Magnetic Particle Inspection (MPI) Equipment

Standard Test Pieces

MPI Test Pieces

Johnson & Allen supply a range of test pieces for validation of MPI systems.

Product Data

TP1 - Test Piece 1

Current Flow 0 to 1,000A
(RRP58004 & BS6072)

TP2 - Test Piece 2 Current Flow 1,000 to 3,000A
TP3 - Test Piece 3 Current Flow 3,000 to 10,000A
TP4 - Test Piece 4 Mag. Flow - Contains 5 Holes
TP5 - Test Piece 5 Mag. Flow & Coil - Contains 1 Hole


Method of use for TP1, TP2 & TP3

For the first use of your test piece, follow the procedure outlined below when the unit has just been calibrated and there is fresh ink in the tank:

  • Ensure that the test piece is thoroughly degreased and free from corrosion and oxidation.
  • Clamp the test piece between the contacts on the head and tailstock of your bench unit.
  • Apply magnetic ink while the current is flowing.
  • Establish the current required to make the hole nearest the outer surface of the ring visible on the outer surface.
  • Further increase the current to establish indications from the other two holes on the outer surface of the ring.
  • Note the current required to establish each hole indication.
  • If the MPI process is functioning correctly each hole should be visible at each subsequent use of the test piece.
  • Repeat the test for each current wave form which your magnetising unit is equipped with.
  • Please note that the deeper hole is unlikely to show positively using an alternating current wave form.

Share This Product