- Tubes in air-conditioning chillers, refinery exchangers / condensers.
- Welds surface inspection under non conductive coatings in pressure vessels, piping, structural and lifting equipment.
- Surface inspection of plates and materials for cracking.
- Surface inspection of plates and materials for cracking.
- Sorting of metals and conductivity checks.
- Eddy current testing electrical currents are generated a conductive material by an induced magnetic field. Distortions in the flow of the electric current (eddy currents) caused by imperfections or changes in a materials conductive properties will cause changes in the induced magnetic field. These changes, when detected, indicate the presence of the imperfection or change in the test material.
EDDY CURRENT TESTING
Eddy-current testing (also commonly seen as eddy current testing and ECT) is one of many electromagnetic testing methods used in nondestructive testing (NDT) making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.
Typical applications include
Applications
ECT finds applications in both tubing and surface applications
Detection capabilities to defect type in tubing
- Several types of defects can be detected in tubing with varying degrees of success:
- Inner-diameter (ID) pitting: excellent
- Outer-diameter (OD) pitting: excellent
- Axial cracking: acceptable, but limited
- Circumferential cracking: acceptable, but limited
- ID corrosion: excellent
- OD corrosion: excellent
- Defects at tubesheet: acceptable, but limited
Sizing capabilities to defect type in tubing
- Several types of defects can be sized in tubing with varying degrees of success:
- Inner-diameter (ID) pitting: good
- Outer-diameter (OD) pitting: excellent
- Axial cracking: good
- Circumferential cracking: unsuitable
- ID corrosion: good
- OD corrosion: excellent
- Defects at tubesheet: good
ECT on surfaces
- When it comes to surface applications, the performance of any given inspection technique depends greatly on the specific conditions — mostly the types of materials and defects, but also surface conditions, etc. However, in most situations, the following are true:
- Effective on coatings/paint: yes
- Computerized record keeping: partial
- 3D/Advanced imaging: none
- User dependence: high
- Speed: low
- Post-inspection analysis: none
- Requires chemicals/consumables: no
