This document provides an overview of eddy current testing. It discusses the history of eddy current theory dating back to Faraday's discovery of electromagnetic induction in 1832. It defines eddy currents as oscillating electrical currents induced in a conductive material by an alternating magnetic field. The document describes the equipment used for eddy current testing, including portable flaw detectors, probes, and reference samples of known materials and defects used for calibration. It explains that calibration is important to ensure consistent, accurate, and reliable readings from eddy current instruments.

1. Presented By,
Joydwip Karmakar
Roll No : 213116008

2. OUTLOOK OF THE PRESENTATION
 History
 What is Eddy Current ??
 Principles of Eddy Current Testing
 Equipment used for Eddy Current Testing
 Reference Samples
 Calibration Method

3. HISTORY
The Scientific Development
of Eddy Current Theory
Started with the Discovery
of the Law of Electromagnetic
Induction by Faraday In 1832.

4. FOUCAULT CURRENT
Eddy Currents are Defined as Oscillating Electrical
Currents Induced in a Conductive Material by an
Alternating Magnetic Field , due to Electromagnetic
Induction.

8. EQUIPMENT FOR EDDY CURRENT
TESTING

9. Portable Eddy Current Flaw Detector

10. Surface Flaw Detector Block

11. Different Kinds of Probes and Sorting
Blocks

14. 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

15. FREQUENCY 100Hz TO 10kHz

17. REFERENCE SAMPLES

18. 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.

19. Common eddy current reference standards include:
Conductivity
standards.
Flat plate
discontinuity
standards.

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

22. 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.

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