Fluorescent magnetic particle testing is sometimes used to determine if there are some present in a fastener product and consequently is used to reject parts.

While this may be required for some special situations “Fluorescent Magnetic Particle Testing” is only and indicator and not accepted as a test for part rejection according the ISO or ANSI standards.

For example, ISO 6157-3 specifies Surface Discontinuities and what is allowed and what is not.

For forged products you may encounter Shear bursts, Forging Cracks, Seams, Laps and Voids each with a different specification of what is allowed and what is not. Fluorescent Magnetic Particle Testing may indicate that some defects are present however it does in no way indicate if the variance falls within the allowances of the quality standard that the parts are manufactured to.

The below example is ISO 6157-3.1.5 socket screw and forging cracks.

In conclusion the “Fluorescent Magnetic Particle Testing” can not be used to reject parts unless there is a prior agreement in place by the provider of the product for any special testing. Any quality testing and subsequent possible non compliance must be according to the relevant standards that determine the mechanical properties of the parts.