Magnetic particle inspection (MPI) can be performed a number of different ways and oftentimes any of these methods are acceptable under the specification called out for performing the test. In many cases, these specifications leave the door open for the nondestructive testing personnel to select the method for performing the inspection. But, be aware that all methods are not created equal. As explained below, they not only vary in terms of ease and time to perform, but also in the level of detail provided in the test results.
Since safety and reliability are priorities for anyone in a position responsible for quality, when given an option, it makes sense to choose the MPI method for your finished products that will provide the most dependable results. When purchasing inspected material, you may want to dig a little deeper to find out how the material was certified: