Document ID: chunk:federal_register_of_legislation:F2011C00880:body:0:p3
Version: federal_register_of_legislation:F2011C00880
Segment Type: other
Provision Reference: 
Character Range: 6070–8821

I

This Appendix specifies procedures for the performance of magnetic particle inspections.

1 Preparation of parts for inspection

      1.1 Wherever possible parts must be disassembled before inspection.

      1.2 The surface of all parts must be free from grease, oil, swarf, corrosion products, moisture or any other matter which interferes with the proper distribution and concentration of magnetic particles applied during inspection, or which would contaminate the inspection liquid used in the wet process.

      1.3 Painted parts may be inspected without removal of the paint provided that the paint layer is continuous and even and does not exceed 0.1 mm in thickness. When current flow methods of magnetisation are to be used, paint must be removed from areas at which electrical contact is to be made.

      1.4 Plated parts may be inspected provided that the thickness of plated layers such as chromium does not exceed 0.1 mm. Sensitivity will be slightly reduced, however, and some advantage may be gained from using dc magnetisation.

2 Magnetisation

       2.1 Current flow method of magnetisation

(a) Copper braid, lead or other suitably malleable electrically conducting material must be used at the contact points between the equipment and the part to provide good electrical contact and minimise the danger of arcing.

(b) The flow of current must be of sufficiently short duration to prevent overheating of the part.

       2.2 Threading bar method of magnetisation

(a) When using a threading bar to inspect a tubular component with a closed end, such as a cylinder barrel, precautions must be taken to ensure good electrical contact at the blind end of the part with both the threading bar and the equipment.

(b) When the part to be inspected is considerably larger in diameter than the threading bar, the bar may be positioned away from the axis of the part. In such cases, only that area of the part adjacent to the threading bar and contained within a circle concentric with the bar and of diameter equal to that which formed the basis of computing the magnetising current value in accordance with Appendix II of this Order, must be inspected at any one time.

       2.3 Coil method of magnetisation

(a) Unless the magnetism current required has been computed for the part placed centrally in the coil in accordance with Appendix II, parts must be placed adjacent to the inside surface of the coil.

(b) Only those surfaces of the part within the coil and protruding not more than 0.25 mm either side of the coil must be inspected at any one time.

(c) The pitch of the turns of the magnetising coil used must be as small as practicable.

       2.4 Magnetic flow method of magnetisation

(a) The pole pieces of