Liquid Penetrant Examination Liquid Penetrant Examination Erkamal (Mechanical) (OP) 9 Jan 15 11:48 Hi Friend, Can anyone explain me that why does MPI test use for LF2 mateiral and not going to use LP test? Regards Kamlesh RE: Liquid Penetrant Examination jwhit (Materials) 9 Jan 15 12:27 LF2 is a ferromagnetic material, therefore, MPI can be performed. The advantage to MPI is that surface and near surface defects may be located depending on method and technique used. As a rule, if the material is strongly magnetic, use MPI. If non-magnetic use LPI. RE: Liquid Penetrant Examination weldstan (Materials) 9 Jan 15 14:24 A-350, section 11.3 permits PT as well. As per jwhit, MT is preferred because subsurface discontinuities can be located.