Method for measuring yield strength of 3D printed metallic member using magnetic incremental permeability and measurement system for the same

A system for measuring a yield strength of a metallic member using magnetic incremental permeability (MIP), comprising:

• an electromagnet including a yoke comprising two legs and an electromagnet coil wound on the yoke, and configured to magnetically excite a metallic member to be measured by allowing a flux of a quasi-static excitation magnetic field generated when a quasi-static current flows in the electromagnet coil to enter and exit through two spaced apart points of the metallic member;
• a Hall sensor disposed between the two legs of the electromagnet and configured to measure an intensity of the quasi-static excitation magnetic field applied to an interior of the metallic member;
• a transmitting coil wound around the Hall sensor and configured to generate an alternating magnetic field smaller than the quasi-static excitation magnetic field while an alternating current flows and apply to the metallic member to overlap with the quasi-static excitation magnetic field;
• a sensing coil wound around the Hall sensor and configured to detect the quasi-static excitation magnetic field and a magnetic field induced by the metallic member magnetized by the alternating magnetic field;
• and
• a central processing unit configured to obtain a reversible permeability of the metallic member using an output signal from the Hall sensor and a detection signal from the sensing coil, to obtain a grain size of the metallic member by calculating the grain size based on a relationship between the obtained reversible permeability and the grain size of the metallic member, and to calculate a yield strength of the metallic member using the obtained grain size,
• wherein the system is capable of non-destructively measuring the grain size and yield strength of the metallic member to be measured.