Reference Standards Notched Shims for Magnetic Particle Inspection
|Publication Date:||1 March 1998|
This SAE Aerospace Standard (AS) establishes requirements for the manufacture of shim-type reference standards containing artificial flaws (notches) for use in the magnetic particle inspection process.
1.2.1 Shims have been used typically on ferromagnetic raw stock such as: bar, tubing, and pipe, forgings and castings, and welded assemblies, but usage is not limited to such applications. Shims are applied to the surface of the part to establish field direction and approximate field strength.
1.2.2 Shims may be used to establish and ensure balance of fields in the multi-directional magnetization method.
1.2.3 Two thicknesses are available, 0.002 inch (0.05 mm) or 0.004 inch (0.10 mm). The 0.002 inch (0.05 mm) shims are used when the thicker shims cannot conform to the surface of the part to be inspected in the area of interest.
1.2.4 Two sizes are available, 0.75 inch (19.0 mm) square, as illustrated in Figures 1 through 4, and 0.79 inch (20.0 mm) square which are cut, by user, into four 0.395 inch (10.03 mm) square shims, as shown in Figures 5 and 6.