Magnetic Particle Testing

Principles of Magnets and Magnetic Fields
- Theory of magnetic fields
- Earth’s magnetic field
- Magnetic fields around magnetized materials
Theory of magnetism
- Magnetic poles
- Law of magnetism
- Materials influenced by magnetic fields
  - Ferromagnetic
  - Paramagnetic
  - Diamagnetic (Magnetic characteristics of nonferrous materials

Terminology associated with magnetic particle testing
Characteristics of Magnetic Fields
- Bar magnet
- Ring magnet
Effect of Discontinuities of Materials
- Surface cracks
- Scratches
- Subsurface defects
Magnetization by Means of Electric Current
- Circular field
  - Field around a straight conductor
  - Right-hand rule
  - Field in parts through which current flow
  - Long, solid, cylindrical, regular parts
  - Irregularly-shaped parts
  - Tubular parts
  - Parts containing machined holes, slots, etc.
  - Methods of inducing current flow in part
    - Contact plates
    - Prods
  - Discontinuities commonly discovered by circular fields
- Longitudinal field
  - Field produced by current flow in a coil
  - Field direction in a current-carrying coil
  - Field strength in a current-carrying coil
  - Discontinuities commonly discovered by longitudinal fields
  - Advantages of longitudinal magnetizatio
  - Disadvantages of longitudinal magnetization