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Middle East Industrial Training Institute

PROPERTIES OF METALS

Permeability

A B

Magnetised using 100 amps

Magnetised using 100 amps

High Permeability:

Easy to be magnetised

Low Permeability:

Difficult to be magnetised

ФФ

1. Permeability

This refers to the ease with which a magnetic flux is

established in the article being inspected

2. Reluctance

This is the opposition of a magnetic materials to the

establishment of a magnetic flux. A material with high permeability will have a low reluctance.

3. Residual Magnetism

This refers to the amount of magnetism retained after the magnetizing force is removed.

4. Retentivity

Refers to the ability of the materials to retain a certain amount of residual magnetism.

5. Coercive Force

Refers to the reverse magnetising force necessary to remove the residual magnetism from the part.

EXAMPLE A PIECE OF HIGH CARBON CONTENT WHEN PLACE IN A MAGNETIZING FIELD

1. It would have low permeability because it would be hard to magnetize

2. It would be highly reluctant to accept magnetic flux because of high carbon content

3. It would have high residual magnetism

4. It would be highly retentive of the magnetic filed that it has

accepted

5. It would take a high coercive force to remove the residual magnetism from the high carbon content steel part