AS 2062:1997 pdf – Non-destructive testing-Penetrant testing of products and components

AS 2062:1997 pdf – Non-destructive testing-Penetrant testing of products and components.
3.1 GENERAL The penetrant test includes the following operations:
(a) Preparation of the test surface.
(b) Application of the penetrant for the required dwell time.
(c) Removal of excess pcnctrant.
(d) Application of the developer for the required dwell time.
(c) Inspection, interpretation and evaluation of the test surface in accordance with the viewing conditions specified in Clause 3.7.
(f) Cleaning after testing and, if required. the application of a corrosion inhibitor. Penetrant inspection should be performed before carrying out any finishing or corrosion-inhibiting process, such as the application of a coating or modification of the component surface, that may bridge over discontinuities or reduce the effectiveness of the inspection process. Such processes include electroplating, anodizing and dichromating.
Penetrant inspection should be performed both before and after any mechanical process that can cause the formation of cracks and other discontinuities. Such processes include grinding and all forms of abrasive cleaning.
Where a Type 3 penetrant is used, the requirements for Type I or Type 2 penetrant shall apply according to the mode of use.
3.2 PREPARATION OF THE TEST SURFACE All surfaces shall be dry and free of contaminants and foreign matter such as scale, dirt, grease, rust, weld spatter or paint that may interfere with the test. Cleaning and preparation of the test surface shall not be detrimental to the product, to its dimensions and surface finish, or to the testing materials.
Chemical methods for the removal of contaminants are preferred, and should be used wherever possible. Physical methods, whilst satisfactory for the cleaning of contaminants from the surface, are generally incapable of removing them from within surface discontinuities. The presence of contaminants contained in surface discontinuities may interfere with the entry of the penetrant, or otherwise degrade the test process. In addition, abrasive methods of cleaning can smear metal over the surface opening of discontinuities and so prevent their detection.
Deformation of the test surface produced by processes such as hammering, sand or shot blasting. peening, grinding or machining, vapour blasting, deburring, applying abrasive paper, buffing and lapping should be avoided before penetrant testing, because these processes often close over or mask discontinuities. The use of a controlled etching procedure may be specified in the relevant product specification to remove flowed metal from the surface of components so treated, prior to penetrant inspection.
NOTES:
1 Penetrant residues from previous tests retained in discontinuities may prevent the entry of fresh penetrant and may interfere with the interpretation of indications, especially when a different penetrant system is used for the retesting.
2 Residues from a previous colour contrast penctrant test may react with a fluorescent penetrant and result in the complete or partial quenching of its fluorescence.