Eddy Current Testing
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, feed water heaters wires, plates, etc. AKMEC uses 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. Eddy current testing is also performed for alloy separation, for the determination of treatment conditions, for making electrical conductivity and for measuring coating thickness. The location of repair welds, girth welds, and seam welds may also be detected on ground-machined surfaces.
AKMEC Group has an in-house team of Eddy Current Testing professionals with deep expertise in inspecting a number of tubing in heat exchangers. AKMEC’s testing devices are portable, contact-less and provide immediate feedback. The eddy current instrument at AKMEC is capable of operating at test frequencies up to 8 kHZ with a high speed of 2-Meter Per Second Inspection Speed.
Pre-requisites:
Prior to the testing, all tubes must be cleaned. Cleaning shall be done using hydro jetting with typical cleaning pressures between 280kg/m² and 560 kg/cm². The adequacy of cleaning must be checked by inserting an appropriate dummy probe / rod.
Equipment:
The electronic apparatus used will be capable of energizing the test coil with alternating currents of suitable frequencies (for example 1 to 125 kHz) and will be capable of sensing the changes in the electromagnetic response of the coils. The instrument will be balanced with the probe in a defect free position of the calibration tube. The spot will be central on the impedance plane display of screen for differential testing and at one division from the top of the screen for absolute testing.
Evaluation:
The expert Eddy Current technicians of AKMEC take the flaw signals generated in tubes under test and then compare it with the signals of the calibration standard.