METHOD FOR EXTRACTING SAMPLE OF NONMETALLIC INCLUSION IN STEEL

摘要

PURPOSE: To extract a nonmetallic inclusion required for accurate evaluation without sacrifice of shape or composition by subjecting a steel sample to electrolysis to float the nonmetallic inclusion from steel matrix and then transferring the nonmetallic inclusion using a conductive tape. CONSTITUTION: A steel containing a nonmetallic inclusion is sliced and mirror- finished to obtain a sample which is then subjected to electrolysis in a chelate- based nonaqueous solution at a potential for electrolyzing only steel thus floating the inclusion without damaging the three-dimensional shape thereof. Impurities are then removed from the surface of the sample using alcohol and a film for enhancing the peeling properties of a transferring tape is deposited on the surface of the sample. Subsequently, a conductive tape is applied tightly to the surface of the sample in order to transfer the inclusion. Finally, the tape is set in the sample holder of a scanning electron microscope where the nonmetallic inclusion is observed and the composition thereof is analyzed.