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Eddy Current Testing Overview

The document provides an overview of eddy current testing, including its history dating back to Faraday's discovery of electromagnetic induction in 1832. It describes what eddy currents are and the principles of eddy current testing. The document discusses the equipment used for eddy current testing, including portable flaw detectors, probes, and reference samples used for calibration. It explains the purpose of calibration is to ensure consistent, accurate, and reliable readings from eddy current testing instruments.

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152 views25 pages

Eddy Current Testing Overview

The document provides an overview of eddy current testing, including its history dating back to Faraday's discovery of electromagnetic induction in 1832. It describes what eddy currents are and the principles of eddy current testing. The document discusses the equipment used for eddy current testing, including portable flaw detectors, probes, and reference samples used for calibration. It explains the purpose of calibration is to ensure consistent, accurate, and reliable readings from eddy current testing instruments.

Uploaded by

sea
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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OUTLOOK OF THE PRESENTATION

 History
 What is Eddy Current ??
 Principles of Eddy Current Testing
 Equipment used for Eddy Current Testing
 Reference Samples
 Calibration Method
HISTORY

The Scientific Development


of Eddy Current Theory
Started with the Discovery
of the Law of Electromagnetic
Induction by Faraday In 1832.
FOUCAULT CURRENT

Eddy Currents are Defined as Oscillating Electrical


Currents Induced in a Conductive Material by an
Alternating Magnetic Field , due to Electromagnetic
Induction.
EQUIPMENT FOR EDDY CURRENT
TESTING
Portable Eddy Current Flaw Detector
Surface Flaw Detector Block
Different Kinds of Probes and Sorting
Blocks
SURFACE PROBES :

1. IDENTIFYING FLAWS ON AND BELOW METAL SURFACES


2 .USUALLY LARGER DIAMETER FOR SCANNING LARGER
AREAS
3.LOWER FREQUENCIES FOR DEEPER PENETRATION
4. USED FOR CORROSION DETECTION.
5. PENETRATE ALUMINIUM OR SIMILAR MATERIALS TO A
DEPTH OF 10 MM
FREQUENCY 100Hz TO 10kHz
REFERENCE SAMPLES
As with most other NDT methods, the most useful information is
obtained when comparing the results from an unknown object to results
from a similar object with well characterized features and defects.

The reference standard should be of the same material as the test article.

Conductivity standards.
Flat plate discontinuity standards.
Flat plate metal thinning standards (step or tapered wedges).
Tube discontinuity standards.
Tube metal thinning standards.
Hole discontinuity standards.
Common eddy current reference standards include:

Conductivity
standards.

Flat plate
discontinuity
standards.
Flat plate metal
thinning standards
(step wedges).

Hole discontinuity
standards.
There are three main reasons for having instruments
calibrated:

1. To ensure readings from an instrument are consistent


with other measurements.
2. To determine the accuracy of the instrument readings.
3. To establish the reliability of the instrument i.e. that it
can be trusted.
0.04”

0.02”

0.008”

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