6th Pan American Conference for NDT 12-14 August 2015, Cartagena, Colombia - www.ndt.net/app.PANNDT2015

Detecting Stress Corrosion Cracking with

Eddy Current Array Technology

Emilie Peloquin

Olympus Scientific Solution

Advanced Technical Support Lead

Houston, Texas

SCC

  Stress

  Corrosion

  Cracking

TIME

SCC

Environment

Detecting SCC

  Wet Fluorescent Magnetic Particle Testing (aka Wet MT)

  White Contrast Magnetic Particle Testing (MT)

  Depth sizing with Ultrasound (UT) or Phased Array (PA)

  Eddy Current Array (ECA)

How does Eddy Current works?

Basic Principles

a► Inducing a current into a coil will

create a magnetic field (in blue).

b► When the coil is placed over a

conductive part, opposed alternating currents (eddy currents,

in red) are generated.

c► The defects in the part will

disturb the path of the eddy currents (in yellow).

This disturbance can be measured by

the coil.

Eddy Current Array is the same X 32!

Basic Principles

► ECA technology provides the

ability to electronically drive multiple

eddy current coils placed side by

side in the same probe assembly.

Data acquisition is performed by

multiplexing the eddy current coils in a special pattern to avoid mutual

inductance between the individual

coils.

Eddy Current Array

•  Allows inspection

through paint or thin coatings

•  No need to clean the part

•  Large coverage (probe length)

•  Very fast scanning

•  C-Scan Color Imagery

•  Defect depth evaluation

•  Easy Archiving (Saving Data) and post- Analysis

Advantages of ECA Testing

Equipment used

Omniscan MX with ECA module

Surface probe or Flex

Array Pipe-Kit

Mini-wheel encoder

Surface Cracks in Process Pipe •  New pipe kit based on Flex Array

•  Easy inter-changeable “wedges” (diameter)

•  Kit of 15 diameters from 1.3” to flat

Easily changeable

wedges (15 in kit)

Standard

ECA Omniscan Results

SCC on Pipelines Detected using

Eddy Current Array

Section of Carbon Steel Pipe with SCC

Found with White

Contrast Magnetic

Particle Testing

Scan with NO defect

Scan direction

Scan stop position

NO CRACKS

Scan over defects

Scan stop position

Results from scan 1

Scan start across 2nd defect zone

Scan Stop position

Results from scan 2

Penetrant test compared to ECA

Surface cracks

Stainless Steel Cladding

With liquid penetrant

Results on the OmniScan mimicking PT

 To recap…

 No need to remove paint or coatings…

 Large coverage (probe length)

VS

 Fast scanning speed

~ 3” / sec

 C-Scan imagery

VS

 Depth Evaluation

VS

 Easy Reporting & Archiving

PT ECA

Questions?

THANK YOU