field Eddy Current, Magnetic Flux Leakage and Internal Rotary Tube Inspection (IRIS) testing of tubular products using internal diameter probe coil (bobbin) for non-ferrous materials and ferrous materials (with magnetic saturation).
Eddy Current Testing
Eddy Current Testing (ECT) is a rapid and accurate technique used to detect discontinuities in the tubing, heat exchangers, condensers, steam generators, air coolers, feedwater heaters wires, plates, etc. We use electromagnetic induction to detect flaws in conductive materials. Eddy current testing can detect very small cracks in or near the surface of the material. The surfaces need minimal preparation, and physically complex geometries can be investigated using this method.
Remote Field Eddy Current Testing
Remote Field is a technique used for the inspection of tubes made of ferrous materials, like Carbon steel and Chrome-Molybdenum. RFT is only one of the techniques available for inspection of carbon steel tubes. Since all inspection techniques that are available for carbon steel have limitations compared to conventional eddy current, it is even more important to select the most suitable technique for each different situation.
For the inspection of carbon steel tubes it is often recommended to use a combination of one or more techniques. Overall wall-loss can be easily detected and accurately quantified. Local defect scan be detected and quantified provided that they have some volume (pit dia >5 mm). RFT can detect both in- and external defects but it is not possible to distinguish between them.
Magnetic Flux Leakage Testing
Magnetic flux leakage (MFL) is an electromagnetic non-destructive technique that is used to detect corrosion and pitting.
MFL uses a powerful magnet to magnetize the conductive material under test (usually steel). Where there are defects — corrosion or material loss — the magnetic field “leaks” from the steel.
- Inspection technique is suitable for wall-loss detection and measurement of sharp defects, such as pitting, grooving, and circumferential cracks.
- Applicable to ferromagnetic tubing.
- Effective for testing aluminum-finned carbon steel tubes because the magnetic field is mostly unaffected by the fins.
- A good Back-up inspection to Remote Field Testing
Internal Rotating Inspection System
IRIS is an ultrasonic method for the nondestructive inspection of tubes. The IRIS probe is inserted into a tube that is flooded with water, and the probe is pulled out slowly as the data is displayed and recorded. The ultrasonic beam allows detection of metal loss from the inside and outside of the tube wall.
Benefits:
- IRIS can provide the location of flaw along the length as well as the circumference of the tube.
- Defect detection capability for IRIS is better than RFET (in ferrous materials) but it is inferior to ECT (in non-magnetic materials) as IRIS is not as capable of detecting smaller defects when compared to ECT.
Limitations:
- The major disadvantage is that it is a very slow technique (scanning speed at 1 inch/second), but accurate in wall measurement of ferrous tubes in range of 0.15mm.
- IRIS inspection requires a better cleaning of surface than eddy current testing
